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Re: Where are all my "memories" gone?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg122710] Re: Where are all my "memories" gone?
  • From: Patrick Scheibe <pscheibe at trm.uni-leipzig.de>
  • Date: Mon, 7 Nov 2011 05:52:23 -0500 (EST)
  • Delivered-to: l-mathgroup@mail-archive0.wolfram.com
  • References: <201111021121.GAA03545@smc.vnet.net>

Hi,

I sent the issue to the support. In the meantime, maybe someone with
Linux could try the toy-example below.
I was able to build a really small sample which reproduces the behaviour
here. I create a multi-tiff and reimport it:

img = ColorConvert[ExampleData[{"TestImage", "Lena"}], "Grayscale"];
Export["tmp/lena_multi.tif", Table[img, {512}], "TIFF"];
m1 = MemoryInUse[];
img3d = Import["tmp/lena_multi.tif", "Data"];
m2 = MemoryInUse[];

Now I have here, inside Mathematica

In[7]:= {(m2 - m1)*2^-20., ByteCount[img3d]*2^-20.}

Out[7]= {512.6, 512.}

while my System-Monitor is saying, that the MathKernel uses over 1.1GB
while Mathematica is assuming that it currently uses only

In[7]:= MemoryInUse[]*2^-20.

Out[7]= 534.48

MB of my memory.

Cheers
Patrick



On Wed, 2011-11-02 at 07:59 -0500, Oliver Ruebenkoenig wrote:
> On Wed, 2 Nov 2011, Patrick Scheibe wrote:
> 
> > Hi,
> >
> > I have a bit of a delicate problem here. On a fresh kernel this
> >
> > data = Table[RandomInteger[{0, 255}], {i, 100*2^20}];
> > ByteCount[data]/2.^20
> >
> > results in exactly 400MB. My resource-manager of the operating system
> > confirms it by telling me the MathKernel occupies 422MB of memory.
> >
> > In real life, I'm working with tif-images stacks. I only import the
> > underlying data and not the images itself.
> >
> > path = "/long/path/to/aLargeImage.tif";
> > data = Import[path, "Data"];
> > ByteCount[data]/2.^30
> >
> > tells me 3.88GB which seems reasonable since the tif is about 2.0GB on
> > the drive. What does *not* look reasonable is, that Mathematica occupies
> > now 9.7GB of my memory and it doesn't seem to know:
> >
> > In[4]:= {MemoryInUse[], MemoryInUse[$FrontEnd]}/2.^30
> >
> > Out[4]= {3.9044, 0.0000874288}
> >
> > Can anyone give any useful information?
> >
> > Cheers
> > Patrick
> >
> > My OS is:
> > Linux-x86-64
> > Ubuntu 10.04
> >
> >
> 
> Hallo Patrick,
> 
> we were not able to reproduce this on a Mac - perhaps it is best you send 
> this to support at wolfram.com.
> 
> Perhaps this is a memory leak in Import - but this speculation and one 
> would have to look at the specific example.
> 
> The support can then also tell you where to out the 2GB picture.
> 
> Oliver
> 





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