Merge pull request #336 from libAtoms/fit_error_parity_sign

Try to fix sign of scalar diffs and parity quantities in error analysis

wfl/fit/error.py

@@ -41,7 +41,8 @@ def calc(inputs, calc_property_prefix, ref_property_prefix,
     Returns
     -------
         errors: dict of RMSE and MAE for each category and property
-        diffs: dict with list of differences for each category and property
+        diffs: dict with list of differences for each category and property (signed for scalar
+            properties, norms for vectors)
         parity: dict with "ref" and "calc" keys, each containing list of property values for
             each category and property, for parity plots
     """
@@ -188,13 +189,13 @@ def _reshape_normalize(quant, prop, atoms, per_atom):
 
                 if len(diff.shape) != 2:
                     raise RuntimeError(f"Should never have diff.shape={diff.shape} with dim != 2 (prop {prop + atom_split_index_label})")
-                # compute norm along vector components
-                diff = np.linalg.norm(diff, axis=1)
-                if not per_component:
+                if diff.shape[1] > 1:
+                    # compute norm along vector components
+                    diff = np.linalg.norm(diff, axis=1)
+                if not per_component and selected_ref_quant.shape[1] > 1:
                     selected_ref_quant = np.linalg.norm(selected_ref_quant, axis=1)
                     selected_calc_quant = np.linalg.norm(selected_calc_quant, axis=1)
 
-
                 _dict_add([all_diffs, all_weights,            all_parity["ref"],  all_parity["calc"]],
                           [diff,      _promote(weight, diff), selected_ref_quant, selected_calc_quant],
                           at_category, prop + atom_split_index_label)
@@ -380,16 +381,15 @@ def select_units(prop, plt_type, units_dict=None):
         "energy/atom": {"parity": ("eV/at", 1.0), "error": ("meV/at", 1.0e3)},
         "forces": {"parity": ("eV/Å", 1.0), "error": ("meV/Å", 1.0e3)},
         "virial": {"parity": ("eV", 1.0), "error": ("meV", 1.0e3)},
-        "virial/atom": {"parity": ("eV/at", 1.0), "error": ("meV/at", 1.0e3)}
+        "virial/atom": {"parity": ("eV/at", 1.0), "error": ("meV/at", 1.0e3)},
+        "stress": {"parity": ("GPa", 1.0), "error": ("MPa", 1.0e3)},
     }
     if units_dict is None:
         units_dict = {}
     use_units_dict.update(units_dict)
 
-    if "virial" in prop:
-        prop = re.sub(r"/comp\b", "", prop)
+    prop = re.sub(r"/comp\b", "", prop)
     if "forces" in prop:
-        prop = re.sub(r"/comp\b", "", prop)
         prop = re.sub(r"/Z_\d+\b", "", prop)
 
     if "energy" in prop: