43 lines
850 B
C
43 lines
850 B
C
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/* Driver for routine gammln */
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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,nval;
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float actual,calc,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,"Gamma Function",14)) {
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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("%10s %21s %21s\n","x","actual","gammln(x)");
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for (i=1;i<=nval;i++) {
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fscanf(fp,"%f %f",&x,&actual);
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if (x > 0.0) {
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calc=(x<1.0 ? gammln(x+1.0)-log(x) : gammln(x));
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printf("%12.2f %20.6f %20.6f\n",x,
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log(actual),calc);
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}
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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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