ufl team mailing list archive

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

Quoting Anders Logg <logg@xxxxxxxxx>:

> This is something we've discussed before, but I want to discuss it
> again.
>
> Could we change the definition of the gradient of a vector to be the
> "normal" definition:
>
>   grad(u) = du_i / dx_j
>
> ?

I think this sounds like an excellent idea.

Kristian

> Then grad would be the derivative of u, and not as today the transpose
> of the derivative of u.
>
>   u(x + dx) = u(x) + u' du + h.o.t.
>
> With the current definition, I need to do this in various places:
>
> from ufl import grad as ufl_grad
> def grad(v):
>     if v.rank() == 1:
>         return ufl_grad(v).T
>     else:
>         return ufl_grad(v)
>
> --
> Anders
>