ffc team mailing list archive

["Garth N. Wells" <gnw20@xxxxxxxxx>]

Marie Rognes wrote:
> Garth N. Wells wrote:
>> There seems to be a nasty bug in the quadrature optimisation. I can
>> compute a result, but it's wrong. I can try to look into it in more
>> detail later, but I'm using a combination of BDM and P0 functions which
>> might be enough of a hint for someone.
>>
>>   
> 
> Could you give a test script?
>


Below is a script which reproduces a bug when the quadrature
optimisation is turned on. The norm of vectors assembled with and
without using optimisation dffer.

Garth



from dolfin import *

mesh = UnitSquare(3, 3)
n = FacetNormal(mesh)

BDM = FunctionSpace(mesh, "Brezzi-Douglas-Marini", 1)
P0 = FunctionSpace(mesh, "Discontinuous Lagrange", 0)
mixed_space = MixedFunctionSpace([BDM, P0])

# Function spaces and functions
r  = TestFunction(P0)
U0 = Function(mixed_space)
u0, s0 = split(U0)

U0.vector()[:] = 1.0

un   = dot(u0, n)/2.0
F    = 1.0/(s0**2 + 1.0)
L = r*F*un*ds

param0 = {"representation": "quadrature", "optimize": False}
param1 = {"representation": "quadrature", "optimize": True}
print "Vec norm (no opt):   ", assemble(L,
                             form_compiler_parameters=param0).norm("l2")
print "Vec norm (with opt): ", assemble(L,
                             form_compiler_parameters=param1).norm("l2")


> -- 
> Marie