Re: Virtual mem problem

[Erich Schneider]

On Thu, 3 Feb 2000 11:01:47 +1300, Guest9 wrote:

>(C:\octave\bin\octave.bin 1017) commit_and_inc: VirtualAlloc failed
>error: memory exhausted -- trying to return to prompt

Depending on what operations I did before I often get this error on
Linux (2.0.14) and OS/2 (2.0.13), too (both with enough memory). At
certain points e.g. a=ones(1000,1) isn't possible any more, although
e.g. a=ones(100,10) works fine. At the moment I don't have an exact
description of the problem at hand (sorry). However, based on my
sporadic observations I too have the impression that octave's memory
allocation doesn't work correctly. This problem has been observed by
Daniel Heiserer, too:

On Wed, 02 Feb 2000 13:08:55 +0100, Daniel Heiserer wrote:

>address@hidden wrote:
>> 
>> On  1-Feb-2000, Daniel Heiserer <address@hidden> wrote:
>> 
>> | The machine has sufficient memory to process my request.
>> 
>> Apparently not. :-(
>> 
>> How much virtual memory do you have?
>> 
>> | octave:2> tic;eval(sprintf("L_%08d=eye(1000);",[1:1000]));toc
>> | error: memory exhausted -- trying to return to prompt

If a more detailed protocol of such an error occurance is needed, I can
try to reproduce this behaviour.

Just an additional comment on the following code:

>here's part of my script:
>
>clear;
>load f5hs3.txt
>load f5ls3.txt
>s=size(f5hs3);
>sum=0;
>x=0;
>C=-636.73*(f5hs3-f5ls3)./f5ls3-0.079098*f5hs3+332.15;
>for i=1:s(1,1)/2
>  for j=1:s(1,2)/2
>     if f5hs3(2*i,2*j)<3400
>       sum=sum+C(2*i,2*j);
>       x=x+1;
>     endif
>  endfor
>endfor
>average=sum/x;

Coded this way, you waste a lot of the power of octave. Since octave is
a matrix oriented language you can do better with:

[m,n]=size(f5hs3);
C_temp = C(2:2:m,2:2:n);
C_temp = C_temp(:); %or reshape
average=mean(C_temp(find(f5hs3(2:2:m,2:2:n)<3400)));
----------------------------------------------------------------------
Erich Schneider, Dipl.-Phys.     | address@hidden
Neurologische Forschung          | address@hidden
Ludwig-Maximilians-Universit"at  | 
Klinikum Grosshadern, M"unchen   | Fax: +49,89,70906,101



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