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- To: eigen@xxxxxxxxxxxxxxxxxxx
- Subject: Re: [eigen] [PATCH] Toeplitz matrix specialization
- From: Gael Guennebaud <gael.guennebaud@xxxxxxxxx>
- Date: Fri, 30 Jan 2009 08:04:29 +0100
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On Fri, Jan 30, 2009 at 12:54 AM, Jitse Niesen <jitse@xxxxxxxxxxxxxxxxx> wrote:
> On Thu, 29 Jan 2009, Gael Guennebaud wrote:
>
>> to start the debate I put some thougths on the wiki:
>> http://eigen.tuxfamily.org/index.php?title=SpecialMatrix
>
> Does "we assume we don't need a special class for triangular storage" mean
> that triangular matrices are stored as general matrices (and thus half the
> memory is wasted)? That strikes me as an assumption that could be regretted
> later. So perhaps we should make sure that a special class for triangular
> storage can be added later.
in short yes for both. actually, in all our current cases (LU, LLt,
QR, Hessenberg, etc.) the triangular/hessenberg matrix are packed
with other data so that there is no overhead. So what we primarily
need is "view" to triangular part of a dense matrix. In the future, I
don't any reason why we could not add a compact triangular storage.