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Message-ID: <c7d45fc70812011449w72d3d8d3if8bcd5e6e2cc152b@mail.gmail.com>
Date: Mon, 1 Dec 2008 14:49:30 -0800
From: "Ted Dunning" <ted.dunning@gmail.com>
To: "Commons Developers List" <dev@commons.apache.org>, sujit.pal@comcast.net
Subject: Re: [math] patch submitted for commons-math sparse matrix support
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This is often handled by using an offset sparse matrix or vector that is
sparse in that only elements different from the offset are stored.  You can
often do this at the algorithmic level by carrying around the requisite
constant matrix in your derivation.  Obviously, a normal sparse matrix is a
special case.

Offset sparse vectors provide simple ways to express row and column sums as
well.

On Mon, Dec 1, 2008 at 2:31 PM, Sujit Pal <sujit.pal@comcast.net> wrote:

> On a slightly different note, I've been thinking about some other ways
> to reduce the memory footprint (of my application), and I think there
> may be some justification for having things like ConstantVector, ie a
> large non-sparse Vector which contains the same data for all its
> elements. The idea is similar, the getEntry() method would return a
> value that is set into the constructor.
>


-- 
Ted Dunning, CTO
DeepDyve
4600 Bohannon Drive, Suite 220
Menlo Park, CA 94025
www.deepdyve.com
650-324-0110, ext. 738
858-414-0013 (m)

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