[R] nls.lm

[Mike meyer]

@pd: you know that a System of equations with more variables than equations is always solvable
and if a unique solution is desired one of mimimal norm can be used.

According to "Methods for nonlinear least squares problems" by Madsen, Nielsen and Tingleff the LM-algorithm
solves Systems of the form 
                            [J(x)'J(x)+\mu*I]x=...
with \mu>0 so that the Matrix on the left is always positive definite, especially nonsingular.