|Re: [eigen] patch for tridiagonal matrices in eigen|
[ Thread Index |
| More lists.tuxfamily.org/eigen Archives
- To: eigen@xxxxxxxxxxxxxxxxxxx
- Subject: Re: [eigen] patch for tridiagonal matrices in eigen
- From: "Mauro Iazzi" <mauro.iazzi@xxxxxxxxx>
- Date: Fri, 9 Jan 2009 01:35:17 +0100
- Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to :subject:in-reply-to:mime-version:content-type :content-transfer-encoding:content-disposition:references; bh=+GrPjZIDn9SLnHEsO4kL2SRn0TmKm+vSb0cuMwI/XCk=; b=euzsU8gNxSv3z7p8rk50MtfLWR2miMaxvauk95G70pjoTYt/sRhGOkpTTKheuhnO14 QSfk0CIuaBJe1cWRMVlq0qbLG15b2codvFvnylSqKE6/EhcWw0OLItDpoX1Mk2X27UWg WpKOypv/xw6nUkvUCCOXVU5LuTmmo0Ah8YuIc=
- Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :references; b=chlNvYqXn5tlp8AoFbPDHhjLW8vhvucieXLIg7/4XfIMaZ0YGQqiS+7MkIW9UFRbjQ UOczsP9O8PCzFztHjdaGy1mEUVwCHFyj9V0rytZJ0J6AXxvBiuxN4q3jbgnQhojKoYVB BtjB2lauiMKw/U+oObO1FRz2rDMfeiEQLgytc=
2009/1/8 Benoit Jacob <jacob.benoit.1@xxxxxxxxx>:
> Hi Mauro,
> 2009/1/8 Mauro Iazzi <mauro.iazzi@xxxxxxxxx>:
>> Hi, sorry for replying so late.
> No worry at all since we're in the rush to release 2.0 we don't have
> much time at the moment for thinking about this either...
> I'll study carefully your mail later, when I have time; for now I just
> want to address this quick point:
>> 2008/12/30 Benoit Jacob <jacob.benoit.1@xxxxxxxxx>:
>>> An expression class MyExpression is a bad idea whenever the
>>> MyExpression::coeff() method is slow and in practice it can be
>>> bypassed when implementing actual algorithms.
>> It's a perfect criterion. However, when something else than an
>> expression is used, memory may be wasted. This is quite a concern with
>> me: a single matrix storage may be the few hundred megs that exceed my
>> memory and start using swap. I have no obvious solutions.
> When I said that we should avoid expressions, I didn't mean that we
> should instead represent as a plain old n*n matrix, storing the
Sorry, I expressed myself badly. I agree that a diagonal matrix should
have its own storage. That comment was about the return types of
operations on diagonal matrices.