... attempting to reduce the value χ2of a fit between a set of data pointsx[1 ndata],y[1 ndata]with individual standard deviationssig[1 ndata],and a nonlinear function dependent onmacoefficientsa[1 ... (k=1;k<=j;k++) alpha[j][k]=0.0;beta[j]=0.0;}*chisq=0.0;for (i=1;i<=ndata;i++) { Summation loop over all data. (*funcs)(x[i],a,&ymod,dyda,ma);sig2i=1.0/(sig[i]*sig[i]);dy=y[i]-ymod;for ... derivativesdyda ≡ ∂y/∂ak.#include "nrutil.h"void mrqmin(float x[], float y[], float sig[], int ndata, float a[], int ia[],int ma, float **covar, float **alpha, float *chisq,void (*funcs)(float,...