exprtk/exprtk_simple_example_19.cpp at master · ArashPartow/exprtk · GitHub

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**************************************************************

* C++ Mathematical Expression Toolkit Library *

* *

* Simple Example 19 *

* Author: Arash Partow (1999-2025) *

* 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 *

* SPDX-License-Identifier: 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;

using namespace exprtk::rtl::vecops::helper;

if (

(1 == ps_index) &&

!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[noise[]] := 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;

}

exprtk/exprtk_simple_example_19.cpp at master · ArashPartow/exprtk · GitHub

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