matrix_reaction.m

function res = matrix_reaction(x, model, df_info, i, j)
%function res = matrix_reaction(x, model, df_info, i, j)

% IM 12.04.2013


hat_phi_i = evaluate_basis_function(df_info, x, i);
hat_phi_j = evaluate_basis_function(df_info, x, j);

r = cache_function(@(xarg, xmodel)xmodel.reaction(df_info.grid, 1: ...
                                         df_info.grid.nelements, ...
                                         xarg, xmodel), x, model);

if ~iscell(r)
    
    res = hat_phi_i' * hat_phi_j * r;
else
    
    res = cell(1, length(r));
    for q = 1:length(r)
        
        res{q} = hat_phi_i' * hat_phi_j * r{q};
    end
end

end