X-Git-Url: https://www.ginac.de/ginac.git//ginac.git?p=ginac.git;a=blobdiff_plain;f=check%2Ftime_gammaseries.cpp;h=96eb85faa2f39aef789c0364db8ad70a0361c3c9;hp=5fb3ddc95af6f7b7a5dfd5abb6c54cb03562b2fa;hb=3d757d6bfa78c9812337e8c5d849fbd2ab75f861;hpb=61434b009f39c40ea85ae7bb4ec14d8d203e2a85 diff --git a/check/time_gammaseries.cpp b/check/time_gammaseries.cpp index 5fb3ddc9..96eb85fa 100644 --- a/check/time_gammaseries.cpp +++ b/check/time_gammaseries.cpp @@ -3,7 +3,7 @@ * Some timings on series expansion of the Gamma function around a pole. */ /* - * GiNaC Copyright (C) 1999-2000 Johannes Gutenberg University Mainz, Germany + * GiNaC Copyright (C) 1999-2003 Johannes Gutenberg University Mainz, Germany * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by @@ -22,64 +22,64 @@ #include "times.h" -unsigned Gammaseries(unsigned order) +unsigned tgammaseries(unsigned order) { - unsigned result = 0; - symbol x; - - ex myseries = series(Gamma(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 - // term in Stirling's formula: - 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 " - << last_coeff << ", violating a simple estimate." << endl; - ++result; - } - - return result; + unsigned result = 0; + symbol x; + + 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 + // term in Stirling's formula: + ex bound = exp(-.57721566490153286*(order-1))/(order-1); + if (abs((last_coeff-pow(-1,order))/bound) > 1) { + clog << "The " << order-1 + << "th order coefficient in the power series expansion of tgamma(0) was erroneously found to be " + << last_coeff << ", violating a simple estimate." << endl; + ++result; + } + + return result; } unsigned time_gammaseries(void) { - unsigned result = 0; - - cout << "timing Laurent series expansion of Gamma function" << flush; - clog << "-------Laurent series expansion of Gamma function:" << endl; - - vector sizes; - vector times; - timer omega; - - sizes.push_back(10); - sizes.push_back(15); - sizes.push_back(20); - sizes.push_back(25); - - for (vector::iterator i=sizes.begin(); i!=sizes.end(); ++i) { - omega.start(); - result += Gammaseries(*i); - times.push_back(omega.read()); - cout << '.' << flush; - } - - if (!result) { - cout << " passed "; - clog << "(no output)" << endl; - } else { - cout << " failed "; - } - // print the report: - cout << endl << " order: "; - for (vector::iterator i=sizes.begin(); i!=sizes.end(); ++i) - cout << '\t' << (*i); - cout << endl << " time/s:"; - for (vector::iterator i=times.begin(); i!=times.end(); ++i) - cout << '\t' << int(1000*(*i))*0.001; - cout << endl; - - return result; + unsigned result = 0; + + cout << "timing Laurent series expansion of Gamma function" << flush; + clog << "-------Laurent series expansion of Gamma function:" << endl; + + vector sizes; + vector times; + timer omega; + + sizes.push_back(10); + sizes.push_back(15); + sizes.push_back(20); + sizes.push_back(25); + + for (vector::iterator i=sizes.begin(); i!=sizes.end(); ++i) { + omega.start(); + result += tgammaseries(*i); + times.push_back(omega.read()); + cout << '.' << flush; + } + + if (!result) { + cout << " passed "; + clog << "(no output)" << endl; + } else { + cout << " failed "; + } + // print the report: + cout << endl << " order: "; + for (vector::iterator i=sizes.begin(); i!=sizes.end(); ++i) + cout << '\t' << (*i); + cout << endl << " time/s:"; + for (vector::iterator i=times.begin(); i!=times.end(); ++i) + cout << '\t' << int(1000*(*i))*0.001; + cout << endl; + + return result; }