Update Mode.plot_component

[mpasson]

Plotting 'abs' func with field component 'x' or 'y' shows some problems #170.

This is my attempt to solve it. Please fell free to disregard if I missed something in the fix.
Best,

[HelgeGehring]

Thanks a lot!

I think this solves the problem, but I'm not sure if that's actually the clean way.
It works I think as we projected on linear lagrange which makes projection and applying such a function almost exchangable

I would somehow expect (especially for anything higher order), that we'd need to

• interpolate -> apply the function -> project
  That way we'd need to apply it to the values at the interpolation points instead of on the degrees of freedom 🤔

I made a proposal, but I think it's a little more complicated - the function would need to be applied on each component (once we interpolated, we have a three dimensional vector (with another dimension over the quadrature points)) - don't know if numpy would do it like this 🤔

Could you give it a try?

I.e. apply the function somewhere between interpolate and project?

(otherwise, we could also merge this as it's better than what we do right now. But I'd guess we're close to having it completely correct)

[HelgeGehring]

Suggested change

	mfield_xy = plot_basis.project(mfield_t_basis.interpolate(mfield_t))
	mfield_xy = plot_basis.project(conv_func(mfield_t_basis.interpolate(mfield_t)))

would this solve the problem?