dolfin team mailing list archive

[Kristian Oelgaard <k.b.oelgaard@xxxxxxxxxx>]

Quoting Marie Rognes <meg@xxxxxxxxxxx>:

> Hi,
> 
> I seem to have a problem with "manually" applying boundary 
> conditions to the system of linear equations. In particular, 
> I get the following error
> 
>     Traceback (most recent call last):
>       File "testbc.py", line 38, in ?
>         bc.apply(A, b, a)
>       File

You need to compile the form first:
(compiled_form, module, form_data) = jit(a)
bc.apply(A, b, compiled_form)

Have a look in src/pydolfin/assemble.py (LinearPDE)

> "/home/meg/src/dolfin/dolfin/local/lib/python2.4/site-packages/dolfin/dolfin.py",
>     line 5742, in apply
>         return _dolfin.DirichletBC_apply(*args)
>     NotImplementedError: Wrong number of arguments for 
> overloaded
>     function 'DirichletBC_apply'.
>       Possible C/C++ prototypes are:
>         apply(dolfin::GenericMatrix &,dolfin::GenericVector
>     &,dolfin::Form const &)
>         apply(dolfin::GenericMatrix &,dolfin::GenericVector 
> &,ufc::form
>     const &)
>         apply(dolfin::GenericMatrix &,dolfin::GenericVector
>     &,dolfin::GenericVector const &,dolfin::Form const &)
>         apply(dolfin::GenericMatrix &,dolfin::GenericVector
>     &,dolfin::GenericVector const &,ufc::form const &)
> 
> with the following code
> 
>     from dolfin import *
> 
>     class Zero(Function):
>         def __init__(self, element, mesh):
>             Function.__init__(self, element, mesh)
>         def eval(self, values, x):
>             values[0] = 0.0
> 
>     class DirichletBoundary(SubDomain):
>         def inside(self, x, on_boundary):
>             return bool(on_boundary)
> 
>     def Mass(element, f):
>         v = TestFunction(element)
>         u = TrialFunction(element)
>         a = v*u*dx
>         L = v*f*dx
>         return [a, L]
> 
>     # The element space
>     element = FiniteElement("Lagrange", "triangle", 1)
> 
>     # The mesh, boundary and boundary conditions
>     mesh = UnitSquare(2,2)
>     boundary = DirichletBoundary()
>     zero = Zero(element, mesh)
>     bc = DirichletBC(zero, mesh, boundary)
> 
>     # Construct and assemble the forms
>     [a, L] = Mass(element, zero)
>     A = assemble(a, mesh)
>     b = assemble(L, mesh)
> 
>     # Try applying boundary conditions:
>     bc.apply(A, b, a)
> 
> 
> Am I missing something obvious here?
> 
> 
> In addition, if I try just using
> 
>     zero = Function(mesh, 0.0)

The function 'f' has to be a FFC function when creating your form. So you have
to initialise it with an element.

Kristian
 
> in the above, I get the following error from ffc. However, I 
> guess that I could just have a look at that when I find some 
> time myself...
> 
>     Traceback (most recent call last):
>       File "testbc.py", line 33, in ?
>         [a, L] = Mass(element, zero)
>       File "testbc.py", line 18, in Mass
>         L = v*f*dx
>       File
>  
> "/home/meg/src/ffc/ffc_current/src/ffc/compiler/language/algebra.py",
>     line 77, in __mul__
>         return Form(self) * other
>       File
>  
> "/home/meg/src/ffc/ffc_current/src/ffc/compiler/language/algebra.py",
>     line 631, in __mul__
>         w.monomials = [p*other for p in self.monomials]
>       File
>  
> "/home/meg/src/ffc/ffc_current/src/ffc/compiler/language/algebra.py",
>     line 446, in __mul__
>         w1 = Monomial(other)
>       File
>  
> "/home/meg/src/ffc/ffc_current/src/ffc/compiler/language/algebra.py",
>     line 405, in __init__
>         self.coefficients = [Coefficient(other, index)]
>       File
>  
> "/home/meg/src/ffc/ffc_current/src/ffc/compiler/language/tokens.py",
>     line 53, in __init__
>         self.n0 = Index(function.n0)
>       File
>  
> "/home/meg/src/dolfin/dolfin/local/lib/python2.4/site-packages/dolfin/dolfin.py",
>     line 2733, in <lambda>
>         __getattr__ = lambda self, name: _swig_getattr(self,
>     cpp_Function, name)
>       File
>  
> "/home/meg/src/dolfin/dolfin/local/lib/python2.4/site-packages/dolfin/dolfin.py",
>     line 34, in _swig_getattr
>         raise AttributeError,name
>     AttributeError: n0
> 
> 
> 
> Thanks!
> 
> -- 
> Marie E. Rognes
> Ph.D Fellow,
> Centre of Mathematics for Applications,
> University of Oslo
> http://folk.uio.no/meg
> 
> 
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