#include "mat_mul.h"

#include <cstdlib>
#include <cstdio>
#include <pthread.h>
#include <algorithm>

static float *A, *B, *C;
static int M, N, K;
static int num_threads;

static void* mat_mul_thread(void *data){
	int pid = *(int*) data;
	int blk = 45;
	
	for(int kk=0; kk<K; kk+=blk)
		for(int i=pid*M/num_threads; i<(pid+1)*M/num_threads; ++i)
			for(int k=kk; k<std::min(kk+blk, K); ++k){
				for(int j=0; j<N; ++j){
					C[i*N+j] += A[i*K+k] * B[k*N+j];
				}
			}
	return NULL;
}


void mat_mul(float *_A, float *_B, float *_C, int _M, int _N, int _K, int _num_threads) {
  A = _A, B = _B, C = _C;
  M = _M, N = _N, K = _K;
  num_threads = _num_threads;

  // TODO: create '_num_threads' pthreads
  pthread_t* threads;
  threads = (pthread_t*) malloc(sizeof(pthread_t) * num_threads);

  for(int i=0; i< num_threads; i++){
	  int* pid = (int*) malloc(sizeof(int));
	  *pid = i;
	  pthread_create(&threads[i], NULL, mat_mul_thread, pid);
  }

  for(int i=0; i<num_threads; i++){
	  pthread_join(threads[i], NULL);
  }
}