数值分析课题九十java源代码.rar_上机实验_东北大学_数值分析_泡泡龙数值_源代码

package nine; public class Nine { private double a; private double b; private double e; private int n; public Nine(){ a = 0; b = 0; n = 0; e = 0; } public Nine(double a,double b,int n,double e){ this.a = a; this.b = b; this.n = n; this.e = e; } public void Tn(int i){ double sum = 0; double h = (b-a)/n; for(int k= 1;k<n;k++){ double x = a + k*h; sum += fx(x,i); } sum = sum*h + (fx(a,i)+fx(b,i))*h/2; System.out.println("复化梯形公式求积分："+sum+" \tn:"+n); } public void Simpson(int i){ double sum = 0; double sum1 = 0; double sum2 = 0; double h = (b-a)/n; for(int k = 1;k<=n;k++){ double x = a + (k-0.5)*h; sum1+= fx(x,i); } for(int k=1;k<n;k++){ double x = a +k*h; sum2+=fx(x,i); } sum+= sum1*h*2/3 + sum2*h/3 + (fx(a,i)+fx(b,i))*h/6; System.out.println("复化Simpson公式求积分："+sum+"\tn:"+n); } public void Romberg(int i){ double sum = (64*C(2*n,i)-C(n,i))/63; System.out.println("Romberg公式求积分："+sum+"\tn:"+n); } public void GetN(int i){ int number = 1; double x1 = T(number,i); double x2 = T(2*number,i); for( number = 1;Math.abs(x2-x1)>=3*e;number*=2){ x1 = x2; x2 = T(4*number,i); } System.out.println("复化梯形公式(逐次分半)在达到精度为"+e+"时，n："+number+"步长："+(b-a)/number); number = 1; x1 = S(number,i); x2 = S(2*number,i); for( number = 1;Math.abs(x2-x1)>15*e;number*=2){ x1 = x2; x2 = S(4*number,i); } System.out.println("复化Simpon公式在达到精度为"+e+"时，n："+number+"步长："+(b-a)/number); number = 1; x1 = C(number,i); x2 = C(2*number,i); for( number = 1;Math.abs(x2-x1)>63*e;number*=2){ x1 = x2; x2 = C(4*number,i); } System.out.println("Romberg公式在达到精度为"+e+"时，n："+number+"步长："+(b-a)/number); } public double T(int n,int i){ if(n==1){ return (b-a)*(fx(a,i)+fx(b,i))/2; } else{ double h = (b-a)*2/n; double sum=0; for(int k = 0;k<n/2;k++){ double x = a + (k+0.5)*h; sum+= fx(x,i); } return T(n/2,i)/2+sum*h/2; } } public double S(int n,int i){ return (4*T(2*n,i)-T(n,i))/3; } public double C(int n,int i){ return (16*S(2*n,i)-S(n,i))/15; } public double fx(double x,int i){ if(i==1){ return Math.pow(4-Math.sin(x)*Math.sin(x), 0.5); } if(i==2){ if(x==0){ return 1; } return Math.sin(x)/x; } if(i==3){ return Math.pow(Math.E, x)/(4+x*x); } if(i==4){ return Math.log(1+x)/(1+x*x); } return 0; } }