xsplie2.c

来自「< C语言数值算法程序大全>>配套程序」· C语言 代码 · 共 44 行

/* Driver for routine splie2 */

#include <stdio.h>
#include "nr.h"
#include "nrutil.h"

#define M 10
#define N 10

main()
{
	int i,j;
	float x1x2,*x1,*x2,**y,**y2;

	x1=vector(1,N);
	x2=vector(1,N);
	y=matrix(1,M,1,N);
	y2=matrix(1,M,1,N);
	for (i=1;i<=M;i++) x1[i]=0.2*i;
	for (i=1;i<=N;i++) x2[i]=0.2*i;
	for (i=1;i<=M;i++)
		for (j=1;j<=N;j++) {
			x1x2=x1[i]*x2[j];
			y[i][j]=x1x2*x1x2;
		}
	splie2(x1,x2,y,M,N,y2);
	printf("\nsecond derivatives from SPLIE2\n");
	printf("natural spline assumed\n");
	for (i=1;i<=5;i++) {
		for (j=1;j<=5;j++) printf("%12.6f",y2[i][j]);
		printf("\n");
	}
	printf("\nactual second derivatives\n");
	for (i=1;i<=5;i++) {
		for (j=1;j<=5;j++) printf("%12.6f",2.0*x1[i]*x1[i]);
		printf("\n");
	}
	free_matrix(y2,1,M,1,N);
	free_matrix(y,1,M,1,N);
	free_vector(x2,1,N);
	free_vector(x1,1,N);
	return 0;
}