ffc team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

I think this is a Python 2.3 problem. Can you update to Python 2.4?

The built-in data type set was added in Python 2.4. If you are unable
to upgrade to Python 2.4, I can change to use the class Set from the
module sets which should work with both 2.3 and 2.4.

Also note that you need the latest CVS version of FFC to run the test
problems (0.1.7 was released before the bug fix).

/Anders

	On Tue, May 03, 2005 at 11:35:35PM +0200, Garth N. Wells wrote:
> Anders,
> 
> I can't try the forms that you gave, because I can't get FFC 0.1.7 + FIAT 0.2.1
> to run. The output from 'ffc Poisson.form' (using the Poisson.form demo in
> ffc-0.1.7/src/demo) is 
> 
> mech136/<4>ffc-0.1.7/src/demo>ffc Poisson.form
> This is FFC, the FEniCS Form Compiler, version 0.1.7.
> For further information, go to http://www/fenics.org/ffc/.
> 
> Parsing Poisson.form
> Output written to Poisson.py
> 
> Compiling form: (dXa0/dxb0)(dXa1/dxb0) | ((d/dXa0)vi1)*((d/dXa1)vi0)*dX
> Finite element of test space:  Lagrange finite element of degree 1 on a Triangle
> Finite element of trial space: Lagrange finite element of degree 1 on a Triangle
> Computing 36 integrals, this may take some time
> ...............................................................................
> Traceback (most recent call last):
>   File "/usr/bin/ffc", line 80, in ?
>     main(sys.argv[1:])
>   File "/usr/bin/ffc", line 58, in main
>     execfile(outname)
>   File "Poisson.py", line 38, in ?
>     compile([a, L], name, "0.1.7", "C++", "GNU GPL Version 2")
>   File "/usr/lib/python2.3/site-packages/ffc/compiler/compiler.py", line 75, in
> compile
>     form.AKi = ElementTensor(form.sum, "interior", format)
>   File "/usr/lib/python2.3/site-packages/ffc/compiler/elementtensor.py", line
> 41, in __init__
>     gK_used = set()
> NameError: global name 'set' is not defined
> 
> Garth
> 
> 
> Quoting Anders Logg <logg@xxxxxxxxx>:
> 
> > You were right, there was a (serious) bug in FFC for handling constant
> > indices. Thanks for pointing this out.
> > 
> > It has been fixed in the latest CVS version of FFC. However, the new
> > version of FFC uses FIAT directly to generate vector-valued elements
> > (previously handled in FFC), and FIAT assumes that a vector-valued
> > Lagrange element on a triangle has two components. I think Rob will
> > fix this shortly. Until then, try the following forms and see that you
> > get the expected results:
> > 
> > element = FiniteElement("Vector Lagrange", "triangle", 1)
> > 
> > v  = BasisFunction(element)
> > u1 = BasisFunction(element)
> > 
> > # Form 1
> > #a = v[1] *(u1[0].dx(0) + u1[1].dx(1)) * dx
> > 
> > #Form 2
> > #a = v[1] *(u1[0] + u1[1]) * dx
> > 
> > #Form 3
> > a = v[1] *(u1[0].dx(0) + u1[1].dx(1)) * dx
> > 
> > #Form 4
> > #a = v[1] *(u1[i].dx(i) ) * dx
> > 
> > /Anders
> > 
> > On Mon, May 02, 2005 at 05:19:37PM +0200, Garth N. Wells wrote:
> > > Dear Anders,
> > > 
> > > I've been trying to use FFC for some forms which cannot be written using
> > > summation convention, so I've been writing out the forms explicitly.
> > > However, I have a problem with terms that involve a derivative, e.g.
> > > u1[0].dx(0). Terms like u1[i].dx(i) (using indices) work fine.
> > > 
> > > Below is the code from an FFC file. What I've labelled Form 1 is basically
> > the
> > > continuity equation for 2D Navier-Stokes. Form 1 and Form 2 produce
> > erroneously
> > > exactly the same header file. In the case of Form 1, the resulting header
> > file
> > > does not involve any terms from the Jacobian (g00, g10, etc.) which it
> > should
> > > do. I would expect Form 3 and Form 4 to produce the same result. However,
> > Form 4
> > > produces the expected result, and Form 3 does not. Is there something wrong
> > with
> > > the synatax that I'm using? Notably, terms like u1[0].dx() do produce the
> > > expected result (no index between the round brackets).
> > > 
> > > We're having some trouble with our mail server here, so I'd be grateful if
> > you
> > > could send a cc of any response to gnwells@xxxxxxxxxxx.
> > > 
> > > Regards,
> > > Garth
> > > 
> > > name = "Test"
> > > vector = FiniteElement("Lagrange", "triangle", 1, 3)
> > > 
> > > v    = BasisFunction(vector)
> > > u1   = BasisFunction(vector)
> > > 
> > > # Form 1
> > > a = v[2] *(u1[0].dx(0) + u1[1].dx(1)) * dx
> > > 
> > > #Form 2
> > > #a = v[2] *(u1[0] + u1[1]) * dx
> > > 
> > > #Form 3
> > > #a = v[2] *(u1[0].dx(0) + u1[1].dx(1) + u1[2].dx(2)) * dx
> > > 
> > > #Form 4
> > > #a = v[2] *(u1[i].dx(i) ) * dx
> > > 
> > > 
> > 
> 

-- 
Anders Logg
Research Assistant Professor
Toyota Technological Institute at Chicago
http://www.tti-c.org/logg/