60 lines
1.3 KiB
C
60 lines
1.3 KiB
C
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/* Driver for routine vegas */
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#include <stdio.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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long idum; /* for ranno */
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int ndim; /* for fxn */
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float xoff;
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float fxn(float pt[],float wgt)
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{
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int j;
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float ans,sum;
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for (sum=0.0,j=1;j<=ndim;j++) sum += (100.0*SQR(pt[j]-xoff));
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ans=(sum < 80.0 ? exp(-sum) : 0.0);
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ans *= pow(5.64189,(double)ndim);
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return ans;
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}
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int main(void)
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{
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int init,itmax,j,ncall,nprn;
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float avgi,chi2a,sd,xoff;
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float *regn;
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regn=vector(1,20);
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printf("IDUM=\n");
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scanf("%ld",&idum);
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if (idum > 0) idum = -idum;
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for (;;) {
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printf("ENTER NDIM,XOFF,NCALL,ITMAX,NPRN\n");
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if (scanf("%d %f %d %d %d",&ndim,&xoff,&ncall,&itmax,&nprn) == EOF) break;
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avgi=sd=chi2a=0.0;
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for (j=1;j<=ndim;j++) {
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regn[j]=0.0;
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regn[j+ndim]=1.0;
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}
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init = -1;
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vegas(regn,ndim,fxn,init,ncall,itmax,nprn,&avgi,&sd,&chi2a);
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printf("Number of iterations performed: %d\n",itmax);
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printf("Integral, Standard Dev., Chi-sq. = %12.6f %12.6f% 12.6f\n",
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avgi,sd,chi2a);
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init = 1;
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vegas(regn,ndim,fxn,init,ncall,itmax,nprn,&avgi,&sd,&chi2a);
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printf("Additional iterations performed: %d \n",itmax);
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printf("Integral, Standard Dev., Chi-sq. = %12.6f %12.6f% 12.6f\n",
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avgi,sd,chi2a);
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}
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free_vector(regn,1,20);
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printf("Normal completion\n");
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return 0;
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}
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#undef NRANSI
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