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\" from: @(#)erf.3 6.4 (Berkeley) 4/20/91
\" $NetBSD: erf.3,v 1.14 2015/11/07 18:17:51 nros Exp $
\"
Dd November 7, 2015
Dt ERF 3
Os
Sh NAME
Nm erf ,
Nm erff ,
Nm erfl ,
Nm erfc ,
Nm erfcf ,
Nm erfcl
Nd error function operators
Sh LIBRARY
Lb libm
Sh SYNOPSIS
In math.h
Ft double
Fn erf "double x"
Ft float
Fn erff "float x"
Ft long double
Fn erfl "long double x"
Ft double
Fn erfc "double x"
Ft float
Fn erfcf "float x"
Ft long double
Fn erfcl "long double x"
Sh DESCRIPTION
These functions calculate the error function of
Fa x .
Pp
The
Fn erf
calculates the error function of x; where
Bd -filled -offset indent
if n \{\
erf(x) = 2/sqrt(pi)\(**\|integral from 0 to x of exp(\-t\(**t) dt. \}
if t \{\
erf\|(x) :=
(2/\(sr\(*p)\|\(is\d\s8\z0\s10\u\u\s8x\s10\d\|exp(\-t\u\s82\s10\d)\|dt. \}
Ed
Pp
The
Fn erfc
function calculates the complementary error function of
Fa x ;
that is
Fn erfc
subtracts the result of the error function
Fn erf x
from 1.0.
This is useful, since for large
Fa x
places disappear.
Sh SEE ALSO
Xr math 3
Sh HISTORY
The
Fn erf
and
Fn erfc
functions appeared in
Bx 4.3 .
