exprtk_montecarlo_e.cpp File Reference

#include <cstdio>
#include <cstdlib>
#include <ctime>
#include <string>
#include "exprtk.hpp"

Include dependency graph for exprtk_montecarlo_e.cpp:

Go to the source code of this file.

Classes
struct	rnd_01< T >

Functions
template<typename T >
void	monte_carlo_e ()
int	main ()

Function Documentation

main()

int main

(

)

Definition at line 86 of file exprtk_montecarlo_e.cpp.

{
   monte_carlo_e<double>();
   return 0;
}

monte_carlo_e()

template<typename T >

void monte_carlo_e

(

)

Definition at line 45 of file exprtk_montecarlo_e.cpp.

{
   typedef exprtk::symbol_table<T> symbol_table_t;
   typedef exprtk::expression<T>   expression_t;
   typedef exprtk::parser<T>       parser_t;
 
   const std::string monte_carlo_e_program =
      " var max_samples := 10^8;                  "
      " var trials      := 0;                     "
      "                                           "
      " for (var i := 0; i < max_samples; i += 1) "
      " {                                         "
      "    var rand_sum := 0;                     "
      "    repeat                                 "
      "       rand_sum += rnd_01;                 "
      "       trials   += 1;                      "
      "    until (rand_sum > 1);                  "
      " };                                        "
      "                                           "
      " trials / max_samples;                     ";
 
   rnd_01<T> rnd01;
 
   symbol_table_t symbol_table;
   symbol_table.add_function("rnd_01",rnd01);
 
   expression_t expression;
   expression.register_symbol_table(symbol_table);
 
   parser_t parser;
   parser.compile(monte_carlo_e_program,expression);
 
   const T approximate_e = expression.value();
 
   const T real_e = T(2.718281828459045235360287471352662); // or close enough...
 
   printf("e ~ %20.17f\terror: %20.17f\n",
          approximate_e,
          std::abs(real_e - approximate_e));
}