数值分析源代码.docVIP

一,三次样条插值 #includeiostream.h #includestdlib.h void ready(double*A,double*B,double*h,double*y,int m,int n,double m0=0,double mn=0) {A=new double[n];B=new double[n]; if(m==2){ A[0]=0;B[0]=2*m0; A[n]=1;B[n]=2*mn; } else {A[0]=1;B[0]=3*(y[1]-y[0])/h[0]; A[n]=0;B[n]=3*(y[n]-y[n-1])/h[n-1]; } for(int i=1;in;i++) {A[i]=h[i-1]/(h[i-1]+h[i]); B[i]=3*((1-A[i])*(y[i]-y[i-1])/h[i-1]+A[i]*(y[i+1]-y[i])/h[i]); } } void calculate1(double*a,double*b,double*A,double*B,int n) {a=new double[n];b=new double[n]; a[0]=-A[0]/2;b[0]=B[0]/2; for(int i=1;i=n;i++) {a[i]=-A[i]/(2+(1-A[i])*a[i-1]); b[i]=(B[i]-(1-A[i])*b[i-1])/(2+(1-A[i])*a[i-1]); } } void calculate2(double*m,double*a,double*b,int n) {m=new double[n+1]; m[n+1]=0; for(int i=n;i=0;i--)m[i]=m[i+1]*a[i]+b[i]; } void main() {int e,t,w,v; out: cout求三次样条插值函数:endl请输入函数表中x,y的对数:endl; cine; double*x,*y,*h,*A,*B,*a,*b,*m,s0,sn,u,s; cout请输入x的一系列值:endl; x=new double[e]; for(int i=0;ie;i++)cinx[i]; cout请输入y的一系列值:endl; y=new double[e]; for(int f=0;fe;f++)ciny[f]; h=new double[e]; for(int d=0;de;d++)h[d]=x[d+1]-x[d]; loop: cout边界条件选择: 1.提供了s\(x1)=0,s\(x2)=0; 2.提供了s(x0)=m0,s(xn)=mn (m0,mn!=0) endl; cint; if(t!=1t!=2){cout输入信息错误!请重新输入!endl;goto loop;} if(t==1)ready(A,B,h,y,t,e); else {cout请输入s(x0),s(xn)的值:endl; cins0sn; ready(A,B,h,y,t,e,s0,sn);} calculate1(a,b,A,B,e); calculate2(m,a,b,e); in: cout请输入所需要计算的x的值: (x[0]xx[e-1])endl; cinu; if(ux[0]||ux[e-1]){cout输入数据错误!endl;goto in;} for(int c=0;ce;c++) {if(ux[c]ux[c+1])w=c;} s=(1+2*(u-x[w])/(x[w+1]-x[w]))*((u-x[w+1])*(u-x[w+1])/((x[w]-x[w+1])*(x[w]-x[w+1])))*y[w]+ (1+2*(u-x[w+1])/(x[w]-x[w+1]))*((u-x[w])*(u-x[w])/((x[w+1]-x[w])*(x[w+1]-x[w])))*y[w+1]+ (u-x[w])*((u-x[w+1])*(u-x[w+1])/((x[w]-x[w+1])*(x[w]-x[w+1])))*m[w]+ (u-x[w+1])*((u-x[w])*(u-x[w])/((x[w+1]-x[w])*(x[w+1]-x[w])))*m[w+1]; coutf(u)的近似值为: endlsendl; In: cout请选择:1,继续进行新的操作计算 2,退出不计算 endl; cinv; if(v!=1v!=2){cout输入错误!请重新输入!endl;goto In;} if(v==1){system(cls);goto out;}