Refuse non-stationary endogenous variables in deflators.

It is not clear what we should do in that case anyways.

preprocessor/ModelTree.cc

@@ -1567,3 +1567,10 @@ ModelTree::computeParamsDerivativesTemporaryTerms()
        it != hessian_params_derivatives.end(); ++it)
     it->second->computeTemporaryTerms(reference_count, params_derivs_temporary_terms, true);
 }
+
+bool ModelTree::isNonstationary(int symb_id) const
+{
+  return (nonstationary_symbols_map.find(symb_id)
+          != nonstationary_symbols_map.end());
+}
+

preprocessor/ModelTree.hh

@@ -307,6 +307,8 @@ public:
   void addTrendVariables(vector<int> trend_vars, expr_t growth_factor) throw (TrendException);
   //! Adds a nonstationary variables with their (common) deflator
   void addNonstationaryVariables(vector<int> nonstationary_vars, bool log_deflator, expr_t deflator) throw (TrendException);
+  //! Is a given variable non-stationary?
+  bool isNonstationary(int symb_id) const;
   void set_cutoff_to_zero();
   //! Helper for writing the Jacobian elements in MATLAB and C
   /*! Writes either (i+1,j+1) or [i+j*no_eq] */

preprocessor/ParsingDriver.cc

@@ -357,6 +357,13 @@ ParsingDriver::end_nonstationary_var(bool log_deflator, expr_t deflator)
     {
       error("Variable " + e.name + " was listed more than once as following a trend.");
     }
+
+  set<pair<int, int> > r;
+  deflator->collectVariables(eEndogenous, r);
+  for (set<pair<int, int> >::const_iterator it = r.begin(); it != r.end(); ++it)
+    if (dynamic_model->isNonstationary(it->first))
+      error("The deflator contains a non-stationary endogenous variable. This is not allowed. Please use only stationary endogenous and/or {log_}trend_vars.");
+
   declared_nonstationary_vars.clear();
   reset_data_tree();
 }