AddAlpha

   Adds a new alpha-element to a policy.

   Adds a new element (with the associated action) to a given
   policy object.
   Returns the updated policy and the identifier assigned to 
   the new element.

   See also Policy.

0001 function [P id]=AddAlpha(P,element,action)
0002 %   Adds a new alpha-element to a policy.
0003 %
0004 %   Adds a new element (with the associated action) to a given
0005 %   policy object.
0006 %   Returns the updated policy and the identifier assigned to
0007 %   the new element.
0008 %
0009 %   See also Policy.
0010 
0011   if P.n==0
0012     P.elements={element};
0013     P.actions={action};
0014     P.n=1;
0015   else
0016     P.elements=[P.elements {element}];
0017     P.actions=[P.actions {action}];
0018     P.n=P.n+1;
0019   end
0020   id=P.n;