基本矩阵运算的Java实现

基本矩阵运算的Java实现

分类： 图像处理2012-09-18
10:36 2537人阅读 评论(3) 收藏 举报

javamatrixparametersstringclassnull

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：

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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 @2012/09/17

result[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();

}

}

}