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	tmain.cpp - numeric - C++ library with numerical algorithms
	git clone git://src.adamsgaard.dk/numeric
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	---
	tmain.cpp (2348B)
	---
	1 #include <iostream>
	2 #include <cstdio> // For fscanf
	3 #include <armadillo>
	4 #include <vector>
	5 #include "header.h"
	6 #include "lsfit.h"
	7
	8 int main(int argc, char* argv[])
	9 {
	10 // Namespace declarations
	11 using std::cout;
	12
	13 // Check that a data file is given as an input argument
	14 if (argc < 2 \|\| argc > 3) {
	15 cout << "Usage: " << argv[0] << " <input file> [output file]\n"
	16 << "If 'output file' is not specified, output data "
	17 << "will be written to stdout.\n"
	18 << "Example: " << argv[0] << " data.A.txt\n";
	19 return 1;
	20 }
	21
	22 FILE *fin; // File pointer
	23
	24 // Check that the input file exists and can be read
	25 if ((fin = fopen(argv[1], "r")) == NULL) {
	26 cout << "Error while reading " << argv[1] << '\n';
	27 return 1;
	28 }
	29
	30 // First, count the number of newline characters
	31 // for preallocation purposes
	32 Lengthtype n = 0;
	33 int c;
	34 while ((c = getc(fin)) != EOF) {
	35 if (c == '\n')
	36 ++n;
	37 }
	38 fclose(fin);
	39 cout << "Input file \"" << argv[1] << "\" consists of n="
	40 << n << " data points.\n";
	41
	42 // Allocate input data structures
	43 arma::Col<Floattype> x = arma::Col<Floattype> (n);
	44 arma::Col<Floattype> y = arma::Col<Floattype> (n);
	45 arma::Col<Floattype> delta_y = arma::Col<Floattype> (n);
	46
	47 // Read data into memory
	48 if ((fin = fopen(argv[1], "r")) == NULL) {
	49 cout << "Error while reading " << argv[1] << '\n';
	50 return 1;
	51 }
	52 float x_tmp, y_tmp, delta_y_tmp;
	53 for (Lengthtype i=0; i<n; ++i) {
	54 fscanf(fin, "%f %f %f", &x_tmp, &y_tmp, &delta_y_tmp);
	55 x(i) = x_tmp;
	56 y(i) = y_tmp;
	57 delta_y(i) = delta_y_tmp;
	58 }
	59 fclose(fin);
	60
	61 // Perform least-squares fit with LSfit class
	62 LSfit lsfit(x, y, delta_y);
	63
	64 // Evaluate fit at a fine resolution
	65 const unsigned int res = 100;
	66 Floattype x_min = x.min();
	67 cout << "x_min = " << x_min;
	68 Floattype x_max = x.max();
	69 cout << ", x_max = " << x_max << '\n';
	70 std::vector<Floattype> xo (res);
	71 std::vector<Floattype> yo (res);
	72 for (unsigned int i=0; i<res; ++i) {
	73 xo[i] = x_min + (x_max - x_min) * ((Floattype)i/res);
	74 yo[i] = lsfit.eval(xo[i]);
	75 }
	76
	77 // Write to file if specified in as command line arguments
	78 if (argc == 3) {
	79 write_output(xo, yo, argv[2]);
	80 } else {
	81 for (unsigned int i=0; i<res; ++i) {
	82 cout << xo[i] << '\t' << yo[i] << '\n';
	83 }
	84 }
	85
	86
	87 // Return successfully
	88 return 0;
	89 }