function dvar=expandvariables(md,variables)

fnames=fieldnames(variables);

for i=1:length(fnames)
    
%  for linear constraints, just copy

    if isa(variables.(fnames{i}),'linear_inequality_constraint') || ...
       isa(variables.(fnames{i}),'linear_equality_constraint'  )
        dvar.(fnames{i})=variables.(fnames{i});

%  for variables, call the setup function

    else
        fhandle=str2func([class(variables.(fnames{i})) '.empty']);
        dvar.(fnames{i})=fhandle();
        for j=1:length(variables.(fnames{i}))
            %call setupdesign
            dvar.(fnames{i})=QmuSetupVariables(md,dvar.(fnames{i}),variables.(fnames{i})(j));
        end
    end
end