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MathGroup Archive 2005

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Re: Re: SparseArray, DensityGraphics, ContourGraphics, and SurfaceGraphics

  • To: mathgroup at smc.vnet.net
  • Subject: [mg54669] Re: [mg54619] Re: SparseArray, DensityGraphics, ContourGraphics, and SurfaceGraphics
  • From: DrBob <drbob at bigfoot.com>
  • Date: Fri, 25 Feb 2005 01:19:36 -0500 (EST)
  • References: <cvc84d$qrb$1@smc.vnet.net> <200502240821.DAA13264@smc.vnet.net>
  • Reply-to: drbob at bigfoot.com
  • Sender: owner-wri-mathgroup at wolfram.com

Maybe, when I set out to create a SparseArray, I don't know that I'll later want to graph it.

Applying Normal at that point solves the problem, however.

Bobby

On Thu, 24 Feb 2005 03:21:22 -0500 (EST), Jens-Peer Kuska <kuska at informatik.uni-leipzig.de> wrote:

> Hi,
>
> what has a sparse matrix to do with a density graphics ?
> ArrayPlot[] is only used to visualize the sparse matrix, but
> all the memory saving of the sparse matrix are destroyed when you
> expand every entry in the matrix (not only the non zero values) to a
> 3D Polygon[] with 4 corners in Plot3D[] ...
> It seems a good design decision not to support this nonsens ...
> Regards
>   Jens
>
> "Mark Fisher" <mark at markfisher.net> schrieb im Newsbeitrag
> news:cvc84d$qrb$1 at smc.vnet.net...
>> DensityGraphics works fine with SparseArray objects, but niether
>> ContourGraphics nor SurfaceGraphics does. (I'm using 5.1 for Windows.)
>> This seems to me like a poor design decision (if it's not a bug).
>>
>> sa=SparseArray[IdentityMatrix[10]];
>> glist=Through[{DensityGraphics,ContourGraphics,SurfaceGraphics}[sa]];
>> Show /@ glist;
>>
>> --Mark.
>>
>
>
>
>
>



-- 
DrBob at bigfoot.com
www.eclecticdreams.net


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