RE: save and load bug.

[GARY FORBIS]

> Date: Sun, 28 Dec 2008 18:55:56 +0100
> From: address@hidden
> To: address@hidden
> Subject: Re: save and load bug.
> CC: address@hidden; address@hidden; address@hidden
>
> On Sun, Dec 28, 2008 at 6:09 PM, GARY FORBIS <address@hidden> wrote:
> > Thanks all. Eliminating one issue lets me focus better.
> >
> > I'm still looking. I'm very new to Octave even though I tried
> > loading it in the spring of 2008. I didn't get as far as I've gotten now
> > when
> > trying to run the software I was using to learn more about ANNs and MathLab
> > at the same time. I gave up quickly.
> >
> > I don't understand the structure of the files on sourceforge.
> > I'm having a bit of trouble getting started. It's one more thing to learn.
> > I saved octave-forge-bundle-20080831.tar.gz to my cygwin home directory,
> > unzipped,
> > and untarred it. It looks like the various pieces are tarred and zipped
> > inside the package.
> >
> > I guess I can just recursively unzip an untar the files. Is there some
> > documentation about
> > where things are in the source files?
> >
>
> I'm confused; maybe we both are. What are you trying to do?
 
I'm trying to run a program written in mathlab that won't run on
my computer under Octave.  I tracked down the problem to load not
working with a file produced by a save.  I discovered that Octave
uses an ascii file to do the save and I tracked down the minimum
file that would fail.  I found the scalar that was in the last position
in the matrix that failed.  I wrote a simple program that kept adding
instances of that scalar to an array until the load of the array failed.
I created another program that only did two saves and two load to
demonstrate that on my machine Octave 3.0.3 loaded with the windows
installer failed predictably.  I can find other numbers that will fail predictable
after different occurrances and as far as I can tell there's nothing remarkable
about the numbers or the number of occurrances of any of the characters
or digits in the record. 
 
> You can
> get the latest stable Octave sources from
> ftp://ftp.gnu.org/pub/gnu/octave/ or one of the GNU mirrors.
> ftp.octave.org should also still work. I guess that building them on
> Cygwin should be as simple as unpacking and doing configure&make,
> provided you have the prerequisities.
> If you have problems with compiling OctaveForge packages, you should
> probably report the issue on the OctaveForge mailing list.

I don't particularly want to compile Octave.  I want to track down the  problem
and propose a solution.  Since other installations do not produce this problem, 
it looks like I'll have to dig deep enough into the code to see what limits exist.

I found dmlread earlier.  I'm assuming load uses a similar algorithm.  I was right
about reading a records at a time:
 
      while (getline (file, line))
 
While this sets an upper limit on the size of a record in characters it's much
bigger than where I am encountering a problem.

> > My first guess was that the file was read a record at a time then parsed and
> > I had hit a
> > 16 bit limit. This didn't make much sense to me so I tried positive numbers
> > and I was able
> > to write records with many more numbers in them and load them back in.
> > Negative number
> > with few significant digits had less poblems as well.
> >
>
> It's hard to tell what can cause your problem, especially as nobody
> seems to be able to reproduce it. So, if you wish it to be
> investigated further, you need to carry out more experiments and tell
> us the results.

Well, as I said the small program works find on the cygwin octave
version 3.0.2 so the problem is specific to the windows version 3.0.3
dated  (2008-11-22 11:55)
 
It isn't a problem with 3.1.50 either so I'll just us that until I find some other problem
I have to deal with.

> regards
>
> --
> RNDr. Jaroslav Hajek
> computing expert
> Aeronautical Research and Test Institute (VZLU)
> Prague, Czech Republic
> url: www.highegg.matfyz.cz