dolfin team mailing list archive

["Garth N. Wells" <g.n.wells@xxxxxxxxxx>]

On Wed, 2006-02-22 at 11:18 +0000, Alexander Jarosch wrote:
> Thanks, I will try, when I use:
> 
> linear_scalar = FiniteElement("Lagrange", "triangle", 1)
> 
> than the form file compiles fine  but when I use
> 
> constant_scalar = FiniteElement("Discontinuous Lagrange", "triangle", 0)
> 
> the ffc gives this error:
> 
> Parsing Stokes2D_vd.form
> Output written to Stokes2D_vd.py
> *** 'module' object has no attribute 'dims'
> 

Works fine for me. This could be an old FIAT bug. Grab the latest
version of FIAT and FFC.

Garth

> Am I using an to old version of ffc, I use 0.2.5
> 
> Alex
> 
> Garth N. Wells wrote:
> 
> >On Wed, 2006-02-22 at 10:45 +0000, Alexander Jarosch wrote:
> >  
> >
> >>Hi,
> >>
> >>I have a rather simple question I guess. I tried to figure out how to 
> >>give the stokes solver a viscosity for each vertex and started of with 
> >>the stokes solver with a constant viscosity nu:
> >>
> >>modified from Anders file:
> >>---------------
> >>P1 = FiniteElement("Lagrange", "triangle", 1)
> >>P2 = FiniteElement("Vector Lagrange", "triangle", 2)
> >>TH = P2 + P1
> >>
> >>(v, q) = BasisFunctions(TH)
> >>(u, p) = BasisFunctions(TH)
> >>nu     = Constant()    #viscosity
> >>
> >>
> >>f = Function(P2)
> >>
> >>a = (dot(nu*grad(u), grad(v)) - p*div(v) + div(u)*q)*dx
> >>L = dot(f, v)*dx
> >>---------------
> >>
> >>now that works fine and now i have the viscosity values for each vertex 
> >>in a vector as values and in a function like:
> >>
> >>Function viscfunc(viscosity, mesh, element);
> >>
> >>    
> >>
> >
> >One other thing, this is implicitly a DiscreteFunction. Trying making a
> >constant as I suggested, and as a next step try a user-defined Function
> >to specify nu as a function of position, in the same way the source term
> >is defined in src/demo/solvers/stokes.
> >
> >Garth   
> >
> >
> >  
> >
> >>Now i tried to get a form file which takes these values like:
> >>---------------
> >>P1 = FiniteElement("Lagrange", "triangle", 1)
> >>P2 = FiniteElement("Vector Lagrange", "triangle", 2)
> >>element1 = FiniteElement("Discontinuous vector Lagrange", "triangle", 0, 1)
> >>
> >>
> >>TH = P2 + P1
> >>
> >>(v, q) = BasisFunctions(TH)
> >>(u, p) = BasisFunctions(TH)
> >>nu     = Function(element1)    #viscosity
> >>
> >>f = Function(P2)
> >>
> >>a = (dot(dot(nu, grad(u)), grad(v)) - p*div(v) + div(u)*q)*dx
> >>L = dot(f, v)*dx
> >>---------------
> >>
> >>well and it does not work, as well as the approach like:
> >>
> >>---------------
> >>P1 = FiniteElement("Lagrange", "triangle", 1)
> >>P2 = FiniteElement("Vector Lagrange", "triangle", 2)
> >>constant_scalar = FiniteElement("Discontinuous Lagrange", "triangle", 1)
> >>
> >>
> >>TH = P2 + P1
> >>
> >>(v, q) = BasisFunctions(TH)
> >>(u, p) = BasisFunctions(TH)
> >>nu     = Function(constant_scalar)    #viscosity
> >>#nu     = Constant()
> >>
> >>f = Function(P2)
> >>
> >>a = (dot(nu*grad(u), grad(v)) - p*div(v) + div(u)*q)*dx
> >>L = dot(f, v)*dx
> >>---------------
> >>
> >>which actually takes my viscosity vector and starts to solve but does 
> >>not converge.
> >>
> >>might be a simple mistake in there, I appreciate any help or hints.
> >>
> >>Alex
> >>
> >>_______________________________________________
> >>DOLFIN-dev mailing list
> >>DOLFIN-dev@xxxxxxxxxx
> >>http://www.fenics.org/cgi-bin/mailman/listinfo/dolfin-dev
> >>    
> >>
> 
> 
-- 
Dr. Garth N. Wells
Faculty of Civil Engineering and Geosciences
Delft University of Technology
Stevinweg 1
2628 CN Delft
The Netherlands

tel.     +31 15 278 7922
fax.     +31 15 278 6383
e-mail   g.n.wells@xxxxxxxxxx
url      http://www.mechanics.citg.tudelft.nl/~garth