[SciPy-User] Sparse Matricies and NNLS

[Jonathan Guyer]

On Mar 28, 2013, at 5:33 PM, Calvin Morrison wrote:

> It seems nobody wants to touch the nnls algorithm because the only implementation that is floating around is the one from the original publication or automatic conversions of it.

For whatever it's worth, the second google hit for "nnls sparse" is

  http://www.michaelpiatek.com/papers/tsnnls.pdf

"tsnnls: A solver for large sparse least squares problems with non-negative variables

The solution of large, sparse constrained least-squares problems is a staple in scientific and engineering applications. However, currently available codes for such problems are proprietary or based on MATLAB. We announce a freely available C implementation of the fast block pivoting algorithm of Portugal, Judice, and Vicente. Our version is several times faster than Matstoms’ MATLAB implementation of the same algorithm. Further, our code matches the accuracy of MATLAB’s built-in lsqnonneg function."

All links to the code seem to be dead, but it's probably worth contacting the authors.