%KINGcommFn - type for user provided communication function (BBDPre).
%
%   The function GCOMFUN must be defined as 
%        FUNCTION FLAG = GCOMFUN(Y)
%   and can be used to perform all interprocess communication necessary
%   to evaluate the approximate right-hand side function for the BBDPre
%   preconditioner module.
%   If a user data structure DATA was specified in KINMalloc, then
%   GCOMFUN must be defined as
%        FUNCTION [FLAG, NEW_DATA] = GCOMFUN(Y, DATA)
%   If the local modifications to the user data structure are needed 
%   in other user-provided functions then the GCOMFUN function must also 
%   set NEW_DATA. Otherwise, it should set NEW_DATA=[] (do not set 
%   NEW_DATA = DATA as it would lead to unnecessary copying).
%
%   The function GCOMFUN must set FLAG=0 if successful, FLAG<0 if an
%   unrecoverable failure occurred, or FLAG>0 if a recoverable error
%   occurred.
%
%   See also KINGlocalFn, KINSetOptions
%
%   NOTES:
%     GCOMFUN is specified through the GcommFn property in KINSetOptions 
%     and is used only if the property PrecModule is set to 'BBDPre'.
%
%     Each call to GCOMFUN is preceded by a call to the system function
%     SYSFUN with the same argument Y. Thus GCOMFUN can omit any communication 
%     done by SYSFUN if relevant to the evaluation of G by GLOCFUN. If all 
%     necessary communication was done by SYSFUN, GCOMFUN need not be provided.     

% Radu Serban <radu@llnl.gov>
% Copyright (c) 2005, The Regents of the University of California.
% $Revision: 1.1 $Date: 2007/05/11 18:48:46 $
