Python Interface to MAPL: Difference between revisions

Retrieved from "https://geos5.org/wiki/index.php?title=Python_Interface_to_MAPL"

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-Here is a very high level example of a MAPL ocean/atmosphere couple model in Python:
+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 of a GEOS-5 application written in Python, the very top root component is implemented entirely in a shared library.
+ import MAPL
+ if __name == "__main__":
+ #   Instantiate the root component
+ #   ------------------------------
+     gcs = MAPL.GridComp(lib='/some/path/libGEOSgcs.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 now implemented in Python.
   import MAPL
+ import GEOSgcs  # the GEOSgcs component is implemented here
-  atm = MAPL.GridComp(rc='atm.rc')
+  if __name == "__main__":
- ocn = MAPL.GridComp(rc='ocn.rc')
+ #   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 implemented in Fortran ==
+In this example, the '''GEOSgcs''' component is implemented in Python, with its children, components '''ANA''' and '''GCM''', implemented in Fortran.
+Notice that every component should be subclass of '''MAPL_GridComp'''.
+ import MAPL
+ class GridComp(MAPL.GridComp):
+     """
+     Implements the GEOSgcs component by subclassing MAPL.GridComp.
+     """
+     def SetServices(self):
+         """
+         SetServices 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)
+Notice that the standard '''Initialize()''', '''Run()''' and '''Finalize()''' methods are inherited from the base class '''MAPL.GridComp'''.
+== A python component with Children implemented in Python ==
+In this example, the '''GEOSgcs''' component is implemented in Python, with its children, components '''ANA''' and '''GCM''', also implemented in Python.
+ import MAPL
+ import GEOSana
+ import GEOSgcm
-  atm.initialize()
+  class GridComp(MAPL.GridComp):
-  ocn.initialize()
+     """
+     Implements the GEOSgcs component by subclassing MAPL.GridComp.
+     """
+     def SetServices(self):
+         """
+         SetServices for a composite component.
+         """
+ #       Instantiate Children component
+ #       ------------------------------
+         ana = GEOSana()
+         gcm = GEOSgcm()
+ #       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)
- for t in clock.tick():
+In this case we implement the standard '''Run()''' method, but inherit '''Initialize()''' and '''Finalize()''' from the base class '''MAPL.GridComp'''
-    atm.run()
-    ocn.run()
-  atm.finalize()
+     def Run(self,clock):
-  ocn.finalize()
+         """
+         Implementation of a simple run method.
+         """
+ #       Run the base class method
+ #       -------------------------
+         MAPL.GridComp.__Run__(self,clock)
+ #       Retrieve some data from a state
+ #       -------------------------------
+         uwnd, vwnd, = self.Export.GetPointer(['UWND', 'VWND'])
+ #       Print states
+ #       ------------
+         self.Internal.print()
+         self.Import.print()
+         sllf.Export.print()
+ #       Just print it
+ #       -------------
+         print "u-wind = ", uwnd.min(), uwnd.max()
+         print "v-wind = ", vwnd.min(), vwnd.max()