Bands align (#21)

The workaround for the issue in osscar-org/widget-bandsplot#55 from the frontend, but it should be fixed from bandsplot widget side.

aiidalab_sssp/inspect/subwidgets/bands.py

@@ -20,6 +20,8 @@
 _RY_TO_EV = 13.6056980659
 _FERMI_SHIFT = 10.0  # eV in protocol FIXME also change title of plot Tab widget
 
+_SMEARING_WIDTH = _DEGAUSS * _RY_TO_EV
+
 
 def _bandview(json_path):
     """
@@ -85,27 +87,41 @@ def _on_pseudo_select(self, _):
             path = pseudo1["accuracy"]["bands"]["band_structure"]
             json_path = Path.joinpath(SSSP_DB, path)
 
-            band = _bandview(json_path)
-            if band:
-                bands.append(band)
+            bandsdata_a = self.bands_align_to_fermi(_bandview(json_path))
+            bands.append(bandsdata_a)
 
         if pseudo2:
             path = pseudo2["accuracy"]["bands"]["band_structure"]
             json_path = Path.joinpath(SSSP_DB, path)
 
-            band = _bandview(json_path)
-            if band:
-                bands.append(band)
+            bandsdata_b = self.bands_align_to_fermi(_bandview(json_path))
+            bands.append(bandsdata_b)
 
         _band_structure_preview = BandsPlotWidget(
             bands=bands,
-            energy_range={"ymin": -30.0, "ymax": 11.0},
+            energy_range={"ymin": -10.0, "ymax": 15.0},
+            fermi_energy=0.0,  # since we have aligned to fermi level
         )
 
         with self.band_structure:
             clear_output(wait=True)
             display(_band_structure_preview)
 
+    def bands_align_to_fermi(self, bandsdata):
+        """
+        align the band structure to fermi level
+        """
+        fermi_energy = bandsdata["fermi_level"]
+
+        for path in bandsdata["paths"]:
+            values = [[y - fermi_energy for y in ys] for ys in path["values"]]
+            path["values"] = values
+
+        # After align to fermi level, we need to update the fermi level to 0.0
+        bandsdata["fermi_level"] = 0.0
+
+        return bandsdata
+
 
 class BandChessboard(ipw.VBox):
     """Band distance compare in chess board"""
@@ -166,7 +182,7 @@ def _render_plot(ax_v, ax_c, arr_v, arr_c, labels):
         for idx, (ax, arr, title) in enumerate(
             [(ax_v, arr_v, r"$\eta_v$"), (ax_c, arr_c, r"$\eta_{10}$")]
         ):
-            ax.imshow(arr)
+            ax.imshow(arr, vmin=0, vmax=50, cmap="viridis")
 
             # Show all ticks and label them with the respective list entries
             # We want to show all ticks...
@@ -234,7 +250,7 @@ def _bands_distance(self, pseudos):
                 distance = get_bands_distance(
                     bandsdata_a=bandsdata1,
                     bandsdata_b=bandsdata2,
-                    smearing=_DEGAUSS * _RY_TO_EV,
+                    smearing=_SMEARING_WIDTH,
                     fermi_shift=fermi_shift,
                     do_smearing=do_smearing,
                     spin=spin,