diff --git a/src/libs/pestpp_common/constraints.cpp b/src/libs/pestpp_common/constraints.cpp
index c860df55..e2958de7 100644
--- a/src/libs/pestpp_common/constraints.cpp
+++ b/src/libs/pestpp_common/constraints.cpp
@@ -127,6 +127,7 @@ void OptObjFunc::throw_optobjfunc_error(string message)
 
 void OptObjFunc::initialize(vector<string> _constraint_names, vector<string> _dv_names)
 {
+    stringstream ss;
 	//initialize the objective function
 	obj_func_str = pest_scenario.get_pestpp_options().get_opt_obj_func();
 	obj_sense = (pest_scenario.get_pestpp_options().get_opt_direction() == 1) ? "minimize" : "maximize";
@@ -143,6 +144,10 @@ void OptObjFunc::initialize(vector<string> _constraint_names, vector<string> _dv
 		use_obj_obs = true;
 		obj_obs = obj_func_str;
 		//check
+        ss.str("");
+        ss << "...objective function defined by observation '" << obj_func_str << "'" << endl;
+        cout << ss.str();
+        f_rec << ss.str();
 		set<string> names(constraint_names.begin(), constraint_names.end());
 		if (names.find(obj_obs) != names.end())
 		{
@@ -162,25 +167,39 @@ void OptObjFunc::initialize(vector<string> _constraint_names, vector<string> _dv
 	{
 		if (obj_func_str.size() == 0)
 		{
-			f_rec << " warning: no ++opt_objective_function-->forming a generic objective function (1.0 coef for each decision var)" << endl;
-			for (auto& name : dv_names)
+			f_rec << " note: no ++opt_objective_function-->forming a generic objective function (1.0 coef for each decision var)" << endl;
+			cout << " note: no ++opt_objective_function-->forming a generic objective function (1.0 coef for each decision var)" << endl;
+            for (auto& name : dv_names)
 				obj_func_coef_map[name] = 1.0;
 		}
 
 		//or if it is a prior info equation
 		else if (pest_scenario.get_prior_info().find(obj_func_str) != pest_scenario.get_prior_info().end())
 		{
+            ss.str("");
+            ss << "...objective function defined by prior information equation '" << obj_func_str << "'" << endl;
+            cout << ss.str();
+            f_rec << ss.str();
 			obj_func_coef_map = pest_scenario.get_prior_info().get_pi_rec(obj_func_str).get_atom_factors();
 			//throw_sequentialLP_error("prior-information-based objective function not implemented");
 		}
 		else
 		{
 			//check if this obj_str is a filename
-			ifstream if_obj(obj_func_str);
+            obj_func_str = pest_scenario.get_pestpp_options().get_org_opt_obj_func();
+            ss.str("");
+            ss << "...objective function defined by 2-column external file '" << obj_func_str << "'" << endl;
+            cout << ss.str();
+            f_rec << ss.str();
+            if (!pest_utils::check_exist_in(obj_func_str))
+            {
+                throw_optobjfunc_error("unable to open objective function file '"+obj_func_str+"' for reading");
+            }
+			/*ifstream if_obj(obj_func_str);
 			if (!if_obj.good())
 				throw_optobjfunc_error("unrecognized ++opt_objective_function arg: " + obj_func_str);
-			else
-				obj_func_coef_map = pest_utils::read_twocol_ascii_to_map(obj_func_str);
+			else*/
+            obj_func_coef_map = pest_utils::read_twocol_ascii_to_map(obj_func_str);
 		}
 
 
diff --git a/src/libs/pestpp_common/pest_data_structs.cpp b/src/libs/pestpp_common/pest_data_structs.cpp
index 262250ae..3bea7f89 100644
--- a/src/libs/pestpp_common/pest_data_structs.cpp
+++ b/src/libs/pestpp_common/pest_data_structs.cpp
@@ -679,6 +679,7 @@ PestppOptions::ARG_STATUS PestppOptions::assign_value_by_key(string key, const s
 		passed_args.insert("OPT_OBJ_FUNC");
 		passed_args.insert("OPT_OBJECTIVE_FUNCTION");
 		convert_ip(value,opt_obj_func);
+        org_opt_obj_func = org_value;
 	}
 	else if (key == "OPT_COIN_LOG")
 	{
@@ -1901,6 +1902,7 @@ void PestppOptions::set_defaults()
 
 
 	set_opt_obj_func("");
+    set_org_opt_obj_func("");
 	set_opt_coin_log(true);
 	set_opt_skip_final(false);
 	set_opt_std_weights(false);
diff --git a/src/libs/pestpp_common/pest_data_structs.h b/src/libs/pestpp_common/pest_data_structs.h
index 0236ef2e..0201bf37 100644
--- a/src/libs/pestpp_common/pest_data_structs.h
+++ b/src/libs/pestpp_common/pest_data_structs.h
@@ -329,7 +329,10 @@ class PestppOptions {
 
 	string get_opt_obj_func()const { return opt_obj_func; }
 	void set_opt_obj_func(string _opt_obj_func) { opt_obj_func = _opt_obj_func; }
-	bool get_opt_coin_log()const { return opt_coin_log; }
+    string get_org_opt_obj_func()const { return org_opt_obj_func; }
+    void set_org_opt_obj_func(string _org_opt_obj_func) { org_opt_obj_func = _org_opt_obj_func; }
+
+    bool get_opt_coin_log()const { return opt_coin_log; }
 	void set_opt_coin_log(bool _log) { opt_coin_log = _log; }
 	bool get_opt_skip_final()const { return opt_skip_final; }
 	void set_opt_skip_final(bool _skip_final) { opt_skip_final = _skip_final; }
@@ -712,6 +715,7 @@ class PestppOptions {
 	bool de_dither_f;
 
 	string opt_obj_func;
+    string org_opt_obj_func;
 	bool opt_coin_log;
 	bool opt_skip_final;
 	vector<string> opt_dec_var_groups;