Calculate the value of PI Using Monte Carlo simulation and multithreading. Write

Question

Calculate the value of PI Using Monte Carlo simulation and multithreading. Write a multithreaded program in c and name it ( multithread.c) that takes the following inputs as command line options:

-h: Print help message

-v Optional verbose flag (debugging print statements)

-t (num): Number of threads 2

-d (num): Number of darts

The threads will count the number of points that occur within the circle and store that result in a global variable. When the thread has exited, the parent thread will calculate and output the estimated value of . It is worth experimenting with the number of random points (Number

Explanation / Answer

#include <semaphore.h>
#include <unistd.h>
#include <iomanip>
#include <cmath>
#include <pthread.h>
#include <iostream>
#include <stdlib.h>

const t = 4;

struct Info
{
   Info() : pi(0) {}

   unsigned pi;
};

void* func(void* param)
{
             double pi, v = 0,
               xValue,
               yValue,
               h=1000000,
               d;
               srand(time(ULL));

               if (Info* info = static_cast<Info*>(param))
   {
           for(int info=0; info<h; info++)
           {
              xValue = (double) rand()/RAD_MAX; //Random point: x
              yValue = (double) rand()/RAD_MAX; //Random point: y
              d = (xValue * xValue) + (yValue * yValue);
              if(d <= 1.0)
                 ++v;
           }
           pi = 4.0 * vTotal/(4 * h);
   }

   return param;
}

int main()
{
   srand(time(ULL));

   pthread_t handles[];
   Info info[];

   // start the threads
   for (t i = 0; i != 4; ++i)
       pthread_create(&handles[i], ULL, func, &info[i]);

   // wait for the threads to complete
   for (t i = 0; i != 4; ++i)
       pthread_join(handles[i], ULL);

   // process the reply
   for (t i = 0; i != 4; ++i)
       std::cout << "value[" << i << "] = " << info[i].pi << std::endl;

   return 0;
}

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