/*****************************************************************************/
/*                                                                           */
/*  Routines for Arbitrary Precision Floating-point Arithmetic               */
/*  and Fast Robust Geometric Predicates                                     */
/*  (predicates.c)                                                           */
/*                                                                           */
/*  May 18, 1996                                                             */
/*                                                                           */
/*  Placed in the public domain by                                           */
/*  Jonathan Richard Shewchuk                                                */
/*  School of Computer Science                                               */
/*  Carnegie Mellon University                                               */
/*  5000 Forbes Avenue                                                       */
/*  Pittsburgh, Pennsylvania  15213-3891                                     */
/*  [email protected]                                                           */
/*                                                                           */
/*  This file contains C implementation of algorithms for exact addition     */
/*    and multiplication of floating-point numbers, and predicates for       */
/*    robustly performing the orientation and incircle tests used in         */
/*    computational geometry.  The algorithms and underlying theory are      */
/*    described in Jonathan Richard Shewchuk.  "Adaptive Precision Floating- */
/*    Point Arithmetic and Fast Robust Geometric Predicates."  Technical     */
/*    Report CMU-CS-96-140, School of Computer Science, Carnegie Mellon      */
/*    University, Pittsburgh, Pennsylvania, May 1996.  (Submitted to         */
/*    Discrete & Computational Geometry.)                                    */
/*                                                                           */
/*  This file, the paper listed above, and other information are available   */
/*    from the Web page http://www.cs.cmu.edu/~quake/robust.html .           */
/*                                                                           */
/*****************************************************************************/

/*****************************************************************************/
/*                                                                           */
/*  Using this code:                                                         */
/*                                                                           */
/*  First, read the short or long version of the paper (from the Web page    */
/*    above).                                                                */
/*                                                                           */
/*  Be sure to call exactinit() once, before calling any of the arithmetic   */
/*    functions or geometric predicates.  Also be sure to turn on the        */
/*    optimizer when compiling this file.                                    */
/*                                                                           */
/*                                                                           */
/*  Several geometric predicates are defined.  Their parameters are all      */
/*    points.  Each point is an array of two or three floating-point         */
/*    numbers.  The geometric predicates, described in the papers, are       */
/*                                                                           */
/*    orient2d(pa, pb, pc)                                                   */
/*    orient2dfast(pa, pb, pc)                                               */
/*    orient3d(pa, pb, pc, pd)                                               */
/*    orient3dfast(pa, pb, pc, pd)                                           */
/*    incircle(pa, pb, pc, pd)                                               */
/*    incirclefast(pa, pb, pc, pd)                                           */
/*    insphere(pa, pb, pc, pd, pe)                                           */
/*    inspherefast(pa, pb, pc, pd, pe)                                       */
/*                                                                           */
/*  Those with suffix "fast" are approximate, non-robust versions.  Those    */
/*    without the suffix are adaptive precision, robust versions.  There     */
/*    are also versions with the suffices "exact" and "slow", which are      */
/*    non-adaptive, exact arithmetic versions, which I use only for timings  */
/*    in my arithmetic papers.                                               */
/*                                                                           */
/*                                                                           */
/*  An expansion is represented by an array of floating-point numbers,       */
/*    sorted from smallest to largest magnitude (possibly with interspersed  */
/*    zeros).  The length of each expansion is stored as a separate integer, */
/*    and each arithmetic function returns an integer which is the length    */
/*    of the expansion it created.                                           */
/*                                                                           */
/*  Several arithmetic functions are defined.  Their parameters are          */
/*                                                                           */
/*    e, f           Input expansions                                        */
/*    elen, flen     Lengths of input expansions (must be >= 1)              */
/*    h              Output expansion                                        */
/*    b              Input scalar                                            */
/*                                                                           */
/*  The arithmetic functions are                                             */
/*                                                                           */
/*    grow_expansion(elen, e, b, h)                                          */
/*    grow_expansion_zeroelim(elen, e, b, h)                                 */
/*    expansion_sum(elen, e, flen, f, h)                                     */
/*    expansion_sum_zeroelim1(elen, e, flen, f, h)                           */
/*    expansion_sum_zeroelim2(elen, e, flen, f, h)                           */
/*    fast_expansion_sum(elen, e, flen, f, h)                                */
/*    fast_expansion_sum_zeroelim(elen, e, flen, f, h)                       */
/*    linear_expansion_sum(elen, e, flen, f, h)                              */
/*    linear_expansion_sum_zeroelim(elen, e, flen, f, h)                     */
/*    scale_expansion(elen, e, b, h)                                         */
/*    scale_expansion_zeroelim(elen, e, b, h)                                */
/*    compress(elen, e, h)                                                   */
/*                                                                           */
/*  All of these are described in the long version of the paper; some are    */
/*    described in the short version.  All return an integer that is the     */
/*    length of h.  Those with suffix _zeroelim perform zero elimination,    */
/*    and are recommended over their counterparts.  The procedure            */
/*    fast_expansion_sum_zeroelim() (or linear_expansion_sum_zeroelim() on   */
/*    processors that do not use the round-to-even tiebreaking rule) is      */
/*    recommended over expansion_sum_zeroelim().  Each procedure has a       */
/*    little note next to it (in the code below) that tells you whether or   */
/*    not the output expansion may be the same array as one of the input     */
/*    expansions.                                                            */
/*                                                                           */
/*                                                                           */
/*  If you look around below, you'll also find macros for a bunch of         */
/*    simple unrolled arithmetic operations, and procedures for printing     */
/*    expansions (commented out because they don't work with all C           */
/*    compilers) and for generating random floating-point numbers whose      */
/*    significand bits are all random.  Most of the macros have undocumented */
/*    requirements that certain of their parameters should not be the same   */
/*    variable; for safety, better to make sure all the parameters are       */
/*    distinct variables.  Feel free to send email to [email protected] if you  */
/*    have questions.                                                        */
/*                                                                           */
/*****************************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <cfloat>
#include "predicates.h"

/* FPU control. We MUST have only double precision (not extended precision) */
#include "rounding.h"

/* On some machines, the exact arithmetic routines might be defeated by the  */
/*   use of internal extended precision floating-point registers.  Sometimes */
/*   this problem can be fixed by defining certain values to be volatile,    */
/*   thus forcing them to be stored to memory and rounded off.  This isn't   */
/*   a great solution, though, as it slows the arithmetic down.              */
/*                                                                           */
/* To try this out, write "#define INEXACT volatile" below.  Normally,       */
/*   however, INEXACT should be defined to be nothing.  ("#define INEXACT".) */

#define INEXACT                          /* Nothing */
/* #define INEXACT volatile */

#define REAL double                      /* float or double */
#define REALPRINT doubleprint
#define REALRAND doublerand
#define NARROWRAND narrowdoublerand
#define UNIFORMRAND uniformdoublerand

/* Which of the following two methods of finding the absolute values is      */
/*   fastest is compiler-dependent.  A few compilers can inline and optimize */
/*   the fabs() call; but most will incur the overhead of a function call,   */
/*   which is disastrously slow.  A faster way on IEEE machines might be to  */
/*   mask the appropriate bit, but that's difficult to do in C.              */

/*#define Absolute(a)  ((a) >= 0.0 ? (a) : -(a)) */
#define Absolute(a)  fabs(a)

/* Many of the operations are broken up into two pieces, a main part that    */
/*   performs an approximate operation, and a "tail" that computes the       */
/*   roundoff error of that operation.                                       */
/*                                                                           */
/* The operations Fast_Two_Sum(), Fast_Two_Diff(), Two_Sum(), Two_Diff(),    */
/*   Split(), and Two_Product() are all implemented as described in the      */
/*   reference.  Each of these macros requires certain variables to be       */
/*   defined in the calling routine.  The variables `bvirt', `c', `abig',    */
/*   `_i', `_j', `_k', `_l', `_m', and `_n' are declared `INEXACT' because   */
/*   they store the result of an operation that may incur roundoff error.    */
/*   The input parameter `x' (or the highest numbered `x_' parameter) must   */
/*   also be declared `INEXACT'.                                             */

#define Fast_Two_Sum_Tail(a, b, x, y) \
 bvirt = x - a; \
 y = b - bvirt

#define Fast_Two_Sum(a, b, x, y) \
 x = (REAL) (a + b); \
 Fast_Two_Sum_Tail(a, b, x, y)

#define Fast_Two_Diff_Tail(a, b, x, y) \
 bvirt = a - x; \
 y = bvirt - b

#define Fast_Two_Diff(a, b, x, y) \
 x = (REAL) (a - b); \
 Fast_Two_Diff_Tail(a, b, x, y)

#define Two_Sum_Tail(a, b, x, y) \
 bvirt = (REAL) (x - a); \
 avirt = x - bvirt; \
 bround = b - bvirt; \
 around = a - avirt; \
 y = around + bround

#define Two_Sum(a, b, x, y) \
 x = (REAL) (a + b); \
 Two_Sum_Tail(a, b, x, y)

#define Two_Diff_Tail(a, b, x, y) \
 bvirt = (REAL) (a - x); \
 avirt = x + bvirt; \
 bround = bvirt - b; \
 around = a - avirt; \
 y = around + bround

#define Two_Diff(a, b, x, y) \
 x = (REAL) (a - b); \
 Two_Diff_Tail(a, b, x, y)

#define Split(a, ahi, alo) \
 c = (REAL) (splitter * a); \
 abig = (REAL) (c - a); \
 ahi = c - abig; \
 alo = a - ahi

#define Two_Product_Tail(a, b, x, y) \
 Split(a, ahi, alo); \
 Split(b, bhi, blo); \
 err1 = x - (ahi * bhi); \
 err2 = err1 - (alo * bhi); \
 err3 = err2 - (ahi * blo); \
 y = (alo * blo) - err3

#define Two_Product(a, b, x, y) \
 x = (REAL) (a * b); \
 Two_Product_Tail(a, b, x, y)

/* Two_Product_Presplit() is Two_Product() where one of the inputs has       */
/*   already been split.  Avoids redundant splitting.                        */

#define Two_Product_Presplit(a, b, bhi, blo, x, y) \
 x = (REAL) (a * b); \
 Split(a, ahi, alo); \
 err1 = x - (ahi * bhi); \
 err2 = err1 - (alo * bhi); \
 err3 = err2 - (ahi * blo); \
 y = (alo * blo) - err3

/* Two_Product_2Presplit() is Two_Product() where both of the inputs have    */
/*   already been split.  Avoids redundant splitting.                        */

#define Two_Product_2Presplit(a, ahi, alo, b, bhi, blo, x, y) \
 x = (REAL) (a * b); \
 err1 = x - (ahi * bhi); \
 err2 = err1 - (alo * bhi); \
 err3 = err2 - (ahi * blo); \
 y = (alo * blo) - err3

/* Square() can be done more quickly than Two_Product().                     */

#define Square_Tail(a, x, y) \
 Split(a, ahi, alo); \
 err1 = x - (ahi * ahi); \
 err3 = err1 - ((ahi + ahi) * alo); \
 y = (alo * alo) - err3

#define Square(a, x, y) \
 x = (REAL) (a * a); \
 Square_Tail(a, x, y)

/* Macros for summing expansions of various fixed lengths.  These are all    */
/*   unrolled versions of Expansion_Sum().                                   */

#define Two_One_Sum(a1, a0, b, x2, x1, x0) \
 Two_Sum(a0, b , _i, x0); \
 Two_Sum(a1, _i, x2, x1)

#define Two_One_Diff(a1, a0, b, x2, x1, x0) \
 Two_Diff(a0, b , _i, x0); \
 Two_Sum( a1, _i, x2, x1)

#define Two_Two_Sum(a1, a0, b1, b0, x3, x2, x1, x0) \
 Two_One_Sum(a1, a0, b0, _j, _0, x0); \
 Two_One_Sum(_j, _0, b1, x3, x2, x1)

#define Two_Two_Diff(a1, a0, b1, b0, x3, x2, x1, x0) \
 Two_One_Diff(a1, a0, b0, _j, _0, x0); \
 Two_One_Diff(_j, _0, b1, x3, x2, x1)

#define Four_One_Sum(a3, a2, a1, a0, b, x4, x3, x2, x1, x0) \
 Two_One_Sum(a1, a0, b , _j, x1, x0); \
 Two_One_Sum(a3, a2, _j, x4, x3, x2)

#define Four_Two_Sum(a3, a2, a1, a0, b1, b0, x5, x4, x3, x2, x1, x0) \
 Four_One_Sum(a3, a2, a1, a0, b0, _k, _2, _1, _0, x0); \
 Four_One_Sum(_k, _2, _1, _0, b1, x5, x4, x3, x2, x1)

#define Four_Four_Sum(a3, a2, a1, a0, b4, b3, b1, b0, x7, x6, x5, x4, x3, x2, \
                     x1, x0) \
 Four_Two_Sum(a3, a2, a1, a0, b1, b0, _l, _2, _1, _0, x1, x0); \
 Four_Two_Sum(_l, _2, _1, _0, b4, b3, x7, x6, x5, x4, x3, x2)

#define Eight_One_Sum(a7, a6, a5, a4, a3, a2, a1, a0, b, x8, x7, x6, x5, x4, \
                     x3, x2, x1, x0) \
 Four_One_Sum(a3, a2, a1, a0, b , _j, x3, x2, x1, x0); \
 Four_One_Sum(a7, a6, a5, a4, _j, x8, x7, x6, x5, x4)

#define Eight_Two_Sum(a7, a6, a5, a4, a3, a2, a1, a0, b1, b0, x9, x8, x7, \
                     x6, x5, x4, x3, x2, x1, x0) \
 Eight_One_Sum(a7, a6, a5, a4, a3, a2, a1, a0, b0, _k, _6, _5, _4, _3, _2, \
               _1, _0, x0); \
 Eight_One_Sum(_k, _6, _5, _4, _3, _2, _1, _0, b1, x9, x8, x7, x6, x5, x4, \
               x3, x2, x1)

#define Eight_Four_Sum(a7, a6, a5, a4, a3, a2, a1, a0, b4, b3, b1, b0, x11, \
                      x10, x9, x8, x7, x6, x5, x4, x3, x2, x1, x0) \
 Eight_Two_Sum(a7, a6, a5, a4, a3, a2, a1, a0, b1, b0, _l, _6, _5, _4, _3, \
               _2, _1, _0, x1, x0); \
 Eight_Two_Sum(_l, _6, _5, _4, _3, _2, _1, _0, b4, b3, x11, x10, x9, x8, \
               x7, x6, x5, x4, x3, x2)

/* Macros for multiplying expansions of various fixed lengths.               */

#define Two_One_Product(a1, a0, b, x3, x2, x1, x0) \
 Split(b, bhi, blo); \
 Two_Product_Presplit(a0, b, bhi, blo, _i, x0); \
 Two_Product_Presplit(a1, b, bhi, blo, _j, _0); \
 Two_Sum(_i, _0, _k, x1); \
 Fast_Two_Sum(_j, _k, x3, x2)

#define Four_One_Product(a3, a2, a1, a0, b, x7, x6, x5, x4, x3, x2, x1, x0) \
 Split(b, bhi, blo); \
 Two_Product_Presplit(a0, b, bhi, blo, _i, x0); \
 Two_Product_Presplit(a1, b, bhi, blo, _j, _0); \
 Two_Sum(_i, _0, _k, x1); \
 Fast_Two_Sum(_j, _k, _i, x2); \
 Two_Product_Presplit(a2, b, bhi, blo, _j, _0); \
 Two_Sum(_i, _0, _k, x3); \
 Fast_Two_Sum(_j, _k, _i, x4); \
 Two_Product_Presplit(a3, b, bhi, blo, _j, _0); \
 Two_Sum(_i, _0, _k, x5); \
 Fast_Two_Sum(_j, _k, x7, x6)

