tiled_matrixmul.c

//
// Created by gunavaran on 12/8/20.
//

#include <stdlib.h>
#include <stdio.h>
#include <time.h>

#define n 1024
#define s 512

double A[n][n];
double B[n][n];
double C[n][n];

int main() {

    //populate the matrices with random values between 0.0 and 1.0
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {

            A[i][j] = (double) rand() / (double) RAND_MAX;
            B[i][j] = (double) rand() / (double) RAND_MAX;
            C[i][j] = 0;
        }
    }

    struct timespec start, end;
    double time_spent;

    //matrix multiplication
//    //i, k, j
    clock_gettime(CLOCK_REALTIME, &start);

    for (int ih = 0; ih < n; ih += s) {
        for (int jh = 0; jh < n; jh += s) {
            for (int kh = 0; kh < n; kh += s) {
                for (int il = 0; il < s; il++) {
                    for (int kl = 0; kl < s; kl++) {
                        for (int jl = 0; jl < s; jl++) {
                            C[ih + il][jh + jl] += A[ih + il][kh + kl] * B[kh + kl][jh + jl];
                        }
                    }
                }
            }

        }
    }

    clock_gettime(CLOCK_REALTIME, &end);
    time_spent = (end.tv_sec - start.tv_sec) + (end.tv_nsec - start.tv_nsec) / 1000000000.0;
    printf("Elapsed time in seconds: %f \n", time_spent);
    return 0;

}