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BallisticLA / RandBLAS

A header-only C++ library for sketching in randomized linear algebra
https://randblas.readthedocs.io/en/stable/
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SASO issue? #73

Closed TeachRaccooon closed 1 year ago

TeachRaccooon commented 1 year ago

Visible in this RandLAPACK commit. I am recursively calling a randomized pivoted QR algorithm that employs SASOs for sketching. At a certain point, we apply SASO to a matrix A with no visible anomalies, resulting in a sketchin with the last row consisting of zeros. Upon performing QRCP on that sketch (via GEQP3), we get an R-factor with the last row consisting of zeros. That, in its turn, causes NANs in subsequent computations. Seems to me like something may have gotten wrong with SASOs due to repeated usage of "state" parameter.

rileyjmurray commented 1 year ago

@TeachRaccooon is this potentially a real issue, or did this stem from a bug in non-RandBLAS code?

TeachRaccooon commented 1 year ago

@rileyjmurray I think this was happening because of me using the outdated version of RandBLAS. Not an issue anymore.

rileyjmurray commented 1 year ago

Excellent. Closing for now.