Improve impact calc error messages when there is a mismatch of impf ids between exposures and impfset (#863)

* Add error handling for missmatching impf ids between exposures and impfset in ImpactCalc.impact()

* Clarify error message for handling of mismatching impf ids between impfset and exposures in ImpactCalc.impact()

* Add unit test for error handling of mismatchin impf ids between impf set and exposures in ImpactCalc.impact()

* Make code compliant with PEP8

* Change ambiguous variable names

* Add impact function in the impf set but not in the exposure for the test_error_handling_mismatch_impf_ids

* Add name to authors's list

* Add changes to changelog

* Use assertRaises instead of assertEqual to test the error handling

* Refine error message so that it provides users with the ids of missing impfs

* Initiate dummy impf in testing function directly setting its attributes

* Correct for pylint warnings for too long lines

---------

Co-authored-by: luseverin <[email protected]>

Author: luseverin

AUTHORS.md

@@ -32,3 +32,4 @@
 * Kam Lam Yeung
 * Sarah Hülsen
 * Timo Schmid
+* Luca Severino

CHANGELOG.md

@@ -14,6 +14,8 @@ Code freeze date: YYYY-MM-DD
 
 ### Changed
 
+- Improved error messages produced by `ImpactCalc.impact()` in case impact function in the exposures is not found in impf_set [#863](https://github.com/CLIMADA-project/climada_python/pull/863)
+
 ### Fixed
 
 ### Deprecated

climada/engine/impact_calc.py

@@ -112,7 +112,7 @@ def impact(self, save_mat=True, assign_centroids=True,
         apply_deductible_to_mat : apply deductible to impact matrix
         apply_cover_to_mat : apply cover to impact matrix
         """
-        # check for compability of exposures and hazard type
+        # check for compatibility of exposures and hazard type
         if all(name not in self.exposures.gdf.columns for
                name in ['if_', f'if_{self.hazard.haz_type}',
                         'impf_', f'impf_{self.hazard.haz_type}']):
@@ -121,14 +121,28 @@ def impact(self, save_mat=True, assign_centroids=True,
                 f"for hazard type {self.hazard.haz_type} in exposures."
                 )
 
-        # check for compability of impact function and hazard type
+        # check for compatibility of impact function and hazard type
         if not self.impfset.get_func(haz_type=self.hazard.haz_type):
             raise AttributeError(
                 "Impact calculation not possible. No impact functions found "
                 f"for hazard type {self.hazard.haz_type} in impf_set."
                 )
 
         impf_col = self.exposures.get_impf_column(self.hazard.haz_type)
+        known_impact_functions = self.impfset.get_ids(haz_type=self.hazard.haz_type)
+
+        # check for compatibility of impact function id between impact function set and exposure
+        if not all(self.exposures.gdf[impf_col].isin(known_impact_functions)):
+            unknown_impact_functions = list(self.exposures.gdf[
+                    ~self.exposures.gdf[impf_col].isin(known_impact_functions)
+                ][impf_col].drop_duplicates().astype(int).astype(str))
+            raise ValueError(
+                f"The associated impact function(s) with id(s) "
+                f"{', '.join(unknown_impact_functions)} have no match in impact function set for"
+                f" hazard type \'{self.hazard.haz_type}\'.\nPlease make sure that all exposure "
+                "points are associated with an impact function that is included in the impact "
+                "function set.")
+
         exp_gdf = self.minimal_exp_gdf(impf_col, assign_centroids, ignore_cover, ignore_deductible)
         if exp_gdf.size == 0:
             return self._return_empty(save_mat)

climada/engine/test/test_impact_calc.py

@@ -135,6 +135,26 @@ def test_error_handling_mismatch_haz_type(self):
         except Exception as e:
             self.assertEqual(str(e), "Impact calculation not possible. No impact "
                              "functions found for hazard type TC in impf_set.")
+    def test_error_handling_mismatch_impf_ids(self):
+        """Test error handling in case impf ids in exposures
+        does not appear in impf_set"""
+        haz = Hazard('TC')
+        exp = Exposures()
+        exp.gdf.loc[0,'impf_TC'] = 1
+        exp.gdf.loc[1,'impf_TC'] = 2
+        impf_exp = ImpactFunc(haz_type='TC', id=1)
+        impf_noexp = deepcopy(impf_exp)
+        impf_noexp.id = 3
+        impfset = ImpactFuncSet([impf_exp, impf_noexp])
+
+        with self.assertRaises(ValueError) as cm:
+            ImpactCalc(exp, impfset, haz).impact()
+        the_exception = cm.exception
+        self.assertEqual(the_exception.args[0],
+                         "The associated impact function(s) with id(s) 2 have no match in "
+                         "impact function set for hazard type \'TC\'.\nPlease make sure "
+                         "that all exposure points are associated with an impact "
+                         "function that is included in the impact function set.")
 
     def test_calc_impact_TC_pass(self):
         """Test compute impact"""