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Re: Simple program leaking memory - why?

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  • Subject: [mg130768] Re: Simple program leaking memory - why?
  • From: Roland Franzius <roland.franzius at>
  • Date: Mon, 13 May 2013 03:47:42 -0400 (EDT)
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Am 07.05.2013 09:53, schrieb gredner at
> Hi folks,
> I'm fighting an issue in which a simple Mathematica program to export a bunch of plots is leaking a huge amount of memory - enough to exhaust the 12G available on my machine.  The problem is, it looks like the program should run in bounded memory!  A simplified version of my code which demonstrates the problem follows:



> ====================
> n = 10000;
> (* just some bogus data *)
> makeData[_] := Table[{{x, y} = RandomReal[{-3, 3}, {2}], {y, -x}}, {200}];
> data = Array[makeData, n];
> ParallelMap[
>    Export[
>      "movie-" <> IntegerString[#, 10, 4] <> ".png",

strg="movie-" <> IntegerString[#, 10, 4] <> ".png";Print[strg];strg,

>      ListVectorPlot[data[[#]]]] &,


>    Range[1, n]];
> ====================
> The problem occurs whether the loop is Map or Do, Parallel- or not.  It occurs in Mathematica 8 and 9, both under Linux.
> The amount of memory leaked per frame is considerable - approximately .6 MB in my tests.  I don't see where it could be going, unless Export is caching every byte which passes through it!
> I've also asked this question on stackexchange [1] but so far nobody has a clue.
> Thanks,
> -Gabe
> [1]

I can't comment on Linux.

In Windows 7 the Windows Explorer interrupts, after generation of about 
1000 files, are stalling suddenly. The Task Manager is still working, 
but only on free parts of the screen. Overlapping windows will be cut in 

You even cannot open  the %user%\Document directory in Windows Explorer, 
so I suspect the file name writing interface to the NTFS system  has 
generated an infinite loop on the medium or its map in memory. Possibly 
there may exist an 1024-overflow error in the file stack interface 

In Windows 7, one hase to delete the whole bunch of .png files using 
DeleteFiles[] in Mathematica or a del in a cmd window.

Since the problem seems to occur on two completely different systems 
there will be an error in the Link library of MathLink, Jlink or 


Roland Franzius

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