Correcting discretization for Eurus

[bsmithyman]

Issue by bsmithyman
Tuesday Nov 17, 2015 at 19:51 GMT
Originally opened as uwoseis/anemoi#8

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Issue created to discuss Eurus testing & corrections.

[bsmithyman]

Comment by bsmithyman
Tuesday Nov 17, 2015 at 19:54 GMT

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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?

[bsmithyman]

Comment by ShaunHadden
Tuesday Nov 17, 2015 at 19:55 GMT

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Sorry!

[bsmithyman]

Comment by ShaunHadden
Tuesday Nov 17, 2015 at 19:56 GMT

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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]

Comment by bsmithyman
Tuesday Nov 17, 2015 at 19:56 GMT

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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]

Comment by bsmithyman
Tuesday Nov 17, 2015 at 19:57 GMT

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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).

[bsmithyman]

Comment by ShaunHadden
Tuesday Nov 17, 2015 at 19:58 GMT

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

[bsmithyman]

@ShaunHadden I ran a script to import this issue from anemoi

[bsmithyman]

To summarize: In meeting with @ShaunHadden and Gerhard, we found some mistakes in Operto (2009) that resulted in amplitude errors when modelling TTI. This was resolved in 9c0d4b6.

[bsmithyman]

Outstanding issue: velocity dispersion exists in Eurus solutions when compared to the analytical Helmholtz equation in stretched coordinates.

See Compare Solutions - Homogenous (Eurus)

This makes quite a noticeable difference for gradient computation; cf. MiniZephyr and Eurus.

[bsmithyman]

Eurus problems were dealt with; see e.g., 161af4e