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[Octave-bug-tracker] [bug #29786] Octave does not save sparse matrices c
From: |
David Bateman |
Subject: |
[Octave-bug-tracker] [bug #29786] Octave does not save sparse matrices correctly in -mat format |
Date: |
Mon, 10 May 2010 12:35:48 +0000 |
User-agent: |
Mozilla/5.0 (Windows; U; Windows NT 5.1; fr; rv:1.9.0.4) Gecko/2008102920 Firefox/3.0.4 |
Update of bug #29786 (project octave):
Status: Confirmed => In Progress
Assigned to: None => dbateman
_______________________________________________________
Follow-up Comment #4:
The matlab file format is ugly in that the size of ech block of data is
stored at the start of the block. However to calculate the size of the block
you basically have to write the file and figure out the size post-hoc. This
leaves two choices. Firstly you write the block once to a temporary location,
calculate its size from there and then write the size to the correct location.
Or secondly, you write a blank to the block size, write the data to the file,
then use fseek to come back and correct the block size. Octave chooses the
second option for performance reasons.
However, if the size of the block calculation is incorrect, then the seeks
will be misperformed and the data of the following variables will be
corruptted. I strongly suspect this is what is happening. I'm however
surprised that I never noticed this issue.
I'll take this one on later in the week
D.
_______________________________________________________
Reply to this item at:
<http://savannah.gnu.org/bugs/?29786>
_______________________________________________
Message posté via/par Savannah
http://savannah.gnu.org/
- [Octave-bug-tracker] [bug #29786] Data file can not be loaded in Octave, anonymous, 2010/05/05
- [Octave-bug-tracker] [bug #29786] Data file can not be loaded in Octave, Beat Fasel, 2010/05/06
- [Octave-bug-tracker] [bug #29786] Octave does not save sparse matrices correctly in -mat format, Rik, 2010/05/08
- [Octave-bug-tracker] [bug #29786] Octave does not save sparse matrices correctly in -mat format, Beat Fasel, 2010/05/08
- [Octave-bug-tracker] [bug #29786] Octave does not save sparse matrices correctly in -mat format,
David Bateman <=
- [Octave-bug-tracker] [bug #29786] Octave does not save sparse matrices correctly in -mat format, Rik, 2010/05/10
- [Octave-bug-tracker] [bug #29786] Octave does not save sparse matrices correctly in -mat format, David Bateman, 2010/05/11
- [Octave-bug-tracker] [bug #29786] Octave does not save sparse matrices correctly in -mat format, David Bateman, 2010/05/11
- [Octave-bug-tracker] [bug #29786] Octave does not save sparse matrices correctly in -mat format, Beat Fasel, 2010/05/12