#define Two_Two_Product(a1, a0, b1, b0, x7, x6, x5, x4, x3, x2, x1, x0) \
 Split(a0, a0hi, a0lo); \
 Split(b0, bhi, blo); \
 Two_Product_2Presplit(a0, a0hi, a0lo, b0, bhi, blo, _i, x0); \
 Split(a1, a1hi, a1lo); \
 Two_Product_2Presplit(a1, a1hi, a1lo, b0, bhi, blo, _j, _0); \
 Two_Sum(_i, _0, _k, _1); \
 Fast_Two_Sum(_j, _k, _l, _2); \
 Split(b1, bhi, blo); \
 Two_Product_2Presplit(a0, a0hi, a0lo, b1, bhi, blo, _i, _0); \
 Two_Sum(_1, _0, _k, x1); \
 Two_Sum(_2, _k, _j, _1); \
 Two_Sum(_l, _j, _m, _2); \
 Two_Product_2Presplit(a1, a1hi, a1lo, b1, bhi, blo, _j, _0); \
 Two_Sum(_i, _0, _n, _0); \
 Two_Sum(_1, _0, _i, x2); \
 Two_Sum(_2, _i, _k, _1); \
 Two_Sum(_m, _k, _l, _2); \
 Two_Sum(_j, _n, _k, _0); \
 Two_Sum(_1, _0, _j, x3); \
 Two_Sum(_2, _j, _i, _1); \
 Two_Sum(_l, _i, _m, _2); \
 Two_Sum(_1, _k, _i, x4); \
 Two_Sum(_2, _i, _k, x5); \
 Two_Sum(_m, _k, x7, x6)

/* An expansion of length two can be squared more quickly than finding the   */
/*   product of two different expansions of length two, and the result is    */
/*   guaranteed to have no more than six (rather than eight) components.     */

#define Two_Square(a1, a0, x5, x4, x3, x2, x1, x0) \
 Square(a0, _j, x0); \
 _0 = a0 + a0; \
 Two_Product(a1, _0, _k, _1); \
 Two_One_Sum(_k, _1, _j, _l, _2, x1); \
 Square(a1, _j, _1); \
 Two_Two_Sum(_j, _1, _l, _2, x5, x4, x3, x2)

/* 2^(-p), where p=DBL_MANT_DIG.  Used to estimate roundoff errors.          */
static const REAL epsilon=0.5*DBL_EPSILON;

/* 2^ceiling(p/2) + 1.  Used to split floats in half. */
static const REAL splitter=sqrt((DBL_MANT_DIG % 2 ? 2.0 : 1.0)/epsilon)+1.0;

/* A set of coefficients used to calculate maximum roundoff errors.          */
const REAL resulterrbound=(3.0 + 8.0 * epsilon) * epsilon;
const REAL ccwerrboundA=(3.0 + 16.0 * epsilon) * epsilon;
const REAL ccwerrboundB=(2.0 + 12.0 * epsilon) * epsilon;
const REAL ccwerrboundC=(9.0 + 64.0 * epsilon) * epsilon * epsilon;
const REAL o3derrboundA=(7.0 + 56.0 * epsilon) * epsilon;
const REAL o3derrboundB=(3.0 + 28.0 * epsilon) * epsilon;
const REAL o3derrboundC=(26.0 + 288.0 * epsilon) * epsilon * epsilon;
const REAL iccerrboundA=(10.0 + 96.0 * epsilon) * epsilon;
const REAL iccerrboundB=(4.0 + 48.0 * epsilon) * epsilon;
const REAL iccerrboundC=(44.0 + 576.0 * epsilon) * epsilon * epsilon;
const REAL isperrboundA=(16.0 + 224.0 * epsilon) * epsilon;
const REAL isperrboundB=(5.0 + 72.0 * epsilon) * epsilon;
const REAL isperrboundC=(71.0 + 1408.0 * epsilon) * epsilon * epsilon;

/*****************************************************************************/
/*                                                                           */
/*  doubleprint()   Print the bit representation of a double.                */
/*                                                                           */
/*  Useful for debugging exact arithmetic routines.                          */
/*                                                                           */
/*****************************************************************************/

/*
void doubleprint(number)
double number;
{
 unsigned long long no;
 unsigned long long sign, expo;
 int exponent;
 int i, bottomi;

 no = *(unsigned long long *) &number;
 sign = no & 0x8000000000000000ll;
 expo = (no >> 52) & 0x7ffll;
 exponent = (int) expo;
 exponent = exponent - 1023;
 if (sign) {
   printf("-");
 } else {
   printf(" ");
 }
 if (exponent == -1023) {
   printf(
     "0.0000000000000000000000000000000000000000000000000000_     (   )");
 } else {
   printf("1.");
   bottomi = -1;
   for (i = 0; i < 52; i++) {
     if (no & 0x0008000000000000ll) {
       printf("1");
       bottomi = i;
     } else {
       printf("0");
     }
     no <<= 1;
   }
   printf("_%d  (%d)", exponent, exponent - 1 - bottomi);
 }
}
*/

/*****************************************************************************/
/*                                                                           */
/*  floatprint()   Print the bit representation of a float.                  */
/*                                                                           */
/*  Useful for debugging exact arithmetic routines.                          */
/*                                                                           */
/*****************************************************************************/

/*
void floatprint(number)
float number;
{
 unsigned no;
 unsigned sign, expo;
 int exponent;
 int i, bottomi;

 no = *(unsigned *) &number;
 sign = no & 0x80000000;
 expo = (no >> 23) & 0xff;
 exponent = (int) expo;
 exponent = exponent - 127;
 if (sign) {
   printf("-");
 } else {
   printf(" ");
 }
 if (exponent == -127) {
   printf("0.00000000000000000000000_     (   )");
 } else {
   printf("1.");
   bottomi = -1;
   for (i = 0; i < 23; i++) {
     if (no & 0x00400000) {
       printf("1");
       bottomi = i;
     } else {
       printf("0");
     }
     no <<= 1;
   }
   printf("_%3d  (%3d)", exponent, exponent - 1 - bottomi);
 }
}
*/

/*****************************************************************************/
/*                                                                           */
/*  expansion_print()   Print the bit representation of an expansion.        */
/*                                                                           */
/*  Useful for debugging exact arithmetic routines.                          */
/*                                                                           */
/*****************************************************************************/

/*
void expansion_print(elen, e)
int elen;
REAL *e;
{
 int i;

 for (i = elen - 1; i >= 0; i--) {
   REALPRINT(e[i]);
   if (i > 0) {
     printf(" +\n");
   } else {
     printf("\n");
   }
 }
}
*/

/*****************************************************************************/
/*                                                                           */
/*  doublerand()   Generate a double with random 53-bit significand and a    */
/*                 random exponent in [0, 511].                              */
/*                                                                           */
/*****************************************************************************/

/*
static double doublerand()
{
 double result;
 double expo;
 long a, b, c;
 long i;

 a = random();
 b = random();
 c = random();
 result = (double) (a - 1073741824) * 8388608.0 + (double) (b >> 8);
 for (i = 512, expo = 2; i <= 131072; i *= 2, expo = expo * expo) {
   if (c & i) {
     result *= expo;
   }
 }
 return result;
}
*/

/*****************************************************************************/
/*                                                                           */
/*  narrowdoublerand()   Generate a double with random 53-bit significand    */
/*                       and a random exponent in [0, 7].                    */
/*                                                                           */
/*****************************************************************************/

/*
static double narrowdoublerand()
{
 double result;
 double expo;
 long a, b, c;
 long i;

 a = random();
 b = random();
 c = random();
 result = (double) (a - 1073741824) * 8388608.0 + (double) (b >> 8);
 for (i = 512, expo = 2; i <= 2048; i *= 2, expo = expo * expo) {
   if (c & i) {
     result *= expo;
   }
 }
 return result;
}
*/

/*****************************************************************************/
/*                                                                           */
/*  uniformdoublerand()   Generate a double with random 53-bit significand.  */
/*                                                                           */
/*****************************************************************************/

/*
static double uniformdoublerand()
{
 double result;
 long a, b;

 a = random();
 b = random();
 result = (double) (a - 1073741824) * 8388608.0 + (double) (b >> 8);
 return result;
}
*/

/*****************************************************************************/
/*                                                                           */
/*  floatrand()   Generate a float with random 24-bit significand and a      */
/*                random exponent in [0, 63].                                */
/*                                                                           */
/*****************************************************************************/

/*
static float floatrand()
{
 float result;
 float expo;
 long a, c;
 long i;

 a = random();
 c = random();
 result = (float) ((a - 1073741824) >> 6);
 for (i = 512, expo = 2; i <= 16384; i *= 2, expo = expo * expo) {
   if (c & i) {
     result *= expo;
   }
 }
 return result;
}
*/

/*****************************************************************************/
/*                                                                           */
/*  narrowfloatrand()   Generate a float with random 24-bit significand and  */
/*                      a random exponent in [0, 7].                         */
/*                                                                           */
/*****************************************************************************/

/*
static float narrowfloatrand()
{
 float result;
 float expo;
 long a, c;
 long i;

 a = random();
 c = random();
 result = (float) ((a - 1073741824) >> 6);
 for (i = 512, expo = 2; i <= 2048; i *= 2, expo = expo * expo) {
   if (c & i) {
     result *= expo;
   }
 }
 return result;
}
*/

/*****************************************************************************/
/*                                                                           */
/*  uniformfloatrand()   Generate a float with random 24-bit significand.    */
/*                                                                           */
/*****************************************************************************/

/*
static float uniformfloatrand()
{
 float result;
 long a;

 a = random();
 result = (float) ((a - 1073741824) >> 6);
 return result;
}
*/

/*****************************************************************************/
/*                                                                           */
/*  fast_expansion_sum_zeroelim()   Sum two expansions, eliminating zero     */
/*                                  components from the output expansion.    */
/*                                                                           */
/*  Sets h = e + f.  See the long version of my paper for details.           */
/*                                                                           */
/*  If round-to-even is used (as with IEEE 754), maintains the strongly      */
/*  nonoverlapping property.  (That is, if e is strongly nonoverlapping, h   */
/*  will be also.)  Does NOT maintain the nonoverlapping or nonadjacent      */
/*  properties.                                                              */
/*                                                                           */
/*****************************************************************************/

static int fast_expansion_sum_zeroelim(int elen, const REAL *e,
                                      int flen, const REAL *f, REAL *h)
    /* h cannot be e or f. */
{
 REAL Q;
 INEXACT REAL Qnew;
 INEXACT REAL hh;
 INEXACT REAL bvirt;
 REAL avirt, bround, around;
 int eindex, findex, hindex;
 REAL enow, fnow;

 enow = e[0];
 fnow = f[0];
 eindex = findex = 0;
 if ((fnow > enow) == (fnow > -enow)) {
   Q = enow;
   enow = e[++eindex];
 } else {
   Q = fnow;
   fnow = f[++findex];
 }
 hindex = 0;
 if ((eindex < elen) && (findex < flen)) {
   if ((fnow > enow) == (fnow > -enow)) {
     Fast_Two_Sum(enow, Q, Qnew, hh);
     enow = e[++eindex];
   } else {
     Fast_Two_Sum(fnow, Q, Qnew, hh);
     fnow = f[++findex];
   }
   Q = Qnew;
   if (hh != 0.0) {
     h[hindex++] = hh;
   }
   while ((eindex < elen) && (findex < flen)) {
     if ((fnow > enow) == (fnow > -enow)) {
       Two_Sum(Q, enow, Qnew, hh);
       enow = e[++eindex];
     } else {
       Two_Sum(Q, fnow, Qnew, hh);
       fnow = f[++findex];
     }
     Q = Qnew;
     if (hh != 0.0) {
       h[hindex++] = hh;
     }
   }
 }
 while (eindex < elen) {
   Two_Sum(Q, enow, Qnew, hh);
   enow = e[++eindex];
   Q = Qnew;
   if (hh != 0.0) {
     h[hindex++] = hh;
   }
 }
 while (findex < flen) {
   Two_Sum(Q, fnow, Qnew, hh);
   fnow = f[++findex];
   Q = Qnew;
   if (hh != 0.0) {
     h[hindex++] = hh;
   }
 }
 if ((Q != 0.0) || (hindex == 0)) {
   h[hindex++] = Q;
 }
 return hindex;
}

/*****************************************************************************/
/*                                                                           */
/*  scale_expansion_zeroelim()   Multiply an expansion by a scalar,          */
/*                               eliminating zero components from the        */
/*                               output expansion.                           */
/*                                                                           */
/*  Sets h = be.  See either version of my paper for details.                */
/*                                                                           */
/*  Maintains the nonoverlapping property.  If round-to-even is used (as     */
/*  with IEEE 754), maintains the strongly nonoverlapping and nonadjacent    */
/*  properties as well.  (That is, if e has one of these properties, so      */
/*  will h.)                                                                 */
/*                                                                           */
/*****************************************************************************/

static int scale_expansion_zeroelim(int elen, const REAL *e, REAL b, REAL *h)
    /* e and h cannot be the same. */
{
 INEXACT REAL Q, sum;
 REAL hh;
 INEXACT REAL product1;
 REAL product0;
 int eindex, hindex;
 REAL enow;
 INEXACT REAL bvirt;
 REAL avirt, bround, around;
 INEXACT REAL c;
 INEXACT REAL abig;
 REAL ahi, alo, bhi, blo;
 REAL err1, err2, err3;

 Split(b, bhi, blo);
 Two_Product_Presplit(e[0], b, bhi, blo, Q, hh);
 hindex = 0;
 if (hh != 0) {
   h[hindex++] = hh;
 }
 for (eindex = 1; eindex < elen; eindex++) {
   enow = e[eindex];
   Two_Product_Presplit(enow, b, bhi, blo, product1, product0);
   Two_Sum(Q, product0, sum, hh);
   if (hh != 0) {
     h[hindex++] = hh;
   }
   Fast_Two_Sum(product1, sum, Q, hh);
   if (hh != 0) {
     h[hindex++] = hh;
   }
 }
 if ((Q != 0.0) || (hindex == 0)) {
   h[hindex++] = Q;
 }
 return hindex;
}

/*****************************************************************************/
/*                                                                           */
/*  estimate()   Produce a one-word estimate of an expansion's value.        */
/*                                                                           */
/*  See either version of my paper for details.                              */
/*                                                                           */
/*****************************************************************************/

static REAL estimate(int elen, const REAL *e)
{
 REAL Q;
 int eindex;

 Q = e[0];
 for (eindex = 1; eindex < elen; eindex++) {
   Q += e[eindex];
 }
 return Q;
}

/*****************************************************************************/
/*                                                                           */
/*  orient2dfast()   Approximate 2D orientation test.  Nonrobust.            */
/*  orient2dexact()   Exact 2D orientation test.  Robust.                    */
/*  orient2dslow()   Another exact 2D orientation test.  Robust.             */
/*  orient2d()   Adaptive exact 2D orientation test.  Robust.                */
/*                                                                           */
/*               Return a positive value if the points pa, pb, and pc occur  */
/*               in counterclockwise order; a negative value if they occur   */
/*               in clockwise order; and zero if they are collinear.  The    */
/*               result is also a rough approximation of twice the signed    */
/*               area of the triangle defined by the three points.           */
/*                                                                           */
/*  Only the first and last routine should be used; the middle two are for   */
/*  timings.                                                                 */
/*                                                                           */
/*  The last three use exact arithmetic to ensure a correct answer.  The     */
/*  result returned is the determinant of a matrix.  In orient2d() only,     */
/*  this determinant is computed adaptively, in the sense that exact         */
/*  arithmetic is used only to the degree it is needed to ensure that the    */
/*  returned value has the correct sign.  Hence, orient2d() is usually quite */
/*  fast, but will run more slowly when the input points are collinear or    */
/*  nearly so.                                                               */
/*                                                                           */
/*****************************************************************************/

REAL orient2dadapt(const REAL *pa, const REAL *pb, const REAL *pc, const REAL detsum)
{
 INEXACT REAL acx, acy, bcx, bcy;
 REAL acxtail, acytail, bcxtail, bcytail;
 INEXACT REAL detleft, detright;
 REAL detlefttail, detrighttail;
 REAL det, errbound;
 REAL B[4], C1[8], C2[12], D[16];
 INEXACT REAL B3;
 int C1length, C2length, Dlength;
 REAL u[4];
 INEXACT REAL u3;
 INEXACT REAL s1, t1;
 REAL s0, t0;

 INEXACT REAL bvirt;
 REAL avirt, bround, around;
 INEXACT REAL c;
 INEXACT REAL abig;
 REAL ahi, alo, bhi, blo;
 REAL err1, err2, err3;
 INEXACT REAL _i, _j;
 REAL _0;

 acx = (REAL) (pa[0] - pc[0]);
 bcx = (REAL) (pb[0] - pc[0]);
 acy = (REAL) (pa[1] - pc[1]);
 bcy = (REAL) (pb[1] - pc[1]);

 Two_Product(acx, bcy, detleft, detlefttail);
 Two_Product(acy, bcx, detright, detrighttail);

