bugGNU Octave - Bugs: bug #49714, 64-bit documentation clarification

 
 

bug #49714: 64-bit documentation clarification

Submitted by:  Michael Godfrey <godfrey>
Submitted on:  Sun 27 Nov 2016 03:18:15 PM UTC  
 
Category: DocumentationSeverity: 3 - Normal
Priority: 5 - NormalItem Group: Other
Status: PostponedAssigned to: None
Originator Name: GodfreyOpen/Closed: Closed
Release: devOperating System: GNU/Linux

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Sun 27 Nov 2016 09:19:24 PM UTC, comment #4:

Yes, it is still experimental and requires an experienced user who knows how to build the required Fortran libraries using 64-bit integers. I don't know if that aspect will ever get easier. Fedora providing blas64 and lapack64 libraries is a small first step, but nowhere close to a full solution that can make this process easier.

It might be possible to look at improving the configure script to try to test the ARPACK, BLAS, LAPACK, QRUPDATE, and SuiteSparse libraries to see whether they use 32-bit or 64-bit integers, possibly by writing a test program that may or may not crash, if that could be done reliably. But for the foreseeable future a user will still have to pass --enable-64 (or some replacement configure option) when building Octave to instruct it to use 64-bit integers when calling Fortran routines.

Closing for now since there's nothing to improve in the docs or the configure script at this point.

Mike Miller <mtmiller>
Project Administrator
Sun 27 Nov 2016 06:24:06 PM UTC, comment #3:

I thought that it was closer to regular use than is the
case. The description in E.3 is quite long and would not
entirely fit with the current Fedora libraries.

The description in E.3 is obviously, as stated, experimental.
Phrases like "Other systems may require a different solution."
do not really qualify as accurate and straightforward.

So, best to close this report until someone has the time
to complete the implementation. The work that John is
proposing should help with this. So, deferring the work may
be best.

I just wanted to report what I found. It would have been
clearer if the build, which went through without any errors or
warnings had instead indicated that other 64bit libraries
were missing.

Michael Godfrey <godfrey>
Project Member
Sun 27 Nov 2016 05:43:40 PM UTC, comment #2:

Can you describe what you think needs to be changed in the docs? Section E.3 still seems accurate and straightforward to me.

Mike Miller <mtmiller>
Project Administrator
Sun 27 Nov 2016 03:22:29 PM UTC, comment #1:

Well, I should have added: make check
fails on lots of tests.... It finally
seg faults on lu.cc-tst.

So, obviously I over simplified a bit, but...

Michael Godfrey <godfrey>
Project Member
Sun 27 Nov 2016 03:18:15 PM UTC, original submission:

The current documentation indicates that for 64-bit addressing
it is necessary to build blas, etc. for 64-bit.
The current Fedora system provides:
blas64-static-3.6.1-2.fc25.x86_64
blas64-devel-3.6.1-2.fc25.x86_64
blas-devel-3.6.1-2.fc25.x86_64
blas-3.6.1-2.fc25.x86_64
blas64-3.6.1-2.fc25.x86_64
(these were also in fc24 and are likely in other linuxes)

If these are installed, and ./configure --enable-64
is used, the makefile does not find the 64bit library.
But,
export BLAS_LIB=/usr/lib64/libblas64.so (or equivalent for
other shells)
causes the make to find the library and it
produces a 64-bit indexing system which at least does:
octave:1> a = zeros (102410241024*3, 1, 'int8');
octave:2> whos
Variables in the current scope:

Attr Name Size Bytes Class
==== ==== ==== ===== =====
a 3221225472x1 3221225472 int8

So, the simplest change would be to explain that only the
definition of the location of BLAS_LIB is needed, or the
makefile could be improved...

It does appear that the implementation of 64bit addressing is
getting close to being functional. Of course, this also
implies that if 64bit is to be offered there will be a need
for 32bit and 64bit versions as is true with other packages...

Michael Godfrey <godfrey>
Project Member

 

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    Follow 3 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Sun 27 Nov 2016 09:19:24 PM UTCmtmillerStatusNeed Info=>Postponed
      Open/ClosedOpen=>Closed
    Sun 27 Nov 2016 05:43:40 PM UTCmtmillerStatusNone=>Need Info

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