Provides tools for working with nonlinear least squares problems. For the estimation of models reliable and robust tools than nls(), where the the GaussNewton method frequently stops with 'singular gradient' messages. This is accomplished by using, where possible, analytic derivatives to compute the matrix of derivatives and a stabilization of the solution of the estimation equations. Tools for approximate or externally supplied derivative matrices are included. Bounds and masks on parameters are handled properly.
Package details 


Author  John C Nash [aut, cre], Duncan Murdoch [aut], Fernando Miguez [ctb], Arkajyoti Bhattacharjee [ctb] 
Maintainer  John C Nash <nashjc@uottawa.ca> 
License  GPL2 
Version  2023.8.31 
Package repository  View on CRAN 
Installation 
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