matrix

serie1/Matrix.java

+public class Matrix {
+
+    public static void printMatrix(int[][] mat) {
+        for (int i = 0; i < mat.length; i++) {
+            for (int j = 0; j < mat[i].length; j++) {
+                System.out.printf("%d ", mat[i][j]);
+            }
+            System.out.println();
+        }
+    }
+
+    public static int[][] mul(int[][] lhs, int[][] rhs) {
+        if (lhs[0].length != rhs.length) {
+            throw new RuntimeException("y axis of lhs doesn't match the x axis of rhs, multiplication cannot be done");
+        }
+
+        int[][] res = new int[lhs.length][rhs[0].length];
+
+        for (int i = 0; i < lhs.length; i++) {
+            for (int j = 0; j < rhs[i].length; j++) {
+                for (int k = 0; k < rhs.length; k++) {
+
+                    res[i][j] += lhs[i][k] * rhs[k][j];
+
+                }
+            }
+        }
+
+        return res;
+    }
+
+    public int[][] add(int[][] lhs, int[][] rhs) {
+        if (lhs.length != rhs.length || lhs[0].length != rhs[0].length) {
+            throw new RuntimeException("y axis of lhs doesn't match the x axis of rhs, multiplication cannot be done");
+        }
+
+        int[][] res = new int[lhs.length][lhs[0].length];
+
+        for (int i = 0; i < res.length; i++) {
+            for (int j = 0; j < res[i].length; j++) {
+                res[i][j] = lhs[i][j] + rhs[i][j];
+            }
+        }
+
+        return res;
+    }
+
+    public static void main(String[] args) {
+        int[][] mat1 = new int[3][5];
+        int[][] mat2 = new int[5][4];
+
+        int res[][] = mul(mat1, mat2);
+
+        printMatrix(res);
+    }
+}