 Two_Two_Diff(detleft, detlefttail, detright, detrighttail,
              B3, B[2], B[1], B[0]);
 B[3] = B3;

 det = estimate(4, B);
 errbound = ccwerrboundB * detsum;
 if ((det >= errbound) || (-det >= errbound)) {
   return det;
 }

 Two_Diff_Tail(pa[0], pc[0], acx, acxtail);
 Two_Diff_Tail(pb[0], pc[0], bcx, bcxtail);
 Two_Diff_Tail(pa[1], pc[1], acy, acytail);
 Two_Diff_Tail(pb[1], pc[1], bcy, bcytail);

 if ((acxtail == 0.0) && (acytail == 0.0)
     && (bcxtail == 0.0) && (bcytail == 0.0)) {
   return det;
 }

 errbound = ccwerrboundC * detsum + resulterrbound * Absolute(det);
 det += (acx * bcytail + bcy * acxtail)
      - (acy * bcxtail + bcx * acytail);
 if ((det >= errbound) || (-det >= errbound)) {
   return det;
 }

 Two_Product(acxtail, bcy, s1, s0);
 Two_Product(acytail, bcx, t1, t0);
 Two_Two_Diff(s1, s0, t1, t0, u3, u[2], u[1], u[0]);
 u[3] = u3;
 C1length = fast_expansion_sum_zeroelim(4, B, 4, u, C1);

 Two_Product(acx, bcytail, s1, s0);
 Two_Product(acy, bcxtail, t1, t0);
 Two_Two_Diff(s1, s0, t1, t0, u3, u[2], u[1], u[0]);
 u[3] = u3;
 C2length = fast_expansion_sum_zeroelim(C1length, C1, 4, u, C2);

 Two_Product(acxtail, bcytail, s1, s0);
 Two_Product(acytail, bcxtail, t1, t0);
 Two_Two_Diff(s1, s0, t1, t0, u3, u[2], u[1], u[0]);
 u[3] = u3;
 Dlength = fast_expansion_sum_zeroelim(C2length, C2, 4, u, D);

 return(D[Dlength - 1]);
}

REAL orient2d(const REAL *pa, const REAL *pb, const REAL *pc)
{
 REAL detleft, detright, det;
 REAL detsum, errbound;
 REAL orient;

 FPU_ROUND_DOUBLE;

 detleft = (pa[0] - pc[0]) * (pb[1] - pc[1]);
 detright = (pa[1] - pc[1]) * (pb[0] - pc[0]);
 det = detleft - detright;

 if (detleft > 0.0) {
   if (detright <= 0.0) {
     FPU_RESTORE;
     return det;
   } else {
     detsum = detleft + detright;
   }
 } else if (detleft < 0.0) {
   if (detright >= 0.0) {
     FPU_RESTORE;
     return det;
   } else {
     detsum = -detleft - detright;
   }
 } else {
   FPU_RESTORE;
   return det;
 }

 errbound = ccwerrboundA * detsum;
 if ((det >= errbound) || (-det >= errbound)) {
   FPU_RESTORE;
   return det;
 }

 orient = orient2dadapt(pa, pb, pc, detsum);
 FPU_RESTORE;
 return orient;
}

REAL orient2d(const REAL ax, const REAL ay, const REAL bx, const REAL by,
             const REAL cx, const REAL cy)
{
 REAL detleft, detright, det;
 REAL detsum, errbound;
 REAL orient;

 FPU_ROUND_DOUBLE;

 detleft = (ax - cx) * (by - cy);
 detright = (ay - cy) * (bx - cx);
 det = detleft - detright;

 if (detleft > 0.0) {
   if (detright <= 0.0) {
     FPU_RESTORE;
     return det;
   } else {
     detsum = detleft + detright;
   }
 } else if (detleft < 0.0) {
   if (detright >= 0.0) {
     FPU_RESTORE;
     return det;
   } else {
     detsum = -detleft - detright;
   }
 } else {
   FPU_RESTORE;
   return det;
 }

 errbound = ccwerrboundA * detsum;
 if ((det >= errbound) || (-det >= errbound)) {
   FPU_RESTORE;
   return det;
 }

 REAL pa[]={ax,ay};
 REAL pb[]={bx,by};
 REAL pc[]={cx,cy};

 orient = orient2dadapt(pa, pb, pc, detsum);
 FPU_RESTORE;
 return orient;
}

/*****************************************************************************/
/*                                                                           */
/*  orient3dfast()   Approximate 3D orientation test.  Nonrobust.            */
/*  orient3dexact()   Exact 3D orientation test.  Robust.                    */
/*  orient3dslow()   Another exact 3D orientation test.  Robust.             */
/*  orient3d()   Adaptive exact 3D orientation test.  Robust.                */
/*                                                                           */
/*               Return a positive value if the point pd lies below the      */
/*               plane passing through pa, pb, and pc; "below" is defined so */
/*               that pa, pb, and pc appear in counterclockwise order when   */
/*               viewed from above the plane.  Returns a negative value if   */
/*               pd lies above the plane.  Returns zero if the points are    */
/*               coplanar.  The result is also a rough approximation of six  */
/*               times the signed volume of the tetrahedron defined by the   */
/*               four points.                                                */
/*                                                                           */
/*  Only the first and last routine should be used; the middle two are for   */
/*  timings.                                                                 */
/*                                                                           */
/*  The last three use exact arithmetic to ensure a correct answer.  The     */
/*  result returned is the determinant of a matrix.  In orient3d() only,     */
/*  this determinant is computed adaptively, in the sense that exact         */
/*  arithmetic is used only to the degree it is needed to ensure that the    */
/*  returned value has the correct sign.  Hence, orient3d() is usually quite */
/*  fast, but will run more slowly when the input points are coplanar or     */
/*  nearly so.                                                               */
/*                                                                           */
/*****************************************************************************/

static REAL orient3dadapt(const REAL *pa, const REAL *pb, const REAL *pc, const REAL *pd,
                         REAL permanent)
{
 INEXACT REAL adx, bdx, cdx, ady, bdy, cdy, adz, bdz, cdz;
 REAL det, errbound;

 INEXACT REAL bdxcdy1, cdxbdy1, cdxady1, adxcdy1, adxbdy1, bdxady1;
 REAL bdxcdy0, cdxbdy0, cdxady0, adxcdy0, adxbdy0, bdxady0;
 REAL bc[4], ca[4], ab[4];
 INEXACT REAL bc3, ca3, ab3;
 REAL adet[8], bdet[8], cdet[8];
 int alen, blen, clen;
 REAL abdet[16];
 int ablen;
 REAL *finnow, *finother, *finswap;
 REAL fin1[192], fin2[192];
 int finlength;

 REAL adxtail, bdxtail, cdxtail;
 REAL adytail, bdytail, cdytail;
 REAL adztail, bdztail, cdztail;
 INEXACT REAL at_blarge, at_clarge;
 INEXACT REAL bt_clarge, bt_alarge;
 INEXACT REAL ct_alarge, ct_blarge;
 REAL at_b[4], at_c[4], bt_c[4], bt_a[4], ct_a[4], ct_b[4];
 int at_blen, at_clen, bt_clen, bt_alen, ct_alen, ct_blen;
 INEXACT REAL bdxt_cdy1, cdxt_bdy1, cdxt_ady1;
 INEXACT REAL adxt_cdy1, adxt_bdy1, bdxt_ady1;
 REAL bdxt_cdy0, cdxt_bdy0, cdxt_ady0;
 REAL adxt_cdy0, adxt_bdy0, bdxt_ady0;
 INEXACT REAL bdyt_cdx1, cdyt_bdx1, cdyt_adx1;
 INEXACT REAL adyt_cdx1, adyt_bdx1, bdyt_adx1;
 REAL bdyt_cdx0, cdyt_bdx0, cdyt_adx0;
 REAL adyt_cdx0, adyt_bdx0, bdyt_adx0;
 REAL bct[8], cat[8], abt[8];
 int bctlen, catlen, abtlen;
 INEXACT REAL bdxt_cdyt1, cdxt_bdyt1, cdxt_adyt1;
 INEXACT REAL adxt_cdyt1, adxt_bdyt1, bdxt_adyt1;
 REAL bdxt_cdyt0, cdxt_bdyt0, cdxt_adyt0;
 REAL adxt_cdyt0, adxt_bdyt0, bdxt_adyt0;
 REAL u[4], v[12], w[16];
 INEXACT REAL u3;
 int vlength, wlength;
 REAL negate;

 INEXACT REAL bvirt;
 REAL avirt, bround, around;
 INEXACT REAL c;
 INEXACT REAL abig;
 REAL ahi, alo, bhi, blo;
 REAL err1, err2, err3;
 INEXACT REAL _i, _j, _k;
 REAL _0;

 adx = (REAL) (pa[0] - pd[0]);
 bdx = (REAL) (pb[0] - pd[0]);
 cdx = (REAL) (pc[0] - pd[0]);
 ady = (REAL) (pa[1] - pd[1]);
 bdy = (REAL) (pb[1] - pd[1]);
 cdy = (REAL) (pc[1] - pd[1]);
 adz = (REAL) (pa[2] - pd[2]);
 bdz = (REAL) (pb[2] - pd[2]);
 cdz = (REAL) (pc[2] - pd[2]);

 Two_Product(bdx, cdy, bdxcdy1, bdxcdy0);
 Two_Product(cdx, bdy, cdxbdy1, cdxbdy0);
 Two_Two_Diff(bdxcdy1, bdxcdy0, cdxbdy1, cdxbdy0, bc3, bc[2], bc[1], bc[0]);
 bc[3] = bc3;
 alen = scale_expansion_zeroelim(4, bc, adz, adet);

 Two_Product(cdx, ady, cdxady1, cdxady0);
 Two_Product(adx, cdy, adxcdy1, adxcdy0);
 Two_Two_Diff(cdxady1, cdxady0, adxcdy1, adxcdy0, ca3, ca[2], ca[1], ca[0]);
 ca[3] = ca3;
 blen = scale_expansion_zeroelim(4, ca, bdz, bdet);

 Two_Product(adx, bdy, adxbdy1, adxbdy0);
 Two_Product(bdx, ady, bdxady1, bdxady0);
 Two_Two_Diff(adxbdy1, adxbdy0, bdxady1, bdxady0, ab3, ab[2], ab[1], ab[0]);
 ab[3] = ab3;
 clen = scale_expansion_zeroelim(4, ab, cdz, cdet);

 ablen = fast_expansion_sum_zeroelim(alen, adet, blen, bdet, abdet);
 finlength = fast_expansion_sum_zeroelim(ablen, abdet, clen, cdet, fin1);

 det = estimate(finlength, fin1);
 errbound = o3derrboundB * permanent;
 if ((det >= errbound) || (-det >= errbound)) {
   return det;
 }

 Two_Diff_Tail(pa[0], pd[0], adx, adxtail);
 Two_Diff_Tail(pb[0], pd[0], bdx, bdxtail);
 Two_Diff_Tail(pc[0], pd[0], cdx, cdxtail);
 Two_Diff_Tail(pa[1], pd[1], ady, adytail);
 Two_Diff_Tail(pb[1], pd[1], bdy, bdytail);
 Two_Diff_Tail(pc[1], pd[1], cdy, cdytail);
 Two_Diff_Tail(pa[2], pd[2], adz, adztail);
 Two_Diff_Tail(pb[2], pd[2], bdz, bdztail);
 Two_Diff_Tail(pc[2], pd[2], cdz, cdztail);

 if ((adxtail == 0.0) && (bdxtail == 0.0) && (cdxtail == 0.0)
     && (adytail == 0.0) && (bdytail == 0.0) && (cdytail == 0.0)
     && (adztail == 0.0) && (bdztail == 0.0) && (cdztail == 0.0)) {
   return det;
 }

 errbound = o3derrboundC * permanent + resulterrbound * Absolute(det);
 det += (adz * ((bdx * cdytail + cdy * bdxtail)
                - (bdy * cdxtail + cdx * bdytail))
         + adztail * (bdx * cdy - bdy * cdx))
      + (bdz * ((cdx * adytail + ady * cdxtail)
                - (cdy * adxtail + adx * cdytail))
         + bdztail * (cdx * ady - cdy * adx))
      + (cdz * ((adx * bdytail + bdy * adxtail)
                - (ady * bdxtail + bdx * adytail))
         + cdztail * (adx * bdy - ady * bdx));
 if ((det >= errbound) || (-det >= errbound)) {
   return det;
 }

 finnow = fin1;
 finother = fin2;

 if (adxtail == 0.0) {
   if (adytail == 0.0) {
     at_b[0] = 0.0;
     at_blen = 1;
     at_c[0] = 0.0;
     at_clen = 1;
   } else {
     negate = -adytail;
     Two_Product(negate, bdx, at_blarge, at_b[0]);
     at_b[1] = at_blarge;
     at_blen = 2;
     Two_Product(adytail, cdx, at_clarge, at_c[0]);
     at_c[1] = at_clarge;
     at_clen = 2;
   }
 } else {
   if (adytail == 0.0) {
     Two_Product(adxtail, bdy, at_blarge, at_b[0]);
     at_b[1] = at_blarge;
     at_blen = 2;
     negate = -adxtail;
     Two_Product(negate, cdy, at_clarge, at_c[0]);
     at_c[1] = at_clarge;
     at_clen = 2;
   } else {
     Two_Product(adxtail, bdy, adxt_bdy1, adxt_bdy0);
     Two_Product(adytail, bdx, adyt_bdx1, adyt_bdx0);
     Two_Two_Diff(adxt_bdy1, adxt_bdy0, adyt_bdx1, adyt_bdx0,
                  at_blarge, at_b[2], at_b[1], at_b[0]);
     at_b[3] = at_blarge;
     at_blen = 4;
     Two_Product(adytail, cdx, adyt_cdx1, adyt_cdx0);
     Two_Product(adxtail, cdy, adxt_cdy1, adxt_cdy0);
     Two_Two_Diff(adyt_cdx1, adyt_cdx0, adxt_cdy1, adxt_cdy0,
                  at_clarge, at_c[2], at_c[1], at_c[0]);
     at_c[3] = at_clarge;
     at_clen = 4;
   }
 }
 if (bdxtail == 0.0) {
   if (bdytail == 0.0) {
     bt_c[0] = 0.0;
     bt_clen = 1;
     bt_a[0] = 0.0;
     bt_alen = 1;
   } else {
     negate = -bdytail;
     Two_Product(negate, cdx, bt_clarge, bt_c[0]);
     bt_c[1] = bt_clarge;
     bt_clen = 2;
     Two_Product(bdytail, adx, bt_alarge, bt_a[0]);
     bt_a[1] = bt_alarge;
     bt_alen = 2;
   }
 } else {
   if (bdytail == 0.0) {
     Two_Product(bdxtail, cdy, bt_clarge, bt_c[0]);
     bt_c[1] = bt_clarge;
     bt_clen = 2;
     negate = -bdxtail;
     Two_Product(negate, ady, bt_alarge, bt_a[0]);
     bt_a[1] = bt_alarge;
     bt_alen = 2;
   } else {
     Two_Product(bdxtail, cdy, bdxt_cdy1, bdxt_cdy0);
     Two_Product(bdytail, cdx, bdyt_cdx1, bdyt_cdx0);
     Two_Two_Diff(bdxt_cdy1, bdxt_cdy0, bdyt_cdx1, bdyt_cdx0,
                  bt_clarge, bt_c[2], bt_c[1], bt_c[0]);
     bt_c[3] = bt_clarge;
     bt_clen = 4;
     Two_Product(bdytail, adx, bdyt_adx1, bdyt_adx0);
     Two_Product(bdxtail, ady, bdxt_ady1, bdxt_ady0);
     Two_Two_Diff(bdyt_adx1, bdyt_adx0, bdxt_ady1, bdxt_ady0,
                 bt_alarge, bt_a[2], bt_a[1], bt_a[0]);
     bt_a[3] = bt_alarge;
     bt_alen = 4;
   }
 }
 if (cdxtail == 0.0) {
   if (cdytail == 0.0) {
     ct_a[0] = 0.0;
     ct_alen = 1;
     ct_b[0] = 0.0;
     ct_blen = 1;
   } else {
     negate = -cdytail;
     Two_Product(negate, adx, ct_alarge, ct_a[0]);
     ct_a[1] = ct_alarge;
     ct_alen = 2;
     Two_Product(cdytail, bdx, ct_blarge, ct_b[0]);
     ct_b[1] = ct_blarge;
     ct_blen = 2;
   }
 } else {
   if (cdytail == 0.0) {
     Two_Product(cdxtail, ady, ct_alarge, ct_a[0]);
     ct_a[1] = ct_alarge;
     ct_alen = 2;
     negate = -cdxtail;
     Two_Product(negate, bdy, ct_blarge, ct_b[0]);
     ct_b[1] = ct_blarge;
     ct_blen = 2;
   } else {
     Two_Product(cdxtail, ady, cdxt_ady1, cdxt_ady0);
     Two_Product(cdytail, adx, cdyt_adx1, cdyt_adx0);
     Two_Two_Diff(cdxt_ady1, cdxt_ady0, cdyt_adx1, cdyt_adx0,
                  ct_alarge, ct_a[2], ct_a[1], ct_a[0]);
     ct_a[3] = ct_alarge;
     ct_alen = 4;
     Two_Product(cdytail, bdx, cdyt_bdx1, cdyt_bdx0);
     Two_Product(cdxtail, bdy, cdxt_bdy1, cdxt_bdy0);
     Two_Two_Diff(cdyt_bdx1, cdyt_bdx0, cdxt_bdy1, cdxt_bdy0,
                  ct_blarge, ct_b[2], ct_b[1], ct_b[0]);
     ct_b[3] = ct_blarge;
     ct_blen = 4;
   }
 }

