DOLFIN

Elementwise quadrature

Asked by Douglas Brinkerhoff

Hi,

I'm trying to implement a streamline upwind/petrov galerkin scheme in DOLFIN, and I need to be able to integrate over individual elements, rather than the whole domain. So rather than:

\int_\Omega F d\Omega

I need

\sum_e \int_e F d\e

is there a way to do this in DOLFIN? Alternatively, does anyone know of an equivalent mathematical relationship for the element averaged terms in a SUPG form that can be implemented in DOLFIN?

Thanks.

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Anders Logg (logg) said : 		#1

On Wed, Dec 07, 2011 at 04:50:53PM -0000, Douglas Brinkerhoff wrote:
> New question #181187 on DOLFIN:
> https://answers.launchpad.net/dolfin/+question/181187
>
> Hi,
>
> I'm trying to implement a streamline upwind/petrov galerkin scheme in DOLFIN, and I need to be able to integrate over individual elements, rather than the whole domain. So rather than:
>
> \int_\Omega F d\Omega
>
> I need
>
> \sum_e \int_e F d\e
>
> is there a way to do this in DOLFIN? Alternatively, does anyone know of an equivalent mathematical relationship for the element averaged terms in a SUPG form that can be implemented in DOLFIN?

DOLFIN computes the integral \int_\Omega F d\Omega by summing over the
individual elements \sum_e \int_e F d\e.

So I'm not sure what you are looking for. Could you give a simple
example?

For upwinding, you could look at the demo

  undocumented/dg-advection-diffusion/

--
Anders

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