octave does not link to openblas

[eigenmaster]

Problem first alerted on Octave forum, but decided to be a Ubuntu issue with Openblas.

https://octave.1599824.n4.nabble.com/Octave-5-2-0-Ubuntu-20-04-Long-duration-of-complex-matrix-inverse-td4696435.html

Using the apt installed version of Octave, the openblas library doesn't seem to be linked.

octave:1> version -lapack
ans = Linear Algebra PACKage Version 3.9.0
octave:2> version -blas
ans = unknown or reference BLAS
octave:3> tic; eig(rand(91)); toc
Elapsed time is 0.00454998 seconds.
octave:4> tic; eig(rand(92)); toc # This hangs forever.

BTW the snap version of Octave under Ubuntu 20.04 seems to work fine.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: libopenblas-base 0.3.8+ds-1
ProcVersionSignature: Ubuntu 5.4.0-28.32-generic 5.4.30
Uname: Linux 5.4.0-28-generic x86_64
ApportVersion: 2.20.11-0ubuntu27
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: XFCE
Date: Sun May 3 12:12:03 2020
InstallationDate: Installed on 2020-05-02 (1 days ago)
InstallationMedia: Xubuntu 20.04 LTS "Focal Fossa" - Release amd64 (20200423)
ProcEnviron:
 LANGUAGE=en_US
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: openblas
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Timothy Robertson (eltimablo)]

I can confirm that the issue is not present in the Octave Flatpak, either.

[Mike Miller (mtmiller)]

I can understand how you might think these commands you have shown are related to the bug summary, but they are in fact separate known issues, and Octave is in fact linked with and is using the OpenBLAS library.

1. The "version -blas" command returns "unknown or reference BLAS" - This is a known issue due to changes in the way OpenBLAS is now packaged for Debian and Ubuntu, it is missing a certain symbol that Octave looks for to identify the version of the library. The text is misleading, because Octave is in fact loading OpenBLAS.

2. The "eig" command does not return - This seems to be a bug in the OpenBLAS library itself, see https://bugs.launchpad.net/bugs/1870138 as well as the duplicates that are linked to that bug report.