exprtk_prime_sieve_vectorized.cpp

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/*
 **************************************************************
 *         C++ Mathematical Expression Toolkit Library        *
 *                                                            *
 * ExprTk Sieve Of Eratosthenes Vectorized                    *
 * 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 <string>
 
#include "exprtk.hpp"
 
 
template <typename T>
void sieve_of_eratosthenes_vectorized()
{
   typedef exprtk::symbol_table<T> symbol_table_t;
   typedef exprtk::expression<T>   expression_t;
   typedef exprtk::parser<T>       parser_t;
 
   const std::string sieve_of_eratosthenes_program =
      " var sieve[10^8] := [false];                     "
      " var m := trunc(sqrt(sieve[]));                  "
      "                                                 "
      " sieve[0] := true;                               "
      " sieve[1] := true;                               "
      "                                                 "
      " for (var i := 0; i <= m; i += 1)                "
      " {                                               "
      "    if (false == sieve[i])                       "
      "    {                                            "
      "       assign(sieve, true, i^2, sieve[] - 1, i); "
      "    }                                            "
      " };                                              "
      "                                                 "
      " var prime_count := sieve[] - sum(sieve);        "
      "                                                 "
      " prime_count == 5761455;                         ";
 
   symbol_table_t symbol_table;
   exprtk::rtl::vecops::package<T> vector_package;
 
   symbol_table.add_package(vector_package);
 
   expression_t expression;
   expression.register_symbol_table(symbol_table);
 
   parser_t parser;
   parser.compile(sieve_of_eratosthenes_program,expression);
 
   exprtk::timer timer;
   timer.start();
 
   const T result = expression.value();
 
   timer.stop();
 
   printf("Result: %8.3f\n",result);
 
   printf("Total time: %8.3fsec\n",timer.time());
}
 
int main()
{
   sieve_of_eratosthenes_vectorized<double>();
   return 0;
}