void covsrt(ref double[,] covar)
{
int i, j, k;
for (i = mfit; i < ma; i++)
{
for (j = 0; j < i + 1; j++)
{
covar[i, j] = covar[j, i] = 0.0;
}
}
k = mfit - 1;
for (j = ma - 1; j >= 0; j--)
{
if (ia[j])
{
for (i = 0; i < ma; i++)
{
GaussJordan.swap(ref covar[i, k], ref covar[i, j]);
}
for (i = 0; i < ma; i++)
{
GaussJordan.swap(ref covar[k, i], ref covar[j, i]);
}
k--;
}
}
}
public double fit(object target)
{
int j, k, l, iter, done = 0;
double alamda = 0.001, ochisq;
mfit = 0;
for (j = 0; j < ma; j++)
{
if (ia[j])
{
mfit++;
}
}
double[,] oneda = new double[mfit, 1];
double[,] temp = new double[mfit, mfit];
mrqcof(target, a, alpha, beta);
for (j = 0; j < ma; j++)
{
atry[j] = a[j];
}
ochisq = chisq;
for (iter = 0; iter < ITMAX; iter++)
{
if (done == NDONE)
{
alamda = 0;
}
for (j = 0; j < mfit; j++)
{
for (k = 0; k < mfit; k++)
{
covar[j, k] = alpha[j, k];
}
covar[j, j] = alpha[j, j] * (1.0 + alamda);
for (k = 0; k < mfit; k++)
{
temp[j, k] = covar[j, k];
}
oneda[j, 0] = beta[j];
}
GaussJordan.gaussj(temp, oneda);
for (j = 0; j < mfit; j++)
{
for (k = 0; k < mfit; k++)
{
covar[j, k] = temp[j, k];
}
da[j] = oneda[j, 0];
}
if (done == NDONE)
{
covsrt(ref covar);
covsrt(ref alpha);
int ndat = 0;
for (j = 0; j < datpos.Length; j++)
{
ndat += datpos[j][1] - datpos[j][0];
}
chisq /= ndat - mfit;
return(chisq);
}
for (j = 0, l = 0; l < ma; l++)
{
if (ia[l])
{
atry[l] = a[l] + da[j++];
}
}
mrqcof(target, atry, covar, da);
if (Math.Abs(chisq - ochisq) < Math.Max(tol, tol * chisq))
{
done++;
}
if (chisq < ochisq)
{
alamda *= 0.1;
ochisq = chisq;
for (j = 0; j < mfit; j++)
{
for (k = 0; k < mfit; k++)
{
alpha[j, k] = covar[j, k];
}
beta[j] = da[j];
}
for (l = 0; l < ma; l++)
{
a[l] = atry[l];
}
}
else
{
alamda *= 10.0;
chisq = ochisq;
}
}
throw new InvalidOperationException("Fitmrq too many iterations");
}
