# -*- org -*-
#+CATEGORY: multifit

The following would also be nice additions to the multifit function suite
(see MS Excel regression output for example):

1. Produce the correlation coefficient (r) and other statistics.
2. Allow fit variable weighting (not observation weighting).
3. Allow for principal factor computations.

The following features should be added to the nonlinear least squares routines:

1. Support for constraints

2. robust nonlinear least squares and robust ridge regression

3. covariance matrices for ridge regression
