Re: [eigen] Partially fixed size matrices. |

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*To*: eigen@xxxxxxxxxxxxxxxxxxx*Subject*: Re: [eigen] Partially fixed size matrices.*From*: Benoit Jacob <jacob.benoit.1@xxxxxxxxx>*Date*: Thu, 11 Jun 2009 14:20:20 +0200*Dkim-signature*: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:content-type :content-transfer-encoding; bh=wqNHNz2BO8C9zPx55YxqDA9CEiK0UXyvWGKlyw8KwPQ=; b=qO0LX5iGjzWH6UI3RwPTk+KL5kdtTtTAgT7EJM5pZUF8LlbAu5f7nrZrN4Y0vhzh8G 6VNU4UYzucO4QRzzhePfNGtNi1Qovbc5k59JdAcywecrEdwwofGQvgyNuFpUujQjBsXC qcYUZOE7ki9VN2TLiyUEoyQjJdmeqWWuA+SvE=*Domainkey-signature*: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type:content-transfer-encoding; b=GS6U7vOU86qTimOGjK4jgZiEECAh/1GkRsLcE/mS9gw1/3D+2KUqSDtHq1SfRpnfS4 YOVcz45vbQmrKLLF2V8LwXXb9MHKnit3pXbt65SQEjT0m3MzKS8zi4PqAJtlUAmBQu8W WlRmVfN8hJu+l4sKhotfv9OCVJ2i1YTWwsYpk=

2009/6/11 Gael Guennebaud <gael.guennebaud@xxxxxxxxx>: > On Thu, Jun 11, 2009 at 1:19 PM, Tim Hutt<tdhutt@xxxxxxxxx> wrote: >> Hi, >> >> One of the examples given in the documentation says that you can do >> things like this: >> >> Eigen::Matrix<double, Dynamic, 1> foo(10); // A 10x1 matrix (ie a vector) >> >> However, it makes no mention of if you can do this: >> >> Eigen::Matrix<double, Dynamic, 2> bar(???); // An Nx2 matrix. > > of course you can do that, and this is even recommended because this > allows Eigen to unroll some inner loops. > >> And none of the constructors seem appropriate for a matrix like this. >> The single argument one is the only one that really makes sense and it >> says it is only for vectors. > > Indeed, you have to specify both sizes even though one is already > known and cannot be changed. Perhaps we could allow the "vector" ctor > to work in that case too ? Right know I don't have a strong opinion. Hm, no strong opinion either. On the one hand it can be convenient / expected by the user. On the other hand it means that the semantics depend on which size is fixed and which is dynamic. We already do that for vectors / rowvectors, though. I'd say 'yes' but it's only a 51% majority among my neurons... >> While on the topic of documentation it would be awesome if you could >> set up a way to append comments to the documentation pages. This can >> be very useful, e.g. the MySQL documentation has (or had, they seem to >> have changed it a bit) a lot of useful comments. > > This is a good idea, however since we are using doxygen to generate > the doc this not going to be easy unless we extend doxygen itself ! > Moreover, since the documentation evolves from one version to the > other, it is probably very tricky to be able to correctly propagate > the comments... Yes, the doc is inseparable from the source code otherwise it would be unmanageable to keep it in sync. Meanwhile the best possibilities to have for commenting are: 1) open issues on the tracker or 2) fork our hg repository and add your comments/changes into the documentation in the source code. then ask us to pull your improvements. Benoit

**References**:**[eigen] Partially fixed size matrices.***From:*Tim Hutt

**Re: [eigen] Partially fixed size matrices.***From:*Gael Guennebaud

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