search

OpenMathLib / OpenBLAS

OpenBLAS is an optimized BLAS library based on GotoBLAS2 1.13 BSD version.
http://www.openblas.net
BSD 3-Clause "New" or "Revised" License
6.29k stars 1.49k forks source link

DTBSM, triangular band matrix solve with multiple right-hand sides #2835

Open langou opened 4 years ago

langou commented 4 years ago

Hi OpenBLAS community, I received an email from a BLAS/LAPACK user and they were wondering why there exists Level 2 DTBSV, and why there does not exist a Level 3 DTBSM. So a DTBSV with multiple right-hand sides. The user has an application where a Level 3 DTBSM and, if speed-up could be obtained by blocking on the multiple right-hand sides, they would not mind the speed-up. DTBSM does not exist in BLAS, and does not exist in BLAS Technical Forum Standard. Few questions: (1) Do you see any reason(s) to exclude DTBSM from BLAS? [ (drawback = Complexity, software maintenance) vs ( not clear how many users ) vs ( not clear how much speedup ) are certainly good reasons. Wondering if there are some more reasons. ] (2) Do you know of requests for DTBSM from users (or yourself)? (3) Do you have DTBSM in OpenBLAS? (typically it could fit neatly and seamlessly under LAPACK DPBTRS). Cheers, Julien.

martin-frbg commented 4 years ago

OpenBLAS does not currently have it (and I am not immediately aware of a library that has). The idea sounds interesting, but I cannot recall this having come up before. No promises regarding implementation, unless we get lucky and somebody has existing research code to donate.

martin-frbg commented 4 years ago

Update: a BSD-licensed project named FEAST appears to have it https://github.com/PFEM/feast/tree/79c7a67167f92ce5ebdc6f28b1ff856575adcbb7/src/banded/spike-smp

http://www.ecs.umass.edu/~polizzi/feast/