diff --git a/msgpi/dakota/interface.py b/msgpi/dakota/interface.py
index 52daf9e..23dc4a9 100644
--- a/msgpi/dakota/interface.py
+++ b/msgpi/dakota/interface.py
@@ -27,6 +27,9 @@ def __init__(self):
         self.das = {}
         self.sgs = {}
 
+        self.dakota_params_file = ''
+        self.dakota_results_file = ''
+
 
     def initialize(self, fn_json_args):
 
@@ -49,18 +52,18 @@ def initialize(self, fn_json_args):
         # ------------------------------------------------------------
 
         try:
-            dakota_params_file = self.settings['dakota_parameters_file']
+            self.dakota_params_file = self.settings['dakota_parameters_file']
         except KeyError:
-            dakota_params_file = 'input.in'
+            self.dakota_params_file = 'input.in'
 
         try:
-            dakota_results_file = self.settings['dakota_results_file']
+            self.dakota_results_file = self.settings['dakota_results_file']
         except KeyError:
-            dakota_results_file = 'output.out'
+            self.dakota_results_file = 'output.out'
 
         try:
             dakota_params, dakota_results = di.read_parameters_file(
-                dakota_params_file, dakota_results_file
+                self.dakota_params_file, self.dakota_results_file
             )
 
             self.evid = int(dakota_params.eval_id)
@@ -152,7 +155,7 @@ def writeOutput(self, status):
             with open('interim.out', 'w') as fo:
                 json.dump(self.outputs['interim'], fo, indent=4)
 
-            with open(self.settings['dakota_results_file'], 'w') as fo:
+            with open(self.dakota_results_file, 'w') as fo:
                 for r in self.outputs['final']:
                     fo.write(f'{r[1]:24.16E} {r[0]}\n')
 
@@ -161,7 +164,7 @@ def writeOutput(self, status):
         elif status == 1:
             # Fail
             self.logger.info(f'{self.log_prompt} failed')
-            with open(self.settings['dakota_results_file'], 'w') as fo:
+            with open(self.dakota_results_file, 'w') as fo:
                 fo.write('FAIL')
 
             e = tb.format_exc()