A set of double precision matrices printed to 16 digits for conversion to integer as described and tested on in the paper "Algorithm 1XXX: SPEX Left LU, Exactly Solving Sparse Linear Systems via a Sparse Left-Looking Integer-Preserving LU Factorization"
If you want to use these matrices please cite Foster and Davis: "Algorithm 933: Reliable Calculation of Numerical Rank, Null Space Bases, Pseudoinverse Solutions, and BasicSolutions Using SuitesparseQR"
Moreoever, to find the matrices in their native format, please refer to Les Foster's page http://www.math.sjsu.edu/singular/matrices/