Finite element spaces for the Stokes complex

[apalha]

I am trying to discretise the Stokes equations using discrete spaces that constitute a discrete Stokes complex (not the standard Taylor-Hood elements). I have a couple of questions regarding this:

1. Are there any elements for this complex implemented in Firedrake?

2. I checked the list of supported finite elements here, but if I try to use Christiansen-Hu (CH) elements, or any of the Guzman-Neilan elements (e.g., GN, GN2, GNH1div), firedrake says that this family is not available. Have they been discontinued? Where can I find an updated list of available elements? Is there a function in firedrake that generates such a list? Of a place in the code where I can find it?

Thank you for your help.

Kind regards,

-artur palha

[pbrubeck]

These elements have been added very recently. You might need to update your firedrake install. Also the implementation of the Christiansen-Hu element might not work on any mesh, as it splits the elements using barycenter, as opposed to the incenter.

[apalha]

@pbrubeck thank you for your reply. That helped.

Does the CH element give an error on an inadequate mesh or do I need to do the check on the mesh myself?

Thanks again.

-artur palha

[pbrubeck]

The CH element does not throw errors or warnings. You will just get the wrong results. I am not sure if this just works on regular meshes, it is widely untested.

[apalha]

Thanks! Just installed the latest version and I can work with them.