FFC

Confused about the spatial_coordinate implementation

Asked by Martin Sandve Alnæs

I'm trying to follow the data flow in the spatial_coordinate implementation and I'm a bit confused. There's an affine map applied to local integration points at compile time, i.e. the line

            self.unique_tables[name] = array([affine_map[len(p)](p) for p in points])

in quadraturetransformerbase.py, what is that affine map? I thought this should be setting "physical_x = J reference_x + vertex0", is the quadrature points not in reference coordinates?

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Kristian B. Ølgaard (k.b.oelgaard) said : 		#1

The function actually just evaluates the basisfunctions of a linear element
at the integration point, so the name could be better.
See the comment in the code about creating a FIAT element and call evaluate
instead.
Note that the values are stored like any other table of basisfunction
values.
These values are then used later in quadraturecodegenerator.py to generate
the mapping from reference_x to physical_x (by using a codesnippet, but
this might have changed).

On 2 April 2013 18:45, Martin Sandve Alnæs <
<email address hidden>> wrote:

> New question #225711 on FFC:
> https://answers.launchpad.net/ffc/+question/225711
>
> I'm trying to follow the data flow in the spatial_coordinate
> implementation and I'm a bit confused. There's an affine map applied to
> local integration points at compile time, i.e. the line
>
> self.unique_tables[name] = array([affine_map[len(p)](p) for p
> in points])
>
> in quadraturetransformerbase.py, what is that affine map? I thought this
> should be setting "physical_x = J reference_x + vertex0", is the quadrature
> points not in reference coordinates?
>
> --
> You received this question notification because you are a member of FFC
> Team, which is an answer contact for FFC.
>

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