92 lines
2.1 KiB
C
92 lines
2.1 KiB
C
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/* Driver for routine mrqmin */
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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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#define NPT 100
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#define MA 6
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#define SPREAD 0.001
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int main(void)
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{
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long idum=(-911);
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int i,*ia,iter,itst,j,k,mfit=MA;
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float alamda,chisq,ochisq,*x,*y,*sig,**covar,**alpha;
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static float a[MA+1]=
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{0.0,5.0,2.0,3.0,2.0,5.0,3.0};
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static float gues[MA+1]=
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{0.0,4.5,2.2,2.8,2.5,4.9,2.8};
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ia=ivector(1,MA);
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x=vector(1,NPT);
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y=vector(1,NPT);
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sig=vector(1,NPT);
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covar=matrix(1,MA,1,MA);
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alpha=matrix(1,MA,1,MA);
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/* First try a sum of two Gaussians */
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for (i=1;i<=NPT;i++) {
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x[i]=0.1*i;
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y[i]=0.0;
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for (j=1;j<=MA;j+=3) {
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y[i] += a[j]*exp(-SQR((x[i]-a[j+1])/a[j+2]));
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}
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y[i] *= (1.0+SPREAD*gasdev(&idum));
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sig[i]=SPREAD*y[i];
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}
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for (i=1;i<=mfit;i++) ia[i]=1;
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for (i=1;i<=MA;i++) a[i]=gues[i];
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for (iter=1;iter<=2;iter++) {
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alamda = -1;
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mrqmin(x,y,sig,NPT,a,ia,MA,covar,alpha,&chisq,fgauss,&alamda);
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k=1;
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itst=0;
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for (;;) {
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printf("\n%s %2d %17s %10.4f %10s %9.2e\n","Iteration #",k,
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"chi-squared:",chisq,"alamda:",alamda);
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printf("%8s %8s %8s %8s %8s %8s\n",
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"a[1]","a[2]","a[3]","a[4]","a[5]","a[6]");
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for (i=1;i<=6;i++) printf("%9.4f",a[i]);
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printf("\n");
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k++;
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ochisq=chisq;
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mrqmin(x,y,sig,NPT,a,ia,MA,covar,alpha,&chisq,fgauss,&alamda);
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if (chisq > ochisq)
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itst=0;
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else if (fabs(ochisq-chisq) < 0.1)
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itst++;
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if (itst < 4) continue;
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alamda=0.0;
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mrqmin(x,y,sig,NPT,a,ia,MA,covar,alpha,&chisq,fgauss,&alamda);
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printf("\nUncertainties:\n");
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for (i=1;i<=6;i++) printf("%9.4f",sqrt(covar[i][i]));
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printf("\n");
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printf("\nExpected results:\n");
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printf(" %7.2f %8.2f %8.2f %8.2f %8.2f %8.2f\n",
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5.0,2.0,3.0,2.0,5.0,3.0);
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break;
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}
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if (iter == 1) {
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printf("press return to continue with constraint\n");
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(void) getchar();
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printf("holding a[2] and a[5] constant\n");
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for (j=1;j<=MA;j++) a[j] += 0.1;
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a[2]=2.0;
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ia[2]=0;
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a[5]=5.0;
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ia[5]=0;
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}
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}
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free_matrix(alpha,1,MA,1,MA);
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free_matrix(covar,1,MA,1,MA);
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free_vector(sig,1,NPT);
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free_vector(y,1,NPT);
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free_vector(x,1,NPT);
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free_ivector(ia,1,MA);
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return 0;
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}
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#undef NRANSI
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