mat_mul_b.c

#include <assert.h>
#include <stdio.h>
#include <string.h>

#ifndef N
#define N 2048
#endif // N
#ifndef T
// #define T 64
#define T 64
#endif // T

float a[N][N], b[N][N], c[N][N], cp[N][N];

void mat_mul()
{
    #pragma omp parallel for 
    for (int i = 0; i < N; i++)
        for (int k = 0; k < N; k++)
            for (int j = 0; j < N; j++)
                c[i][j] += a[i][k] * b[k][j];
}

int main()
{
    FILE *fa = fopen("a.dat", "rb"), *fb = fopen("b.dat", "rb"), *fc = fopen("c.dat", "rb");
    fread(a, sizeof(float), sizeof a / sizeof(float), fa);
    fread(b, sizeof(float), sizeof b / sizeof(float), fb);
    fread(cp, sizeof(float), sizeof cp / sizeof(float), fc);
    fclose(fa);
    fclose(fb);
    fclose(fc);

    for (int i = 0; i < T; i++)
    {
        memset(c, 0, sizeof c);
        mat_mul();
    }

    assert(!memcmp(c, cp, sizeof c));

    return 0;
}