38 lines
777 B
C
38 lines
777 B
C
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#include "nrutil.h"
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void mrqcof(x,y,sig,ndata,a,ia,ma,alpha,beta,chisq,funcs)
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float **alpha,*chisq,a[],beta[],sig[],x[],y[];
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int ia[],ma,ndata;
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void (*funcs)();
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{
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int i,j,k,l,m,mfit=0;
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float ymod,wt,sig2i,dy,*dyda;
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dyda=vector(1,ma);
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for (j=1;j<=ma;j++)
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if (ia[j]) mfit++;
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for (j=1;j<=mfit;j++) {
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for (k=1;k<=j;k++) alpha[j][k]=0.0;
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beta[j]=0.0;
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}
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*chisq=0.0;
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for (i=1;i<=ndata;i++) {
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(*funcs)(x[i],a,&ymod,dyda,ma);
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sig2i=1.0/(sig[i]*sig[i]);
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dy=y[i]-ymod;
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for (j=0,l=1;l<=ma;l++) {
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if (ia[l]) {
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wt=dyda[l]*sig2i;
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for (j++,k=0,m=1;m<=l;m++)
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if (ia[m]) alpha[j][++k] += wt*dyda[m];
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beta[j] += dy*wt;
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}
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}
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*chisq += dy*dy*sig2i;
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}
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for (j=2;j<=mfit;j++)
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for (k=1;k<j;k++) alpha[k][j]=alpha[j][k];
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free_vector(dyda,1,ma);
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}
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