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Message #00016
Re: orientation
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To:
Discussion of FIAT development <fiat-dev@xxxxxxxxxx>
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From:
Anders Logg <logg@xxxxxxxxx>
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Date:
Mon, 16 May 2005 16:24:29 -0500
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In-reply-to:
<75d3fbad28514815214b80722fc84ab1@cs.uchicago.edu>
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Mail-followup-to:
Discussion of FIAT development <fiat-dev@xxxxxxxxxx>
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On Mon, May 16, 2005 at 04:03:38PM -0500, Robert Kirby wrote:
> Anders,
> 1.) Triangles are fine.
ok, good.
> 2.) Edges on tets are fine -- I think that's what I've got in FIAT
> already.
In shapes.py it says
tetrahedron_edges = {0:(1,2), \
1:(2,3), \
2:(3,1), \
3:(3,0), \
4:(0,2), \
5:(0,1)}
According to my convention, I would like to have
1 2
2 0
0 1
0 3
1 3
2 3
This is formula (4) in the FFC manual.
> 3.) I don't know about faces. Our convention for edges is just one of
> convenience, and I like the aesthetics of i-->( (i+1)%4,(i+2)%4,(i+3)%4
> ) as they match with how we define edges on triangles. That doesn't
> have the external orientation that your approach has, but we will have
> to handle orientation one way or the other.
In shapes.py it says
tetrahedron_faces = {0:(1,2,3), \
1:(0,3,2), \
2:(0,1,3), \
3:(0,2,1)}
If I understand your convention correctly, it should be
1 2 3
2 3 0
3 0 1
0 1 2
Right?
I can live with that. I will change formula (5) in the FFC manual if
this is what you mean.
> I will not have the time to sit down and work this into FIAT before I
> go, but I will do it soon after I get back. While I'm setting this up,
> I might as well put a wrapper onto the tabulation of basis functions to
> get them working on the (0,1) interval as well.
Thanks.
I will have plenty to do anyway with implementing the
projections/interpolations.
/Anders