[dune-functions] Problems writing vector-valued vtk files

[Carsten Gräser]

Am 19.03.2015 um 10:19 schrieb Christian Engwer:
> On Thu, Mar 19, 2015 at 10:12:40AM +0100, Carsten Gräser wrote:
>> Am 18.03.2015 um 22:14 schrieb Christian Engwer:
>>> This would become easier when introducing tensors ;-)
>> Perhaps. However I still think that the user will have
>> to decide in the nontrivial cases.
> 
> well, when properly implementing tensors (don't get me wrong, I'm not
> sure we want to implement this...), the type of the tensors involved
> in a multiplication would imply whether this is a contraction or a
> tensor product.
Sure this would be possible. But assume that the local basis as FV<K,n>
as range and the coefficients are of type FV<K,m> then the user may
not want to have a fixed type CovariantTensor<K,n,m> but a type fitting
to the application like e.g. FM<K,m,n>, FM<K,n,M>, FV<K,m*n>. The latter
is especially important if n=1 or m=1.

I propose to not try solving this problem until someone needs
a solution for this.

Best,
Carsten