ceph/src/boost/libs/math/tools/factorial_tables.cpp

   1 //  (C) Copyright John Maddock 2007.
   2 //  Use, modification and distribution are subject to the
   3 //  Boost Software License, Version 1.0. (See accompanying file
   4 //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   5
   6 #include <boost/limits.hpp>
   7 #include <vector>
   8 #include "mp_t.hpp"
   9
  10 void write_table(unsigned max_exponent)
  11 {
  12    mp_t max = ldexp(mp_t(1), (int)max_exponent);
  13
  14    std::vector<mp_t> factorials;
  15    factorials.push_back(1);
  16
  17    mp_t f(1);
  18    unsigned i = 1;
  19
  20    while(f < max)
  21    {
  22       factorials.push_back(f);
  23       ++i;
  24       f *= i;
  25    }
  26
  27    //
  28    // now write out the results to cout:
  29    //
  30    std::cout << std::scientific << std::setprecision(40);
  31    std::cout << "   static const std::array<T, " << factorials.size() << "> factorials = {\n";
  32    for(unsigned j = 0; j < factorials.size(); ++j)
  33       std::cout << "      " << factorials[j] << "L,\n";
  34    std::cout << "   };\n\n";
  35 }
  36
  37
  38 int main()
  39 {
  40    write_table(16384/*std::numeric_limits<float>::max_exponent*/);
  41 }