java操作矩阵运算（基本运算及求逆）
前一段时间使用JAVA进行一些矩阵运算，看了JAVA的JAMA类，但看起来很多地方不明白，因此自己重新对矩阵的运算使用了一个类进行了实现，发出来希望可以对大家有用！
package Matrix_src;
public class Matrix {
private int r_num;
private int c_num;
private double[][] content;
public Matrix(int r, int c) {
this.r_num = r;
this.c_num = c;
this.content = new double[this.r_num][this.c_num];
for (int i = 0; i < r_num; i++)
for (int j = 0; j < c_num; j++) {
this.content[i][j] = 0;
}
}
public Matrix(double[][] in) {
this.r_num = in.length;
this.c_num = in[0].length;
this.content = new double[this.r_num][this.c_num];
for (int i = 0; i < r_num; i++)
for (int j = 0; j < c_num; j++) {
this.content[i][j] = in[i][j];
}
}
public Matrix(int r, int c, int module) {
this.r_num = r;
this.c_num = c;
this.content = new double[this.r_num][this.c_num];
for (int i = 0; i < this.r_num; i++)
for (int j = 0; j < this.c_num; j++) {
this.content[i][j] = (int) (Math.random() * module);
}
}
public Matrix add(Matrix A) {
if (this.r_num != A.r_num || this.c_num != A.c_num) {
return null;
}
Matrix B = new Matrix(A.r_num, A.c_num);
for (int i = 0; i < r_num; i++) {
for (int j = 0; j < c_num; j++) {
B.content[i][j] = this.content[i][j] + A.content[i][j];
}
}
return B;
}
public Matrix add(Matrix A, double module) {
if (this.r_num != A.r_num || this.c_num != A.c_num) {
return null;
}
Matrix B = new Matrix(A.r_num, A.c_num);
for (int i = 0; i < r_num; i++) {
for (int j = 0; j < c_num; j++) {
B.content[i][j] = (this.content[i][j] + A.content[i][j]) % module;
}
}
return B;
}
// compute this-A
public Matrix sub(Matrix A) {
if (this.r_num != A.r_num || this.c_num != A.c_num) {
return null;
}
Matrix B = new Matrix(A.r_num, A.c_num);
for (int i = 0; i < r_num; i++) {
for (int j = 0; j < c_num; j++) {
B.content[i][j] = this.content[i][j] - A.content[i][j];
}
}
return B;
}
public Matrix sub(Matrix A, double module) {
if (this.r_num != A.r_num || this.c_num != A.c_num) {
return null;
}
Matrix B = new Matrix(A.r_num, A.c_num);
for (int i = 0; i < r_num; i++) {
for (int j = 0; j < c_num; j++) {
double tmp = this.content[i][j] - A.content[i][j];
if (tmp >= 0)
B.content[i][j] = tmp % module;
if (tmp < 0)
B.content[i][j] = tmp % module + module;
}
}
return B;
}
// compute this*A
public Matrix multiply(Matrix A) {
if (this.c_num != A.r_num) {
return null;
}
Matrix B = new Matrix(this.r_num, A.c_num);
for (int i = 0; i < this.r_num; i++) // the row of the this
{
for (int j = 0; j < A.c_num; j++) // the column of the A
{
double temp = 0;
for (int k = 0; k < A.r_num; k++) // the row of A
{
temp += this.content[i][k] * A.content[k][j];
}
B.content[i][j] = temp;
}
}
return B;
}
public Matrix multiply(Matrix A,int module) {
if (this.c_num != A.r_num) {
return null;
}
Matrix B = new Matrix(this.r_num, A.c_num);
for (int i = 0; i < this.r_num; i++) // the row of the this
{
for (int j = 0; j < A.c_num; j++) // the column of the A
{
double temp = 0;
for (int k = 0; k < A.r_num; k++) // the row of A
{
temp += this.content[i][k] * A.content[k][j]%module;
}
B.content[i][j] = temp;
}
}
return B;
}
public double Matrix2Det(){
double sum=this.content[0][0]*this.content[1][1]-this.content[0][1]*this.content[1][0];
