Found in
Addressed by
Problem
When running LST-DA data assimilation experiments with the LESTKF filter, results in the RELEASE build differ from the DEBUG build. Specifically:
- LESTKF experiments using PDAF-OMI and PDAF-non-OMI produce different results in
RELEASE, but are identical in DEBUG.
- EnKF experiments are identical across both build types, suggesting the issue is localized to the LESTKF localization routines.
Root Cause (Assumption)
Intel's default floating-point optimization (-O2) appears to trigger numerically inconsistent results in the LESTKF localization routines. Adding -fp-model=precise to the Intel Fortran compiler flags for RELEASE builds restores identical results.
Reference: https://www.intel.com/content/www/us/en/docs/fortran-compiler/developer-guide-reference/2023-0/fp-model-fp.html
Found in
Addressed by
Problem
When running LST-DA data assimilation experiments with the LESTKF filter, results in the
RELEASEbuild differ from theDEBUGbuild. Specifically:RELEASE, but are identical inDEBUG.Root Cause (Assumption)
Intel's default floating-point optimization (
-O2) appears to trigger numerically inconsistent results in the LESTKF localization routines. Adding-fp-model=preciseto the Intel Fortran compiler flags forRELEASEbuilds restores identical results.Reference: https://www.intel.com/content/www/us/en/docs/fortran-compiler/developer-guide-reference/2023-0/fp-model-fp.html