add numerical recipes library

lib/nr/k_and_r/recipes/mrqcof.c

@@ -0,0 +1,37 @@
+
+#include "nrutil.h"
+
+void mrqcof(x,y,sig,ndata,a,ia,ma,alpha,beta,chisq,funcs)
+float **alpha,*chisq,a[],beta[],sig[],x[],y[];
+int ia[],ma,ndata;
+void (*funcs)();
+{
+	int i,j,k,l,m,mfit=0;
+	float ymod,wt,sig2i,dy,*dyda;
+
+	dyda=vector(1,ma);
+	for (j=1;j<=ma;j++)
+		if (ia[j]) mfit++;
+	for (j=1;j<=mfit;j++) {
+		for (k=1;k<=j;k++) alpha[j][k]=0.0;
+		beta[j]=0.0;
+	}
+	*chisq=0.0;
+	for (i=1;i<=ndata;i++) {
+		(*funcs)(x[i],a,&ymod,dyda,ma);
+		sig2i=1.0/(sig[i]*sig[i]);
+		dy=y[i]-ymod;
+		for (j=0,l=1;l<=ma;l++) {
+			if (ia[l]) {
+				wt=dyda[l]*sig2i;
+				for (j++,k=0,m=1;m<=l;m++)
+					if (ia[m]) alpha[j][++k] += wt*dyda[m];
+				beta[j] += dy*wt;
+			}
+		}
+		*chisq += dy*dy*sig2i;
+	}
+	for (j=2;j<=mfit;j++)
+		for (k=1;k<j;k++) alpha[k][j]=alpha[j][k];
+	free_vector(dyda,1,ma);
+}