<?xml version="1.0" encoding="UTF-8"?><rss version="2.0"
	xmlns:content="http://purl.org/rss/1.0/modules/content/"
	xmlns:dc="http://purl.org/dc/elements/1.1/"
	xmlns:atom="http://www.w3.org/2005/Atom"
	xmlns:sy="http://purl.org/rss/1.0/modules/syndication/"
		>
<channel>
	<title>Comments on: SciPy &#8211; some more thoughts</title>
	<atom:link href="http://www.vetta.org/2008/05/scipy-some-more-thoughts/feed/" rel="self" type="application/rss+xml" />
	<link>http://www.vetta.org/2008/05/scipy-some-more-thoughts/</link>
	<description></description>
	<lastBuildDate>Tue, 27 Jul 2010 16:18:49 +0000</lastBuildDate>
	<sy:updatePeriod>hourly</sy:updatePeriod>
	<sy:updateFrequency>1</sy:updateFrequency>
	<generator>http://wordpress.org/?v=3.0</generator>
	<item>
		<title>By: Recent Links Tagged With "lapack" - JabberTags</title>
		<link>http://www.vetta.org/2008/05/scipy-some-more-thoughts/comment-page-1/#comment-19089</link>
		<dc:creator>Recent Links Tagged With "lapack" - JabberTags</dc:creator>
		<pubDate>Mon, 06 Oct 2008 18:49:36 +0000</pubDate>
		<guid isPermaLink="false">http://www.vetta.org/?p=53#comment-19089</guid>
		<description>[...] public links &gt;&gt; lapack   SciPy - some more thoughts Saved by fzx750 on Sun 05-10-2008   Build notes Saved by rikitora on Thu 02-10-2008   Working with [...]</description>
		<content:encoded><![CDATA[<p>[...] public links &gt;&gt; lapack   SciPy &#8211; some more thoughts Saved by fzx750 on Sun 05-10-2008   Build notes Saved by rikitora on Thu 02-10-2008   Working with [...]</p>
]]></content:encoded>
	</item>
	<item>
		<title>By: Shane Legg</title>
		<link>http://www.vetta.org/2008/05/scipy-some-more-thoughts/comment-page-1/#comment-18906</link>
		<dc:creator>Shane Legg</dc:creator>
		<pubDate>Wed, 04 Jun 2008 20:26:36 +0000</pubDate>
		<guid isPermaLink="false">http://www.vetta.org/?p=53#comment-18906</guid>
		<description>@ Alexander:

Regarding fast SciPy.  The problem is that you need to use ATLAS to tune the BLAS and LAPACK code to your system and then compile it yourself for your specific hardware.  The standard libraries you get aren&#039;t optimised for specific hardware.  At least that is what I understand... I haven&#039;t bothered doing this myself yet.</description>
		<content:encoded><![CDATA[<p>@ Alexander:</p>
<p>Regarding fast SciPy.  The problem is that you need to use ATLAS to tune the BLAS and LAPACK code to your system and then compile it yourself for your specific hardware.  The standard libraries you get aren&#8217;t optimised for specific hardware.  At least that is what I understand&#8230; I haven&#8217;t bothered doing this myself yet.</p>
]]></content:encoded>
	</item>
	<item>
		<title>By: Shane Legg</title>
		<link>http://www.vetta.org/2008/05/scipy-some-more-thoughts/comment-page-1/#comment-18905</link>
		<dc:creator>Shane Legg</dc:creator>
		<pubDate>Wed, 04 Jun 2008 20:22:51 +0000</pubDate>
		<guid isPermaLink="false">http://www.vetta.org/?p=53#comment-18905</guid>
		<description>@ Alexander:

The problem is that the top level of scipy is in python.  Thus when you call some scipy matrix operations from pyrex code it has to go from compiled C into the python interpreter and then through a few levels of python wrapper code before going into the compiled BLAS libraries to perform the computation.  Same coming back out from a matrix operation.  As interpreted python is around 100 times slower than C, this wrapper code kills the performance when making a large number of calls to small matrices.  Ideally somebody should make a pyrex wrapper for BLAS to avoid this overhead...</description>
		<content:encoded><![CDATA[<p>@ Alexander:</p>
<p>The problem is that the top level of scipy is in python.  Thus when you call some scipy matrix operations from pyrex code it has to go from compiled C into the python interpreter and then through a few levels of python wrapper code before going into the compiled BLAS libraries to perform the computation.  Same coming back out from a matrix operation.  As interpreted python is around 100 times slower than C, this wrapper code kills the performance when making a large number of calls to small matrices.  Ideally somebody should make a pyrex wrapper for BLAS to avoid this overhead&#8230;</p>
]]></content:encoded>
	</item>
	<item>
		<title>By: Alexander Yuryshev</title>
		<link>http://www.vetta.org/2008/05/scipy-some-more-thoughts/comment-page-1/#comment-18904</link>
		<dc:creator>Alexander Yuryshev</dc:creator>
		<pubDate>Wed, 04 Jun 2008 20:11:07 +0000</pubDate>
		<guid isPermaLink="false">http://www.vetta.org/?p=53#comment-18904</guid>
		<description>hmm..
Realy strange.
Pyrex(Cython) did not help you?
&gt;&gt;If you want to have fast SciPy then you need to install BLAS, LAPACK and ATLAS yourself.  

