/
exprtk_simple_example_19.cpp
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/
exprtk_simple_example_19.cpp
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/*
**************************************************************
* C++ Mathematical Expression Toolkit Library *
* *
* Simple Example 19 *
* Author: Arash Partow (1999-2023) *
* URL: https://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 MIT License. *
* https://www.opensource.org/licenses/MIT *
* *
**************************************************************
*/
#include <cstdio>
#include <cstdlib>
#include <ctime>
#include <string>
#include "exprtk.hpp"
template <typename T>
class randu : public exprtk::igeneric_function<T>
{
public:
typedef typename exprtk::igeneric_function<T> igfun_t;
typedef typename igfun_t::parameter_list_t parameter_list_t;
typedef typename igfun_t::generic_type generic_type;
typedef typename generic_type::vector_view vector_t;
using exprtk::igeneric_function<T>::operator();
randu()
: exprtk::igeneric_function<T>("V|VTT")
/*
Overloads:
0. V - vector
1. VTT - vector, r0, r1
*/
{ ::srand(static_cast<unsigned int>(time(NULL))); }
inline T operator()(const std::size_t& ps_index, parameter_list_t parameters)
{
vector_t v(parameters[0]);
std::size_t r0 = 0;
std::size_t r1 = v.size() - 1;
if (
(1 == ps_index) &&
!exprtk::rtl::vecops::helper::
load_vector_range<T>::process(parameters, r0, r1, 1, 2, 0)
)
return T(0);
for (std::size_t i = r0; i <= r1; ++i)
{
v[i] = rnd();
}
return T(1);
}
private:
inline T rnd()
{
// Note: Do not use this in production
// Result is in the interval [0,1)
return T(::rand() / T(RAND_MAX + 1.0));
}
};
template <typename T>
void vector_randu()
{
typedef exprtk::symbol_table<T> symbol_table_t;
typedef exprtk::expression<T> expression_t;
typedef exprtk::parser<T> parser_t;
const std::string vecrandu_program =
" var noise[6] := [0]; "
" "
" if (randu(noise,0,5) == false) "
" { "
" println('Failed to generate noise'); "
" return [false]; "
" } "
" "
" var noisy[6] := signal + (noise - 1/2); "
" "
" for (var i := 0; i < noisy[]; i += 1) "
" { "
" println('noisy[',i,'] = ', noisy[i]); "
" } "
" "
" println('avg: ', avg(noisy)); "
" ";
T signal[] = { T(1.1), T(2.2), T(3.3), T(4.4), T(5.5), T(6.6), T(7.7) };
exprtk::rtl::io::println<T> println;
randu<T> randu;
symbol_table_t symbol_table;
symbol_table.add_vector ("signal" , signal );
symbol_table.add_function("println", println);
symbol_table.add_function("randu" , randu );
expression_t expression;
expression.register_symbol_table(symbol_table);
parser_t parser;
parser.compile(vecrandu_program,expression);
expression.value();
}
int main()
{
vector_randu<double>();
return 0;
}