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Re: sparse matrix support in MathML

From: Jason Davis <jasonkarldavis@gmail.com>
Date: Thu, 31 May 2007 09:38:15 -0400
Message-Id: <BF93FD8B-518C-42D2-B1CA-D4AF94FCDB92@gmail.com>
To: www-math@w3.org

How wise is it to require specifying every row? You get the benefit  
of having sparse columns, but the markup is still dense in the rows.  
I would suggest:

<smatrix rows="m" cols="n">
	<smatrixdefault><cn>0</cn></smatrixdefault>
	<smatrixelement row="i" col="j"><cn>5</cn></smatrixelement>
	...
</smatrix>

As far as I know, programs like Matlab simply uses a list of (i,j)- 
 >value tuples in their sparse matrix implementation (or at least  
makes it appear that way to the user), and this is a direct  
reflection of it.

-Jason Davis


On May 31, 2007, at 9:16 AM, Max Berger wrote:

> Dear David,
>
> David Carlisle schrieb:
>>> - Reuse mtable, mrow, mcolumn (otherwise functionality is  
>>> duplicated).
>>
>> wouldn't you want to use content markup rather than presentation for
>> this?
>
> You are right. Assuming display math is for displaying only, and
> therefore it wouldn't matter to insert numerous extra <mtd>, the
> original idea of introducing a <smatrix> for content markup seems fine
> to me. However, I think the ideas of attribute handling are still  
> valid.
>
> Here is an idea for the "rest" of the matrix:
>
> <smatrix columns="4">
>   <smatrixdefalut><cn>0</cn><smatrixdefault>
>   <smatrixrow>
>     <smatrixelem col="1"><cn>1</cn></smatrixelem>
>     <smatrixelem col="2"><cn>2</cn></smatrixelem>
>   </smatrixrow>
>   <smatrixrow>
>     <smatrixelem col="4"><cn>3</cn></smatrixelem>
>   </smatrixrow>
>   <smatrixrow>
>     <smatrixelem col="4"><cn>4</cn></smatrixelem>
>   </smatrixrow>
> </smatrix>
>
> the "smatrixdefault" element would give the "default" value for all
> unspecified elements. If not given, I believe <cn>0</cn> seems like a
> good default value. However, one would have to use <smatrixdefault/ 
> > to
> empty the default element.
>
>
>> David
>
>
> mfG
>
> Max Berger
> e-mail: max@berger.name
>
> -- 
> OpenPG ID: E81592BC   Print: F489F8759D4132923EC4 BC7E072AB73AE81592BC
> For information about me and my work please see http://max.berger.name
>
Received on Thursday, 31 May 2007 23:41:46 GMT

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