*Cancel out Z_to_H factors in MOM_hor_visc.F90 #417
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Cancelled out factors of GV%Z_to_H in MOM_hor_visc.F90 to simplify the code and reduce the dependence on the value of GV%Rho_0 in non-Boussinesq mode. This involved changing the units of 3 internal variables in horizontal_viscosity and one element in the hor_visc_CS type to use thickness units or their inverse. Because GV%Z_to_H is an exact power of 2 in Boussinesq mode, all answers are bitwise identical in that mode, but in non-Boussinesq mode this conversion involves multiplication and division by GV%Rho_0, so while all answers are mathematically equivalent, this change does change answers at roundoff in non-Boussinesq mode.
Hallberg-NOAA
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Codecov Report
@@ Coverage Diff @@
## dev/gfdl #417 +/- ##
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- Coverage 38.15% 38.15% -0.01%
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Files 269 269
Lines 76786 76786
Branches 14131 14131
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- Hits 29301 29299 -2
- Misses 42201 42203 +2
Partials 5284 5284
... and 1 file with indirect coverage changes 📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more |
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Gaea regression: https://gitlab.gfdl.noaa.gov/ogrp/MOM6/-/pipelines/20063 ✔️ |
This was referenced Nov 13, 2023
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Cancelled out factors of GV%Z_to_H in MOM_hor_visc.F90 to simplify the code and reduce the dependence on the value of GV%Rho_0 in non-Boussinesq mode. This involved changing the units of 3 internal variables in horizontal_viscosity and one element in the hor_visc_CS type to use thickness units or their inverse. Because GV%Z_to_H is an exact power of 2 in Boussinesq mode, all answers are bitwise identical in that mode, but in non-Boussinesq mode this conversion involves multiplication and division by GV%Rho_0, so while all answers are mathematically equivalent, this change does change answers at roundoff in non-Boussinesq mode.