% -*- texinfo -*-
% @deftypefn {Function File} @
% {@var{C}} = BIM3Areaction (@var{mesh}, @var{delta}, @var{zeta})
%
% Builds the mass matrix for the discretization of the LHS of the
% equation
% @iftex
% @tex
% $ \delta \zeta u = f $
% @end tex
% @end iftex
% @ifnottex
% @var{delta} * @var{zeta} * @var{u} = f
% @end ifnottex
%
% Input:
% @itemize @minus
% @item @var{mesh}: PDEtool-like mesh structure with required fields 'p', 'e', 't'.
% @item @var{delta}: element-wise constant scalar function.
% @item @var{zeta}: piecewise linear conforming scalar function.
% @end itemize
%
% @seealso{BIM3Arhs, BIM3Alaplacian, BIM3Cmeshproperties}
% @end deftypefn