dtype when creating elements

[mscroggs]

• Default dtype updated to match DOLFINx (if installed)
• dtype input added to custom element

Will allow us to do FEniCS/dolfinx#3136

[jhale]

What's the status of this?

[garth-wells]

I'm not wild about bringing DOLFINx into this. I'd favour defaulting to float64 or being completely explicit on the type.

[jorgensd]

I'm not wild about bringing DOLFINx into this. I'd favour defaulting to float64 or being completely explicit on the type.

I agree with Garth

[mscroggs]

What's the status of this?

Needs a bit of work before it's ready. Should have time to do this work in the next couple of weeks

[mscroggs]

What's the status of this?

Needs a bit of work before it's ready. Should have time to do this work in the next couple of weeks

It was less work to fix that I thought it might be. Ready for review now