% $Id$
%
% Earth System Modeling Framework
% Copyright (c) 2002-2023, University Corporation for Atmospheric Research, 
% Massachusetts Institute of Technology, Geophysical Fluid Dynamics 
% Laboratory, University of Michigan, National Centers for Environmental 
% Prediction, Los Alamos National Laboratory, Argonne National Laboratory, 
% NASA Goddard Space Flight Center.
% Licensed under the University of Illinois-NCSA License.


FieldBundle, Field, and Array classes all have regrid methods that transform their
data from one {\tt ESMF\_Grid} to another.  Regrid operations compute addresses
and interpolation weights for remapping between different grids.  All
the information necessary to perform a regridding, including {\tt ESMF\_Routes}
to collect non-local data and the addresses and weights, are contained in the
{\tt ESMF\_RouteHandle} which is returned to the user.  Since interpolation
weights are based solely on the grids' geometries and addresses are stored
as offsets, regrids can be shared by data classes providing
they have the same {\tt ESMF\_Rellocs}.  Some of the algorithms and 
implementation in ESMF's regridding routines are adapted from a software package
called SCRIP that was developed at the Los Alamos National Laboratory by Phil
Jones.  However, SCRIP is a serial code and the ESMF regridding routines have
been parallelized.

