Re: [ublas] [bindings] Workspaces

Subject: Re: [ublas] [bindings] Workspaces
From: Jesse Manning (manning.jesse_at_[hidden])
Date: 2008-12-10 22:42:56

The lack of an overloaded function for specifying an iwork workspace was an
oversight on my part, there should be an overload for it. When I was
implementing the bindings i remember being a little confused about the iwork
and i didn't see the heevd implementation so i settled on creating it with
the size specified in the intel MKL reference manual using the function
ilaenv with a parameter of 9 for getting the number of subproblems.

For the iwork parameter should the user be able to select a minimum/optimal
configuration like the other workspaces?

Jesse

On Wed, Dec 10, 2008 at 6:28 PM, Thomas Klimpel <Thomas.Klimpel_at_[hidden]
> wrote:

> Rutger ter Borg wrote:
> > I had the impression the workspaces (user interface) where something
> along
> > the line of
> >
> >  * minimal
> >  * optimal
> >  * user-defined
>
> This impression is absolutely correct.
>
> > and looking at workspace.hpp, a user is allowed to pass up to two
> arguments
> > to the workspace template functions. Doesn't this mean that a user is
> not
> > able to pass an all workspaces in cases of three different value types
> /
> > workspaces?
>
> No, the user is able to pass all workspaces in case of three different
> workspaces, as the example from heevd shows:
>
> template <typename T, typename R>
> void operator() (..., optimal_workspace, ...)
>
> template <typename T, typename R, typename W, typename RW, typename WI>
> void operator() (..., std::pair<detail::workspace2<W,RW>,
> detail::workspace1<WI> > work, ...)
>
> >>> Perhaps it's safer to select the number of workspaces by the number
> of
> >>> workspaces defined in the Fortran code :-).
> >>
> >> Not really.
> >
> >Please elaborate, (fortran) workspaces are marked explicitly in the
> code.
> >Are you saying the number of C++ workspaces does not equal the number
> of
> >fortran workspaces?
>
> I'm saying that "n_workspace_args<value_type>::value" and
> "detail::workspace2" don't refer to the number of fortran workspaces.
> Perhaps the names are misleading, but it is actually true that
> detail::workspace2 holds two workspaces.
>
> This solution was proposed in
> http://lists.boost.org/MailArchives/ublas/2008/05/2762.php
> Since no objections were raised, I assume that this solution was
> accepted. Feel free to raise objections, than we can see whether there
> is a better solution.
>
>
> I will use the same strategy for the 64-bit modification. I proposed a
> solution in
> http://lists.boost.org/MailArchives/ublas/2008/11/3109.php
> and as long as no objection are raised, I assume that the proposed
> solution is accepted.
>
> Regards,
> Thomas
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