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C++ Mathematical Expression Library (ExprTk) http://www.partow.net/programming/exprtk/index.html

This commit is contained in:
Arash Partow 2016-09-01 09:21:23 +10:00
parent ed5eec1836
commit e0b0aa5130
4 changed files with 110 additions and 33 deletions
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1
Makefile
View File

@ -40,6 +40,7 @@ BUILD_LIST+=exprtk_simple_example_13
BUILD_LIST+=exprtk_simple_example_14
BUILD_LIST+=exprtk_simple_example_15
BUILD_LIST+=exprtk_simple_example_16
BUILD_LIST+=exprtk_simple_example_17
all: $(BUILD_LIST)

40
exprtk_simple_example_09.cpp
View File

@ -44,18 +44,18 @@ void primes()
.add(
function_t(
"is_prime_impl1",
"if (y == 1,true, "
" if (y == 1,true, "
" if (0 == (x % y),false, "
" is_prime_impl1(x,y - 1)))",
" is_prime_impl1(x,y - 1))) ",
"x","y"));
compositor
.add(
function_t(
"is_prime1",
"if (frac(x) != 0, false, "
" if (frac(x) != 0, false, "
" if (x <= 0, false, "
" is_prime_impl1(x,min(x - 1,trunc(sqrt(x)) + 1))))",
" is_prime_impl1(x,min(x - 1,trunc(sqrt(x)) + 1)))) ",
"x"));
//Mode 2 - switch statement based
@ -63,24 +63,24 @@ void primes()
.add(
function_t(
"is_prime_impl2",
"switch "
"{ "
" switch "
" { "
" case y == 1 : true; "
" case (x % y) == 0 : false; "
" default : is_prime_impl2(x,y - 1);"
"} ",
" default : is_prime_impl2(x,y - 1); "
" } ",
"x","y"));
compositor
.add(
function_t(
"is_prime2",
"switch "
"{ "
" switch "
" { "
" case x <= 0 : false; "
" case frac(x) != 0 : false; "
" default : is_prime_impl2(x,min(x - 1,trunc(sqrt(x)) + 1));"
"} ",
" default : is_prime_impl2(x,min(x - 1,trunc(sqrt(x)) + 1)); "
" } ",
"x"));
//Mode 3 - switch statement and while-loop based
@ -88,27 +88,27 @@ void primes()
.add(
function_t(
"is_prime_impl3",
"while (y > 0) "
"{ "
" while (y > 0) "
" { "
" switch "
" { "
" case y == 1 : ~(y := 0,true); "
" case (x % y) == 0 : ~(y := 0,false);"
" case (x % y) == 0 : ~(y := 0,false); "
" default : y := y - 1; "
" } "
"} ",
" } ",
"x","y"));
compositor
.add(
function_t(
"is_prime3",
"switch "
"{ "
" switch "
" { "
" case x <= 0 : false; "
" case frac(x) != 0 : false; "
" default : is_prime_impl3(x,min(x - 1,trunc(sqrt(x)) + 1));"
"} ",
" default : is_prime_impl3(x,min(x - 1,trunc(sqrt(x)) + 1)); "
" } ",
"x"));
std::string expression_str1 = "is_prime1(x)";

75
exprtk_simple_example_17.cpp Normal file
View File

@ -0,0 +1,75 @@
/*
**************************************************************
* C++ Mathematical Expression Toolkit Library *
* *
* Simple Example 17 *
* Author: Arash Partow (1999-2016) *
* URL: http://www.partow.net/programming/exprtk/index.html *
* *
* Copyright notice: *
* Free use of the Mathematical Expression Toolkit Library is *
* permitted under the guidelines and in accordance with the *
* most current version of the Common Public License. *
* http://www.opensource.org/licenses/cpl1.0.php *
* *
**************************************************************
*/
#include <cstdio>
#include <cstdlib>
#include <ctime>
#include <string>
#include "exprtk.hpp"
template <typename T>
struct rnd_01 : public exprtk::ifunction<T>
{
rnd_01() : exprtk::ifunction<T>(0)
{ ::srand(static_cast<unsigned int>(time(NULL))); }
inline T operator()()
{
// Note: Do not use this in production
return T(::rand() / T(RAND_MAX + 1));
}
};
template <typename T>
void monte_carlo_pi()
{
typedef exprtk::symbol_table<T> symbol_table_t;
typedef exprtk::expression<T> expression_t;
typedef exprtk::parser<T> parser_t;
std::string monte_carlo_pi_program =
" var experiments[5 * 10^7] := [(rnd_01^2 + rnd_01^2) <= 1]; "
" 4 * sum(experiments) / experiments[]; ";
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_pi_program,expression);
const T approximate_pi = expression.value();
const T real_pi = T(3.141592653589793238462);
printf("pi ~ %20.17f\terror: %20.17f\n",
approximate_pi,
std::abs(real_pi - approximate_pi));
}
int main()
{
monte_carlo_pi<double>();
return 0;
}

1
readme.txt
View File

@ -2900,6 +2900,7 @@ files:
(18) exprtk_simple_example_14.cpp
(19) exprtk_simple_example_15.cpp
(20) exprtk_simple_example_16.cpp
(21) exprtk_simple_example_17.cpp
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~