c

#include "stdio.h"
#include "stdlib.h"
#include "string.h"
#include "sys/time.h"
 
#define TRIALS 1
#define EXPERIMENTS 4
#define MATRIX_SIZE 2048
 
// [!!] this _CAN_ break if doing something like max(0, ++i)
//      due to double evaluation. Be super extra careful with
//      this. At least know it"s here...
#define max(a, b) (((a) > (b)) ? (a) : (b))
 
short A[MATRIX_SIZE][MATRIX_SIZE],
      B[MATRIX_SIZE][MATRIX_SIZE],
      C[MATRIX_SIZE][MATRIX_SIZE];
 
int main(int argc, char*  argv[])
{
	// Initalize array A and B with "1"s
	for (int i = 0; i < MATRIX_SIZE; ++i)
		for (int k = 0; k < MATRIX_SIZE; ++k)
			A[i][k] = B[i][k] = 1;
 
	// Iterate through the block sizes
	for (int block_size = 4; block_size <= (1 << EXPERIMENTS); block_size *= 2)
	{
		long average = 0;
 
		printf("%d: ", block_size);
 
		// Run TRIALS number of trials for each block size
		for (int trial = 0; trial < TRIALS; ++trial)
		{
			memset(C, 0, sizeof(C[0][0] * MATRIX_SIZE * MATRIX_SIZE));
 
			// Keep track of when we start doing work
			struct timeval time_start;
			gettimeofday(&time_start, NULL);
 
			// Do the matrix multiplication task
			for (int k = 0; k < MATRIX_SIZE; k += block_size) {
				printf("%s", "a");
				for (int j = 0; j < MATRIX_SIZE; j += block_size) {
					printf("%s", "b");
					for (int i = 0; i < MATRIX_SIZE; i++) {
						printf("%s", "c");
						for (int jj = j; jj < max(j + block_size, MATRIX_SIZE); jj++) {
							printf("%s", "d");
							for (int kk = k; kk < max(k + block_size, MATRIX_SIZE); kk++)
							{
								printf("%s", "e");
							}
						}
					}
				}
			}

							//	C[i][jj] = C[i][jj] + A[i][kk] * B[kk][jj];
 
			// Keep track of when we finish our work
			struct timeval time_end;
			gettimeofday(&time_end, NULL);
 
			// Keep track of the time for averaging later
			long execution_time = (long) (time_end.tv_usec - time_start.tv_usec);
 
			printf("%lu,", execution_time);
		}
		
		printf("%lu\n", average / TRIALS);
	}
 
	return 0;
}