// LAB 22.03 - PRZYBLIZENIE PI

#include <stdlib.h>
#include <stdio.h>
#include <mpi.h>
#include <math.h>

#define ROOT 0
#define MSG_TAG 100

int main(int argc,char **argv)
{
    int size,tid;
    float R=1;

    MPI_Init(&argc, &argv);

    MPI_Comm_size( MPI_COMM_WORLD, &size );
    MPI_Comm_rank( MPI_COMM_WORLD, &tid );

    srand( tid );

    float res;

    if ( tid == 0 ) {
	MPI_Status status;
        int i;
        long double pi;
        float sum_results = 0;
	// pewnie jakiś for tutaj
    for(i = 1; i<size; i++) {
	    MPI_Recv( &res, 1, MPI_FLOAT, MPI_ANY_SOURCE, MPI_ANY_TAG, MPI_COMM_WORLD, &status);
        sum_results+=res;
    }
    pi = (long double)(sum_results / (size-1));
        printf("Przybliżenie pi po zebraniu danych od %d procesów wynosi %.20llf\n", i, pi);
    } else {
        int in_circle_counter = 0;
        float x, y, left;
        int number_of_iterations = 800000000, i;
        for (i = 0; i < number_of_iterations; i++) {
            x = rand() / (float)RAND_MAX;
            y = rand() / (float)RAND_MAX;
            left = x*x + y*y;
            if (left <= R) in_circle_counter++;
        }
        float pi_estimated = 4 * ((float)in_circle_counter / number_of_iterations);
        // printf("pi_estimated %f, id: %d\n", pi_estimated, tid);
	    MPI_Send( &pi_estimated, 1, MPI_FLOAT, ROOT, MSG_TAG, MPI_COMM_WORLD );
    }

    MPI_Finalize();
}