Correcting discretization for Eurus

[bsmithyman]

Issue created to discuss Eurus testing & corrections.

[bsmithyman]

At #7, @ShaunHadden said:

I've made the change to the 'Dz' calculation that was wrong on the timedomain branch for eurus.py. This still needs more work so perhaps we should wait to merge it into master?

[ShaunHadden]

Sorry!

[ShaunHadden]

I am currently going through the paper Gerhard sent us and comparing it to our discretization to see if I can spot the error that's causing the amplitudes to be unstable

[bsmithyman]

So yeah, I think that the change on the Dz term in the stencil could probably be merged in now. It's a bugfix anyway, so it's not like it's going to break anything outside Eurus. However, if it's hard to separate it from the other commits we can wait, I guess. Is it amenable to being cherry-picked? I seem to recall that there are a number of other changes to different files on that branch, and I think we're going to need a more complex merge.

[bsmithyman]

Sorry!
No worries :)

Okay, good. Why don't you work on that, and then think about a good way to make an atomic change vs. master (i.e., don't drag in all the other stuff from the timedomain branch yet).

[ShaunHadden]

feel free to just 'cherrypick' the one change, I don't think anything else is required just yet