Re: saving plot to file, Ghostscript collision error?

[Nicholas Jankowski]

On Fri, Jun 15, 2012 at 10:26 PM, Ben Abbott <address@hidden> wrote:
>
> On Jun 15, 2012, at 10:14 PM, Nicholas Jankowski wrote:
>
>> Using Octave3.6.2gcc4.6.2 on windows (mingw) running the same octave
>> script on separate cores for some brute force 'parallel processing', I
>> have the script generate and save a bunch of plots as it goes along.
>> Done this a number of times, and this was the first I noticed the
>> following error message popping up:
>>
>> -----
>> GPL Ghostscript 9.05: Unrecoverable error, exit code 1
>> The process cannot access the file because it is being used by another 
>> process.
>> -----
>>
>> Octave continues with the loop, running followon iterations. Looking
>> in the output folder, a couple of the plot files are missing. others
>> are there but missing elements (usually the plot is there but the
>> label I put on each graphic is missing).
>>
>> certain scripts run faster, so in the past the different processes
>> usually hit this part of the script at different times. this time I
>> restarted them all at this spot, and noticed all of these error
>> messages.
>>
>> So, is ghostscript using some temporary files to generate plot images
>> and I can't have separate Octave instances calling it?
>>
>> here's the sloppy code creating the two plots per iteration. I think
>> the jpg one is the one that runs into problems
>>
>> fig1=plot(ZZ,normtemps,"*");
>> hold on;
>> plot(sortedtrue(:,1),sortedtrue(:,2),"linewidth",3,'k');
>> axis('square');
>> text(get(gca(),"xlim")(2)*.75,get(gca(),"ylim")(2)*.75,"stringtoprinthere");
>> hold off;
>> saveas(fig1,"filenamehere",".jpg"));
>>
>> fig3=plot(anasteptimes,xxana_l,"b",steptimes,xx,"xr"); axis("square");
>> text(get(gca(),"xlim")(2)*.75,get(gca(),"ylim")(2)*.75,"stringtoprinthere");
>> saveas(fig3,"filenamehere",".emf"))
>
>
> Octave does use temporary files when printing, but their names have random 
> content, so there should be no conflict.
>
> Are the different instances of Octave trying to save a figure to the same 
> file name?
>
> Are you able to determine the name of the file that ghostscript cannot access?
>
> Ben
>
>

yes, if started at the same time the two files would probably have the
same filename (different folder). maybe the random name hashes based
on filename so there was a temp file collision? how much overhead
would an ifexist() check add?