缓存机制小实验

for (int i=0;i<z.n;i++)
  for (int k=0;k<x.m;k++)
		for (int j=0;j<z.m;j++)
          z.a[i][j] = z.a[i][j] + x.a[i][k] * y.a[k][j];
	//ijk 6.097s
	//kji 7.807s
	//ikj 2.912s
	//jki 10.66s
	//jik 5.495s
	//kij 3.165s