Hello Wolfgang,

When I use a FESystem, I have to write a couple of lines of code to get
function values. I thought if FEValues could figure this, it would be nice,
and make my code compact.

But making this automatic inside FEValues seems difficult, since all FE in
an FESystem may not even have support points.

I guess I will do this myself in my code.

But,... if FEValues constructor could take an optional boolean argument
where user can say whether support points == quadrature points, or not. For
FESystem, one has to pass a vector of boolean.

Thanks
praveen

On Sat, Oct 1, 2016 at 8:40 AM, Wolfgang Bangerth <bange...@colostate.edu>
wrote:

> On 09/30/2016 08:59 PM, Praveen C wrote:
>
>>
>> In many cases, we use same nodes as support points for FE space and
>> quadrature. In this case, FEValues.get_function_values can just read off
>> the
>> function values without performing a sum over all basis functions. Does
>> FEValues actually recognise and make this optimization ? If not, is it
>> possible to get this behaviour ?
>>
>
> No.
>
>
> In my codes, I write my own code to get function values in this case
>> without
>> doing a sum over all basis functions.
>>
>
> Yes, this is special knowledge that is hard to figure out automatically,
> but easy to do if you know that it's true. In that case, you wouldn't want
> to use FEValues to evaluate your shape functions -- you *know* up front
> that they're either zero or one!
>
>
> But it would be great if FEValues.get_function_values could automatically
>> do this.
>>
>
> But why would you want to use FEValues in that case?
>
> Best
>  W.
>
> --
> ------------------------------------------------------------------------
> Wolfgang Bangerth          email:                 bange...@colostate.edu
>                            www: http://www.math.colostate.edu/~bangerth/
>
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