 bctlen = fast_expansion_sum_zeroelim(bt_clen, bt_c, ct_blen, ct_b, bct);
 wlength = scale_expansion_zeroelim(bctlen, bct, adz, w);
 finlength = fast_expansion_sum_zeroelim(finlength, finnow, wlength, w,
                                         finother);
 finswap = finnow; finnow = finother; finother = finswap;

 catlen = fast_expansion_sum_zeroelim(ct_alen, ct_a, at_clen, at_c, cat);
 wlength = scale_expansion_zeroelim(catlen, cat, bdz, w);
 finlength = fast_expansion_sum_zeroelim(finlength, finnow, wlength, w,
                                         finother);
 finswap = finnow; finnow = finother; finother = finswap;

 abtlen = fast_expansion_sum_zeroelim(at_blen, at_b, bt_alen, bt_a, abt);
 wlength = scale_expansion_zeroelim(abtlen, abt, cdz, w);
 finlength = fast_expansion_sum_zeroelim(finlength, finnow, wlength, w,
                                         finother);
 finswap = finnow; finnow = finother; finother = finswap;

 if (adztail != 0.0) {
   vlength = scale_expansion_zeroelim(4, bc, adztail, v);
   finlength = fast_expansion_sum_zeroelim(finlength, finnow, vlength, v,
                                           finother);
   finswap = finnow; finnow = finother; finother = finswap;
 }
 if (bdztail != 0.0) {
   vlength = scale_expansion_zeroelim(4, ca, bdztail, v);
   finlength = fast_expansion_sum_zeroelim(finlength, finnow, vlength, v,
                                           finother);
   finswap = finnow; finnow = finother; finother = finswap;
 }
 if (cdztail != 0.0) {
   vlength = scale_expansion_zeroelim(4, ab, cdztail, v);
   finlength = fast_expansion_sum_zeroelim(finlength, finnow, vlength, v,
                                           finother);
   finswap = finnow; finnow = finother; finother = finswap;
 }

 if (adxtail != 0.0) {
   if (bdytail != 0.0) {
     Two_Product(adxtail, bdytail, adxt_bdyt1, adxt_bdyt0);
     Two_One_Product(adxt_bdyt1, adxt_bdyt0, cdz, u3, u[2], u[1], u[0]);
     u[3] = u3;
     finlength = fast_expansion_sum_zeroelim(finlength, finnow, 4, u,
                                             finother);
     finswap = finnow; finnow = finother; finother = finswap;
     if (cdztail != 0.0) {
       Two_One_Product(adxt_bdyt1, adxt_bdyt0, cdztail, u3, u[2], u[1], u[0]);
       u[3] = u3;
       finlength = fast_expansion_sum_zeroelim(finlength, finnow, 4, u,
                                               finother);
       finswap = finnow; finnow = finother; finother = finswap;
     }
   }
   if (cdytail != 0.0) {
     negate = -adxtail;
     Two_Product(negate, cdytail, adxt_cdyt1, adxt_cdyt0);
     Two_One_Product(adxt_cdyt1, adxt_cdyt0, bdz, u3, u[2], u[1], u[0]);
     u[3] = u3;
     finlength = fast_expansion_sum_zeroelim(finlength, finnow, 4, u,
                                             finother);
     finswap = finnow; finnow = finother; finother = finswap;
     if (bdztail != 0.0) {
       Two_One_Product(adxt_cdyt1, adxt_cdyt0, bdztail, u3, u[2], u[1], u[0]);
       u[3] = u3;
       finlength = fast_expansion_sum_zeroelim(finlength, finnow, 4, u,
                                               finother);
       finswap = finnow; finnow = finother; finother = finswap;
     }
   }
 }
 if (bdxtail != 0.0) {
   if (cdytail != 0.0) {
     Two_Product(bdxtail, cdytail, bdxt_cdyt1, bdxt_cdyt0);
     Two_One_Product(bdxt_cdyt1, bdxt_cdyt0, adz, u3, u[2], u[1], u[0]);
     u[3] = u3;
     finlength = fast_expansion_sum_zeroelim(finlength, finnow, 4, u,
                                             finother);
     finswap = finnow; finnow = finother; finother = finswap;
     if (adztail != 0.0) {
       Two_One_Product(bdxt_cdyt1, bdxt_cdyt0, adztail, u3, u[2], u[1], u[0]);
       u[3] = u3;
       finlength = fast_expansion_sum_zeroelim(finlength, finnow, 4, u,
                                               finother);
       finswap = finnow; finnow = finother; finother = finswap;
     }
   }
   if (adytail != 0.0) {
     negate = -bdxtail;
     Two_Product(negate, adytail, bdxt_adyt1, bdxt_adyt0);
     Two_One_Product(bdxt_adyt1, bdxt_adyt0, cdz, u3, u[2], u[1], u[0]);
     u[3] = u3;
     finlength = fast_expansion_sum_zeroelim(finlength, finnow, 4, u,
                                             finother);
     finswap = finnow; finnow = finother; finother = finswap;
     if (cdztail != 0.0) {
       Two_One_Product(bdxt_adyt1, bdxt_adyt0, cdztail, u3, u[2], u[1], u[0]);
       u[3] = u3;
       finlength = fast_expansion_sum_zeroelim(finlength, finnow, 4, u,
                                               finother);
       finswap = finnow; finnow = finother; finother = finswap;
     }
   }
 }
 if (cdxtail != 0.0) {
   if (adytail != 0.0) {
     Two_Product(cdxtail, adytail, cdxt_adyt1, cdxt_adyt0);
     Two_One_Product(cdxt_adyt1, cdxt_adyt0, bdz, u3, u[2], u[1], u[0]);
     u[3] = u3;
     finlength = fast_expansion_sum_zeroelim(finlength, finnow, 4, u,
                                             finother);
     finswap = finnow; finnow = finother; finother = finswap;
     if (bdztail != 0.0) {
       Two_One_Product(cdxt_adyt1, cdxt_adyt0, bdztail, u3, u[2], u[1], u[0]);
       u[3] = u3;
       finlength = fast_expansion_sum_zeroelim(finlength, finnow, 4, u,
                                               finother);
       finswap = finnow; finnow = finother; finother = finswap;
     }
   }
   if (bdytail != 0.0) {
     negate = -cdxtail;
     Two_Product(negate, bdytail, cdxt_bdyt1, cdxt_bdyt0);
     Two_One_Product(cdxt_bdyt1, cdxt_bdyt0, adz, u3, u[2], u[1], u[0]);
     u[3] = u3;
     finlength = fast_expansion_sum_zeroelim(finlength, finnow, 4, u,
                                             finother);
     finswap = finnow; finnow = finother; finother = finswap;
     if (adztail != 0.0) {
       Two_One_Product(cdxt_bdyt1, cdxt_bdyt0, adztail, u3, u[2], u[1], u[0]);
       u[3] = u3;
       finlength = fast_expansion_sum_zeroelim(finlength, finnow, 4, u,
                                               finother);
       finswap = finnow; finnow = finother; finother = finswap;
     }
   }
 }

 if (adztail != 0.0) {
   wlength = scale_expansion_zeroelim(bctlen, bct, adztail, w);
   finlength = fast_expansion_sum_zeroelim(finlength, finnow, wlength, w,
                                           finother);
   finswap = finnow; finnow = finother; finother = finswap;
 }
 if (bdztail != 0.0) {
   wlength = scale_expansion_zeroelim(catlen, cat, bdztail, w);
   finlength = fast_expansion_sum_zeroelim(finlength, finnow, wlength, w,
                                           finother);
   finswap = finnow; finnow = finother; finother = finswap;
 }
 if (cdztail != 0.0) {
   wlength = scale_expansion_zeroelim(abtlen, abt, cdztail, w);
   finlength = fast_expansion_sum_zeroelim(finlength, finnow, wlength, w,
                                           finother);
   finswap = finnow; finnow = finother; finother = finswap;
 }

 return finnow[finlength - 1];
}

REAL orient3d(const REAL *pa, const REAL *pb, const REAL *pc, const REAL *pd)
{
 REAL adx, bdx, cdx, ady, bdy, cdy, adz, bdz, cdz;
 REAL bdxcdy, cdxbdy, cdxady, adxcdy, adxbdy, bdxady;
 REAL det;
 REAL permanent, errbound;
 REAL orient;

 FPU_ROUND_DOUBLE;

 adx = pa[0] - pd[0];
 bdx = pb[0] - pd[0];
 cdx = pc[0] - pd[0];
 ady = pa[1] - pd[1];
 bdy = pb[1] - pd[1];
 cdy = pc[1] - pd[1];
 adz = pa[2] - pd[2];
 bdz = pb[2] - pd[2];
 cdz = pc[2] - pd[2];

 bdxcdy = bdx * cdy;
 cdxbdy = cdx * bdy;

 cdxady = cdx * ady;
 adxcdy = adx * cdy;

 adxbdy = adx * bdy;
 bdxady = bdx * ady;

 det = adz * (bdxcdy - cdxbdy)
     + bdz * (cdxady - adxcdy)
     + cdz * (adxbdy - bdxady);

 permanent = (Absolute(bdxcdy) + Absolute(cdxbdy)) * Absolute(adz)
           + (Absolute(cdxady) + Absolute(adxcdy)) * Absolute(bdz)
           + (Absolute(adxbdy) + Absolute(bdxady)) * Absolute(cdz);
 errbound = o3derrboundA * permanent;
 if ((det > errbound) || (-det > errbound)) {
   FPU_RESTORE;
   return det;
 }

 orient = orient3dadapt(pa, pb, pc, pd, permanent);
 FPU_RESTORE;
 return orient;
}

/*****************************************************************************/
/*                                                                           */
/*  incirclefast()   Approximate 2D incircle test.  Nonrobust.               */
/*  incircleexact()   Exact 2D incircle test.  Robust.                       */
/*  incircleslow()   Another exact 2D incircle test.  Robust.                */
/*  incircle()   Adaptive exact 2D incircle test.  Robust.                   */
/*                                                                           */
/*               Return a positive value if the point pd lies inside the     */
/*               circle passing through pa, pb, and pc; a negative value if  */
/*               it lies outside; and zero if the four points are cocircular.*/
/*               The points pa, pb, and pc must be in counterclockwise       */
/*               order, or the sign of the result will be reversed.          */
/*                                                                           */
/*  Only the first and last routine should be used; the middle two are for   */
/*  timings.                                                                 */
/*                                                                           */
/*  The last three use exact arithmetic to ensure a correct answer.  The     */
/*  result returned is the determinant of a matrix.  In incircle() only,     */
/*  this determinant is computed adaptively, in the sense that exact         */
/*  arithmetic is used only to the degree it is needed to ensure that the    */
/*  returned value has the correct sign.  Hence, incircle() is usually quite */
/*  fast, but will run more slowly when the input points are cocircular or   */
/*  nearly so.                                                               */
/*                                                                           */
/*****************************************************************************/

static REAL incircleadapt(const REAL *pa, const REAL *pb, const REAL *pc, const REAL *pd,
                         REAL permanent)
{
 INEXACT REAL adx, bdx, cdx, ady, bdy, cdy;
 REAL det, errbound;

 INEXACT REAL bdxcdy1, cdxbdy1, cdxady1, adxcdy1, adxbdy1, bdxady1;
 REAL bdxcdy0, cdxbdy0, cdxady0, adxcdy0, adxbdy0, bdxady0;
 REAL bc[4], ca[4], ab[4];
 INEXACT REAL bc3, ca3, ab3;
 REAL axbc[8], axxbc[16], aybc[8], ayybc[16], adet[32];
 int axbclen, axxbclen, aybclen, ayybclen, alen;
 REAL bxca[8], bxxca[16], byca[8], byyca[16], bdet[32];
 int bxcalen, bxxcalen, bycalen, byycalen, blen;
 REAL cxab[8], cxxab[16], cyab[8], cyyab[16], cdet[32];
 int cxablen, cxxablen, cyablen, cyyablen, clen;
 REAL abdet[64];
 int ablen;
 REAL fin1[1152], fin2[1152];
 REAL *finnow, *finother, *finswap;
 int finlength;

 REAL adxtail, bdxtail, cdxtail, adytail, bdytail, cdytail;
 INEXACT REAL adxadx1, adyady1, bdxbdx1, bdybdy1, cdxcdx1, cdycdy1;
 REAL adxadx0, adyady0, bdxbdx0, bdybdy0, cdxcdx0, cdycdy0;
 REAL aa[4], bb[4], cc[4];
 INEXACT REAL aa3, bb3, cc3;
 INEXACT REAL ti1, tj1;
 REAL ti0, tj0;
 REAL u[4], v[4];
 INEXACT REAL u3, v3;
 REAL temp8[8], temp16a[16], temp16b[16], temp16c[16];
 REAL temp32a[32], temp32b[32], temp48[48], temp64[64];
 int temp8len, temp16alen, temp16blen, temp16clen;
 int temp32alen, temp32blen, temp48len, temp64len;
 REAL axtbb[8], axtcc[8], aytbb[8], aytcc[8];
 int axtbblen, axtcclen, aytbblen, aytcclen;
 REAL bxtaa[8], bxtcc[8], bytaa[8], bytcc[8];
 int bxtaalen, bxtcclen, bytaalen, bytcclen;
 REAL cxtaa[8], cxtbb[8], cytaa[8], cytbb[8];
 int cxtaalen, cxtbblen, cytaalen, cytbblen;
 REAL axtbc[8], aytbc[8], bxtca[8], bytca[8], cxtab[8], cytab[8];
 int axtbclen = 0, aytbclen = 0;
 int bxtcalen = 0, bytcalen = 0;
 int cxtablen = 0, cytablen = 0;
 REAL axtbct[16], aytbct[16], bxtcat[16], bytcat[16], cxtabt[16], cytabt[16];
 int axtbctlen, aytbctlen, bxtcatlen, bytcatlen, cxtabtlen, cytabtlen;
 REAL axtbctt[8], aytbctt[8], bxtcatt[8];
 REAL bytcatt[8], cxtabtt[8], cytabtt[8];
 int axtbcttlen, aytbcttlen, bxtcattlen, bytcattlen, cxtabttlen, cytabttlen;
 REAL abt[8], bct[8], cat[8];
 int abtlen, bctlen, catlen;
 REAL abtt[4], bctt[4], catt[4];
 int abttlen, bcttlen, cattlen;
 INEXACT REAL abtt3, bctt3, catt3;
 REAL negate;

 INEXACT REAL bvirt;
 REAL avirt, bround, around;
 INEXACT REAL c;
 INEXACT REAL abig;
 REAL ahi, alo, bhi, blo;
 REAL err1, err2, err3;
 INEXACT REAL _i, _j;
 REAL _0;

 adx = (REAL) (pa[0] - pd[0]);
 bdx = (REAL) (pb[0] - pd[0]);
 cdx = (REAL) (pc[0] - pd[0]);
 ady = (REAL) (pa[1] - pd[1]);
 bdy = (REAL) (pb[1] - pd[1]);
 cdy = (REAL) (pc[1] - pd[1]);

