Package lufact provides sparse LU factorization with partial pivoting as
described in "Sparse Partial Pivoting in Time Proportional to Arithmetic
Operations" by John R. Gilbert and Tim Peierls.

@article{Gilbert1988,
  doi = {10.1137/0909058},
  url = {https://doi.org/10.1137/0909058},
  year  = {1988},
  month = {sep},
  publisher = {Society for Industrial {\&} Applied Mathematics ({SIAM})},
  volume = {9},
  number = {5},
  pages = {862--874},
  author = {John R. Gilbert and Tim Peierls},
  title = {Sparse Partial Pivoting in Time Proportional to Arithmetic Operations},
  journal = {{SIAM} Journal on Scientific and Statistical Computing}
}

This package is translated from the gp FORTRAN code distributed in
Sivan Toledo's work on incomplete-factorization, from PARC in the early
1990s, as found in the ILU package on Netlib:

http://www.netlib.org/linalg/ilu.tgz

This source code is distributed, with the kind permission of John Gilbert
and Tim Peierls, under a 3-clause BSD license.