Plotting

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Plotting

Vincent PAROUX Stagiaire ENIB
Hello,

My problem is that I have a matrice[101;201] of values that I want to
plot in 2D dimension using a colormap.

Is it possible and how can I do ?

Best regards
                        Vincent


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|  Vincent PAROUX                             |
|  GESMA                                       |
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Re: Plotting

Andres Weingessel
>>>>> On Fri, 14 Mar 1997 13:47:48 +0100,
>>>>> Vincent PAROUX Stagiaire ENIB wrote:

> Hello,
> My problem is that I have a matrice[101;201] of values that I want to
> plot in 2D dimension using a colormap.

> Is it possible and how can I do ?

There should be a file "image.m" in your octave distribution.


----------------------------------------------------------------------
octave:68> help image
image is the function defined from:
/usr/local/lib/octave/2.0.5/m/image/image.m

 Display an octave image matrix.

 image (x) displays a matrix as a color image. The elements of x are
 indices into the current colormap and should have values between 1
 and the length of the colormap.

 image (x, zoom) changes the zoom factor.  The default value is 4.

 SEE ALSO: imshow, imagesc, colormap.

----------------------------------------------------------------------

The default colormap consists of 64 gray values. You can change this
with the colormap function.

Best regards,
        Andreas

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Hard drive crashed!!

Lynn Chen
In reply to this post by Vincent PAROUX Stagiaire ENIB
I ran 3 octaves in X windows last night. The next day, I found the
program half finished with messages saying program error. Then I reboot
the system and it won't reboot. Kernel panic. Ran fsck.ext2 to fix
the drive, there are unrecoverable errors.

What happened could be that the memory (16m) ran out and it did a lot
of disk caching and crashed the disk.

After fsck failed, I decide to reinstall Linux, all the partition
informations are still there, but when I try to format the swap
partition, it would run forever (> 10 mins) with some occasional
cracking
sound ( not the usall noise from WD drive). I then downloaded the
Western digital WDDIAG.EXE, it stopped saying error exceeded maximum.
WD rep said if the error is <10, then low level format it.

Just let you know I learned the lesson the hard way. I would not run
more that one copy of octave at the same time any more.

guoqiang

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Re: Hard drive crashed!!

John Utz-3
Hello;

        This would not really be an octave problem per se, this could have
happened with any other swap intensive operation, i would expect.

        I assume u are running linux. This might be an important thing to
mention on a linux mailing list, because this is more a kernel problem
then an application problem, IMHO.

        I used to have a problem where i would get a memory leak when i
did a lot of plotting from octave with gnuplot. It wouldn't crash my
machine tho, it would just run out of swap and kill octave and gnuplot.
That problem seems to be gone now, fwiw. ( this was on FreeBSD
2.1.5-RELEASE, with a 386/387 with 12meg of ram )

just my us$ 0.02

john


On Fri, 14 Mar 1997, Lynn Chen wrote:

> I ran 3 octaves in X windows last night. The next day, I found the
> program half finished with messages saying program error. Then I reboot
> the system and it won't reboot. Kernel panic. Ran fsck.ext2 to fix
> the drive, there are unrecoverable errors.
>
> What happened could be that the memory (16m) ran out and it did a lot
> of disk caching and crashed the disk.
>
> After fsck failed, I decide to reinstall Linux, all the partition
> informations are still there, but when I try to format the swap
> partition, it would run forever (> 10 mins) with some occasional
> cracking
> sound ( not the usall noise from WD drive). I then downloaded the
> Western digital WDDIAG.EXE, it stopped saying error exceeded maximum.
> WD rep said if the error is <10, then low level format it.
>
> Just let you know I learned the lesson the hard way. I would not run
> more that one copy of octave at the same time any more.
>
> guoqiang
>

*******************************************************************************
 John Utz [hidden email]
        idiocy is the impulse function in the convolution of life


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Re: Hard drive crashed!!

John W. Eaton-6
On 14-Mar-1997, John Utz <[hidden email]> wrote:

| On Fri, 14 Mar 1997, Lynn Chen wrote:
|
| > I ran 3 octaves in X windows last night. The next day, I found the
| > program half finished with messages saying program error. Then I reboot
| > the system and it won't reboot. Kernel panic. Ran fsck.ext2 to fix
| > the drive, there are unrecoverable errors.
| >
| > What happened could be that the memory (16m) ran out and it did a lot
| > of disk caching and crashed the disk.
| >
| > ...
| >
| > Just let you know I learned the lesson the hard way. I would not run
| > more that one copy of octave at the same time any more.

| This would not really be an octave problem per se, this could have
| happened with any other swap intensive operation, i would expect.

It's unfortunate that your hardware failed, but I agree, it is not
likely that Octave is responsible for that.  16MB is not much for
running Linux and X and Octave.  Without more memory than that, I
would certainly not recommend running lots of memory-intensive jobs
simultaneously.  But on systems with much more memory, it should not
be a problem.

jwe

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Re: Hard drive crashed!!

Mike Blatchley
In reply to this post by Lynn Chen
On Fri, 14 Mar 1997, Lynn Chen wrote:

>
> After fsck failed, I decide to reinstall Linux, all the partition
> informations are still there, but when I try to format the swap
> partition, it would run forever (> 10 mins) with some occasional
> cracking
> sound ( not the usall noise from WD drive). I then downloaded the
> Western digital WDDIAG.EXE, it stopped saying error exceeded maximum.
> WD rep said if the error is <10, then low level format it.
>
> Just let you know I learned the lesson the hard way. I would not run
> more that one copy of octave at the same time any more.

This sounds like it had _nothing_ to do with Octave or Linux.  Instead,
the hard drive is probably "growing" new media defects.  As drive
capacities have gone up, drive manufacturers have had to fly the heads
closer to the disks, making them much more sensitive to any contamination
inside the drive unit.  That's why WDDIAG is failing.  It sees these new
media flaws, and low level formatting is needed to repair them.

The cracking sound you hear is probably due to the drive detecting the
problem and trying to retry the operation, or the embedded servo
information written on the disk is damaged and the unit can't keep the
heads positioned over the right track.  If the latter, formatting
probably won't fix it.

A word of warning...if it's happened with this drive once, it'll probably
happen again!!  If the drive is new, and still under warranty, demand a
replacement!

Mike
[hidden email]