/** @file time_gammaseries.cpp
*
- * Some timings on series expansion of the gamma function around a pole. */
+ * Some timings on series expansion of the Gamma function around a pole. */
/*
* GiNaC Copyright (C) 1999-2000 Johannes Gutenberg University Mainz, Germany
#include "times.h"
-unsigned gammaseries(unsigned order)
+unsigned tgammaseries(unsigned order)
{
unsigned result = 0;
symbol x;
- ex myseries = series(gamma(x),x,0,order);
+ ex myseries = series(tgamma(x),x==0,order);
// compute the last coefficient numerically:
ex last_coeff = myseries.coeff(x,order-1).evalf();
// compute a bound for that coefficient using a variation of the leading
ex bound = evalf(exp(ex(-.57721566490153286*(order-1)))/(order-1));
if (evalf(abs((last_coeff-pow(-1,order))/bound)) > numeric(1)) {
clog << "The " << order-1
- << "th order coefficient in the power series expansion of gamma(0) was erroneously found to be "
+ << "th order coefficient in the power series expansion of tgamma(0) was erroneously found to be "
<< last_coeff << ", violating a simple estimate." << endl;
++result;
}
{
unsigned result = 0;
- cout << "timing Laurent series expansion of gamma function" << flush;
- clog << "-------Laurent series expansion of gamma function:" << endl;
+ cout << "timing Laurent series expansion of Gamma function" << flush;
+ clog << "-------Laurent series expansion of Gamma function:" << endl;
vector<unsigned> sizes;
vector<double> times;
for (vector<unsigned>::iterator i=sizes.begin(); i!=sizes.end(); ++i) {
omega.start();
- result += gammaseries(*i); cout << '.' << flush;
+ result += tgammaseries(*i);
times.push_back(omega.read());
+ cout << '.' << flush;
}
if (!result) {
}
// print the report:
cout << endl << " order: ";
- for (vector<unsigned>::iterator i=sizes.begin(); i!=sizes.end(); ++i) {
+ for (vector<unsigned>::iterator i=sizes.begin(); i!=sizes.end(); ++i)
cout << '\t' << (*i);
- }
cout << endl << " time/s:";
- for (vector<double>::iterator i=times.begin(); i!=times.end(); ++i) {
- cout << '\t' << (*i);
- }
+ for (vector<double>::iterator i=times.begin(); i!=times.end(); ++i)
+ cout << '\t' << int(1000*(*i))*0.001;
cout << endl;
return result;