Replacing derivative coefficients fail (since recently)

[Marie Rognes]

This snippet

--
from ufl import *

V = FiniteElement("CG", triangle, 1)
u = Coefficient(V)
g = Coefficient(V)
J = inner(u, u)*dx
a = derivative(J, u)
G = replace(a, {u:g})
--

gives this error

--
Applying replace with arguments among derivative coefficients is not correctly implemented.
Traceback (most recent call last):
  File "foo.py", line 8, in <module>
    G = replace(a, {u:g})
  File "/home/meg/local/fenics/lib/python2.7/site-packages/ufl/algorithms/transformations.py", line 890, in replace
    return apply_transformer(e, Replacer(mapping2))
  File "/home/meg/local/fenics/lib/python2.7/site-packages/ufl/algorithms/transformations.py", line 867, in apply_transformer
    return transform_integrands(e, _transform)
  File "/home/meg/local/fenics/lib/python2.7/site-packages/ufl/algorithms/transformations.py", line 842, in transform_integrands
    integrand = transform(itg.integrand())
  File "/home/meg/local/fenics/lib/python2.7/site-packages/ufl/algorithms/transformations.py", line 866, in _transform
    return transformer.visit(expr)
  File "/home/meg/local/fenics/lib/python2.7/site-packages/ufl/algorithms/transformations.py", line 160, in visit
    r = h(o)
  File "/home/meg/local/fenics/lib/python2.7/site-packages/ufl/algorithms/transformations.py", line 284, in coefficient_derivative
    error("Applying replace with arguments among derivative coefficients is not correctly implemented.")
  File "/home/meg/local/fenics/lib/python2.7/site-packages/ufl/log.py", line 148, in error
    raise self._exception_type(self._format_raw(*message))
ufl.log.UFLException: Applying replace with arguments among derivative coefficients is not correctly implemented.
--

This error seems to have been put in last week. The functionality is sorely missed though. Is a fix planned?

[Martin Sandve Alnæs (martinal)]

I added this to protect against another bug. It may not be a problem in your case, maybe we can adjust the error check a bit.

Martin

Den 23. jan. 2012 kl. 22:38 skrev Marie Rognes <email address hidden>:

> Public bug reported:
>
>
> This snippet
>
> --
> from ufl import *
>
> V = FiniteElement("CG", triangle, 1)
> u = Coefficient(V)
> g = Coefficient(V)
> J = inner(u, u)*dx
> a = derivative(J, u)
> G = replace(a, {u:g})
> --
>
> gives this error
>
> --
> Applying replace with arguments among derivative coefficients is not correctly implemented.
> Traceback (most recent call last):
> File "foo.py", line 8, in <module>
> G = replace(a, {u:g})
> File "/home/meg/local/fenics/lib/python2.7/site-packages/ufl/algorithms/transformations.py", line 890, in replace
> return apply_transformer(e, Replacer(mapping2))
> File "/home/meg/local/fenics/lib/python2.7/site-packages/ufl/algorithms/transformations.py", line 867, in apply_transformer
> return transform_integrands(e, _transform)
> File "/home/meg/local/fenics/lib/python2.7/site-packages/ufl/algorithms/transformations.py", line 842, in transform_integrands
> integrand = transform(itg.integrand())
> File "/home/meg/local/fenics/lib/python2.7/site-packages/ufl/algorithms/transformations.py", line 866, in _transform
> return transformer.visit(expr)
> File "/home/meg/local/fenics/lib/python2.7/site-packages/ufl/algorithms/transformations.py", line 160, in visit
> r = h(o)
> File "/home/meg/local/fenics/lib/python2.7/site-packages/ufl/algorithms/transformations.py", line 284, in coefficient_derivative
> error("Applying replace with arguments among derivative coefficients is not correctly implemented.")
> File "/home/meg/local/fenics/lib/python2.7/site-packages/ufl/log.py", line 148, in error
> raise self._exception_type(self._format_raw(*message))
> ufl.log.UFLException: Applying replace with arguments among derivative coefficients is not correctly implemented.
> --
>
> This error seems to have been put in last week. The functionality is
> sorely missed though. Is a fix planned?
>
> ** Affects: ufl
> Importance: Undecided
> Status: New
>
> --
> You received this bug notification because you are subscribed to FEniCS
> Project.
> https://bugs.launchpad.net/bugs/920674
>
> Title:
> Replacing derivative coefficients fail (since recently)
>
> Status in Unified Form Language:
> New
>
> Bug description:
>
> This snippet
>
> --
> from ufl import *
>
> V = FiniteElement("CG", triangle, 1)
> u = Coefficient(V)
> g = Coefficient(V)
> J = inner(u, u)*dx
> a = derivative(J, u)
> G = replace(a, {u:g})
> --
>
> gives this error
>
> --
> Applying replace with arguments among derivative coefficients is not correctly implemented.
> Traceback (most recent call last):
> File "foo.py", line 8, in <module>
> G = replace(a, {u:g})
> File "/home/meg/local/fenics/lib/python2.7/site-packages/ufl/algorithms/transformations.py", line 890, in replace
> return apply_transformer(e, Replacer(mapping2))
> File "/home/meg/local/fenics/lib/python2.7/site-packages/ufl/algorithms/transformations.py", line 867, in apply_transformer
> r...

[Patrick Farrell (pefarrell)]

Marie asked me to test r1276 of ufl -- it fixes the problem nicely. Thanks!