Refactor PressureForce_FV before ice shelf fixes #629
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Refactored PressureForce_FV_nonBouss and PressureForce_FV_Bouss to use more 3-dimensional arrays in preparation for the changes that we are expecting from Claire Yung to reduce the pressure gradient errors in ice shelf cavities. These anticipated changes will involve selecting an internal interface at which to define the shape of the interfaces with depth when there is an ice shelf, rather than assuming that the top surface pressure varies linearly with depth between the two top corners. In PressureForce_FV_nonBouss, this refactoring includes turning za, intx_za and inty_za into 3-d arrays and moving the code setting these arrays outside of the k-loop setting the pressure gradient forces. Changes in PressureForce_FV_Bouss are analogous but involve turning 7 arrays (pa, dpa, intz_dpa, intx_pa, intx_dpa, inty_pa and inty_dpa) into 3-d arrays. In both cases, the code for a reduced gravity model is consolidated into a single block toward the end of the routines. These changes to use more 3-d arrays could increase the computational time for the pressure gradient calculations, but in short regression tests any such increase in computational time appears to be small. No external interfaces are changed, and all answers are bitwise identical.
Hallberg-NOAA
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On Gaea, I saw a 5% slowdown with Intel and 6% slowdown with GNU.
On my laptop - which has very low specs - the GCC slowdown was much higher at 20%. But I would not say this is the sort of machine that we are targeting.
As long as we're comfortable with those numbers, then I can merge this one.
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Double checked these numbers on my RAM-heavy home desktop. Again observed 6% slowdown on GCC. I think the 20% is likely just cache swapping, which we can put under "Minimum Hardware Requirements". I'm not so sure about the 5% slowdown. I could guess, but I'll resist for now. We've agreed to merge this in and open an issue to investigate when it makes more sense. |
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Gaea regression: https://gitlab.gfdl.noaa.gov/ogrp/mom6ci/MOM6/-/pipelines/23774 ✔️ |
Refactored
PressureForce_FV_nonBouss()andPressureForce_FV_Bouss()to use more 3-dimensional arrays in preparation for the changes that we are expecting from Claire Yung to reduce the pressure gradient errors in ice shelf cavities. These anticipated changes will involve selecting an internal interface at which to define the shape of the interfaces with depth when there is an ice shelf, rather than assuming that the top surface pressure varies linearly with depth between the two top corners. InPressureForce_FV_nonBouss(), this refactoring includes turningza,intx_zaandinty_zainto 3-d arrays and moving the code setting these arrays outside of the k-loop setting the pressure gradient forces. Changes inPressureForce_FV_Bouss()are analogous but involve turning 7 arrays (pa,dpa,intz_dpa,intx_pa,intx_dpa,inty_paandinty_dpa) into 3-d arrays. In both cases, the code for a reduced gravity model is consolidated into a single block toward the end of the routines. These changes to use more 3-d arrays could increase the computational time for the pressure gradient calculations, but in short regression tests any such increase in computational time appears to be small. No external interfaces are changed, and all answers are bitwise identical.