make_ex_.m: correct matrix dimensions with datafile and exo_nbr==0

homotopy expects a matrix conformable with the initval_series

matlab/perfect-foresight-models/make_ex_.m

@@ -49,14 +49,18 @@ if isempty(oo_.initval_series)
             error('histval and endval cannot be used simultaneously')
         end
     end
-elseif M_.exo_nbr > 0
+else
+    if M_.exo_nbr > 0
         x = oo_.initval_series{M_.exo_names{:}}.data;
         oo_.exo_simul = x(M_.orig_maximum_lag-M_.maximum_lag+1:M_.orig_maximum_lag + options_.periods + M_.maximum_lead,:);
         if ~isempty(M_.exo_histval)
             oo_.exo_simul(1:M_.maximum_lag, :) ...
                 = M_.exo_histval(:, 1:M_.maximum_lag)';
         end
-elseif M_.exo_det_nbr > 0
+    else
+        oo_.exo_simul=zeros(M_.maximum_lag + options_.periods + M_.maximum_lead,M_.exo_nbr);
+    end
+    if M_.exo_det_nbr > 0
         x_det = oo_.initval_series{M_.exo_det_names{:}}.data;
         oo_.exo_det_simul = x_det(M_.orig_maximum_lag-M_.maximum_lag+1:M_.orig_maximum_lag + options_.periods + M_.maximum_lead,:);
         if ~isempty(M_.exo_det_histval)
@@ -64,7 +68,7 @@ elseif M_.exo_det_nbr > 0
                 = M_.exo_det_histval(:, 1:M_.maximum_lag)';
         end
     end
-
+end
 % Initialize oo_.exo_det_simul
 if M_.exo_det_nbr > 0
     if isempty(M_.exo_det_histval)