updated on June 18 2016

maintained by Julien Langou, U. Colorado Denver and Julie Langou, U. Tennessee

RED means BUG WAS CONFIRMED but IT IS STILL HERE

MARRON means BUG WAS NOT CONFIRMED

GREEN means BUG WAS CORRECTED :

bug 159 DSTEMR - consolidates bugs 113 and 126

  • CONFIRMED

  • Present in LAPACK 3.6.0

  • Assigned to Osni.

  • Osni: We have a new subroutine to replace the subroutine causing us trouble.  We will be sitting together (OM and Prof. Parlett) tomorrow to discuss how this will behave.

  • I expect the new version of the subroutine will fix bug 113

  • 02/10/16 Osni: The bug has been traced to the factorization(s) performed by dlarrf.

  • The current implementation of dlarrf can lead to NaNs or element growth (this is expected) but the tests to deal with these cases are not working properly.

  • Beresford and I have experimented changing a few things in dlarrf, which fixes this bug and also bug 126, but we know that a more robust strategy needs to be devised. 

  • 2/11/16: We were able to trace the issue down here to the factorizations. We have some tests to cope with extreme growth in elements and NaNs,

  • but these tests are not robust. So we end up with linearly dependent eigenvectors when eigenvalues are close to each other.

  • 5/9/16: (Osni) We had a meeting in Berkeley (Prof. Parlett, Jim, Osni, I Dhillon) Some safeguards were removed over the years thinking we did not need them;

  • perhaps they must come back (this was the focus of our discussion). For some matrices, the vectors that are returned are not orthogonal the way we would

  • like them to be---the level of orthogonality is not ideal for nearly multiple eigenvalues. Prof Parlett and I will sit together to determine the best strategy for future LAPACK release.

bug 158 problem with DC SVD least squares

  • CONFIRMED

  • Present in LAPACK 3.6.0

  • Bug reported by Alexander Kobotov in 2015 to Julien

  • Problem of size ~22K with a large number of singular values close to 1.

  • dlasd7 fails to merge two sets of (very close) singular values together into a single sorted set, and subsequently dlasd4 (secular equation solver) fails to converge.

  • See email to LAPACK team

  • Assigned to Osni.

bug 130 :: Ambiguous lapacke interfaces to Cosine/Sine decomposition - 2 Trans parameters

bug 126 :: DSTEMR - misbehaviour of DLARRF

  • CONFIRMED on Jun 24th 2015

  • Present in LAPACK 3.5.0

  • Bug reported by Miroslav Ilias on Jun 27th

  • Link: http://icl.cs.utk.edu/lapack-forum/viewtopic.php?f=2&t=1820

  • Assigned to Osni

  • 02/10/16 Osni: The bug was originally thought to be related to splitting but is rather a misbehavior of DLARRF (in the presence of very tight eigenvalues); see bug 113.

  • SEE BUG 113 for all updates (will be closed along with 113)

bug116 :: ZGGEV fails but Matlab works

bug0061 :: zgehrd.f is overflowing

  • CONFIRMED

  • bug report by Victor Liu on Tuesday August 03rd, 2010

  • zgehrd.f is overflowing the maximum size in bytes of the largest array that

  • can be put on the stack with gfortran (⇒ leads ,e.g., to non-reproducible and uncorrect execution

  • of zgeev in multithreaded context

  • lapackers involved in the bug fix process: Julie and Julien Langou and Mathieu Faverge

  • bug fix by Victor Liu on Wednesday August 04th, 2010

  • Assigned to Julien (UC Denver) on Feb 11th 2015

  • see forum topic 1930

  • two outstanding issues: (1) how do we go to fix this?, (2) more LAPACK subroutines might be concerned.