ffc team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Fri, Feb 12, 2010 at 10:25:52AM +0100, Patrick Riesen wrote:
> hi all of you,
>
> in dolfin0.9.6 i'm having a hard time with the following problem:
>
> i'm solving for a variable viscosity, depending on the power x of
> the strain-rate tensor's 2nd invariant.
>
> the invariant i compute in a separate form, and then i compute the
> power by iterating through all the dofs, extracting/reinserting the
> values in the vector of the function inside the code.
>
> this was all fine for dolfin < 0.9.6 but now i think i have a
> problem with choosing the right function space for the viscosity
> coefficient in my nonlinear problem, since for those i used before
> (Quadrature, DG) i have serious problem which i do not understand
> (they all worked before dolfin0.9.6)
>
> my problem is a mixed problem with space definitions:
> #--------------------------------------
> velocity = VectorElement("CG" , geom, 2)
> pressure = FiniteElement("CG" , geom, 1)
> ME = MixedElement(velocity, pressure)
>
> # viscosity element
> visc = FiniteElement("DG", geom, 2)
>
> # placeholder variable viscosity
> eta = Coefficient(qe)
> #---------------------------------------
>
> using this has worked well before, but i don't follow why it
> shouldn't work in dolfin0.9.6/ffc0.9. Or else somebody can propose
> me another approach.
>
> regards,
> patrick

Is the problem the quadrature element for eta? What is the problem exactly?

--
Anders

Attachment: signature.asc
Description: Digital signature