return sum;
}
public void CompanionMatrix(Matrix in,int r,int c){
this.r_num=in.r_num-1;
this.c_num=in.c_num-1;
int k=0;
for(int i=0;i<in.r_num;i++)
{
int z=0;
if(i==r)
i++;
if(i==in.r_num)
break;
for(int j=0;j<in.c_num;j++)
{
if(j==c)
j++;
if(j==in.c_num)
break;
this.content[k][z]=in.content[i][j];
z++;
}
k++;
}
}
private int IndexOfNe1(int n){
int sum=1;
for(int i=0;i1;
return sum;
}
//comput the determinant of a matrix
public double MatrixDet(){
if(this.c_num!=this.r_num)
return 0;
else{
int num=this.c_num;
double sum=0;
if(this.c_num==2){
return this.Matrix2Det();
}
if(this.c_num>3){
for(int i=0;inew Matrix(num-1,num-1);
tmp.CompanionMatrix(this, 0, i);
sum+=this.content[0][i]*tmp.MatrixDet()*IndexOfNe1(i);
}
return sum;
}
else{
return this.Matrix3Det();
}
}
}
//comput the determinant of a 3-matrix
public double Matrix3Det(){
if(this.r_num!=this.c_num)
return 0;
int num=this.r_num;
double[] re_tmp=new double[this.c_num];
double sum1=0;
double sum2=0;
for(int k=0;k1;
int i=0;
int j=0;
for(int z=0;zif(k+zthis.content[z][k+z];
}
else{
re_tmp[k]*=this.content[num-i-1][k-j-1];
i++;
j++;
}
}
sum1+=re_tmp[k];
}
for(int k=num-1;k>=0;k--){
re_tmp[k]=1;
int i=0;
int j=0;
for(int z=0;zif(k-z>=0){
re_tmp[k]*=this.content[z][k-z];
}
else{
re_tmp[k]*=this.content[num-i-1][k+j+1];
i++;
j++;
}
}
sum2+=re_tmp[k];
}
return sum1-sum2;
}
public Matrix MatrixInverse(){
double det=this.MatrixDet();
if(det==0)
return null;
Matrix re=new Matrix(this.r_num,this.c_num);
for(int i=0;i<this.r_num;i++){
for(int j=0;j<this.c_num;j++){
Matrix tmp=new Matrix(this.r_num-1,this.c_num-1);
tmp.CompanionMatrix(this, i, j);
re.content[i][j]=tmp.MatrixDet()/det*IndexOfNe1(i+j);
}
}
return re.Transpose();
}
public Matrix Transpose() {
Matrix re = new Matrix(this.r_num, this.c_num);
for (int i = 0; i < this.r_num; i++) {
for (int j = 0; j < this.c_num; j++) {
re.content[j][i] = this.content[i][j];
}
}
return re;
}
public void printMatlab() {
System.out.print("[");
for (int i = 0; i < this.r_num; i++) {
for (int j = 0; j < this.c_num; j++)
{
System.out.print(this.content[i][j]);
if(j!=this.c_num-1)
System.out.print(" ");
}
if(i<this.r_num-1)
System.out.print(";");
}
System.out.println("]");
}
public void print() {
for (int i = 0; i < this.r_num; i++) {
for (int j = 0; j < this.c_num; j++)
{
System.out.print(this.content[i][j]);
System.out.print(" ");
}
System.out.println(" ");
}
System.out.println(" ");
}
public static void main(String[] args) {
double[][] a = { { 10, 22 }, { 15, 23 } };
double[][] a1 = { { 0, 1,2 }, { 1, 1,4 } ,{2,-1,0}};
double[][] a2={{1,2,3},{2,2,1},{3,4,3}};
double[][] a3={{1,1,1,1},{2,4,3,1},{4,16,9,1},{8,64,27,1}};
double[][] a4={{-2,2,-4,0,5},{2,1,2,0,5},{4,3,1,2,7},{3,1,2,4,-5},{6,-1,2,7,-5}};
Matrix A = new Matrix(a4);
Matrix B = new Matrix(5,5);
System.out.println(A.MatrixDet());
A.print();
B=A.MatrixInverse();
B.print();
//System.out.println("attention"+" "+A.MatrixDet());
Matrix C=A.multiply(B);
C.print();
}
}
JAVA也是刚开始尝试着写，可能还存在较多的缺陷，例如矩阵求逆算法的效率存在较大问题，希望大家谅解，谢谢！
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