Georeferencing of grids. Either choose the attribute fields (x/y) with the projected coordinates for the reference points (origin) or supply a additional points layer with correspondend points in the target projection.
This library uses the Minpack routines for solving the nonlinear equations and nonlinear least squares problem. You find minpack and more information about minpack at:
http://www.netlib.org/minpack
or download the C source codes:
http://www.netlib.org/minpack/cminpack.tar