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MathGroup Archive 2005

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Re: BinaryIO

  • To: mathgroup at smc.vnet.net
  • Subject: [mg57826] Re: BinaryIO
  • From: dh <dh at metrohm.ch>
  • Date: Thu, 9 Jun 2005 05:18:39 -0400 (EDT)
  • References: <d86b4j$dgs$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

Hi Marko,
First,
FromDate[{2000, 1, 1, 0, 0, 0}] + i
is an integer and you need the format: Integer64 instead of Real64

Second, "BinaryReadList" used without specifying the numbers of elements 
does not always work properly and returns a superfloues last element. 
Further, if the file is not close before calling "BinaryReadList" 
without numbers of elements, it returns subsequently more elements.
"BinaryReadList" is not properly implemented! Mayby Wolfram takes a not.

Best is always to specify the number of elements in "BinaryReadList".

sincerely, Daniel



Marko Kastens wrote:
> Hi,
> 
> I have just updated to Mathematica 5.1.1.0 and trying the new BinaryIO-Commands to 
> increase the IO speed. But ... here is something strange:
> 
> 
> n = 1000000;
> TSout = Table[{FromDate[{2000, 1, 1, 0, 0, 0}] + i, Random[]}, {i, n}];
> BinaryWrite["binTS.dat", TSout, {"Real64", "Real64"}]; // Timing
> TSin = BinaryReadList["binTS.dat", {"Real64", "Real64"}]; // Timing
> TSout == TSin
> 
> 
> Evaluating these lines with a fresh kernel: everything is ok. Evaluate them a 
> second time and TSout==TSin produce a _False_. Restarting the kernel: 
> everything is ok. 
> Every time I (try to) overwrite the file _binTS.dat_ I got a False. It seems to 
> me that the routine is not able to overwrite files.
> 
> Hmmm, any suggestions?
> 
> marko
> 


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