matrix.java.bak

能完成矩阵的基本操作(加,减,乘,除,转置,求逆等)

public class Matrix{
	private int h;//成员变量，矩阵行数		
	private int w;//成员变量，矩阵列数
    private int[][] matrix;
	public Matrix(int h,int w){//构造函数，h为行数，w为列数
		if(!(h > 0 && w > 0))
			throw new ArrayIndexOutOfBoundsException("h or w  < " + 1);
		matrix = new int[h][w];	//创建有h行的对象
		this.h = h;
		this.w = w;
	}
	
	public void set(int row,int col,int value){//置元素
		if(!(row >= 0 && w >= 0 && row < h && col <w))
			throw new ArrayIndexOutOfBoundsException("h or w  < " + "-1");
		matrix[row][col]=(int)value;
	}
	
	public Object get(int row,int col){	//取元素
		if(!(row >= 0 && w >= 0 && row < h && col <w))
			throw new ArrayIndexOutOfBoundsException("h or w  < " + "-1");
		return matrix[row][col]; 
	}
	
	public int width(){	//矩阵列数
		return w;
	}
	
	public int height(){//矩阵行数
		return h;
	}
	
	public Matrix add(Matrix b){//矩阵加
		if(height() != b.height() || width()!= b.width()){
			throw new ArrayIndexOutOfBoundsException("Matrix h and w error");
		}
		
		Matrix result = new Matrix(height(),width());
		
		for(int i = 0;i < height();i ++){
			for(int j = 0;j < width(); j ++){
				Integer i1 = (Integer)get(i,j);
				Integer i2 = (Integer)(b.get(i,j));				
				result.set(i,j,new Integer(i1.intValue()+i2.intValue()));
			}
		}
		
		return result;
	}

	public Matrix minus(Matrix b){//矩阵减
		if(height() != b.height() || width()!= b.width()){
			throw new ArrayIndexOutOfBoundsException("Matrix h and w error");
		}
		
		Matrix result = new Matrix(height(),width());
		
		for(int i = 0;i < height();i ++){
			for(int j = 0;j < width(); j ++){
				Integer i1 = (Integer)get(i,j);
				Integer i2 = (Integer)(b.get(i,j));				
				result.set(i,j,new Integer(i1.intValue()-i2.intValue()));
			}
		}
		
		return result;
	}

	public Matrix mul(Matrix b){//矩阵乘
	        if(width()!=b.height()){
			throw new ArrayIndexOutOfBoundsException("Matrix h and w error");
		}

		Matrix result = new Matrix(height(),b.width());
		
		for (int i = 0; i < height(); i++) { 
			for (int j = 0; j < b.width(); j++) { 
			int sum = 0; 
				for (int k = 0; k < width(); k++) { 
					Integer i1 = (Integer)get(i,k);
					Integer i2 = (Integer)(b.get(k,j));
					sum =sum+i1.intValue()*i2.intValue(); 
					} 
			result.set(i,j,sum);
			}
		}
		return result;
	}

	public Matrix turn(){//矩阵转置
		
		Matrix result = new Matrix(width(),height());
		
		for(int i = 0;i < height();i ++){
			for(int j = 0;j < width(); j ++){
				Integer i1 = (Integer)get(j,i);
				result.set(i,j,new Integer(i1.intValue()));
			}
		}
		
		return result;
	}

	public Matrix det(int m, int n){ //求行列式的amn的余子式
		 
		Matrix result = new Matrix(h-1,w-1); 

		if (m > h || n > w){ 
			throw new ArrayIndexOutOfBoundsException("求行列式的a" + m + n + "的余子式时参数错误."); 
		}
		if(h!=w){
			throw new ArrayIndexOutOfBoundsException("不是方阵，不存在余子式。"); 
		}
		for (int i = 0,a = 0; i < h; i++){ //a为新行
			if ((m-1) != i){ 
				for (int j = 0, b = 0; j <w; j++){ //b为新列
					if ((n - 1) != j){ 
						Integer i1 = (Integer)get(i,j);
						result.set(a,b,new Integer(i1.intValue())); 
							 

								b++; 
								} 
							} 
							a++; 
						} 
					} 
					return result; 
		} 

	public double getvalue(){ //求行列式的值
		int result=0;
		if(h==w){
			if(h==1){
				return matrix[0][0];
			}
			else{
				for(int i=0;i<w;i++){
					Matrix temp=det(1,i+1);
					if ((i+2) % 2 == 1){
					result += -1*matrix[0][i] * temp.getvalue(); }
					else{
						result += matrix[0][i] * temp.getvalue();
					}	
				}
				return result;
			}
		}
		else{
			throw new ArrayIndexOutOfBoundsException("不是方阵，不能求值。"); 
			}			
		}

	public Matrix bansui(){  //求伴随矩阵
		if(h!=w){
			throw new ArrayIndexOutOfBoundsException("不是方阵，不存在伴随矩阵。"); 
		}
		
		Matrix result=new Matrix(h,w);
		for(int i=0;i<h;i++){
			for(int j=0;j<w;j++){
				int temp=(int)(this.det(i+1,j+1).getvalue());
				if((i+j+2)%2==1){
				result.set(j,i,-1*temp);}
				else{
					result.set(j,i,temp);}
			}	
		}
		return result;
	}

	public Matrix ni(){  //求逆矩阵
		if(h!=w){
			throw new ArrayIndexOutOfBoundsException("不是方阵，不存在逆矩阵。"); 
		}

		if(this.getvalue()==0){
			throw new ArrayIndexOutOfBoundsException("行列式值为0，逆矩阵不存在。"); 
		}
		Matrix result=new Matrix(h,w);
		for(int i=0;i<h;i++){
			for(int j=0;j<w;j++){
				int temp=(int)(this.matrix[i][j]/(this.getvalue()));
				result.set(i,j,temp);
			}
		}
		return result;
	}

	public void print(){  //输出矩阵元素
		for(int i = 0; i < h; i++){
			for(int j = 0; j < w; j++){
				System.out.print(matrix[i][j]+"\t");
			}
			System.out.println();
		}
	}	
}