public static void Lfit(double[] x, double[] y, double[] sig, double[] a, out double[,] covar, out double chisq,
LfitFunc funcs)
{
int ndat = x.Length;
int i, j;
int l;
int ma = a.Length;
int mfit = a.Length;
double[,] beta = new double[ma, 1];
double[] afunc = new double[ma];
covar = new double[ma, ma];
for (i = 0; i < ndat; i++)
{
funcs(x[i], afunc);
double ym = y[i];
double sig2i = 1.0 / (sig[i] * sig[i]);
for (l = 0; l < ma; l++)
{
double wt = afunc[l] * sig2i;
for (int m = 0; m <= l; m++)
{
covar[l, m] += wt * afunc[m];
}
beta[l, 0] += ym * wt;
}
}
for (j = 1; j < mfit; j++)
{
int k;
for (k = 0; k < j; k++)
{
covar[k, j] = covar[j, k];
}
}
Gaussj(covar, mfit, beta, 1);
for (l = 0; l < ma; l++)
{
a[l] = beta[l, 0];
}
chisq = 0.0;
for (i = 0; i < ndat; i++)
{
funcs(x[i], afunc);
double sum = 0.0;
for (j = 0; j < ma; j++)
{
sum += a[j] * afunc[j];
}
chisq += ((y[i] - sum) / sig[i]) * ((y[i] - sum) / sig[i]);
}
Covsrt(covar);
}
public static void LinFit2(double[] x, double[] y, double[] sig, double[] a,
out double chisq, LfitFunc funcs)
{
double[,] covar;
if (sig == null)
{
sig = new double[x.Length];
for (int i = 0; i < sig.Length; i++)
{
sig[i] = 1E-2;
}
}
Lfit(x, y, sig, a, out covar, out chisq, funcs);
}
public static void LinFit2(double[] x, double[] y, double[] a, LfitFunc funcs)
{
double chisq;
LinFit2(x, y, null, a, out chisq, funcs);
}
