Reuse RUNOPT and RCLUSTZ in voronoi step of kkr_imp workflow

During scf a KKRhost calculation might have overwritten the RCLSUTZ and RUNOPT inputs.
When a KKRimp calculation is not done we need to make sure that the impurity potential takes over the same setting as the voronoi run from where the KKRhost calculation started.
This in particular means that the FINDSIZE run option is required to ensure that the radial mesh is the same.

aiida_kkr/workflows/kkr_imp.py

@@ -542,6 +542,7 @@ def run_voroaux(self):
         kkrcode = self.inputs.kkr
         imp_info = self.inputs.impurity_info
         voro_params = self.ctx.voro_params_dict
+
         if self.ctx.do_gf_calc:
             self.report('INFO: get converged host remote from inputs to extract structure for Voronoi calculation')
             converged_host_remote = self.inputs.remote_data_host
@@ -553,6 +554,9 @@ def run_voroaux(self):
             GF_host_calc = remote_data_gf_node.get_incoming(link_label_filter=u'remote_folder').first().node
             converged_host_remote = GF_host_calc.inputs.parent_folder
 
+        # find host structure
+        structure_host, voro_calc = VoronoiCalculation.find_parent_structure(converged_host_remote)
+
         # get previous kkr parameters following remote_folder->calc->parameters links
         prev_kkrparams = converged_host_remote.get_incoming(link_label_filter='remote_folder'
                                                             ).first().node.get_incoming(link_label_filter='parameters'
@@ -570,10 +574,24 @@ def run_voroaux(self):
         # add or overwrite some parameters (e.g. things that are only used by voronoi)
         calc_params_dict = calc_params.get_dict()
         # add some voronoi specific parameters automatically if found (RMTREF should also set RMTCORE to the same value)
-        if '<RMTREF>' in list(calc_params_dict.keys()):
+        if calc_params_dict.get('<RMTREF>', None) is not None:
             self.report('INFO: add rmtcore to voro params')
             self.ctx.change_voro_params['<RMTCORE>'] = calc_params_dict['<RMTREF>']
             self.report(self.ctx.change_voro_params)
+
+        # add some voronoi-specific settings starting from host's voronoi run (might have been overwritten in between)
+        # this is necessary to make sure that voronoi creates the same radial mesh for the impurity potential, otherwise KKRimp will fail
+        if voro_calc.inputs.parameters.get_dict().get('RUNOPT', None) is not None:
+            self.report("INFO: copy runopt from host's voronoi run")
+            runopt = self.ctx.change_voro_params.get('RUNOPT', None)
+            if runopt is None:
+                runopt = []
+            runopt += voro_calc.inputs.parameters['RUNOPT']
+            self.ctx.change_voro_params['RUNOPT'] = runopt
+        if voro_calc.inputs.parameters.get_dict().get('RCLUSTZ', None) is not None:
+            self.report("INFO: copy RCLUSTZ from host's voronoi run")
+            self.ctx.change_voro_params['RCLUSTZ'] = voro_calc.inputs.parameters['RCLUSTZ']
+
         changed_params = False
         for key, val in self.ctx.change_voro_params.items():
             if key in ['RUNOPT', 'TESTOPT']:
@@ -589,9 +607,6 @@ def run_voroaux(self):
             updatenode.description = 'Overwritten voronoi input parameter from kkr_imp_wc input.'
             calc_params = update_params_wf(calc_params, updatenode)
 
-        # find host structure
-        structure_host, voro_calc = VoronoiCalculation.find_parent_structure(converged_host_remote)
-
         # for every impurity, generate a structure and launch the voronoi workflow
         # to get the auxiliary impurity startpotentials
         self.ctx.voro_calcs = {}