 Two_Product(bdx, cdy, bdxcdy1, bdxcdy0);
 Two_Product(cdx, bdy, cdxbdy1, cdxbdy0);
 Two_Two_Diff(bdxcdy1, bdxcdy0, cdxbdy1, cdxbdy0, bc3, bc[2], bc[1], bc[0]);
 bc[3] = bc3;
 axbclen = scale_expansion_zeroelim(4, bc, adx, axbc);
 axxbclen = scale_expansion_zeroelim(axbclen, axbc, adx, axxbc);
 aybclen = scale_expansion_zeroelim(4, bc, ady, aybc);
 ayybclen = scale_expansion_zeroelim(aybclen, aybc, ady, ayybc);
 alen = fast_expansion_sum_zeroelim(axxbclen, axxbc, ayybclen, ayybc, adet);

 Two_Product(cdx, ady, cdxady1, cdxady0);
 Two_Product(adx, cdy, adxcdy1, adxcdy0);
 Two_Two_Diff(cdxady1, cdxady0, adxcdy1, adxcdy0, ca3, ca[2], ca[1], ca[0]);
 ca[3] = ca3;
 bxcalen = scale_expansion_zeroelim(4, ca, bdx, bxca);
 bxxcalen = scale_expansion_zeroelim(bxcalen, bxca, bdx, bxxca);
 bycalen = scale_expansion_zeroelim(4, ca, bdy, byca);
 byycalen = scale_expansion_zeroelim(bycalen, byca, bdy, byyca);
 blen = fast_expansion_sum_zeroelim(bxxcalen, bxxca, byycalen, byyca, bdet);

 Two_Product(adx, bdy, adxbdy1, adxbdy0);
 Two_Product(bdx, ady, bdxady1, bdxady0);
 Two_Two_Diff(adxbdy1, adxbdy0, bdxady1, bdxady0, ab3, ab[2], ab[1], ab[0]);
 ab[3] = ab3;
 cxablen = scale_expansion_zeroelim(4, ab, cdx, cxab);
 cxxablen = scale_expansion_zeroelim(cxablen, cxab, cdx, cxxab);
 cyablen = scale_expansion_zeroelim(4, ab, cdy, cyab);
 cyyablen = scale_expansion_zeroelim(cyablen, cyab, cdy, cyyab);
 clen = fast_expansion_sum_zeroelim(cxxablen, cxxab, cyyablen, cyyab, cdet);

 ablen = fast_expansion_sum_zeroelim(alen, adet, blen, bdet, abdet);
 finlength = fast_expansion_sum_zeroelim(ablen, abdet, clen, cdet, fin1);

 det = estimate(finlength, fin1);
 errbound = iccerrboundB * permanent;
 if ((det >= errbound) || (-det >= errbound)) {
   return det;
 }

 Two_Diff_Tail(pa[0], pd[0], adx, adxtail);
 Two_Diff_Tail(pa[1], pd[1], ady, adytail);
 Two_Diff_Tail(pb[0], pd[0], bdx, bdxtail);
 Two_Diff_Tail(pb[1], pd[1], bdy, bdytail);
 Two_Diff_Tail(pc[0], pd[0], cdx, cdxtail);
 Two_Diff_Tail(pc[1], pd[1], cdy, cdytail);
 if ((adxtail == 0.0) && (bdxtail == 0.0) && (cdxtail == 0.0)
     && (adytail == 0.0) && (bdytail == 0.0) && (cdytail == 0.0)) {
   return det;
 }

 errbound = iccerrboundC * permanent + resulterrbound * Absolute(det);
 det += ((adx * adx + ady * ady) * ((bdx * cdytail + cdy * bdxtail)
                                    - (bdy * cdxtail + cdx * bdytail))
         + 2.0 * (adx * adxtail + ady * adytail) * (bdx * cdy - bdy * cdx))
      + ((bdx * bdx + bdy * bdy) * ((cdx * adytail + ady * cdxtail)
                                    - (cdy * adxtail + adx * cdytail))
         + 2.0 * (bdx * bdxtail + bdy * bdytail) * (cdx * ady - cdy * adx))
      + ((cdx * cdx + cdy * cdy) * ((adx * bdytail + bdy * adxtail)
                                    - (ady * bdxtail + bdx * adytail))
         + 2.0 * (cdx * cdxtail + cdy * cdytail) * (adx * bdy - ady * bdx));
 if ((det >= errbound) || (-det >= errbound)) {
   return det;
 }

 finnow = fin1;
 finother = fin2;

 if ((bdxtail != 0.0) || (bdytail != 0.0)
     || (cdxtail != 0.0) || (cdytail != 0.0)) {
   Square(adx, adxadx1, adxadx0);
   Square(ady, adyady1, adyady0);
   Two_Two_Sum(adxadx1, adxadx0, adyady1, adyady0, aa3, aa[2], aa[1], aa[0]);
   aa[3] = aa3;
 }
 if ((cdxtail != 0.0) || (cdytail != 0.0)
     || (adxtail != 0.0) || (adytail != 0.0)) {
   Square(bdx, bdxbdx1, bdxbdx0);
   Square(bdy, bdybdy1, bdybdy0);
   Two_Two_Sum(bdxbdx1, bdxbdx0, bdybdy1, bdybdy0, bb3, bb[2], bb[1], bb[0]);
   bb[3] = bb3;
 }
 if ((adxtail != 0.0) || (adytail != 0.0)
     || (bdxtail != 0.0) || (bdytail != 0.0)) {
   Square(cdx, cdxcdx1, cdxcdx0);
   Square(cdy, cdycdy1, cdycdy0);
   Two_Two_Sum(cdxcdx1, cdxcdx0, cdycdy1, cdycdy0, cc3, cc[2], cc[1], cc[0]);
   cc[3] = cc3;
 }

 if (adxtail != 0.0) {
   axtbclen = scale_expansion_zeroelim(4, bc, adxtail, axtbc);
   temp16alen = scale_expansion_zeroelim(axtbclen, axtbc, 2.0 * adx,
                                         temp16a);

   axtcclen = scale_expansion_zeroelim(4, cc, adxtail, axtcc);
   temp16blen = scale_expansion_zeroelim(axtcclen, axtcc, bdy, temp16b);

   axtbblen = scale_expansion_zeroelim(4, bb, adxtail, axtbb);
   temp16clen = scale_expansion_zeroelim(axtbblen, axtbb, -cdy, temp16c);

   temp32alen = fast_expansion_sum_zeroelim(temp16alen, temp16a,
                                           temp16blen, temp16b, temp32a);
   temp48len = fast_expansion_sum_zeroelim(temp16clen, temp16c,
                                           temp32alen, temp32a, temp48);
   finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp48len,
                                           temp48, finother);
   finswap = finnow; finnow = finother; finother = finswap;
 }
 if (adytail != 0.0) {
   aytbclen = scale_expansion_zeroelim(4, bc, adytail, aytbc);
   temp16alen = scale_expansion_zeroelim(aytbclen, aytbc, 2.0 * ady,
                                         temp16a);

   aytbblen = scale_expansion_zeroelim(4, bb, adytail, aytbb);
   temp16blen = scale_expansion_zeroelim(aytbblen, aytbb, cdx, temp16b);

   aytcclen = scale_expansion_zeroelim(4, cc, adytail, aytcc);
   temp16clen = scale_expansion_zeroelim(aytcclen, aytcc, -bdx, temp16c);

   temp32alen = fast_expansion_sum_zeroelim(temp16alen, temp16a,
                                           temp16blen, temp16b, temp32a);
   temp48len = fast_expansion_sum_zeroelim(temp16clen, temp16c,
                                           temp32alen, temp32a, temp48);
   finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp48len,
                                           temp48, finother);
   finswap = finnow; finnow = finother; finother = finswap;
 }
 if (bdxtail != 0.0) {
   bxtcalen = scale_expansion_zeroelim(4, ca, bdxtail, bxtca);
   temp16alen = scale_expansion_zeroelim(bxtcalen, bxtca, 2.0 * bdx,
                                         temp16a);

   bxtaalen = scale_expansion_zeroelim(4, aa, bdxtail, bxtaa);
   temp16blen = scale_expansion_zeroelim(bxtaalen, bxtaa, cdy, temp16b);

   bxtcclen = scale_expansion_zeroelim(4, cc, bdxtail, bxtcc);
   temp16clen = scale_expansion_zeroelim(bxtcclen, bxtcc, -ady, temp16c);

   temp32alen = fast_expansion_sum_zeroelim(temp16alen, temp16a,
                                           temp16blen, temp16b, temp32a);
   temp48len = fast_expansion_sum_zeroelim(temp16clen, temp16c,
                                           temp32alen, temp32a, temp48);
   finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp48len,
                                           temp48, finother);
   finswap = finnow; finnow = finother; finother = finswap;
 }
 if (bdytail != 0.0) {
   bytcalen = scale_expansion_zeroelim(4, ca, bdytail, bytca);
   temp16alen = scale_expansion_zeroelim(bytcalen, bytca, 2.0 * bdy,
                                         temp16a);

   bytcclen = scale_expansion_zeroelim(4, cc, bdytail, bytcc);
   temp16blen = scale_expansion_zeroelim(bytcclen, bytcc, adx, temp16b);

   bytaalen = scale_expansion_zeroelim(4, aa, bdytail, bytaa);
   temp16clen = scale_expansion_zeroelim(bytaalen, bytaa, -cdx, temp16c);

   temp32alen = fast_expansion_sum_zeroelim(temp16alen, temp16a,
                                           temp16blen, temp16b, temp32a);
   temp48len = fast_expansion_sum_zeroelim(temp16clen, temp16c,
                                           temp32alen, temp32a, temp48);
   finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp48len,
                                           temp48, finother);
   finswap = finnow; finnow = finother; finother = finswap;
 }
 if (cdxtail != 0.0) {
   cxtablen = scale_expansion_zeroelim(4, ab, cdxtail, cxtab);
   temp16alen = scale_expansion_zeroelim(cxtablen, cxtab, 2.0 * cdx,
                                         temp16a);

   cxtbblen = scale_expansion_zeroelim(4, bb, cdxtail, cxtbb);
   temp16blen = scale_expansion_zeroelim(cxtbblen, cxtbb, ady, temp16b);

   cxtaalen = scale_expansion_zeroelim(4, aa, cdxtail, cxtaa);
   temp16clen = scale_expansion_zeroelim(cxtaalen, cxtaa, -bdy, temp16c);

   temp32alen = fast_expansion_sum_zeroelim(temp16alen, temp16a,
                                           temp16blen, temp16b, temp32a);
   temp48len = fast_expansion_sum_zeroelim(temp16clen, temp16c,
                                           temp32alen, temp32a, temp48);
   finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp48len,
                                           temp48, finother);
   finswap = finnow; finnow = finother; finother = finswap;
 }
 if (cdytail != 0.0) {
   cytablen = scale_expansion_zeroelim(4, ab, cdytail, cytab);
   temp16alen = scale_expansion_zeroelim(cytablen, cytab, 2.0 * cdy,
                                         temp16a);

   cytaalen = scale_expansion_zeroelim(4, aa, cdytail, cytaa);
   temp16blen = scale_expansion_zeroelim(cytaalen, cytaa, bdx, temp16b);

   cytbblen = scale_expansion_zeroelim(4, bb, cdytail, cytbb);
   temp16clen = scale_expansion_zeroelim(cytbblen, cytbb, -adx, temp16c);

   temp32alen = fast_expansion_sum_zeroelim(temp16alen, temp16a,
                                           temp16blen, temp16b, temp32a);
   temp48len = fast_expansion_sum_zeroelim(temp16clen, temp16c,
                                           temp32alen, temp32a, temp48);
   finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp48len,
                                           temp48, finother);
   finswap = finnow; finnow = finother; finother = finswap;
 }

 if ((adxtail != 0.0) || (adytail != 0.0)) {
   if ((bdxtail != 0.0) || (bdytail != 0.0)
       || (cdxtail != 0.0) || (cdytail != 0.0)) {
     Two_Product(bdxtail, cdy, ti1, ti0);
     Two_Product(bdx, cdytail, tj1, tj0);
     Two_Two_Sum(ti1, ti0, tj1, tj0, u3, u[2], u[1], u[0]);
     u[3] = u3;
     negate = -bdy;
     Two_Product(cdxtail, negate, ti1, ti0);
     negate = -bdytail;
     Two_Product(cdx, negate, tj1, tj0);
     Two_Two_Sum(ti1, ti0, tj1, tj0, v3, v[2], v[1], v[0]);
     v[3] = v3;
     bctlen = fast_expansion_sum_zeroelim(4, u, 4, v, bct);

     Two_Product(bdxtail, cdytail, ti1, ti0);
     Two_Product(cdxtail, bdytail, tj1, tj0);
     Two_Two_Diff(ti1, ti0, tj1, tj0, bctt3, bctt[2], bctt[1], bctt[0]);
     bctt[3] = bctt3;
     bcttlen = 4;
   } else {
     bct[0] = 0.0;
     bctlen = 1;
     bctt[0] = 0.0;
     bcttlen = 1;
   }

   if (adxtail != 0.0) {
     temp16alen = scale_expansion_zeroelim(axtbclen, axtbc, adxtail, temp16a);
     axtbctlen = scale_expansion_zeroelim(bctlen, bct, adxtail, axtbct);
     temp32alen = scale_expansion_zeroelim(axtbctlen, axtbct, 2.0 * adx,
                                           temp32a);
     temp48len = fast_expansion_sum_zeroelim(temp16alen, temp16a,
                                             temp32alen, temp32a, temp48);
     finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp48len,
                                             temp48, finother);
     finswap = finnow; finnow = finother; finother = finswap;
     if (bdytail != 0.0) {
       temp8len = scale_expansion_zeroelim(4, cc, adxtail, temp8);
       temp16alen = scale_expansion_zeroelim(temp8len, temp8, bdytail,
                                             temp16a);
       finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp16alen,
                                               temp16a, finother);
       finswap = finnow; finnow = finother; finother = finswap;
     }
     if (cdytail != 0.0) {
       temp8len = scale_expansion_zeroelim(4, bb, -adxtail, temp8);
       temp16alen = scale_expansion_zeroelim(temp8len, temp8, cdytail,
                                             temp16a);
       finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp16alen,
                                               temp16a, finother);
       finswap = finnow; finnow = finother; finother = finswap;
     }

     temp32alen = scale_expansion_zeroelim(axtbctlen, axtbct, adxtail,
                                           temp32a);
     axtbcttlen = scale_expansion_zeroelim(bcttlen, bctt, adxtail, axtbctt);
     temp16alen = scale_expansion_zeroelim(axtbcttlen, axtbctt, 2.0 * adx,
                                           temp16a);
     temp16blen = scale_expansion_zeroelim(axtbcttlen, axtbctt, adxtail,
                                           temp16b);
     temp32blen = fast_expansion_sum_zeroelim(temp16alen, temp16a,
                                             temp16blen, temp16b, temp32b);
     temp64len = fast_expansion_sum_zeroelim(temp32alen, temp32a,
                                             temp32blen, temp32b, temp64);
     finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp64len,
                                             temp64, finother);
     finswap = finnow; finnow = finother; finother = finswap;
   }
   if (adytail != 0.0) {
     temp16alen = scale_expansion_zeroelim(aytbclen, aytbc, adytail, temp16a);
     aytbctlen = scale_expansion_zeroelim(bctlen, bct, adytail, aytbct);
     temp32alen = scale_expansion_zeroelim(aytbctlen, aytbct, 2.0 * ady,
                                           temp32a);
     temp48len = fast_expansion_sum_zeroelim(temp16alen, temp16a,
                                             temp32alen, temp32a, temp48);
     finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp48len,
                                             temp48, finother);
     finswap = finnow; finnow = finother; finother = finswap;


     temp32alen = scale_expansion_zeroelim(aytbctlen, aytbct, adytail,
                                           temp32a);
     aytbcttlen = scale_expansion_zeroelim(bcttlen, bctt, adytail, aytbctt);
     temp16alen = scale_expansion_zeroelim(aytbcttlen, aytbctt, 2.0 * ady,
                                           temp16a);
     temp16blen = scale_expansion_zeroelim(aytbcttlen, aytbctt, adytail,
                                           temp16b);
     temp32blen = fast_expansion_sum_zeroelim(temp16alen, temp16a,
                                             temp16blen, temp16b, temp32b);
     temp64len = fast_expansion_sum_zeroelim(temp32alen, temp32a,
                                             temp32blen, temp32b, temp64);
     finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp64len,
                                             temp64, finother);
     finswap = finnow; finnow = finother; finother = finswap;
   }
 }
 if ((bdxtail != 0.0) || (bdytail != 0.0)) {
   if ((cdxtail != 0.0) || (cdytail != 0.0)
       || (adxtail != 0.0) || (adytail != 0.0)) {
     Two_Product(cdxtail, ady, ti1, ti0);
     Two_Product(cdx, adytail, tj1, tj0);
     Two_Two_Sum(ti1, ti0, tj1, tj0, u3, u[2], u[1], u[0]);
     u[3] = u3;
     negate = -cdy;
     Two_Product(adxtail, negate, ti1, ti0);
     negate = -cdytail;
     Two_Product(adx, negate, tj1, tj0);
     Two_Two_Sum(ti1, ti0, tj1, tj0, v3, v[2], v[1], v[0]);
     v[3] = v3;
     catlen = fast_expansion_sum_zeroelim(4, u, 4, v, cat);

