Python Interface to MAPL

This document presents a very high level description of a python interface to MAPL.

GEOS-5 Use Cases

The examples below are based on the actual GEOS-5 GCM Application, and a few components at the very top of the hierarchy. Here we assumed that MAPL Grid Components can be implemented entirely in C/Fortran or in Python.

GEOS-5 Application with Fortran Root Component

In this example, the very top root component is implemented entirely in a shared library.

""""
The GEOSgcm application written in python, starting from a 
Root Component implemented in Fortran.
"""

import MAPL

if __name == "__main__":

#   Instantiate the root component
#   ------------------------------
    gcs = MAPL.GridComp(lib='/some/path/libGEOSana.so')

#   Instantiate MAPL
#   ----------------
    mapl = MAPL(root=gcs)

#   Run the cap
#   -----------
    mapl.go()

GEOS-5 Application with Python Root Component

In this example, the very top root component is implemented in Python.

""""
The GEOSgcm application written in python, starting from a 
Root Component implemented in Fortran.
"""

import MAPL
import GEOSgcs  # the GEOSgcs component is implemented here

if __name == "__main__":

#   Instantiate the Python root component
#   -------------------------------------
    gcs = GEOSgcs(rc='gcs.rc')

#   Instantiate MAPL
#   ----------------
    mapl = MAPL(root=gcs)

#   Run the cap
#   -----------
    mapl.go()

A python component with Children in Fortran

In this example, the GEOSgcs component is implemented in Python, with its children, components ANA and GCM, implemented in Fortran.

import MAPL

class GridComp(MAPL.GridComp):
    """Implements the GEOSgcs component by subclassing MAPL.GridComp"""

    def SetServices(self):
        """SerServices for a composite component"""

#       Instantiate Children component
#       ------------------------------
        ana = MAPL.GridComp(lib='/some/path/libGEOSana.so')
        gcm = MAPL.GridComp(lib='/some/path/libGEOSgcm.so')

#       Adopt children
#       --------------
        self.AddChild(ana)
        self.AddChild(gcm)

#       Set connectivity among children
#       -------------------------------
        vars = ('Tinc', 'Sinc', 'Uinc', 'Vinc', 'SSHinc' )
        self.AddConnectivity(src=[ana,vars], dst=[gcm,vars])
        self.AddConnectivity(src=[gcm,'LWI'], dst=[ana,'ORO'])

#       Run the base class SetServices
#       ------------------------------
        MAPL.GridComp.__SetServices__(self)