46 lines
936 B
C
46 lines
936 B
C
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/* Driver for routine plgndr */
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <math.h>
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#define NRANSI
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#include "nr.h"
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#include "nrutil.h"
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#define MAXSTR 80
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int main(void)
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{
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char txt[MAXSTR];
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int i,j,m,n,nval;
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float fac,val,x;
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FILE *fp;
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if ((fp = fopen("fncval.dat","r")) == NULL)
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nrerror("Data file fncval.dat not found\n");
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fgets(txt,MAXSTR,fp);
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while (strncmp(txt,"Legendre Polynomials",20)) {
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fgets(txt,MAXSTR,fp);
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if (feof(fp)) nrerror("Data not found in fncval.dat\n");
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}
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fscanf(fp,"%d %*s",&nval);
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printf("\n%s\n",txt);
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printf("%4s %4s %10s %17s %24s\n","n",
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"m","x","actual","plgndr(n,m,x)");
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for (i=1;i<=nval;i++) {
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fscanf(fp,"%d %d %f %f",&n,&m,&x,&val);
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fac=1.0;
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if (m > 0)
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for (j=n-m+1;j<=n+m;j++) fac *= j;
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fac *= 2.0/(2.0*n+1.0);
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val *= sqrt(fac);
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printf("%4d %4d %13.6f %19.6e %19.6e\n",
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n,m,x,val,plgndr(n,m,x));
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}
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fclose(fp);
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return 0;
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}
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#undef NRANSI
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