基本矩阵运算的Java实现
一： 矩阵的加法与减法
规则：矩阵的加法与减法要求两个矩阵的行列完全相等，方可以完成两个矩阵的之间的运算。
举例说明如下
二：矩阵的乘法
规则：矩阵的乘法要求两个矩阵符合A(mx k), B( k x n)即矩阵A的列数与矩阵B的行数相等，否
则无法完成矩阵运算。举例说明如下：
Java代码如下：
package pet.shop;public class BasicMatrixMath {public final static int OPERATION_ADD = 1;public final static int OPERATION_SUB = 2;public final static int OPERATION_MUL = 4;/** * To be able to add two matrices, they must be of the same size * @param matrixa * @param matrixb */public int[][] add(int[][] matrixa, int[][] matrixb) {if(legalOperation(matrixa, matrixb, OPERATION_ADD)) {for(int i=0; i<matrixa.length; i++) {for(int j=0; j<matrixa[0].length; j++) {matrixa[i][j] = matrixa[i][j] + matrixb[i][j];}}}return matrixa;}/** * To be able to substract two matrices, they must be of the same size * * @param matrixa * @param matrixb */public int[][] substract(int[][] matrixa, int[][] matrixb) {if(legalOperation(matrixa, matrixb, OPERATION_SUB)) {for(int i=0; i<matrixa.length; i++) {for(int j=0; j<matrixa[0].length; j++) {matrixa[i][j] = matrixa[i][j] - matrixb[i][j];}}}return matrixa;}/** * * @param matrixa * @param matrixb */public int[][] multiplication(int[][] matrixa, int[][] matrixb) {if(legalOperation(matrixa, matrixb, OPERATION_SUB)) {int[][] result = new int[matrixa.length][matrixb[0].length];for(int i=0; i<matrixa.length; i++) {for(int j=0; j<matrixb[0].length; j++) {// i will complete this tomorrow @2012/09/17result[i][j] = calculateSingleResult(matrixa, matrixb, i, j); }}return result;} else{return null;}}private int calculateSingleResult(int[][] matrixa, int[][] matrixb, int row, int col) {int result = 0;for(int k=0; k<matrixa[0].length; k++) {result += matrixa[row][k] * matrixb[k][col];}return result;}/** * * @param matrixa * @param b */public int[][] multiplication(int[][] matrixa, int b) {for(int i=0; i<matrixa.length; i++) {for(int j=0; j<matrixa[0].length; j++) {matrixa[i][j] = matrixa[i][j] * b;}}return matrixa;}/** * validate whether the parameters is valid parameters. * * @param a * @param b * @param type * @return */private boolean legalOperation(int[][] a, int[][] b, int type) {boolean legal = true;if(type == OPERATION_ADD || type == OPERATION_SUB){if(a.length != b.length || a[0].length != b[0].length) {legal = false;}} else if(type == OPERATION_MUL){if(a[0].length != b.length) {legal = false;}}return legal;}/** * test code here !!!! * @param args */public static void main(String[] args) {int[][] a = new int[][]{{1,2},{3,4}};int[][] b = new int[][]{{7, 8}, {6, 5}};BasicMatrixMath bmm = new BasicMatrixMath();System.out.println("addition two matrix");int[][] result = bmm.add(a, b);for(int i=0; i<result.length; i++) {for(int j=0; j<result[0].length; j++) {System.out.print("\t" + result[i][j]);}System.out.println();}System.out.println("substract two matrix");result = bmm.substract(a, b);for(int i=0; i<result.length; i++) {for(int j=0; j<result[0].length; j++) {System.out.print("\t" + result[i][j]);}System.out.println();}System.out.println("multiplex one matrix");result = bmm.multiplication(a, 3);for(int i=0; i<result.length; i++) {for(int j=0; j<result[0].length; j++) {System.out.print("\t" + result[i][j]);}System.out.println();}System.out.println("multiplex two matrix");result = bmm.multiplication(a, b);for(int i=0; i<result.length; i++) {for(int j=0; j<result[0].length; j++) {System.out.print("\t" + result[i][j]);}System.out.println();}}}