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Glas :Re: [glas] when to evaluate scalar expressions |
From: Andreas Pokorny (andreas.pokorny_at_[hidden])
Date: 2006-04-24 15:59:08
On Sun, Apr 23, 2006 at 10:26:23PM +0200, Toon Knapen <toon.knapen_at_[hidden]> wrote:
> Andreas Pokorny wrote:
> >
> > Can you attach a specific backend to a subtree, and have another one
> > in the final assignment? I just wonder if you have control over the
> > backend used to preevaluate the scalar value.
>
>
> Partial dispatching, i.e. dispatching only a specific part of an
> expression to one backend and the rest of the expression to another
> backend, is not directly supported. We thought long and hard about this
> but partial dispatching leads to a lot of ambiguous situations.
>
> Thus currently only when assigning a rhs to the lhs we dispatch the
> /whole/ expression to a specific backend. However the backend itself can
> decide to dispatch parts of the expression to another backend and/or
> create temporaries.
I was asking because, the user would want to control the backend used in
the pre evaluation of the scalar.
Regards
Andreas Pokorny