[Gnuplot-py-users] Gnuplot.py, FIFOs and threading

[Ken S. <k.w...@qu...>]

Folks

Apologies in advance if there's an FAQ, but I can't find it...  (Feel  
free to point it out to me...)  There also doesn't seem to be a simple  
way to search the Sourceforge archives for this group...

I've been using Gnuplot.py for a while now, and I keep running into  
the same problem.  I'm creating postscript plots, but at the end of my  
script I'd like to convert them into JPEGs using ImageMagick (convert).

The problem is that (presumably because of threading) Gnuplot.py is  
sometimes not completing its work before I attempt to convert the  
plot.  Hence ImageMagic complains about missing postscript files - or  
the postscript files are incomplete when conversion starts.

Is there a way to turn threading/FIFOs OFF?  Or is there a way I can  
use "join" to force my python program to WAIT for the plot to be  
completed before attempting to convert it?

I've tried setting the following after my Gnuplot import:

Gnuplot.GnuplotOpts.prefer_fifo_data = 0
Gnuplot.GnuplotOpts.support_fifo = 0
Gnuplot.GnuplotOpts.prefer_inline_data = 1

but to no avail.  The only thing I'm doing at the moment is checking  
that the postscript file exists - but this is just a fudge and doesn't  
prevent other issues if the file is incomplete.  Below are example  
errors...

Ken



Example errors:

MISSING ps file

convert: unable to open image `/tmp/tempPSPlots/ 
1095652401023547700_lc.ps':  @
error/blob.c/OpenBlob/2584.
convert: missing an image filename
`/psdb/images/ps1ss/lightcurves/1095652401023547700_lc.jpeg' @
error/convert.c/ConvertImageCommand/2949.


INCOMPLETE ps file (presumably that's what causes ghostscript to barf)

Error: /syntaxerror in -file-
Operand stack:
    MLshow
Execution stack:
    %interp_exit   .runexec2   --nostringval--   --nostringval--
    %--nostringval--   2   %stopped_push   --nostringval--   -- 
nostringval--
    %--nostringval--   false   1   %stopped_push   1894   1   3    
%oparray_pop
    %1893   1   3   %oparray_pop   1877   1   3   %oparray_pop    
1771   1   3
    %%oparray_pop   --nostringval--   %errorexec_pop   .runexec2
    %--nostringval--   --nostringval--   --nostringval--   2    
%stopped_push
Dictionary stack:
    --dict:1158/1684(ro)(G)--   --dict:0/20(G)--   --dict:80/200(L)--
--dict:176/256(L)--
Current allocation mode is local
Last OS error: 2
GPL Ghostscript  9.00: Unrecoverable error, exit code 1