CCPP Framework Meeting Minutes 2020 03 05

Agenda

• No progress on moving towards cap_gen.py from Dom
• Eliminate runtime reading of namelists in parameterizations

Runtime reading of namelists in parameterizations

• Host model to read namelists for parameterizations
• Augment metadata (see https://github.com/NCAR/ccpp-framework/wiki/CCPP-Framework-Meeting-Minutes-2020-01-30 for a proposal)
  • This should only be applied to namelist variables - does the presence of default_value make it a namelist variable? Or add runtime_parameter = .true. (redundant)? Maybe better to call it init_default_value for clarity?
  • Opportunity for the host model to define the value; if it is not found in the host model dictionary during init, then the CCPP framework will set it to the default value
• host model defines what type of namelist to use (json, Fortran namelist, ...)
  • there is no scheme namelist any longer, all this information is part of the metadata
  • standard names as keys in the host model namelist - one section per parameterization or a single section for CCPP?

Level of expensiveness of CCPP checking etc

• Do we need to define how expensive CCPP can/should be depending on the checking level (debug, info, ...)

CCPP NUOPC generator

• CISL has money to do some GPU work on CCPP (Steve to meet with them)
• Steve's project does not have a deliverable for the NUOPC cap prototype, but would like to do it
• What is discussed above (namelists etc) will help this effort
• Should we come up with a new proposal that includes the NOAA chemistry people to fund this work?
  • note: CARMA microphysics package (which has chemistry aspects) will be implemented by NCAR, funded by NOAA

Blocked data structures in init/finalize routines

• substitute ccpp_block_number to with : in auto-generated static caps?
• Steve will create a test for this, we need to check that this is supported by all compilers
• this will cause problems: how to declare the dimensions in the variable declaration inside the subroutine
• better: use horizontal_dimension for _init and _finalize etc., the run routine uses horizontal_loop_extent; the auto-generated cap will recast a variable A(:)%B(:,:,:) to C(:,:,:) where the horizontal dimension is set correctly