[dune-functions] [Dune-functions-commit] [Commit] dune-functions - c7b3989: Resize must now be done manually before interpolate()

[Carsten Gräser]

Hi Oliver,

Am 14.09.2015 um 22:55 schrieb Carsten Gräser:
[...]
>> ... which is kind-of ugly, as a matter of fact.  I keep thinking that maybe
>> we should replace array<size_t,1> by size_t whenever that appears as
>> a multi-index.
> But this would mean to teach users things that will not work
> in general. Even worse you cannot write code that works in both,
> the simple and not so simple cases. If you really think it's so ugly
> we may consider to derive from array and add a cast to size_t
> in the simple case. However I'd prefer to hide the complicated
> multiindex stuff in a simple wrapper (that's the backend) that
> can also be explained easily.
> 
> Best,
> Carsten
> 
>>> Maybe a cleaner solution would be, to provide some kind of vector
>>> adaptor providing operator()(MultiIndex) and a hierachic resize.
>>> Then we would write
>>>
>>>   SomeVector v;
>>>   auto&& v_coeff = basisCoefficients(v, basis);
>>>   v_coeff.resize();
>>>   interpolate(v_coeff, treePath, f);
>>>
>>> This would also allow to exchange the now hard wired backend
>>> more easily.
>> Possibly.
if this is implemented as operator[] instead and the cast proposed
above is also implemented it has the nice side effect, that we can
(almost) use a flat vector in simple cases and a wrapped one in the
complicated ones. It's only 'almost', because we have to write

  v.resize(basis.size());

in the simple case, whereas we need something like

  v.resize(basis);

in the complicated ones. If we change the interface of basis.size()
without prefix to return some object that provides all size information
we can even get around this.

Best,
Carsten



>>
>> Best,
>> Oliver
>>
>>> Best,
>>> Carsten
> 
> 
> 
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> 


-- 
Prof. Dr. Carsten Gräser
Freie Universität Berlin
Institut für Mathematik
Arnimallee 6
14195 Berlin, Germany
phone: +49 30 838 72637
fax  : +49 30 838 472637
email: graeser at mi.fu-berlin.de
URL  : http://page.mi.fu-berlin.de/graeser

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