Updated the LSODE integrator to be thread-safe#147
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Sorry, I don't know much about thread-safe coding, so I won't be able to
contribute anything useful here...
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Thanks @RolfSander. We can hold off on merging until someone else reviews it. @obin1 would you be willing take a look? |
int/lsode.f90 - Refactored (with Claude AI) to be thread-safe. Removed the COMMON /DLS001/ block and replaced with threadprivate variables. CHANGELOG.md - Updated accordingly Signed-off-by: Bob Yantosca <yantosca@seas.harvard.edu>
STEPMIN is written by INTEGRATE() on every call and read back by some integrators (e.g. the TLM) as the next call's starting step, so a shared STEPMIN races across OpenMP threads and can leak one thread's step size into another's. Declare it THREADPRIVATE in gen.c so all generated _Global.f90 files pick it up (STEPMAX is write-once/read-only and does not need this). Also declare LUNIT/MESFLG THREADPRIVATE inside IXSAV in lsode.f90: despite the COMMON /DLS001/ removal, these SAVE locals still have static storage shared across all threads and calls, and XERRWD reads them via IXSAV on every error/warning path.
docs/source/reference/known-bugs.rst docs/source/tech_info/07_numerical_methods.rst - Removed warnings that LSODE is not thread safe, as we have now fixed this. CHANGELOG.md - Updated accordingly Signed-off-by: Bob Yantosca <yantosca@seas.harvard.edu>
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In this PR we have modified the
int/lsode.f90integrator to be OpenMP thread-safe. This is done by removing theCOMMON /DLS001/common block declaration. All variables that used to be in the common block are now declared as local variables within routineDLSODEand are therefore reachable by other internal routines used by LSODE under itsCONTAINSstatement.The refactoring was done with Claude Code AI.
Summary of Changes Applied
Do_Update_*flags!$OMP THREADPRIVATE(...)directive after the threeLOGICALdeclarationsDLSODEdeclarationsINTEGER INIT,MXSTEP,...,IOWNS+KPP_REAL ROWNS,CCMAX,...+COMMON /DLS001/block; replaced with named local variablesCONIT,CRATE,EL(13),ELCO(13,12),...covering all 218 reals and 37 integersDINTDYINTEGER IOWND,IOWNS,...+KPP_REAL ROWNS,...+COMMON /DLS001/; variables now reached via host associationDPREPJIERretained as a local integerDSOLSYDSRCOMCOMMON /DLS001/no longer exists)DSTODEINTEGER IOWND,IALTH,...+KPP_REAL CONIT,CRATE,EL,...+COMMON /DLS001/; all state reached via host associationLUNIT!$OMP THREADPRIVATEin functionIXSAVMESFLG!$OMP THREADPRIVATEin functionIXSAVSTEPMIN!$OMP THREADPRIVATEinROOT_Global.f90orROOT_Global.F90