Add adaptive timestepping for lateral melt and growth

[lettie-roach]

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PR checklist

• Short (1 sentence) summary of your PR:
  Add adaptive timestepping for lateral melt and growth - this ensures that the code can deal with large heat fluxes/FSD tendencies
• Developer(s):
  Lettie Roach
• Suggest PR reviewers from list in the column to the right.
• Please copy the PR test results link or provide a summary of testing completed below.
  I ran the base_suite tests, and the three FSD tests fail with 'different-data'
  I then ran the QC test for 'cheyenne_intel_smoke_gx3_8x2_medium_qc' and this passed Quality Control
• How much do the PR code changes differ from the unmodified code?
  • bit for bit
  • different at roundoff level
  • more substantial
• Does this PR create or have dependencies on CICE or any other models?
  • Yes
  • No
• Does this PR add any new test cases?
  • Yes
  • No
• Is the documentation being updated? ("Documentation" includes information on the wiki or in the .rst files from doc/source/, which are used to create the online technical docs at https://readthedocs.org/projects/cice-consortium-cice/.)
  • Yes
  • No, does the documentation need to be updated at a later time?
    • Yes
    • No
• Please provide any additional information or relevant details below:

[apcraig]

Just to confirm @lettie-roach, only the fsd results changed answers? This adaptive timestepping is not used outside fsd? Did you manually turn on the fsd in the qc test? Otherwise, I'd expect it to be bit-for-bit if only fsd is changing.

I will try to run a full test suite on a couple other machines, just to check everything. Do we also want to do a qc test with fsd on (if that wasn't done)? I'm not suggesting we do, just asking the question.

[lettie-roach]

Yes, only the FSD results change the answers. The adaptive timestepping is not used outside the FSD. I turned on the FSD in the run I did for the QC test -I set tr_fsd=.true. and nfsd=12.

…

On Tue, 11 Feb 2020 at 11:18, Tony Craig ***@***.***> wrote: Just to confirm @lettie-roach <https://github.com/lettie-roach>, only the fsd results changed answers? This adaptive timestepping is not used outside fsd? Did you manually turn on the fsd in the qc test? Otherwise, I'd expect it to be bit-for-bit if only fsd is changing. I will try to run a full test suite on a couple other machines, just to check everything. Do we also want to do a qc test with fsd on (if that wasn't done)? I'm not suggesting we do, just asking the question. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#298?email_source=notifications&email_token=AGIYTCMAQX7GLU3R3Z74KHLRCL2X3A5CNFSM4KTGXV3KYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOELNWTJY#issuecomment-584804775>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AGIYTCLKYUIAFP7ZIQPCYDDRCL2X3ANCNFSM4KTGXV3A> .

[eclare108213]

I like that you're using the same code for different processes. This looks fine to me. If @apcraig's tests come back fine, I think this is fine to merge. One question: is this capability mentioned in the documentation? Seems like it is. Since it's not something the user has to configure (right?), they might not realize it's happening.

[apcraig]

I ran full test suites on conrad with 4 compilers using master + dtlatm ( #298 ) + ifsd3 ( #299 ) and everything looks good. Ran both icepack and cice suites. fsd tests fail regression but that's expected. Think both #298 and #299 are fine. Test results are here,

https://github.com/CICE-Consortium/Test-Results/wiki/icepack_by_hash_forks#122fb3d35defebafb202cb576309ba34b23b01d9
https://github.com/CICE-Consortium/Test-Results/wiki/cice_by_hash_forks#0bd9cdc1574fe86110039c43fd53ce5e2b1c5548