Initial commit

libs/math/tools/igamma_data.cpp

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+//  (C) Copyright John Maddock 2006.
+//  Use, modification and distribution are subject to the
+//  Boost Software License, Version 1.0. (See accompanying file
+//  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#include <boost/math/special_functions/gamma.hpp>
+#include <boost/math/constants/constants.hpp>
+#include <boost/lexical_cast.hpp>
+#include <fstream>
+#include <boost/math/tools/test_data.hpp>
+#include "mp_t.hpp"
+
+using namespace boost::math::tools;
+
+//
+// Force trunctation to float precision of input values:
+// we must ensure that the input values are exactly representable
+// in whatever type we are testing, or the output values will all
+// be thrown off:
+//
+float external_f;
+float force_truncate(const float* f)
+{
+   external_f = *f;
+   return external_f;
+}
+
+float truncate_to_float(mp_t r)
+{
+   float f = boost::math::tools::real_cast<float>(r);
+   return force_truncate(&f);
+}
+
+//
+// Our generator takes two arguments, but the second is interpreted
+// as an instruction not a value, the second argument won't be placed
+// in the output matrix by class test_data, so we add our algorithmically
+// derived second argument to the output.
+//
+struct igamma_data_generator
+{
+   boost::math::tuple<mp_t, mp_t, mp_t, mp_t, mp_t> operator()(mp_t a, mp_t x)
+   {
+      // very naively calculate spots:
+      mp_t z;
+      switch((int)real_cast<float>(x))
+      {
+      case 1:
+         z = truncate_to_float((std::min)(mp_t(1), a/100));
+         break;
+      case 2:
+         z = truncate_to_float(a / 2);
+         break;
+      case 3:
+         z = truncate_to_float((std::max)(0.9*a, a - 2));
+         break;
+      case 4:
+         z = a;
+         break;
+      case 5:
+         z = truncate_to_float((std::min)(1.1*a, a + 2));
+         break;
+      case 6:
+         z = truncate_to_float(a * 2);
+         break;
+      case 7:
+         z = truncate_to_float((std::max)(mp_t(100), a*100));
+         break;
+      default:
+         BOOST_ASSERT(0 == "Can't get here!!");
+      }
+
+      //mp_t g = boost::math::tgamma(a);
+      mp_t lg = boost::math::tgamma_lower(a, z);
+      mp_t ug = boost::math::tgamma(a, z);
+      mp_t rlg = boost::math::gamma_p(a, z);
+      mp_t rug = boost::math::gamma_q(a, z);
+
+      return boost::math::make_tuple(z, ug, rug, lg, rlg);
+   }
+};
+
+struct gamma_inverse_generator
+{
+   boost::math::tuple<mp_t, mp_t> operator()(const mp_t a, const mp_t p)
+   {
+      mp_t x1 = boost::math::gamma_p_inv(a, p);
+      mp_t x2 = boost::math::gamma_q_inv(a, p);
+      std::cout << "Inverse for " << a << " " << p << std::endl;
+      return boost::math::make_tuple(x1, x2);
+   }
+};
+
+struct gamma_inverse_generator_a
+{
+   boost::math::tuple<mp_t, mp_t> operator()(const mp_t x, const mp_t p)
+   {
+      mp_t x1 = boost::math::gamma_p_inva(x, p);
+      mp_t x2 = boost::math::gamma_q_inva(x, p);
+      std::cout << "Inverse for " << x << " " << p << std::endl;
+      return boost::math::make_tuple(x1, x2);
+   }
+};
+
+
+int main(int argc, char*argv [])
+{
+   bool cont;
+   std::string line;
+
+   parameter_info<mp_t> arg1, arg2;
+   test_data<mp_t> data;
+
+   if((argc >= 2) && (std::strcmp(argv[1], "-inverse") == 0))
+   {
+      std::cout << "Welcome.\n"
+         "This program will generate spot tests for the inverse incomplete gamma function:\n"
+         "  gamma_p_inv(a, p) and gamma_q_inv(a, q)\n\n";
+      do{
+         get_user_parameter_info(arg1, "a");
+         get_user_parameter_info(arg2, "p");
+         data.insert(gamma_inverse_generator(), arg1, arg2);
+
+         std::cout << "Any more data [y/n]?";
+         std::getline(std::cin, line);
+         boost::algorithm::trim(line);
+         cont = (line == "y");
+      }while(cont);
+   }
+   else if((argc >= 2) && (std::strcmp(argv[1], "-inverse_a") == 0))
+   {
+      std::cout << "Welcome.\n"
+         "This program will generate spot tests for the inverse incomplete gamma function:\n"
+         "  gamma_p_inva(a, p) and gamma_q_inva(a, q)\n\n";
+      do{
+         get_user_parameter_info(arg1, "x");
+         get_user_parameter_info(arg2, "p");
+         data.insert(gamma_inverse_generator_a(), arg1, arg2);
+
+         std::cout << "Any more data [y/n]?";
+         std::getline(std::cin, line);
+         boost::algorithm::trim(line);
+         cont = (line == "y");
+      }while(cont);
+   }
+   else
+   {
+      arg2 = make_periodic_param(mp_t(1), mp_t(8), 7);
+      arg2.type |= boost::math::tools::dummy_param;
+
+      std::cout << "Welcome.\n"
+         "This program will generate spot tests for the incomplete gamma function:\n"
+         "  gamma(a, z)\n\n";
+
+      do{
+         get_user_parameter_info(arg1, "a");
+         data.insert(igamma_data_generator(), arg1, arg2);
+
+         std::cout << "Any more data [y/n]?";
+         std::getline(std::cin, line);
+         boost::algorithm::trim(line);
+         cont = (line == "y");
+      }while(cont);
+   }
+
+   std::cout << "Enter name of test data file [default=igamma_data.ipp]";
+   std::getline(std::cin, line);
+   boost::algorithm::trim(line);
+   if(line == "")
+      line = "igamma_data.ipp";
+   std::ofstream ofs(line.c_str());
+   ofs << std::scientific << std::setprecision(40);
+   write_code(ofs, data, "igamma_data");
+   
+   return 0;
+}
+