dolfin team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

On Tue, Mar 11, 2008 at 10:09:44AM +0100, Anne Voigt wrote:
> Hello,
> 
> I'm working with a Tensor which was assembled with the help of the
> following ffc-form:
> 
> element = FiniteElement("Lagrange", "triangle", 1)
> 
> v = BasisFunction(element)
> u = BasisFunction(element)
> w = BasisFunction(element)
> 
> a = v*u*D(w, 0)*dx
> 
> Now I have some trouble with my calculations and I want to make sure
> that I didn't make a mistake during my access to my tensor. That's whya
> my question: When I want to have the information about my w it's the
> third dimension in my tensor (u = 2nd dimension, v = 1st dimension),
> right???

Yes, the tensor you assemble will have the elements

  A_{ijk} = \int_{\Omega} \phi_i \phi_j d\phi_k/dx dx

But note that as far as I know you're the first one ever to actually 
assemble trilinear forms so there may be bugs.

-- 
Anders