[Dune-devel] Replacing SGrid by YaspGrid

[Dominic Kempf]

Hey Oli,

check out the feature branch with the implementation of the feature and
give feedback!

Dominic

On Mon, Oct 13, 2014 at 11:21 AM, Dominic Kempf <dominic.r.kempf at gmail.com>
wrote:

> Hey Oliver,
> unfortunately, having the user create his own coordinate object is only a
> good idea for sequential grids. For parallel grids, the coordinate object
> implicitly contains information about the partitioning. Especially with
> TensorProduct grids this should not be touched by the user. It would also
> violates the "Simple things should be simple" paradigm.
> Best,
> Dominic
>
> On Mon, Oct 13, 2014 at 10:38 AM, Oliver Sander <
> sander at igpm.rwth-aachen.de> wrote:
>
>> Hi Dominic,
>> thanks for measuring.  It's always good to make informed choices.
>> Frankly, I wouldn't
>> have expected it to make that much of a difference.
>> Concerning the additional information: I guess the most general way would
>> be to require
>> the user to create the Coordinate object herself, and pass it to the
>> YaspGrid constructor.
>> That way a single YaspGrid constructor works for all possible Coordinate
>> types.
>> On the other hand I think that one additional YaspGrid constructor for
>> the case considered
>> here wouldn't be a bad thing.
>> Best,
>> Oliver
>>
>>
>> Am 13.10.2014 um 10:31 schrieb Dominic Kempf:
>> > Hey Oliver,
>> > this is indeed something to think about.
>> > I have bad news though. I have done a quick measurement of option b).
>> > I added a parameter origin to EquidistantCoordinates and defaulted it
>> to 0.
>> > This slowed down the finitevolume example by roughly 10%.
>> > You're option a) is of course VERY simple to implement. The only
>> question
>> > that bugs me about it, is how to pass the additional information. I
>> would
>> > be very happy
>> > if there was a good way, that does not involve introducing an additional
>> > constructor.
>> > Any opinions?
>> > Best,
>> > Dominic
>> >
>> > On Fri, Oct 10, 2014 at 7:13 PM, Oliver Sander <
>> sander at igpm.rwth-aachen.de>
>> > wrote:
>> >
>> >> Hi all,
>> >> while thinking about how to replace SGrid by YaspGrid I came about the
>> >> following
>> >> small inconvenience: SGrid are uniformly spaced, and both the lower
>> left
>> >> and the
>> >> upper right corners are free.  YaspGrid, OTOH, when they are not
>> >> tensor-product grids,
>> >> constrain the lower-left corner to be (0,...,0).  So currently, in
>> order
>> >> to replace
>> >> SGrids I sometimes have to use tensor-product YaspGrids even though
>> they
>> >> are uniformly
>> >> spaced.
>> >> Should we
>> >> a) introduce a third Coordinates class in YaspGrid for uniformly spaced
>> >> grids with
>> >>    a nonzero left corner?
>> >> b) generalize the current EquidistantCoordinate class to allow for a
>> >> nonzero left
>> >>    corner?
>> >>
>> >> a) would be preferable if b) would lead to a measurable slowdown.  Does
>> >> anybody
>> >> have experience with this?
>> >> Thanks,
>> >> Oliver
>> >>
>> >>
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>> >>
>> >>
>> >
>>
>>
>>
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>
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