     Two_Product(cdxtail, adytail, ti1, ti0);
     Two_Product(adxtail, cdytail, tj1, tj0);
     Two_Two_Diff(ti1, ti0, tj1, tj0, catt3, catt[2], catt[1], catt[0]);
     catt[3] = catt3;
     cattlen = 4;
   } else {
     cat[0] = 0.0;
     catlen = 1;
     catt[0] = 0.0;
     cattlen = 1;
   }

   if (bdxtail != 0.0) {
     temp16alen = scale_expansion_zeroelim(bxtcalen, bxtca, bdxtail, temp16a);
     bxtcatlen = scale_expansion_zeroelim(catlen, cat, bdxtail, bxtcat);
     temp32alen = scale_expansion_zeroelim(bxtcatlen, bxtcat, 2.0 * bdx,
                                           temp32a);
     temp48len = fast_expansion_sum_zeroelim(temp16alen, temp16a,
                                             temp32alen, temp32a, temp48);
     finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp48len,
                                             temp48, finother);
     finswap = finnow; finnow = finother; finother = finswap;
     if (cdytail != 0.0) {
       temp8len = scale_expansion_zeroelim(4, aa, bdxtail, temp8);
       temp16alen = scale_expansion_zeroelim(temp8len, temp8, cdytail,
                                             temp16a);
       finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp16alen,
                                               temp16a, finother);
       finswap = finnow; finnow = finother; finother = finswap;
     }
     if (adytail != 0.0) {
       temp8len = scale_expansion_zeroelim(4, cc, -bdxtail, temp8);
       temp16alen = scale_expansion_zeroelim(temp8len, temp8, adytail,
                                             temp16a);
       finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp16alen,
                                               temp16a, finother);
       finswap = finnow; finnow = finother; finother = finswap;
     }

     temp32alen = scale_expansion_zeroelim(bxtcatlen, bxtcat, bdxtail,
                                           temp32a);
     bxtcattlen = scale_expansion_zeroelim(cattlen, catt, bdxtail, bxtcatt);
     temp16alen = scale_expansion_zeroelim(bxtcattlen, bxtcatt, 2.0 * bdx,
                                           temp16a);
     temp16blen = scale_expansion_zeroelim(bxtcattlen, bxtcatt, bdxtail,
                                           temp16b);
     temp32blen = fast_expansion_sum_zeroelim(temp16alen, temp16a,
                                             temp16blen, temp16b, temp32b);
     temp64len = fast_expansion_sum_zeroelim(temp32alen, temp32a,
                                             temp32blen, temp32b, temp64);
     finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp64len,
                                             temp64, finother);
     finswap = finnow; finnow = finother; finother = finswap;
   }
   if (bdytail != 0.0) {
     temp16alen = scale_expansion_zeroelim(bytcalen, bytca, bdytail, temp16a);
     bytcatlen = scale_expansion_zeroelim(catlen, cat, bdytail, bytcat);
     temp32alen = scale_expansion_zeroelim(bytcatlen, bytcat, 2.0 * bdy,
                                           temp32a);
     temp48len = fast_expansion_sum_zeroelim(temp16alen, temp16a,
                                             temp32alen, temp32a, temp48);
     finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp48len,
                                             temp48, finother);
     finswap = finnow; finnow = finother; finother = finswap;


     temp32alen = scale_expansion_zeroelim(bytcatlen, bytcat, bdytail,
                                           temp32a);
     bytcattlen = scale_expansion_zeroelim(cattlen, catt, bdytail, bytcatt);
     temp16alen = scale_expansion_zeroelim(bytcattlen, bytcatt, 2.0 * bdy,
                                           temp16a);
     temp16blen = scale_expansion_zeroelim(bytcattlen, bytcatt, bdytail,
                                           temp16b);
     temp32blen = fast_expansion_sum_zeroelim(temp16alen, temp16a,
                                             temp16blen, temp16b, temp32b);
     temp64len = fast_expansion_sum_zeroelim(temp32alen, temp32a,
                                             temp32blen, temp32b, temp64);
     finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp64len,
                                             temp64, finother);
     finswap = finnow; finnow = finother; finother = finswap;
   }
 }
 if ((cdxtail != 0.0) || (cdytail != 0.0)) {
   if ((adxtail != 0.0) || (adytail != 0.0)
       || (bdxtail != 0.0) || (bdytail != 0.0)) {
     Two_Product(adxtail, bdy, ti1, ti0);
     Two_Product(adx, bdytail, tj1, tj0);
     Two_Two_Sum(ti1, ti0, tj1, tj0, u3, u[2], u[1], u[0]);
     u[3] = u3;
     negate = -ady;
     Two_Product(bdxtail, negate, ti1, ti0);
     negate = -adytail;
     Two_Product(bdx, negate, tj1, tj0);
     Two_Two_Sum(ti1, ti0, tj1, tj0, v3, v[2], v[1], v[0]);
     v[3] = v3;
     abtlen = fast_expansion_sum_zeroelim(4, u, 4, v, abt);

     Two_Product(adxtail, bdytail, ti1, ti0);
     Two_Product(bdxtail, adytail, tj1, tj0);
     Two_Two_Diff(ti1, ti0, tj1, tj0, abtt3, abtt[2], abtt[1], abtt[0]);
     abtt[3] = abtt3;
     abttlen = 4;
   } else {
     abt[0] = 0.0;
     abtlen = 1;
     abtt[0] = 0.0;
     abttlen = 1;
   }

   if (cdxtail != 0.0) {
     temp16alen = scale_expansion_zeroelim(cxtablen, cxtab, cdxtail, temp16a);
     cxtabtlen = scale_expansion_zeroelim(abtlen, abt, cdxtail, cxtabt);
     temp32alen = scale_expansion_zeroelim(cxtabtlen, cxtabt, 2.0 * cdx,
                                           temp32a);
     temp48len = fast_expansion_sum_zeroelim(temp16alen, temp16a,
                                             temp32alen, temp32a, temp48);
     finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp48len,
                                             temp48, finother);
     finswap = finnow; finnow = finother; finother = finswap;
     if (adytail != 0.0) {
       temp8len = scale_expansion_zeroelim(4, bb, cdxtail, temp8);
       temp16alen = scale_expansion_zeroelim(temp8len, temp8, adytail,
                                             temp16a);
       finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp16alen,
                                               temp16a, finother);
       finswap = finnow; finnow = finother; finother = finswap;
     }
     if (bdytail != 0.0) {
       temp8len = scale_expansion_zeroelim(4, aa, -cdxtail, temp8);
       temp16alen = scale_expansion_zeroelim(temp8len, temp8, bdytail,
                                             temp16a);
       finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp16alen,
                                               temp16a, finother);
       finswap = finnow; finnow = finother; finother = finswap;
     }

     temp32alen = scale_expansion_zeroelim(cxtabtlen, cxtabt, cdxtail,
                                           temp32a);
     cxtabttlen = scale_expansion_zeroelim(abttlen, abtt, cdxtail, cxtabtt);
     temp16alen = scale_expansion_zeroelim(cxtabttlen, cxtabtt, 2.0 * cdx,
                                           temp16a);
     temp16blen = scale_expansion_zeroelim(cxtabttlen, cxtabtt, cdxtail,
                                           temp16b);
     temp32blen = fast_expansion_sum_zeroelim(temp16alen, temp16a,
                                             temp16blen, temp16b, temp32b);
     temp64len = fast_expansion_sum_zeroelim(temp32alen, temp32a,
                                             temp32blen, temp32b, temp64);
     finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp64len,
                                             temp64, finother);
     finswap = finnow; finnow = finother; finother = finswap;
   }
   if (cdytail != 0.0) {
     temp16alen = scale_expansion_zeroelim(cytablen, cytab, cdytail, temp16a);
     cytabtlen = scale_expansion_zeroelim(abtlen, abt, cdytail, cytabt);
     temp32alen = scale_expansion_zeroelim(cytabtlen, cytabt, 2.0 * cdy,
                                           temp32a);
     temp48len = fast_expansion_sum_zeroelim(temp16alen, temp16a,
                                             temp32alen, temp32a, temp48);
     finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp48len,
                                             temp48, finother);
     finswap = finnow; finnow = finother; finother = finswap;


     temp32alen = scale_expansion_zeroelim(cytabtlen, cytabt, cdytail,
                                           temp32a);
     cytabttlen = scale_expansion_zeroelim(abttlen, abtt, cdytail, cytabtt);
     temp16alen = scale_expansion_zeroelim(cytabttlen, cytabtt, 2.0 * cdy,
                                           temp16a);
     temp16blen = scale_expansion_zeroelim(cytabttlen, cytabtt, cdytail,
                                           temp16b);
     temp32blen = fast_expansion_sum_zeroelim(temp16alen, temp16a,
                                             temp16blen, temp16b, temp32b);
     temp64len = fast_expansion_sum_zeroelim(temp32alen, temp32a,
                                             temp32blen, temp32b, temp64);
     finlength = fast_expansion_sum_zeroelim(finlength, finnow, temp64len,
                                             temp64, finother);
     finswap = finnow; finnow = finother; finother = finswap;
   }
 }

 return finnow[finlength - 1];
}

REAL incircle(const REAL *pa, const REAL *pb, const REAL *pc, const REAL *pd)
{
 REAL adx, bdx, cdx, ady, bdy, cdy;
 REAL bdxcdy, cdxbdy, cdxady, adxcdy, adxbdy, bdxady;
 REAL alift, blift, clift;
 REAL det;
 REAL permanent, errbound;
 REAL inc;

 FPU_ROUND_DOUBLE;

 adx = pa[0] - pd[0];
 bdx = pb[0] - pd[0];
 cdx = pc[0] - pd[0];
 ady = pa[1] - pd[1];
 bdy = pb[1] - pd[1];
 cdy = pc[1] - pd[1];

 bdxcdy = bdx * cdy;
 cdxbdy = cdx * bdy;
 alift = adx * adx + ady * ady;

 cdxady = cdx * ady;
 adxcdy = adx * cdy;
 blift = bdx * bdx + bdy * bdy;

 adxbdy = adx * bdy;
 bdxady = bdx * ady;
 clift = cdx * cdx + cdy * cdy;

 det = alift * (bdxcdy - cdxbdy)
     + blift * (cdxady - adxcdy)
     + clift * (adxbdy - bdxady);

 permanent = (Absolute(bdxcdy) + Absolute(cdxbdy)) * alift
           + (Absolute(cdxady) + Absolute(adxcdy)) * blift
           + (Absolute(adxbdy) + Absolute(bdxady)) * clift;
 errbound = iccerrboundA * permanent;
 if ((det > errbound) || (-det > errbound)) {
   FPU_RESTORE;
   return det;
 }

 inc = incircleadapt(pa, pb, pc, pd, permanent);
 FPU_RESTORE;
 return inc;
}

REAL incircle(REAL ax, REAL ay, REAL bx, REAL by, REAL cx, REAL cy, REAL dx,
             REAL dy)
{
 REAL adx, bdx, cdx, ady, bdy, cdy;
 REAL bdxcdy, cdxbdy, cdxady, adxcdy, adxbdy, bdxady;
 REAL alift, blift, clift;
 REAL det;
 REAL permanent, errbound;
 REAL inc;

 FPU_ROUND_DOUBLE;

 adx = ax - dx;
 bdx = bx - dx;
 cdx = cx - dx;
 ady = ay - dy;
 bdy = by - dy;
 cdy = cy - dy;

 bdxcdy = bdx * cdy;
 cdxbdy = cdx * bdy;
 alift = adx * adx + ady * ady;

 cdxady = cdx * ady;
 adxcdy = adx * cdy;
 blift = bdx * bdx + bdy * bdy;

 adxbdy = adx * bdy;
 bdxady = bdx * ady;
 clift = cdx * cdx + cdy * cdy;

 det = alift * (bdxcdy - cdxbdy)
     + blift * (cdxady - adxcdy)
     + clift * (adxbdy - bdxady);

 permanent = (Absolute(bdxcdy) + Absolute(cdxbdy)) * alift
           + (Absolute(cdxady) + Absolute(adxcdy)) * blift
           + (Absolute(adxbdy) + Absolute(bdxady)) * clift;
 errbound = iccerrboundA * permanent;
 if ((det > errbound) || (-det > errbound)) {
   FPU_RESTORE;
   return det;
 }

 REAL pa[]={ax,ay};
 REAL pb[]={bx,by};
 REAL pc[]={cx,cy};
 REAL pd[]={dx,dy};

 inc = incircleadapt(pa, pb, pc, pd, permanent);
 FPU_RESTORE;
 return inc;
}

/*****************************************************************************/
/*                                                                           */
/*  inspherefast()   Approximate 3D insphere test.  Nonrobust.               */
/*  insphereexact()   Exact 3D insphere test.  Robust.                       */
/*  insphereslow()   Another exact 3D insphere test.  Robust.                */
/*  insphere()   Adaptive exact 3D insphere test.  Robust.                   */
/*                                                                           */
/*               Return a positive value if the point pe lies inside the     */
/*               sphere passing through pa, pb, pc, and pd; a negative value */
/*               if it lies outside; and zero if the five points are         */
/*               cospherical.  The points pa, pb, pc, and pd must be ordered */
/*               so that they have a positive orientation (as defined by     */
/*               orient3d()), or the sign of the result will be reversed.    */
/*                                                                           */
/*  Only the first and last routine should be used; the middle two are for   */
/*  timings.                                                                 */
/*                                                                           */
/*  The last three use exact arithmetic to ensure a correct answer.  The     */
/*  result returned is the determinant of a matrix.  In insphere() only,     */
/*  this determinant is computed adaptively, in the sense that exact         */
/*  arithmetic is used only to the degree it is needed to ensure that the    */
/*  returned value has the correct sign.  Hence, insphere() is usually quite */
/*  fast, but will run more slowly when the input points are cospherical or  */
/*  nearly so.                                                               */
/*                                                                           */
/*****************************************************************************/

static REAL insphereexact(const REAL *pa, const REAL *pb, const REAL *pc, const REAL *pd, const REAL *pe)
{
 INEXACT REAL axby1, bxcy1, cxdy1, dxey1, exay1;
 INEXACT REAL bxay1, cxby1, dxcy1, exdy1, axey1;
 INEXACT REAL axcy1, bxdy1, cxey1, dxay1, exby1;
 INEXACT REAL cxay1, dxby1, excy1, axdy1, bxey1;
 REAL axby0, bxcy0, cxdy0, dxey0, exay0;
 REAL bxay0, cxby0, dxcy0, exdy0, axey0;
 REAL axcy0, bxdy0, cxey0, dxay0, exby0;
 REAL cxay0, dxby0, excy0, axdy0, bxey0;
 REAL ab[4], bc[4], cd[4], de[4], ea[4];
 REAL ac[4], bd[4], ce[4], da[4], eb[4];
 REAL temp8a[8], temp8b[8], temp16[16];
 int temp8alen, temp8blen, temp16len;
 REAL abc[24], bcd[24], cde[24], dea[24], eab[24];
 REAL abd[24], bce[24], cda[24], deb[24], eac[24];
 int abclen, bcdlen, cdelen, dealen, eablen;
 int abdlen, bcelen, cdalen, deblen, eaclen;
 REAL temp48a[48], temp48b[48];
 int temp48alen, temp48blen;
 REAL abcd[96], bcde[96], cdea[96], deab[96], eabc[96];
 int abcdlen, bcdelen, cdealen, deablen, eabclen;
 REAL temp192[192];
 REAL det384x[384], det384y[384], det384z[384];
 int xlen, ylen, zlen;
 REAL detxy[768];
 int xylen;
 REAL adet[1152], bdet[1152], cdet[1152], ddet[1152], edet[1152];
 int alen, blen, clen, dlen, elen;
 REAL abdet[2304], cddet[2304], cdedet[3456];
 int ablen, cdlen;
 REAL deter[5760];
 int deterlen;
 int i;

