Description of libf purpose and contents
----------------------------------------

All the LMDZ source code is located in subdirectories of libf.
The various directories (and their respective subdirectories) are there to 
separate codes with various functionalities. The main driver in this
organization is to cleanly separate dynamics, physics and their
interface. In practice:

dyn3d     : dynamics, serial version
  
dyn3dpar  : dynamics, parallel version. Obsolete (many arrays remained global
            requiring more overall memory with increasing core number)

dyn3dmem  : dynamics, parallel (optimized) version with improved
            memory management (all arrays are local to each core)

dyn3d_common: routines used by all dynamics (serial or parallel)

filtre: high-latitude longitudinal filter for lonxlat grid
        (used by the dynamics, serial or parallel)

grid: routine for model's grid generation 
      (used by the dynamics, serial or parallel)


phy* : various physics packages
       phylmd: standard terrestrial lmd physics
       phylmdiso: version with isotopes (temporary, should be merged in phylmd)
       phymar: physics of the 'modele atmospherique regional', obsolete
       phydev: 'physics that does nothing but does it well'

phy_common: common routines to all physics 
            (different modules for parallelism, abort_physics, geometry,
            getin wrapper, ...)

dynphy_lonlat: contains the dynamics/physics interface
               with at a first level common routines to all physics 
               and dedicated specific routines for each physics
               (e.g., call physics + physics initialization) in a
               subdirectory of the same name as the physics package's
               (phylmd, phydev, ...).
               In addition the subdirectory stores main programs,
               other than the gcm, which require access to both physics
               and dynamics routines
               (e.g. to generate initial states, such as ce0l).
               Note that if a physics package name is an extension of
               an already existing physics package (e.g. phylmdiso and
               phylmd) then they share the same interface (phylmd here).  

phy*/dyn1d: the 1D model (and links to some required dyn3d/* routines)  

misc (misceallenous): dynamics and physics independent routines which can be
                      used by either but rely on neither
                      (e.g. random number generator,
                      tridiagonal matrix solver, NetCDF function wrappers,
                      CRAY-specific routines, ...)

obsolete: obsolete code not used anymore but moved and stored here for an
          easy quick look.

11/10/2021