updated on November 16 2013

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




bug125 :: xLAHQR v3.5 does not converge on some matrices while xLAHQR v2 converges

  • CORRECTED, rev 1537

  • Present in LAPACK 3.5.0

  • Bug reported by Yoshihide Okimi on July 16, 2014

  • Link: https://icl.cs.utk.edu/lapack-forum/viewtopic.php?f=13&t=4566

  • and, independently, by Marco Caliari (Universit√† di Verona) on February 11, 2015.

  • Involved in bug fix: Yoshihide Okimi, Marco Caliari (Universit√† di Verona),

  • Meiyue Shao (LBL), Julien Langou, and Daniel Kressner (EPFL).

  • Confirmed and Corrected by Julien Langou on Mar 25th 2015.

bug124 :: dpstf2 returns incorrect value of rank

bug123 :: csytrf_rook test fails for dimensions 127, 260

bug122 :: Wrong Info code when checking input parameter QSIZ in SLASD7 and DLASD7

  • CORRECTED, rev 1504

  • Present in LAPACK 3.5.0

  • Bug report by Elena Ivanova (Oracle) directly to Julie on Oct 2nd 2014

  • Corrected by Julie Langou on October 6th

bug121 :: Bugs in DLASD8 and DLASD6

bug120 :: Workspace query return too small value for xGESDD

bug119 :: CBLAS - missing the floating point constant argument in sdsdotsub

  • CORRECTED, rev 1493

  • Present in CBLAS

  • Bug report by by Shandong Lao fron Oracle on LAPACK Mailing List - Aug 11th 2014

bug118 :: ZLANHF and CLANHF Norm Calculation

bug117 :: NSPLIT unitialized; N=2 code wrong

bug116 :: ZGGEV fails but Matlab works

bug115 :: DSYEVD fails to converge

bug114 :: (C, Z)GESVD stack corruption issue

bug113 :: DLARRB() infinite loop bug

bug111 :: incorrect RWORK size for ZGESDD

bug0061 :: zgehrd.f is overflowing


  • 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.

bug0057 :: Non-eigenvectors from DGEEV, problem in balancing

  • CORRECTED, rev 1413

  • bug report sent by Numpy team on April 22nd, 2010

  • see forum topic 1818

  • see follow-up on lapackers on April 22nd from Jim "bug in DGEHRD" "The balancing is choosing to scale some rows/columns by factors like 1e18, which rather amplifies tiny rounding errors in the (presumably correctly) computed eigenvectors of the balanced matrix, when balancing is undone at the end. The expert driver interface dgeevx would let the user disable balancing, until we figure out whether this is a bug or a feature, I’m not sure which."

  • Corrected by Bradley Lowery, Rodney James, Julien Langou on May 26 2013

bug0056 :: Non-orthogonal eigenvectors returned from DSYEVR


  • bug report sent by Scipy team on April 22nd

  • see LAPACK Mailing list msg 874

  • Confirmed by Rodney on Tue, 17 Feb 2011

  • " I can reproduce similar problems that the user encountered with non-orthogonal eigenvectors when only

  • a few eigenvalues are requested. This also happens with SSYEVR. If I set ABSTOL to SLAMCH(Safe minimum),

  • the problem goes away in SSYEVR, and improves with DSYEVR but does not completely go away."

  • Assigned to Osni (UC Berkeley) and Julien (UC Denver)? on Feb 11th 2015

bug0033 :: failure of zheevd on a specific matrix

bug0032 :: matrix splitting problem with dstebz and sstebz


  • bug report sent by Phil DeMier (IBM) on Mon 29 Jun 2009 to "lapack@cs.utk.edu". "matrix splitting problem with dstebz and sstebz"

  • see Phil DeMier’s email and Phil DeMier’s test code

  • Confirmed by Rodney on Tue, 17 Feb 2011