Why not?
If you work for a customer, you can create separate installation for customer-platform, don&#039;t you?

It&#039;s not a criticizm - I suppose you&#039;re more experienced in this area (and I&#039;m not even novice yet)

Anyway:
 1. Thanks. I will track your blog
 2. I apologize for my English =)</description>
		<content:encoded><![CDATA[<p>hmm..<br />
Realy strange.<br />
Pyrex(Cython) did not help you?<br />
&gt;&gt;If you want to have fast SciPy then you need to install BLAS, LAPACK and ATLAS yourself.  </p>
<p>Why not?<br />
If you work for a customer, you can create separate installation for customer-platform, don&#8217;t you?</p>
<p>It&#8217;s not a criticizm &#8211; I suppose you&#8217;re more experienced in this area (and I&#8217;m not even novice yet)</p>
<p>Anyway:<br />
 1. Thanks. I will track your blog<br />
 2. I apologize for my English =)</p>
]]></content:encoded>
	</item>
	<item>
		<title>By: Shane Legg</title>
		<link>http://www.vetta.org/2008/05/scipy-some-more-thoughts/comment-page-1/#comment-18847</link>
		<dc:creator>Shane Legg</dc:creator>
		<pubDate>Sat, 10 May 2008 22:31:25 +0000</pubDate>
		<guid isPermaLink="false">http://www.vetta.org/?p=53#comment-18847</guid>
		<description>Tobu: I&#039;m not sure how weave would help much?  

If I have some nice ndarrays that I&#039;m working with and want to do something like an efficient dot product then I&#039;m going to hove to somehow cross from the ndarray world into the BLAS world.  I guess that Numpy has to do a bit of magic to make this happen and that&#039;s what slowing down the calls.  I guess that I would have to essentially replicate this... which might end up being just as slow?

Maybe I should look into the guts of Numpy to see what is actually going on... :-)</description>
		<content:encoded><![CDATA[<p>Tobu: I&#8217;m not sure how weave would help much?  </p>
<p>If I have some nice ndarrays that I&#8217;m working with and want to do something like an efficient dot product then I&#8217;m going to hove to somehow cross from the ndarray world into the BLAS world.  I guess that Numpy has to do a bit of magic to make this happen and that&#8217;s what slowing down the calls.  I guess that I would have to essentially replicate this&#8230; which might end up being just as slow?</p>
<p>Maybe I should look into the guts of Numpy to see what is actually going on&#8230; <img src='http://www.vetta.org/wp-includes/images/smilies/icon_smile.gif' alt=':-)' class='wp-smiley' /> </p>
]]></content:encoded>
	</item>
	<item>
		<title>By: Stephen Donnelly</title>
		<link>http://www.vetta.org/2008/05/scipy-some-more-thoughts/comment-page-1/#comment-18841</link>
		<dc:creator>Stephen Donnelly</dc:creator>
		<pubDate>Fri, 09 May 2008 23:28:49 +0000</pubDate>
		<guid isPermaLink="false">http://www.vetta.org/?p=53#comment-18841</guid>
		<description>The eve-online cluster uses twisted-python?

Also if your server is bogging down, you could offload visitors to the LJ feed, http://syndicated.livejournal.com/vetta_project_2/</description>
		<content:encoded><![CDATA[<p>The eve-online cluster uses twisted-python?</p>
<p>Also if your server is bogging down, you could offload visitors to the LJ feed, <a href="http://syndicated.livejournal.com/vetta_project_2/" rel="nofollow">http://syndicated.livejournal.com/vetta_project_2/</a></p>
]]></content:encoded>
	</item>
	<item>
		<title>By: Tobu</title>
		<link>http://www.vetta.org/2008/05/scipy-some-more-thoughts/comment-page-1/#comment-18840</link>
		<dc:creator>Tobu</dc:creator>
		<pubDate>Fri, 09 May 2008 23:15:30 +0000</pubDate>
		<guid isPermaLink="false">http://www.vetta.org/?p=53#comment-18840</guid>
		<description>You could use weave to avoid crossing the language boundary inside a loop. There is a &lt;a href=&quot;http://projects.scipy.org/scipy/scipy/browser/trunk/scipy/weave/doc/tutorial.txt?format=txt&quot; rel=&quot;nofollow&quot;&gt;tutorial&lt;/a&gt; and here are some &lt;a href=&quot;http://www.scipy.org/PerformancePython&quot; rel=&quot;nofollow&quot;&gt;alternatives&lt;/a&gt;.</description>
		<content:encoded><![CDATA[<p>You could use weave to avoid crossing the language boundary inside a loop. There is a <a href="http://projects.scipy.org/scipy/scipy/browser/trunk/scipy/weave/doc/tutorial.txt?format=txt" rel="nofollow">tutorial</a> and here are some <a href="http://www.scipy.org/PerformancePython" rel="nofollow">alternatives</a>.</p>
]]></content:encoded>
	</item>
</channel>
</rss>