 INEXACT REAL bvirt;
 REAL avirt, bround, around;
 INEXACT REAL c;
 INEXACT REAL abig;
 REAL ahi, alo, bhi, blo;
 REAL err1, err2, err3;
 INEXACT REAL _i, _j;
 REAL _0;

 Two_Product(pa[0], pb[1], axby1, axby0);
 Two_Product(pb[0], pa[1], bxay1, bxay0);
 Two_Two_Diff(axby1, axby0, bxay1, bxay0, ab[3], ab[2], ab[1], ab[0]);

 Two_Product(pb[0], pc[1], bxcy1, bxcy0);
 Two_Product(pc[0], pb[1], cxby1, cxby0);
 Two_Two_Diff(bxcy1, bxcy0, cxby1, cxby0, bc[3], bc[2], bc[1], bc[0]);

 Two_Product(pc[0], pd[1], cxdy1, cxdy0);
 Two_Product(pd[0], pc[1], dxcy1, dxcy0);
 Two_Two_Diff(cxdy1, cxdy0, dxcy1, dxcy0, cd[3], cd[2], cd[1], cd[0]);

 Two_Product(pd[0], pe[1], dxey1, dxey0);
 Two_Product(pe[0], pd[1], exdy1, exdy0);
 Two_Two_Diff(dxey1, dxey0, exdy1, exdy0, de[3], de[2], de[1], de[0]);

 Two_Product(pe[0], pa[1], exay1, exay0);
 Two_Product(pa[0], pe[1], axey1, axey0);
 Two_Two_Diff(exay1, exay0, axey1, axey0, ea[3], ea[2], ea[1], ea[0]);

 Two_Product(pa[0], pc[1], axcy1, axcy0);
 Two_Product(pc[0], pa[1], cxay1, cxay0);
 Two_Two_Diff(axcy1, axcy0, cxay1, cxay0, ac[3], ac[2], ac[1], ac[0]);

 Two_Product(pb[0], pd[1], bxdy1, bxdy0);
 Two_Product(pd[0], pb[1], dxby1, dxby0);
 Two_Two_Diff(bxdy1, bxdy0, dxby1, dxby0, bd[3], bd[2], bd[1], bd[0]);

 Two_Product(pc[0], pe[1], cxey1, cxey0);
 Two_Product(pe[0], pc[1], excy1, excy0);
 Two_Two_Diff(cxey1, cxey0, excy1, excy0, ce[3], ce[2], ce[1], ce[0]);

 Two_Product(pd[0], pa[1], dxay1, dxay0);
 Two_Product(pa[0], pd[1], axdy1, axdy0);
 Two_Two_Diff(dxay1, dxay0, axdy1, axdy0, da[3], da[2], da[1], da[0]);

 Two_Product(pe[0], pb[1], exby1, exby0);
 Two_Product(pb[0], pe[1], bxey1, bxey0);
 Two_Two_Diff(exby1, exby0, bxey1, bxey0, eb[3], eb[2], eb[1], eb[0]);

 temp8alen = scale_expansion_zeroelim(4, bc, pa[2], temp8a);
 temp8blen = scale_expansion_zeroelim(4, ac, -pb[2], temp8b);
 temp16len = fast_expansion_sum_zeroelim(temp8alen, temp8a, temp8blen, temp8b,
                                         temp16);
 temp8alen = scale_expansion_zeroelim(4, ab, pc[2], temp8a);
 abclen = fast_expansion_sum_zeroelim(temp8alen, temp8a, temp16len, temp16,
                                      abc);

 temp8alen = scale_expansion_zeroelim(4, cd, pb[2], temp8a);
 temp8blen = scale_expansion_zeroelim(4, bd, -pc[2], temp8b);
 temp16len = fast_expansion_sum_zeroelim(temp8alen, temp8a, temp8blen, temp8b,
                                         temp16);
 temp8alen = scale_expansion_zeroelim(4, bc, pd[2], temp8a);
 bcdlen = fast_expansion_sum_zeroelim(temp8alen, temp8a, temp16len, temp16,
                                      bcd);

 temp8alen = scale_expansion_zeroelim(4, de, pc[2], temp8a);
 temp8blen = scale_expansion_zeroelim(4, ce, -pd[2], temp8b);
 temp16len = fast_expansion_sum_zeroelim(temp8alen, temp8a, temp8blen, temp8b,
                                         temp16);
 temp8alen = scale_expansion_zeroelim(4, cd, pe[2], temp8a);
 cdelen = fast_expansion_sum_zeroelim(temp8alen, temp8a, temp16len, temp16,
                                      cde);

 temp8alen = scale_expansion_zeroelim(4, ea, pd[2], temp8a);
 temp8blen = scale_expansion_zeroelim(4, da, -pe[2], temp8b);
 temp16len = fast_expansion_sum_zeroelim(temp8alen, temp8a, temp8blen, temp8b,
                                         temp16);
 temp8alen = scale_expansion_zeroelim(4, de, pa[2], temp8a);
 dealen = fast_expansion_sum_zeroelim(temp8alen, temp8a, temp16len, temp16,
                                      dea);

 temp8alen = scale_expansion_zeroelim(4, ab, pe[2], temp8a);
 temp8blen = scale_expansion_zeroelim(4, eb, -pa[2], temp8b);
 temp16len = fast_expansion_sum_zeroelim(temp8alen, temp8a, temp8blen, temp8b,
                                         temp16);
 temp8alen = scale_expansion_zeroelim(4, ea, pb[2], temp8a);
 eablen = fast_expansion_sum_zeroelim(temp8alen, temp8a, temp16len, temp16,
                                      eab);

 temp8alen = scale_expansion_zeroelim(4, bd, pa[2], temp8a);
 temp8blen = scale_expansion_zeroelim(4, da, pb[2], temp8b);
 temp16len = fast_expansion_sum_zeroelim(temp8alen, temp8a, temp8blen, temp8b,
                                         temp16);
 temp8alen = scale_expansion_zeroelim(4, ab, pd[2], temp8a);
 abdlen = fast_expansion_sum_zeroelim(temp8alen, temp8a, temp16len, temp16,
                                      abd);

 temp8alen = scale_expansion_zeroelim(4, ce, pb[2], temp8a);
 temp8blen = scale_expansion_zeroelim(4, eb, pc[2], temp8b);
 temp16len = fast_expansion_sum_zeroelim(temp8alen, temp8a, temp8blen, temp8b,
                                         temp16);
 temp8alen = scale_expansion_zeroelim(4, bc, pe[2], temp8a);
 bcelen = fast_expansion_sum_zeroelim(temp8alen, temp8a, temp16len, temp16,
                                      bce);

 temp8alen = scale_expansion_zeroelim(4, da, pc[2], temp8a);
 temp8blen = scale_expansion_zeroelim(4, ac, pd[2], temp8b);
 temp16len = fast_expansion_sum_zeroelim(temp8alen, temp8a, temp8blen, temp8b,
                                         temp16);
 temp8alen = scale_expansion_zeroelim(4, cd, pa[2], temp8a);
 cdalen = fast_expansion_sum_zeroelim(temp8alen, temp8a, temp16len, temp16,
                                      cda);

 temp8alen = scale_expansion_zeroelim(4, eb, pd[2], temp8a);
 temp8blen = scale_expansion_zeroelim(4, bd, pe[2], temp8b);
 temp16len = fast_expansion_sum_zeroelim(temp8alen, temp8a, temp8blen, temp8b,
                                         temp16);
 temp8alen = scale_expansion_zeroelim(4, de, pb[2], temp8a);
 deblen = fast_expansion_sum_zeroelim(temp8alen, temp8a, temp16len, temp16,
                                      deb);

 temp8alen = scale_expansion_zeroelim(4, ac, pe[2], temp8a);
 temp8blen = scale_expansion_zeroelim(4, ce, pa[2], temp8b);
 temp16len = fast_expansion_sum_zeroelim(temp8alen, temp8a, temp8blen, temp8b,
                                         temp16);
 temp8alen = scale_expansion_zeroelim(4, ea, pc[2], temp8a);
 eaclen = fast_expansion_sum_zeroelim(temp8alen, temp8a, temp16len, temp16,
                                      eac);

 temp48alen = fast_expansion_sum_zeroelim(cdelen, cde, bcelen, bce, temp48a);
 temp48blen = fast_expansion_sum_zeroelim(deblen, deb, bcdlen, bcd, temp48b);
 for (i = 0; i < temp48blen; i++) {
   temp48b[i] = -temp48b[i];
 }
 bcdelen = fast_expansion_sum_zeroelim(temp48alen, temp48a,
                                       temp48blen, temp48b, bcde);
 xlen = scale_expansion_zeroelim(bcdelen, bcde, pa[0], temp192);
 xlen = scale_expansion_zeroelim(xlen, temp192, pa[0], det384x);
 ylen = scale_expansion_zeroelim(bcdelen, bcde, pa[1], temp192);
 ylen = scale_expansion_zeroelim(ylen, temp192, pa[1], det384y);
 zlen = scale_expansion_zeroelim(bcdelen, bcde, pa[2], temp192);
 zlen = scale_expansion_zeroelim(zlen, temp192, pa[2], det384z);
 xylen = fast_expansion_sum_zeroelim(xlen, det384x, ylen, det384y, detxy);
 alen = fast_expansion_sum_zeroelim(xylen, detxy, zlen, det384z, adet);

 temp48alen = fast_expansion_sum_zeroelim(dealen, dea, cdalen, cda, temp48a);
 temp48blen = fast_expansion_sum_zeroelim(eaclen, eac, cdelen, cde, temp48b);
 for (i = 0; i < temp48blen; i++) {
   temp48b[i] = -temp48b[i];
 }
 cdealen = fast_expansion_sum_zeroelim(temp48alen, temp48a,
                                       temp48blen, temp48b, cdea);
 xlen = scale_expansion_zeroelim(cdealen, cdea, pb[0], temp192);
 xlen = scale_expansion_zeroelim(xlen, temp192, pb[0], det384x);
 ylen = scale_expansion_zeroelim(cdealen, cdea, pb[1], temp192);
 ylen = scale_expansion_zeroelim(ylen, temp192, pb[1], det384y);
 zlen = scale_expansion_zeroelim(cdealen, cdea, pb[2], temp192);
 zlen = scale_expansion_zeroelim(zlen, temp192, pb[2], det384z);
 xylen = fast_expansion_sum_zeroelim(xlen, det384x, ylen, det384y, detxy);
 blen = fast_expansion_sum_zeroelim(xylen, detxy, zlen, det384z, bdet);

 temp48alen = fast_expansion_sum_zeroelim(eablen, eab, deblen, deb, temp48a);
 temp48blen = fast_expansion_sum_zeroelim(abdlen, abd, dealen, dea, temp48b);
 for (i = 0; i < temp48blen; i++) {
   temp48b[i] = -temp48b[i];
 }
 deablen = fast_expansion_sum_zeroelim(temp48alen, temp48a,
                                       temp48blen, temp48b, deab);
 xlen = scale_expansion_zeroelim(deablen, deab, pc[0], temp192);
 xlen = scale_expansion_zeroelim(xlen, temp192, pc[0], det384x);
 ylen = scale_expansion_zeroelim(deablen, deab, pc[1], temp192);
 ylen = scale_expansion_zeroelim(ylen, temp192, pc[1], det384y);
 zlen = scale_expansion_zeroelim(deablen, deab, pc[2], temp192);
 zlen = scale_expansion_zeroelim(zlen, temp192, pc[2], det384z);
 xylen = fast_expansion_sum_zeroelim(xlen, det384x, ylen, det384y, detxy);
 clen = fast_expansion_sum_zeroelim(xylen, detxy, zlen, det384z, cdet);

 temp48alen = fast_expansion_sum_zeroelim(abclen, abc, eaclen, eac, temp48a);
 temp48blen = fast_expansion_sum_zeroelim(bcelen, bce, eablen, eab, temp48b);
 for (i = 0; i < temp48blen; i++) {
   temp48b[i] = -temp48b[i];
 }
 eabclen = fast_expansion_sum_zeroelim(temp48alen, temp48a,
                                       temp48blen, temp48b, eabc);
 xlen = scale_expansion_zeroelim(eabclen, eabc, pd[0], temp192);
 xlen = scale_expansion_zeroelim(xlen, temp192, pd[0], det384x);
 ylen = scale_expansion_zeroelim(eabclen, eabc, pd[1], temp192);
 ylen = scale_expansion_zeroelim(ylen, temp192, pd[1], det384y);
 zlen = scale_expansion_zeroelim(eabclen, eabc, pd[2], temp192);
 zlen = scale_expansion_zeroelim(zlen, temp192, pd[2], det384z);
 xylen = fast_expansion_sum_zeroelim(xlen, det384x, ylen, det384y, detxy);
 dlen = fast_expansion_sum_zeroelim(xylen, detxy, zlen, det384z, ddet);

 temp48alen = fast_expansion_sum_zeroelim(bcdlen, bcd, abdlen, abd, temp48a);
 temp48blen = fast_expansion_sum_zeroelim(cdalen, cda, abclen, abc, temp48b);
 for (i = 0; i < temp48blen; i++) {
   temp48b[i] = -temp48b[i];
 }
 abcdlen = fast_expansion_sum_zeroelim(temp48alen, temp48a,
                                       temp48blen, temp48b, abcd);
 xlen = scale_expansion_zeroelim(abcdlen, abcd, pe[0], temp192);
 xlen = scale_expansion_zeroelim(xlen, temp192, pe[0], det384x);
 ylen = scale_expansion_zeroelim(abcdlen, abcd, pe[1], temp192);
 ylen = scale_expansion_zeroelim(ylen, temp192, pe[1], det384y);
 zlen = scale_expansion_zeroelim(abcdlen, abcd, pe[2], temp192);
 zlen = scale_expansion_zeroelim(zlen, temp192, pe[2], det384z);
 xylen = fast_expansion_sum_zeroelim(xlen, det384x, ylen, det384y, detxy);
 elen = fast_expansion_sum_zeroelim(xylen, detxy, zlen, det384z, edet);

 ablen = fast_expansion_sum_zeroelim(alen, adet, blen, bdet, abdet);
 cdlen = fast_expansion_sum_zeroelim(clen, cdet, dlen, ddet, cddet);
 cdelen = fast_expansion_sum_zeroelim(cdlen, cddet, elen, edet, cdedet);
 deterlen = fast_expansion_sum_zeroelim(ablen, abdet, cdelen, cdedet, deter);

 return deter[deterlen - 1];
}

static REAL insphereadapt(const REAL *pa, const REAL *pb, const REAL *pc, const REAL *pd, const REAL *pe,
                         REAL permanent)
{
 INEXACT REAL aex, bex, cex, dex, aey, bey, cey, dey, aez, bez, cez, dez;
 REAL det, errbound;

 INEXACT REAL aexbey1, bexaey1, bexcey1, cexbey1;
 INEXACT REAL cexdey1, dexcey1, dexaey1, aexdey1;
 INEXACT REAL aexcey1, cexaey1, bexdey1, dexbey1;
 REAL aexbey0, bexaey0, bexcey0, cexbey0;
 REAL cexdey0, dexcey0, dexaey0, aexdey0;
 REAL aexcey0, cexaey0, bexdey0, dexbey0;
 REAL ab[4], bc[4], cd[4], da[4], ac[4], bd[4];
 INEXACT REAL ab3, bc3, cd3, da3, ac3, bd3;
 REAL abeps, bceps, cdeps, daeps, aceps, bdeps;
 REAL temp8a[8], temp8b[8], temp8c[8], temp16[16], temp24[24], temp48[48];
 int temp8alen, temp8blen, temp8clen, temp16len, temp24len, temp48len;
 REAL xdet[96], ydet[96], zdet[96], xydet[192];
 int xlen, ylen, zlen, xylen;
 REAL adet[288], bdet[288], cdet[288], ddet[288];
 int alen, blen, clen, dlen;
 REAL abdet[576], cddet[576];
 int ablen, cdlen;
 REAL fin1[1152];
 int finlength;

