求矩阵伴随矩阵 java实现

[java]代码库

import java.util.Scanner;

/*求矩阵的伴随矩阵*/
public class ajoint_matrix {
	
	private static float[][] get_complement(float[][] data, int i, int j) {

		/* x和y为矩阵data的行数和列数 */
		int x = data.length;
		int y = data[0].length;

		/* data2为所求剩余矩阵 */
		float data2[][] = new float[x - 1][y - 1];
		for (int k = 0; k < x - 1; k++) {
			if (k < i) {
				for (int kk = 0; kk < y - 1; kk++) {
					if (kk < j) {
						data2[k][kk] = data[k][kk];
					} else {
						data2[k][kk] = data[k][kk + 1];
					}
				}

			} else {
				for (int kk = 0; kk < y - 1; kk++) {
					if (kk < j) {
						data2[k][kk] = data[k + 1][kk];
					} else {
						data2[k][kk] = data[k + 1][kk + 1];
					}
				}
			}
		}
		return data2;

	}

	/* 计算矩阵行列式 */
	private static float cal_det(float[][] data) {
		float ans=0;
		/*若为2*2的矩阵可直接求值并返回*/
		if(data[0].length==2){
			 ans=data[0][0]*data[1][1]-data[0][1]*data[1][0];
		}
		else{
			for(int i=0;i<data[0].length;i++){
				/*若矩阵不为2*2那么需求出矩阵第一行代数余子式的和*/
				float[][] data_temp=get_complement(data, 0, i);
				if(i%2==0){
					/*递归*/
					ans=ans+data[0][i]*cal_det(data_temp);
				}
				else{
					ans=ans-data[0][i]*cal_det(data_temp);
				}
			}
		}
		return ans;

	}
	
	/*计算矩阵的伴随矩阵*/
	private static float[][] ajoint(float[][] data) {
		int M=data.length;
		int N=data[0].length;
		float data2[][]=new float[M][N];
		for(int i=0;i<M;i++){
			for(int j=0;j<N;j++){
			if((i+j)%2==0){
				data2[i][j]=cal_det(get_complement(data, i, j));
			}
			else{
				data2[i][j]=-cal_det(get_complement(data, i, j));
			}
			}
		}
		
		/*将矩阵转置*/
		return trans(data2);
		

	}
	
	/*转置矩阵*/
	private static float [][]trans(float[][] data){
		int i=data.length;
		int j=data[0].length;
		float[][] data2=new float[j][i];
		for(int k2=0;k2<j;k2++){
			for(int k1=0;k1<i;k1++){
				data2[k2][k1]=data[k1][k2];
			}
		}
		
		return data2;
		
	}

	public static void main(String[] args) {
		/* 输入原矩阵矩阵 */
		Scanner scan = new Scanner(System.in);
		System.out.println("输入矩阵的行数和列数");
		int x = scan.nextInt();
		int y = scan.nextInt();
		float data[][] = new float[x][y];
		System.out.println("输入矩阵");
		for (int k = 0; k < x; k++) {
			for (int kk = 0; kk < y; kk++) {
				data[k][kk] = scan.nextFloat();
			}
		}
		System.out.println("该矩阵的伴随矩阵为：");
		float data2[][]=new float[x][y];
		
		data2=ajoint(data);
		for(int i=0;i<data2.length;i++)
		{
			for(int j=0;j<data2[0].length;j++){
				System.out.print(data2[i][j]+" ");
			}
			System.out.println();
		}

	}

}
//源代码片段来自云代码http://yuncode.net