泛型矩阵类进行加乘运算

Posted 2022-12-08 夏芷雨涵梦

题目描述：对于所有的矩阵，除了元素类型不同以外，他们的加法和乘法操作都是类似的。因此，可以设计一个父类，不管他们的元素类型是什么，该父类描述所有类型的矩阵共享的通用的操作，还可以创建若干个适用于指定矩阵类型的子类。本文给出了Int和有理数类Rational的实现。

时间：2019.3.30

代码：

public abstract class GenericMatrix <E extends Number>
	protected abstract E add(E o1,E o2);
	protected abstract E multiply(E o1,E o2);
	protected abstract E zero();
	public E[][] addMatrix(E[][]matrix1,E[][]matrix2)
		if((matrix1.length!=matrix2.length)||(matrix1[0].length!=matrix2[0].length))
			throw new RuntimeException("The matrices do not have the same size");
			
		
		E[][] result=(E[][])new Number[matrix1.length][matrix1[0].length];
		for(int i=0;i<result.length;i++)
			for(int j=0;j<result[i].length;j++)
				result[i][j]=add(matrix1[i][j],matrix2[i][j]);
			
		return result;
	
	public E[][] mulyiplyMartix(E[][]matrix1,E[][]matrix2)
		if((matrix1.length!=matrix2.length)||(matrix1[0].length!=matrix2[0].length))
			throw new RuntimeException("The matrices do not have the same size");
			
		
		E[][] result=(E[][])new Number[matrix1.length][matrix2[0].length];
		for(int i=0;i<result.length;i++)
			for(int j=0;j<result[0].length;j++)
				result[i][j]=zero();
				for(int k=0;k<matrix1[0].length;k++)
					result[i][j]=add(result[i][j],multiply(matrix1[i][k],matrix2[k][j]));
				
				
			
		return result;
		
	
	public static void printResult(Number[][] m1,Number[][] m2,Number[][]m3,char op)
		for(int i=0;i<m1.length;i++)
			for(int j=0;j<m1[0].length;j++)
				System.out.print(" "+m1[i][j]);
			if(i==m1.length/2)
				System.out.print(" "+op+" ");
			else
				System.out.print("   ");
			for(int j=0;j<m2.length;j++)
				System.out.print(" "+m2[i][j]);
			if(i==m1.length/2)
				System.out.print(" = ");
			else
				System.out.print("   ");
			for(int j=0;j<m3.length;j++)
				System.out.print(m3[i][j]+" ");
			System.out.println();
			
		
	

public class IntegerMatrix extends GenericMatrix<Integer>

	@Override
	protected Integer add(Integer o1, Integer o2) 
		return o1+o2;
	

	@Override
	protected Integer multiply(Integer o1, Integer o2) 
		return o1*o2;
	

	@Override
	protected Integer zero() 
		return 0;
	
	

public class RationalMatrix extends GenericMatrix<Rational>
	@Override
	protected Rational add(Rational o1, Rational o2) 
		return o1.add(o2);
	

	@Override
	protected Rational multiply(Rational o1, Rational o2) 
		return o1.multiply(o2);
	
	
	@Override
	protected Rational zero() 
		return new Rational(0,1);
	

public class Rational extends Number
	private long numerator=0;
	private long denominator=1;
	public Rational()
		this(0,1);
	
	public Rational(long num1,long num2)
		long gcd=gcd(num1,num2);
		this.numerator=(num2>0?1:-1)*num1/gcd;
		this.denominator=Math.abs(num2)/gcd;
	
	private static long gcd(long n,long d)
		long n1=Math.abs(n);
		long n2=Math.abs(d);
		int gcd=1;
		for(int k=1;k<=n1&&k<=n2;k++)
			if(n1%k==0&&n2%k==0)
				gcd=k;
		
		return gcd;
	
	public String toString()
		if(denominator==1)
			return numerator+"";
		else
			return numerator+"/"+denominator;
	
	@Override
	public double doubleValue() 
		// TODO 自动生成的方法存根
		return numerator*1.0/denominator;
	
	@Override
	public float floatValue() 
		// TODO 自动生成的方法存根
		return (float) doubleValue();
	
	@Override
	public int intValue() 
		// TODO 自动生成的方法存根
		return (int) doubleValue();
	
	@Override
	public long longValue() 
		// TODO 自动生成的方法存根
		return (long) doubleValue();
	
	public long getNumerator()
		return numerator;
	
	public long GetDenominator()
		return denominator;
	
	public Rational add(Rational second)
		long n=numerator*second.GetDenominator()+denominator*second.getNumerator();
		long d=denominator*second.GetDenominator();
		return new Rational(n,d);
	
	public Rational multiply(Rational second)
		long n=numerator*second.getNumerator();
		long d=denominator*second.GetDenominator();
		return new Rational(n,d);
	

public class TestIntegerMatrix 
	public static void main(String args[])
		Integer[][] m1=new Integer[][]1,2,3,4,5,6,1,1,1;
		Integer[][] m2=new Integer[][]1,1,1,2,2,2,0,0,0;
		IntegerMatrix integerMatrix=new IntegerMatrix();
		System.out.println("\\nm1+m2 is");
		GenericMatrix.printResult(m1, m2, integerMatrix.addMatrix(m1, m2), '+');
		System.out.println("\\nm1*m2 is");
		GenericMatrix.printResult(m1, m2, integerMatrix.mulyiplyMartix(m1, m2), '+');
	

public class TestRationalMatrix 
	public static void main(String []args)
	Rational[][] m1=new Rational[3][3];
	Rational[][] m2=new Rational[3][3];
	for(int i=0;i<m1.length;i++)
	   for(int j=0;j<m1[0].length;j++)
		m1[i][j]=new Rational(i+1,j+5);
		m2[i][j]=new Rational(i+1,j+6);
		
	
	RationalMatrix rationalMartrix=new RationalMatrix();
	System.out.println("\\nm1+m2 is");
	GenericMatrix.printResult(m1, m2, rationalMartrix.addMatrix(m1, m2), '+');
	
	System.out.println("\\nm1*m2 is");
	GenericMatrix.printResult(m1, m2, rationalMartrix.mulyiplyMartix(m1, m2), '*');
	

IntegerMatrix和RationalMatrix是GenericMatrix的具体子类。这两个类实现了在GenericMatrix类中定义的add、multiply和zero方法。矩阵元素的类型Number的泛型子类。这样就可以使用任意Number子类的对象，只要在子类中实现了add、multiply和zero方法就可以使用它们。