1 import java.util.Random;
 2 
 3 public class MatrixCalculate {
 4     public static void main(String[] args) {
 5         int size = 2000;
 6         float[][] m1 = new float[size][size];
 7         float[][] m2 = new float[size][size];
 8         randomFill(m1);
 9         randomFill(m2);
10 
11         //m1·m2
12         float[][] result1 = new float[size][size];
13         long start = System.currentTimeMillis();
14         for (int i = 0; i < size; i++) {
15             for (int k = 0; k < size; k++) {
16                 for (int j = 0; j < size; j++) {
17                     result1[i][j] += m1[i][k] * m2[k][j];
18                 }
19             }
20         }
21         System.out.println("耗时：" + (System.currentTimeMillis() - start));
22         float[][] result2 = new float[size][size];
23         start = System.currentTimeMillis();
24         for (int i = 0; i < size; i++) {
25             for (int j = 0; j < size; j++) {
26                 for (int k = 0; k < size; k++) {
27                     result2[i][j] += m1[i][k] * m2[k][j];
28                 }
29             }
30         }
31         System.out.println("耗时：" + (System.currentTimeMillis() - start));
32         for (int i = 0; i < size; i++) {
33             for (int j = 0; j < size; j++) {
34                 if (result1[i][j] != result2[i][j]) {
35                     System.out.println("======ERROR====");
36                     System.out.println(result1[i][j]);
37                     System.out.println(result2[i][j]);
38                 }
39             }
40         }
41     }
42 
43     public static void randomFill(float[][] floats) {
44         for (int i = 0; i < floats.length; i++) {
45             for (int j = 0; j < floats[i].length; j++) {
46                 floats[i][j] = new Random().nextFloat();
47             }
48         }
49     }
50 }