ffc team mailing list archive

[Patrick Riesen <priesen@xxxxxxxxxxxxxxx>]

> > can i do something like this:
> > if i have an operator yielding actually a constant as
> >
> > def V(v):
> >      return dot(grad(v),grad(v))*dot(grad(v),grad(v))

> If you use 'V' (and similar functions) in many places of your form I'm not
> surprised that it runs out of memory. It's not an 'error' on your account it's
> just due to the way things work currently which means that premultiplying terms
> with derivatives of functions makes the compile time blow up or in some cases
> even prevent compilation as it did in your case.

aha, so it is better to write out full things in the forms for a,L, that 
would mean i shouldn't use further terms à la V(v).

due to the powerlaw behavior if have dot-products which have the form as 
(here v=test,u=trial,u0=func)

dot(|grad(u0)|*|grad(u0)| * grad(u), grad(v))

where |grad(u0)| is dot(grad(u0),grad(u0))

so using

M=dot(grad(u0),grad(u0))*dot(grad(u0),grad(u0))*dx

in another form-file should may work?

patrick
> > can i use
> >
> > vv=Constant("triangle")
> >
> > for this term and implement the above term in another form file as
> >
> > M=dot(grad(v),grad(v))*dot(grad(v),grad(v))*dx ?
>
> That would be an excellent idea.
>  
> > or does it help when i define the (other) possible terms in the way of 
> > V(v) in the same form file so that the bilinear & linear forms are reduced?
>
> I'm not sure I understand this.
>
> Kristian
>  
> > thanks for the help,
> > patrick