[Dune] [Dune-Commit] dune-grid r7391 - trunk/dune/grid/common

[Oliver Sander]

Hi!
I have a question regarding the new capability isCartesian,
and I would like the answer to be added to the documentation:
Are all elements of a cartesian grid of equal size, or can,
say, the x-coordinate, vary with unequal spacings?

I have also been wondering if that capability is general enough
in the long run.  Think for example of prism grids.  I may want
to specify that a grid is cartesian in one direction, but unstructured
in another.  Also, there are grids that are topologically structured,
but not geometrically (like a YaspGrid deformed by a GeometryGrid).
These grids are not cartesian, but they still have extra information
that may be useful.

Food for thought.  I am not proposing any changes for the upcoming
release, but I think we should consider these questions eventually.

Best,
Oliver

Am 08.02.2011 14:34, schrieb robertk at dune-project.org:
> Author: robertk
> Date: 2011-02-08 14:34:17 +0100 (Tue, 08 Feb 2011)
> New Revision: 7391
>
> Modified:
>     trunk/dune/grid/common/capabilities.hh
> Log:
> docu bug fix, the new capabilities were not in the correct group.
>
>
>
> Modified: trunk/dune/grid/common/capabilities.hh
> ===================================================================
> --- trunk/dune/grid/common/capabilities.hh	2011-02-08 11:26:32 UTC (rev 7390)
> +++ trunk/dune/grid/common/capabilities.hh	2011-02-08 13:34:17 UTC (rev 7391)
> @@ -16,6 +16,7 @@
>       of the grid has only one possible geometry type. In this case the
>       topologyId of this geometry type has also to be specified.
>       (default=false, topologyId=undefined)
> +    \ingroup GICapabilities
>   */
>   template<class Grid>
>   struct hasSingleGeometryType
> @@ -26,10 +27,17 @@
>     static const unsigned int topologyId = ~0u;
>   };
>
> -/** \brief Specialize with 'true' if the grid is a Cartesian grid,
> -    meaning that the normal can be calculated by the formula
> -    \f$n[ face/2 ] = 2( face % 2 ) - 1 \f$ and furthermore, the geometry mapping is
> -    affine. (default = false)
> +/** \brief Specialize with 'true' if the grid is a Cartesian grid.
> +    Cartesian grids satisfy the following properties:
> +      - all geometries are affine
> +      - The unit outer normal for an intersection with indexInInside = face
> +        can be computed by the following code:
> +      \code
> +         FieldVector<  ctype, dim>  n( 0 );
> +         n[ face / 2 ] = ctype( 2*(face % 2) - 1 );
> +      \endcode
> +    (default=false).
> +    \ingroup GICapabilities
>   */
>   template<class Grid>
>   struct isCartesian
>
>
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