java实现牛顿插值法

[java]代码库

import java.util.Scanner;


public class Newton_interpolation {
	/*拷贝向量*/
	private static void copy_vector(double from[],double to[]){
		int k=from.length;
		int k2=to.length;
		if(k!=k2){
			System.out.println("the two vector's length is not equal!");
			System.exit(0);
		}
		for(int i=0;i<k;i++){
			to[i]=from[i];
		}
		
	}
	
	/*牛顿插值法*/
	private static double[] Newton_inter_method(double[] X,double[] Y,double X0[]){
		int m=X.length;
		int n=X0.length;
		double[] Y0=new double[n];
		double[] cp_Y=new double[m];
		for(int i1=0;i1<n;i1++){//遍历X0
			double t=0;
			int j=0;
			copy_vector(Y, cp_Y);
			int kk=j;
			/*求各级均差*/
			while(kk<m-1){
				kk=kk+1;
				for(int i2=kk;i2<m;i2++){
					cp_Y[i2]=(cp_Y[i2]-cp_Y[kk-1])/(X[i2]-X[kk-1]);
				}
			}
			/*求插值结果*/
			double temp=cp_Y[0];
			for(int i=1;i<=m-1;i++){
				double u=1;
				int jj=0;
				while(jj<i){
					u*=(X0[i1]-X[jj]);
					jj++;
				}
				temp+=cp_Y[i]*u;
			}
			
			Y0[i1]=temp;
		}
		
		return Y0;
	}
	

	public static void main(String[] args) {
		/*输入插值点横纵坐标*/
		System.out.println("Input number of interpolation point:");
		Scanner scan=new Scanner(System.in);
		int m=scan.nextInt();
		System.out.println("Input number of test point:");
		int n=scan.nextInt();
		double X[]=new double[m];
		double Y[]=new double[m];
		double X0[]=new double[n];
		System.out.println("Input the elements of X:");//已知插值点
		for(int i=0;i<m;i++){
			X[i]=scan.nextDouble();
		}
		
		System.out.println("Input the elements of Y:");//已知插值点的函数值
		for(int i=0;i<m;i++){
			Y[i]=scan.nextDouble();
		}
		
		System.out.println("Input the elements of X0:");//需要求的插值点的横坐标标值
		for(int i=0;i<n;i++){
			X0[i]=scan.nextDouble();
		}
		
		

	}

}
//源代码片段来自云代码http://yuncode.net