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Re: Problems writing output-files

  • To: mathgroup at smc.vnet.net
  • Subject: [mg14684] Re: Problems writing output-files
  • From: "P.J. Hinton" <paulh>
  • Date: Sun, 8 Nov 1998 21:15:42 -0500
  • Organization: "Wolfram Research, Inc."
  • References: <720sm6$1u6@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

On 7 Nov 1998, Michael Bunk wrote:

> I have the following problem with the command
> 
> 	solution >> solution-file .
> 
> solution is a table with parameters and InterpolatingFunctions. The file
> is about 15 MB. At a given size it's no more possible to write this
> file. 
> 
> What happens? MATHEMATICA starts to use a lot of memory and fails with
> 
> 	Out Of Memory,
> 
> on our machine at about 250MB RAM.
> 
> Why MATHEMATICA needs this amount of RAM to write 'only' a 15 MB file?

It's not really possible to say exactly why this is happening from the
information that has been provided.  It might be that the memory
consumption is occurring while the kernel is trying to format a very
large, complicated expression.

What are your objectives with writing this large amount of data out to a
file?  Is it for human inspection or for later input back into
Mathematica or another application?  If human readability is not a key
factor, and you are using a release of Mathematica 3.0.x, you can use
DumpSave[] to write the expression into a file that is in an internal
Mathematica format.  

The advantage of writing a file out this way is that the kernel can read
it back in quickly with the Get[] command.  However, the file that is
platform dependent and cannot be read in by a Mathematica kernel for a
different architecture.

Information on DumpSave[] can be found in Section 2.11.1 of _The
Mathematica Book_ (Third Edition).  If you have access to the online
version of the book via the Help Browser, you can look up this topic by
pasting the following expression in a notebook and evaluating it.

FrontEndExecute[FrontEnd`HelpBrowserLookup["MainBook", {"2.11.1",
"1.34"}]]

--
P.J. Hinton
Mathematica Programming Group           paulh at wolfram.com Wolfram
Research, Inc.                  http://www.wolfram.com/~paulh/
Disclaimer: Opinions expressed herein are those of the author alone.



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