#include <stdio.h>
#include <math.h>
#define NRANSI
#include "nrutil.h"
#define NE 3
#define M 41
#define NB 1
#define NSI NE
#define NYJ NE
#define NYK M
#define NCI NE
#define NCJ (NE-NB+1)
#define NCK (M+1)
#define NSJ (2*NE+1)

int mm,n,mpt=M;
float h,c2=0.0,anorm,x[M+1];

int main(void)  /* Program sfroid */
{
	float plgndr(int l, int m, float x);
	void solvde(int itmax, float conv, float slowc, float scalv[],
		int indexv[], int ne, int nb, int m, float **y, float ***c, float **s);
	int i,itmax,k,indexv[NE+1];
	float conv,deriv,fac1,fac2,q1,slowc,scalv[NE+1];
	float **y,**s,***c;

	y=matrix(1,NYJ,1,NYK);
	s=matrix(1,NSI,1,NSJ);
	c=f3tensor(1,NCI,1,NCJ,1,NCK);
	itmax=100;
	conv=5.0e-6;
	slowc=1.0;
	h=1.0/(M-1);
	printf("\nenter m n\n");
	scanf("%d %d",&mm,&n);
	if (n+mm & 1) {
		indexv[1]=1;
		indexv[2]=2;
		indexv[3]=3;
	} else {
		indexv[1]=2;
		indexv[2]=1;
		indexv[3]=3;
	}
	anorm=1.0;
	if (mm) {
		q1=n;
		for (i=1;i<=mm;i++) anorm = -0.5*anorm*(n+i)*(q1--/i);
	}
	for (k=1;k<=(M-1);k++) {
		x[k]=(k-1)*h;
		fac1=1.0-x[k]*x[k];
		fac2=exp((-mm/2.0)*log(fac1));
		y[1][k]=plgndr(n,mm,x[k])*fac2;
		deriv = -((n-mm+1)*plgndr(n+1,mm,x[k])-
			(n+1)*x[k]*plgndr(n,mm,x[k]))/fac1;
		y[2][k]=mm*x[k]*y[1][k]/fac1+deriv*fac2;
		y[3][k]=n*(n+1)-mm*(mm+1);
	}
	x[M]=1.0;
	y[1][M]=anorm;
	y[3][M]=n*(n+1)-mm*(mm+1);
	y[2][M]=(y[3][M]-c2)*y[1][M]/(2.0*(mm+1.0));
	scalv[1]=fabs(anorm);
	scalv[2]=(y[2][M] > scalv[1] ? y[2][M] : scalv[1]);
	scalv[3]=(y[3][M] > 1.0 ? y[3][M] : 1.0);
	for (;;) {
		printf("\nEnter c**2 or 999 to end.\n");
		scanf("%f",&c2);
		if (c2 == 999) {
			free_f3tensor(c,1,NCI,1,NCJ,1,NCK);
			free_matrix(s,1,NSI,1,NSJ);
			free_matrix(y,1,NYJ,1,NYK);
			return 0;
		}
		solvde(itmax,conv,slowc,scalv,indexv,NE,NB,M,y,c,s);
		printf("\n %s %2d %s %2d %s %7.3f %s %10.6f\n",
			"m =",mm,"  n =",n,"  c**2 =",c2,
			" lamda =",y[3][1]+mm*(mm+1));
	}
}
#undef NRANSI
