zhuigf.cpp

计算方法计算方法程序sanciyangtiaochazhi 三次样条插值法.rar

#include<iostream.h>

void zhuigf(double *u,double*l,double*d,int N)
{
//	int N;
//	cout<<"输入未知数个数:";
//	cin>>N;
	double *a,*b,*c,*f;
	a=new double[N+1];
	b=new double[N+1];
	c=new double[N+1];
	f=new double[N+1];

	int i;

//	cout<<"请输入矩阵下面次对角线的各数:"<<endl;
	for(i=2;i<=N;i++)
	a[i]=u[i-1];

//	cout<<"请输入矩阵主对角线的各数:"<<endl;
	for(i=1;i<=N;i++)
	b[i]=2;

//	cout<<"请输入矩阵上面次对角线的各数:"<<endl;
	for(i=1;i<=N-1;i++)
	c[i]=l[i-1];

//	cout<<"请输入右侧矩阵的各数:"<<endl;
	for(i=1;i<=N;i++)
	f[i]=d[i-1];
	

	c[1]=c[1]/b[1];
	for(i=2;i<=N;i++)
	{
		c[i]=c[i]/(b[i]-a[i]*c[i-1]);
	}

	f[1]=f[1]/b[1];	
	for(i=2;i<=N;i++)
	{
		f[i]=(f[i]-a[i]*f[i-1])/(b[i]-a[i]*c[i-1]);
	}

	
	for(i=N-1;i>=1;i--)
	{
		f[i]=f[i]-c[i]*f[i+1];
	}

//	cout<<endl<<"方程组的解为:"<<endl;
	for(i=1;i<=N;i++)
	{
		d[i-1]=f[i];
		cout<<"M["<<i-1<<"]="<<d[i-1]<<endl;
	}
	delete []a;
	delete []b;
	delete []c;
	delete []f;

	
}