[GSLL-devel] [PATCH] ode-system: 'next-step' should be exported

Liam Healy lhealy at common-lisp.net
Wed May 4 18:37:53 UTC 2011


On Wed, May 4, 2011 at 2:18 PM, Matt Peddie <mpeddie at gmail.com> wrote:

> Liam,
>
> On Wed, May 04, 2011 at 10:20:42AM -0400, Liam Healy wrote:
> > Unless I'm misunderstanding this request, this is already possible, in
> > fact I'd regard it as the basic usage.  Perhaps you are thrown off by
> > the with-ode-integration macro and example.
>
> Great!  I followed the example to begin with, so that was my starting
> point.
>
> > I made up this macro in order to easily accommodate the case of
> > non-array usage in the ODE solvers, because I wanted to show a simple
> > example with scalars.  However if you look at how that macro expands,
> > there is a symbol #:DEP that is bound to a foreign array with the
> > appropriate dimensions:
> >
> > [ macro definition ]
> >
> > So what you want to do is mimic this form, but instead define your
> > foreign array directly.  Is this what you're asking about?  If it's an
> > issue of CL array vs. foreign array, then you can use #'cl-array or
> > just copy it over at the beginning and end.
>
> Thanks.  I saw the way that DEP works within the macro, and I rewrote it
> a few times in an attempt to pass around the array directly and use
> grid:gref inside my dynamics function.  I guess I just need to try a few
> more things (like I said, newbie here).  I want to use the foreign array
> and avoid copying.
>
> > P.S.  Please join the mailing list to post.  Thank you.
>
> I joined right after I got the `your message needs to be approved' mail;
> sorry.
>
> Matt
>

Good.  Having said all that, I think there is definitely room for a more
meaningful and more general macro than with-ode-integration.  Though I'd
like GSLL to be easier to use than GSL, at least calling make-ode-stepper,
make-y-control, make-ode-evolution, apply-evolution, etc. on your own isn't
any worse than GSL.  And the macro expansion is what I would use as a
"tutorial"; I understand for a CL newcomer it's still a tough task.

Liam
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