You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: refined_gridvar.m
    path of file: ./repos/tracacode/1911-COAWST/script/mfiles/rutgers/grid
    
    the code of the file until where you have to start completion: function [Fvalues,S] = refined_gridvar(Cinp, Finp, field, varargin)

%
% REFINED_GRIDVAR: Sets requested refined grid field from ROMS coarse grid
%
% [Fvalues,S] = refined_gridvar(Cinp, Finp, field, DivideCoarse)
%
% Sets requested refined grid variable from ROMS coarse grid division or
% quadratic conservative interpolation (Clark and Farley, 1984), such
% that the coarse-to-fine and fine-to-coarse are reversible:
%
%       AVG[F.field(:,:)_i , i=1,rfactor] = C.field(Idg,Jdg)
%
% where (Idg,Jdg) are the indices of the coarse grid donor cell contatining
% the finer grid.
%
% If field to process is uniform, the interpolation is not performed to
% avoid round-off. It should be only used to process 2D ROMS grid fields
% like: 'angle', 'dmde', 'dmdx', 'f', 'h', 'pm', and 'pn'.
%
% On Input:
%
%    Cinp          ROMS coarse Grid NetCDF files/URL name (string)
%              or, an existing ROMS coarse grid structure (struct array)
%
%    Finp          ROMS finer Grid NetCDF files/URL name (string)
%              or, an existing ROMS finer grid structure (struct array)
%
%    field         Field name to process (NetCDF variable name or
%                  structure field)
%

    
function [Fvalues,S] = refined_gridvar(Cinp, Finp, field, varargin)

%
% REFINED_GRIDVAR: Sets requested refined grid field from ROMS coarse grid
%
% [Fvalues,S] = refined_gridvar(Cinp, Finp, field, DivideCoarse)
%
% Sets requested refined grid variable from ROMS coarse grid division or
% quadratic conservative interpolation (Clark and Farley, 1984), such
% that the coarse-to-fine and fine-to-coarse are reversible:
%
%       AVG[F.field(:,:)_i , i=1,rfactor] = C.field(Idg,Jdg)
%
% where (Idg,Jdg) are the indices of the coarse grid donor cell contatining
% the finer grid.
%
% If field to process is uniform, the interpolation is not performed to
% avoid round-off. It should be only used to process 2D ROMS grid fields
% like: 'angle', 'dmde', 'dmdx', 'f', 'h', 'pm', and 'pn'.
%
% On Input:
%
%    Cinp          ROMS coarse Grid NetCDF files/URL name (string)
%              or, an existing ROMS coarse grid structure (struct array)
%
%    Finp          ROMS finer Grid NetCDF files/URL name (string)
%              or, an existing ROMS finer grid structure (struct array)
%
%    field         Field name to process (NetCDF variable name or
%                  structure field)
%
%    DivideCoarse  Switch to return the coarse value divided by the grid
%                  refinement ratio.  This only apply for 'pm' or 'pn'
%                  fields to garanttee exact area conservation (OPTIONAL,
%                  default = false)
%
% On Output:
%
%    Fvalues       Interpolated field (2D Array)
%
%    S             Interpolation information structure (struct, OPTIONAL):
%
%                    S.grid_time       Arakawa grid C-type (PSI, RHO, u, v)
%                    S.is2d            processing 2D field (false for 3D)
%                    S.spherical       spherical switch
%                    S.uniform         uniform field switch
%                    S.masked          land masked weights switch
%                    S.refine_factor   grid refinement factor
%                    S.parent_Imin     coarse grid lower-left  I-coordinate
%                    S.parent_Imax     coarse grid upper-right I-coordinate
%                    S.parent_Jmin     coarse grid lower-left  J-coordinate
%                    S.parent_Jmax     coarse grid upper-right J-coordinate
%                    S.x               Cartesian or spherical X-coordinate
%                    S.y               Cartesian or spherical Y-coordinate
%                    S.val             interpolated values
%                    S.p               interpolation p-fractional distance
%                    S.q               interpolation q-fractional distance
%                    S.w               quadratic interpolation weights
%                    S.xavg            averaged field interior X-coordinate
%                    S.yavg            averaged field interior Y-coordinate
%                    S.avg             averaged field values: fine2coarse
%                    S.sum             accumulate field values: fine2coarse
%
% You can plot interpolation fields as follows:
%
%  pcolor(S.x, S.y, V); shading facetted; colorbar;
%  pcolor(S.x, S.y, S.val); shading facetted; colorbar;   % same as above
%
%  pcolor(S.xavg, S.yavg, S.avg); shading facetted; colorbar;
%  pcolor(S.xavg, S.yavg, S.sum); shading facetted; colorbar;
%
  
% svn $Id: refined_gridvar.m 940 2019-01-28 07:22:54Z arango $
%=========================================================================%
%  Copyright (c) 2002-2019 The ROMS/TOMS Group                            %
%    Licensed under a MIT/X style license                                 %
%    See License_ROMS.txt                           Hernan G. Arango      %
%=========================================================================%

% Initialize.
  
masked = false;         % interpolation weights are not scaled by land mask
isgridspacing = false;  % processing 'pm' or 'pn'
got_xy = false;         % Cartesian coodinates (x_rho, y_rho) ...

% Set optional parameters.

DivideCoarse = false;

switch numel(varargin)
  case 1
    DivideCoarse = varargin{1};
end