Groups > comp.soft-sys.math.mathematica > #1762

Re: Importing text file as machine-precision array

From	David Bailey <dave@removedbailey.co.uk>
Newsgroups	comp.soft-sys.math.mathematica
Subject	Re: Importing text file as machine-precision array
Date	2011-04-17 11:53 +0000
Organization	Steven M. Christensen and Associates, Inc and MathTensor, Inc.
Message-ID	<ioekb0$n0q$1@smc.vnet.net> (permalink)
References	<inpfu3$9as$1@smc.vnet.net> <inqkt3$e73$1@smc.vnet.net> <inun9l$2aj$1@smc.vnet.net>

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On 11/04/2011 12:05, Sidney Cadot wrote:
>> The only way that you will obtain an array as compact as you calculate
>> (plus a small overhead) is to use the function Developer`ToPackedArray
>> on the result after applying N.
>
> Thanks for the hint -- I didn't know about thgat package. As I
> discovered by trial and error, this also works:
>
> data = data + ConstantArray[0., Dimensions[data]];
>
> Regards Sidney
>
Mathematica uses some heuristics to decide when to convert to packed 
arrays, and one of these obviously kicks in in this case, but I would 
guess that it would be marginally faster to use the ToPackedArray 
function. Although the Developer context could in theory change at 
future versions, the packed array functions have been there for many 
versions, and are widely used, so I can't imagine these would get moved 
without a lot of warning.

David Bailey
http://www.dbaileyconsultancy.co.uk

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Thread

Importing text file as machine-precision array Sidney Cadot <sidney@jigsaw.nl> - 2011-04-09 11:29 +0000
  Re: Importing text file as machine-precision array David Bailey <dave@removedbailey.co.uk> - 2011-04-09 22:00 +0000
    Re: Importing text file as machine-precision array Sidney Cadot <sidney.cadot@gmail.com> - 2011-04-11 11:05 +0000
      Re: Importing text file as machine-precision array David Bailey <dave@removedbailey.co.uk> - 2011-04-17 11:53 +0000

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