52 lines
1.3 KiB
C
52 lines
1.3 KiB
C
#include <stdio.h>
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#include <omp.h>
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#include <math.h>
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#include <stdlib.h>
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#include <stdbool.h>
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#include <string.h>
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static inline bool in_circle(double x, double y)
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{
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return (x*x + y*y < 1.0);
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}
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int main(int argc, const char *argv[])
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{
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omp_set_num_threads(10);
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// A constant seed is used to keep our results reproducible
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srand48(42);
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double x;
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double y;
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int in_circle_count = 0;
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int total_count = 0;
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unsigned short rand_state[3] = {22, 24, 90};
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double start = omp_get_wtime();
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// We use now use the Monte Carlo method of approximating pi
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// TODO: parallelize this block while avoiding data races:
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{
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rand_state[0] = rand_state[0] * (unsigned short)omp_get_num_threads();
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// TODO: Use the omp for directive to paralellize
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// a loop inside a parallel block
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for (int i = 0; i < 90000000; i++) {
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x = erand48(rand_state);
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y = erand48(rand_state);
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if (in_circle(x, y)) {
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in_circle_count++;
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}
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total_count++;
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}
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}
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double quater_pi = (double)in_circle_count / (double)total_count;
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double end = omp_get_wtime();
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printf("Pi is: %f\n", quater_pi * 4);
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printf("That took a total of %f seconds.\n", end - start);
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return 0;
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}
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