bugGNU Scientific Library - Bugs: bug #45797, Possible problem with LAPACK...


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bug #45797: Possible problem with LAPACK Fortran routine ZGESVD

Submitted by:  Andrew Mackay <andrewm>
Submitted on:  Wed 19 Aug 2015 11:39:09 AM UTC  
Category: Accuracy problemSeverity: 3 - Normal
Operating System: Ubuntu LinuxStatus: None
Assigned to: NoneOpen/Closed: Open
Release: 2.6.32-40

Wed 19 Aug 2015 11:39:09 AM UTC, original submission:

Error in some singular vectors that appear in the standard library release for this version of Ubuntu using Fortran routine ZGESVD. Was not present in standard release for 2.6.31-16.
Test routine supplied for a 4x4 complex matrix and two log files. The first log file when compiled under Linux version 2.6.31-16 (correct), the second when compiled under Linux version 2.6.32-40 (incorrect).

The test routine is compiled by "make" with executable "svdtest"
This generates the singular values and vectors and reconstitutes the original complex matrix. The error appears in the imaginary part of one of the left singular vectors. Check the differences in the log files.

Andrew Mackay <andrewm>


Attached Files
file #34678:  svdcheck.zip added by andrewm (9KiB - application/zip - zipped directory containing Fortran test program and log files)


Depends on the following items: None found

Items that depend on this one: None found


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    Follows 1 latest change.

    Date Changed By Updated Field Previous Value => Replaced By
    Wed 19 Aug 2015 11:39:09 AM UTCandrewmAttached File-=>Added svdcheck.zip, #34678

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