[MITgcm-devel] Conversation with Ed about MNC Flags

[Baylor Fox-Kemper]

Hello all,
   As a heavy user of mnc, and one who routinely scripts rm *.meta 
*.data, I would like to make a plea for simplicity in the mnc and mdsio 
flags.  Ed told me this morning that there is a lot of fuss about how 
the flags get set to ensure backward compatibility.  Rather than coming 
to the development meeting to argue this case, I am writing this email 
since my future schedule is unclear.

I have a proposal, which seems to me to be the simplest:

1) two flags: usemdsio and usemnc which select for two sets of standard 
values.
2) the default can be usemdsio=.true. and usemnc=.false.  So that 
anyone not specifying either will get mdsio only as usual.
3) when usemdsio=.true. all mdsio outputs occur.
4) when usemnc=.true. all mnc outputs occur, even if usemdsio=.true.
5) all of the other little messy flags, grid output to *.meta *.data, 
etc. should be flagged such that by default they are equal to usemnc if 
they are mnc flags or usemdsio if they are mdsioflags.  Thus, it should 
not be necessary to also specify pickup_write_mnc as well as usemnc.  
If both usemnc and usemdsio are on, then the model should just write 
out pickup files in both formats.
6) Obviously, which files to read needs a more subtlety, but currently 
the pickup_read_mnc=.false. indicating that mdsio will be used seems OK 
for now.

   Cheers,
     -Baylor