 REAL aextail, bextail, cextail, dextail;
 REAL aeytail, beytail, ceytail, deytail;
 REAL aeztail, beztail, ceztail, deztail;

 INEXACT REAL bvirt;
 REAL avirt, bround, around;
 INEXACT REAL c;
 INEXACT REAL abig;
 REAL ahi, alo, bhi, blo;
 REAL err1, err2, err3;
 INEXACT REAL _i, _j;
 REAL _0;

 aex = (REAL) (pa[0] - pe[0]);
 bex = (REAL) (pb[0] - pe[0]);
 cex = (REAL) (pc[0] - pe[0]);
 dex = (REAL) (pd[0] - pe[0]);
 aey = (REAL) (pa[1] - pe[1]);
 bey = (REAL) (pb[1] - pe[1]);
 cey = (REAL) (pc[1] - pe[1]);
 dey = (REAL) (pd[1] - pe[1]);
 aez = (REAL) (pa[2] - pe[2]);
 bez = (REAL) (pb[2] - pe[2]);
 cez = (REAL) (pc[2] - pe[2]);
 dez = (REAL) (pd[2] - pe[2]);

 Two_Product(aex, bey, aexbey1, aexbey0);
 Two_Product(bex, aey, bexaey1, bexaey0);
 Two_Two_Diff(aexbey1, aexbey0, bexaey1, bexaey0, ab3, ab[2], ab[1], ab[0]);
 ab[3] = ab3;

 Two_Product(bex, cey, bexcey1, bexcey0);
 Two_Product(cex, bey, cexbey1, cexbey0);
 Two_Two_Diff(bexcey1, bexcey0, cexbey1, cexbey0, bc3, bc[2], bc[1], bc[0]);
 bc[3] = bc3;

 Two_Product(cex, dey, cexdey1, cexdey0);
 Two_Product(dex, cey, dexcey1, dexcey0);
 Two_Two_Diff(cexdey1, cexdey0, dexcey1, dexcey0, cd3, cd[2], cd[1], cd[0]);
 cd[3] = cd3;

 Two_Product(dex, aey, dexaey1, dexaey0);
 Two_Product(aex, dey, aexdey1, aexdey0);
 Two_Two_Diff(dexaey1, dexaey0, aexdey1, aexdey0, da3, da[2], da[1], da[0]);
 da[3] = da3;

 Two_Product(aex, cey, aexcey1, aexcey0);
 Two_Product(cex, aey, cexaey1, cexaey0);
 Two_Two_Diff(aexcey1, aexcey0, cexaey1, cexaey0, ac3, ac[2], ac[1], ac[0]);
 ac[3] = ac3;

 Two_Product(bex, dey, bexdey1, bexdey0);
 Two_Product(dex, bey, dexbey1, dexbey0);
 Two_Two_Diff(bexdey1, bexdey0, dexbey1, dexbey0, bd3, bd[2], bd[1], bd[0]);
 bd[3] = bd3;

 temp8alen = scale_expansion_zeroelim(4, cd, bez, temp8a);
 temp8blen = scale_expansion_zeroelim(4, bd, -cez, temp8b);
 temp8clen = scale_expansion_zeroelim(4, bc, dez, temp8c);
 temp16len = fast_expansion_sum_zeroelim(temp8alen, temp8a,
                                         temp8blen, temp8b, temp16);
 temp24len = fast_expansion_sum_zeroelim(temp8clen, temp8c,
                                         temp16len, temp16, temp24);
 temp48len = scale_expansion_zeroelim(temp24len, temp24, aex, temp48);
 xlen = scale_expansion_zeroelim(temp48len, temp48, -aex, xdet);
 temp48len = scale_expansion_zeroelim(temp24len, temp24, aey, temp48);
 ylen = scale_expansion_zeroelim(temp48len, temp48, -aey, ydet);
 temp48len = scale_expansion_zeroelim(temp24len, temp24, aez, temp48);
 zlen = scale_expansion_zeroelim(temp48len, temp48, -aez, zdet);
 xylen = fast_expansion_sum_zeroelim(xlen, xdet, ylen, ydet, xydet);
 alen = fast_expansion_sum_zeroelim(xylen, xydet, zlen, zdet, adet);

 temp8alen = scale_expansion_zeroelim(4, da, cez, temp8a);
 temp8blen = scale_expansion_zeroelim(4, ac, dez, temp8b);
 temp8clen = scale_expansion_zeroelim(4, cd, aez, temp8c);
 temp16len = fast_expansion_sum_zeroelim(temp8alen, temp8a,
                                         temp8blen, temp8b, temp16);
 temp24len = fast_expansion_sum_zeroelim(temp8clen, temp8c,
                                         temp16len, temp16, temp24);
 temp48len = scale_expansion_zeroelim(temp24len, temp24, bex, temp48);
 xlen = scale_expansion_zeroelim(temp48len, temp48, bex, xdet);
 temp48len = scale_expansion_zeroelim(temp24len, temp24, bey, temp48);
 ylen = scale_expansion_zeroelim(temp48len, temp48, bey, ydet);
 temp48len = scale_expansion_zeroelim(temp24len, temp24, bez, temp48);
 zlen = scale_expansion_zeroelim(temp48len, temp48, bez, zdet);
 xylen = fast_expansion_sum_zeroelim(xlen, xdet, ylen, ydet, xydet);
 blen = fast_expansion_sum_zeroelim(xylen, xydet, zlen, zdet, bdet);

 temp8alen = scale_expansion_zeroelim(4, ab, dez, temp8a);
 temp8blen = scale_expansion_zeroelim(4, bd, aez, temp8b);
 temp8clen = scale_expansion_zeroelim(4, da, bez, temp8c);
 temp16len = fast_expansion_sum_zeroelim(temp8alen, temp8a,
                                         temp8blen, temp8b, temp16);
 temp24len = fast_expansion_sum_zeroelim(temp8clen, temp8c,
                                         temp16len, temp16, temp24);
 temp48len = scale_expansion_zeroelim(temp24len, temp24, cex, temp48);
 xlen = scale_expansion_zeroelim(temp48len, temp48, -cex, xdet);
 temp48len = scale_expansion_zeroelim(temp24len, temp24, cey, temp48);
 ylen = scale_expansion_zeroelim(temp48len, temp48, -cey, ydet);
 temp48len = scale_expansion_zeroelim(temp24len, temp24, cez, temp48);
 zlen = scale_expansion_zeroelim(temp48len, temp48, -cez, zdet);
 xylen = fast_expansion_sum_zeroelim(xlen, xdet, ylen, ydet, xydet);
 clen = fast_expansion_sum_zeroelim(xylen, xydet, zlen, zdet, cdet);

 temp8alen = scale_expansion_zeroelim(4, bc, aez, temp8a);
 temp8blen = scale_expansion_zeroelim(4, ac, -bez, temp8b);
 temp8clen = scale_expansion_zeroelim(4, ab, cez, temp8c);
 temp16len = fast_expansion_sum_zeroelim(temp8alen, temp8a,
                                         temp8blen, temp8b, temp16);
 temp24len = fast_expansion_sum_zeroelim(temp8clen, temp8c,
                                         temp16len, temp16, temp24);
 temp48len = scale_expansion_zeroelim(temp24len, temp24, dex, temp48);
 xlen = scale_expansion_zeroelim(temp48len, temp48, dex, xdet);
 temp48len = scale_expansion_zeroelim(temp24len, temp24, dey, temp48);
 ylen = scale_expansion_zeroelim(temp48len, temp48, dey, ydet);
 temp48len = scale_expansion_zeroelim(temp24len, temp24, dez, temp48);
 zlen = scale_expansion_zeroelim(temp48len, temp48, dez, zdet);
 xylen = fast_expansion_sum_zeroelim(xlen, xdet, ylen, ydet, xydet);
 dlen = fast_expansion_sum_zeroelim(xylen, xydet, zlen, zdet, ddet);

 ablen = fast_expansion_sum_zeroelim(alen, adet, blen, bdet, abdet);
 cdlen = fast_expansion_sum_zeroelim(clen, cdet, dlen, ddet, cddet);
 finlength = fast_expansion_sum_zeroelim(ablen, abdet, cdlen, cddet, fin1);

 det = estimate(finlength, fin1);
 errbound = isperrboundB * permanent;
 if ((det >= errbound) || (-det >= errbound)) {
   return det;
 }

 Two_Diff_Tail(pa[0], pe[0], aex, aextail);
 Two_Diff_Tail(pa[1], pe[1], aey, aeytail);
 Two_Diff_Tail(pa[2], pe[2], aez, aeztail);
 Two_Diff_Tail(pb[0], pe[0], bex, bextail);
 Two_Diff_Tail(pb[1], pe[1], bey, beytail);
 Two_Diff_Tail(pb[2], pe[2], bez, beztail);
 Two_Diff_Tail(pc[0], pe[0], cex, cextail);
 Two_Diff_Tail(pc[1], pe[1], cey, ceytail);
 Two_Diff_Tail(pc[2], pe[2], cez, ceztail);
 Two_Diff_Tail(pd[0], pe[0], dex, dextail);
 Two_Diff_Tail(pd[1], pe[1], dey, deytail);
 Two_Diff_Tail(pd[2], pe[2], dez, deztail);
 if ((aextail == 0.0) && (aeytail == 0.0) && (aeztail == 0.0)
     && (bextail == 0.0) && (beytail == 0.0) && (beztail == 0.0)
     && (cextail == 0.0) && (ceytail == 0.0) && (ceztail == 0.0)
     && (dextail == 0.0) && (deytail == 0.0) && (deztail == 0.0)) {
   return det;
 }

 errbound = isperrboundC * permanent + resulterrbound * Absolute(det);
 abeps = (aex * beytail + bey * aextail)
       - (aey * bextail + bex * aeytail);
 bceps = (bex * ceytail + cey * bextail)
       - (bey * cextail + cex * beytail);
 cdeps = (cex * deytail + dey * cextail)
       - (cey * dextail + dex * ceytail);
 daeps = (dex * aeytail + aey * dextail)
       - (dey * aextail + aex * deytail);
 aceps = (aex * ceytail + cey * aextail)
       - (aey * cextail + cex * aeytail);
 bdeps = (bex * deytail + dey * bextail)
       - (bey * dextail + dex * beytail);
 det += (((bex * bex + bey * bey + bez * bez)
          * ((cez * daeps + dez * aceps + aez * cdeps)
             + (ceztail * da3 + deztail * ac3 + aeztail * cd3))
          + (dex * dex + dey * dey + dez * dez)
          * ((aez * bceps - bez * aceps + cez * abeps)
             + (aeztail * bc3 - beztail * ac3 + ceztail * ab3)))
         - ((aex * aex + aey * aey + aez * aez)
          * ((bez * cdeps - cez * bdeps + dez * bceps)
             + (beztail * cd3 - ceztail * bd3 + deztail * bc3))
          + (cex * cex + cey * cey + cez * cez)
          * ((dez * abeps + aez * bdeps + bez * daeps)
             + (deztail * ab3 + aeztail * bd3 + beztail * da3))))
      + 2.0 * (((bex * bextail + bey * beytail + bez * beztail)
                * (cez * da3 + dez * ac3 + aez * cd3)
                + (dex * dextail + dey * deytail + dez * deztail)
                * (aez * bc3 - bez * ac3 + cez * ab3))
               - ((aex * aextail + aey * aeytail + aez * aeztail)
                * (bez * cd3 - cez * bd3 + dez * bc3)
                + (cex * cextail + cey * ceytail + cez * ceztail)
                * (dez * ab3 + aez * bd3 + bez * da3)));
 if ((det >= errbound) || (-det >= errbound)) {
   return det;
 }

 return insphereexact(pa, pb, pc, pd, pe);
}

REAL insphere(const REAL *pa, const REAL *pb, const REAL *pc, const REAL *pd, const REAL *pe)
{
 REAL aex, bex, cex, dex;
 REAL aey, bey, cey, dey;
 REAL aez, bez, cez, dez;
 REAL aexbey, bexaey, bexcey, cexbey, cexdey, dexcey, dexaey, aexdey;
 REAL aexcey, cexaey, bexdey, dexbey;
 REAL alift, blift, clift, dlift;
 REAL ab, bc, cd, da, ac, bd;
 REAL abc, bcd, cda, dab;
 REAL aezplus, bezplus, cezplus, dezplus;
 REAL aexbeyplus, bexaeyplus, bexceyplus, cexbeyplus;
 REAL cexdeyplus, dexceyplus, dexaeyplus, aexdeyplus;
 REAL aexceyplus, cexaeyplus, bexdeyplus, dexbeyplus;
 REAL det;
 REAL permanent, errbound;
 REAL ins;

 FPU_ROUND_DOUBLE;

 aex = pa[0] - pe[0];
 bex = pb[0] - pe[0];
 cex = pc[0] - pe[0];
 dex = pd[0] - pe[0];
 aey = pa[1] - pe[1];
 bey = pb[1] - pe[1];
 cey = pc[1] - pe[1];
 dey = pd[1] - pe[1];
 aez = pa[2] - pe[2];
 bez = pb[2] - pe[2];
 cez = pc[2] - pe[2];
 dez = pd[2] - pe[2];

 aexbey = aex * bey;
 bexaey = bex * aey;
 ab = aexbey - bexaey;
 bexcey = bex * cey;
 cexbey = cex * bey;
 bc = bexcey - cexbey;
 cexdey = cex * dey;
 dexcey = dex * cey;
 cd = cexdey - dexcey;
 dexaey = dex * aey;
 aexdey = aex * dey;
 da = dexaey - aexdey;

 aexcey = aex * cey;
 cexaey = cex * aey;
 ac = aexcey - cexaey;
 bexdey = bex * dey;
 dexbey = dex * bey;
 bd = bexdey - dexbey;

 abc = aez * bc - bez * ac + cez * ab;
 bcd = bez * cd - cez * bd + dez * bc;
 cda = cez * da + dez * ac + aez * cd;
 dab = dez * ab + aez * bd + bez * da;

 alift = aex * aex + aey * aey + aez * aez;
 blift = bex * bex + bey * bey + bez * bez;
 clift = cex * cex + cey * cey + cez * cez;
 dlift = dex * dex + dey * dey + dez * dez;

 det = (dlift * abc - clift * dab) + (blift * cda - alift * bcd);

 aezplus = Absolute(aez);
 bezplus = Absolute(bez);
 cezplus = Absolute(cez);
 dezplus = Absolute(dez);
 aexbeyplus = Absolute(aexbey);
 bexaeyplus = Absolute(bexaey);
 bexceyplus = Absolute(bexcey);
 cexbeyplus = Absolute(cexbey);
 cexdeyplus = Absolute(cexdey);
 dexceyplus = Absolute(dexcey);
 dexaeyplus = Absolute(dexaey);
 aexdeyplus = Absolute(aexdey);
 aexceyplus = Absolute(aexcey);
 cexaeyplus = Absolute(cexaey);
 bexdeyplus = Absolute(bexdey);
 dexbeyplus = Absolute(dexbey);
 permanent = ((cexdeyplus + dexceyplus) * bezplus
              + (dexbeyplus + bexdeyplus) * cezplus
              + (bexceyplus + cexbeyplus) * dezplus)
           * alift
           + ((dexaeyplus + aexdeyplus) * cezplus
              + (aexceyplus + cexaeyplus) * dezplus
              + (cexdeyplus + dexceyplus) * aezplus)
           * blift
           + ((aexbeyplus + bexaeyplus) * dezplus
              + (bexdeyplus + dexbeyplus) * aezplus
              + (dexaeyplus + aexdeyplus) * bezplus)
           * clift
           + ((bexceyplus + cexbeyplus) * aezplus
              + (cexaeyplus + aexceyplus) * bezplus
              + (aexbeyplus + bexaeyplus) * cezplus)
           * dlift;
 errbound = isperrboundA * permanent;
 if ((det > errbound) || (-det > errbound)) {
   FPU_RESTORE;
   return det;
 }

 ins = insphereadapt(pa, pb, pc, pd, pe, permanent);
 FPU_RESTORE;
 return ins;
}