> If you change the definition of derivative in firedrake/ufl_expr.py to

> take an optional coefficient_derivatives argument:

>

> def derivative(F, u, du=None, coefficient_derivatives=None):

>    ...

>

>

> And just pass that value through to the ufl.derivative call:

>

>    ufl.derivative(..., coefficient_derivatives=coefficient_derivatives)

>

> If you do this in the firedrake source directly, you will be able to

> commit your change in the local git repository.  You can send us these

> changes by forking firedrake on github and proposing a pull-request that

> way.

Hmm... Okay I did this. Then I did a "make" in the firedrake directory. But then I'm still getting a

TypeError: derivative() takes at most 3 arguments (4 given)

So how can I test this? Thank you!

It depends a little on how you originally installed firedrake. If you installed firedrake by running firedrake-install (i.e. not with --developer) then you change to the firedrake/src directory and (with the virtualenv active) type:

pip install --upgrade firedrake/

If you have installed firedrake some other way, please say how and we can tell you how to build.

[Buesing, Henrik] I followed the „Installing from individual components” manual. I cloned the firedrake repository

git clone https://github.com/firedrakeproject/firedrake.git

Then I did make in the firedrake directory.

cd firedrake
export PYTHONPATH=$PWD:$PYTHONPATH
make

Henrik