Convergence plot correction: Use step plots (#2528)

* Change convergence plots to step plots

* - Add dummy x-point while plotting convergence plots, to draw the last step correctly
- Rebase master
- Run black formatter on convergence_plot.py

* Fix convergence plot tests

* Run black formatter

tardis/visualization/tools/convergence_plot.py

@@ -1,7 +1,9 @@
 """Convergence Plots to see the convergence of the simulation in real time."""
+
 from collections import defaultdict
 import matplotlib.cm as cm
 import matplotlib.colors as clr
+import numpy as np
 import plotly.graph_objects as go
 from IPython.display import display
 import matplotlib as mpl
@@ -330,8 +332,11 @@ def update_plasma_plots(self):
         # add a radiation temperature vs shell velocity trace to the plasma plot
         self.plasma_plot.add_scatter(
             x=velocity_km_s,
-            y=self.iterable_data["t_rad"],
+            y=np.append(
+                self.iterable_data["t_rad"], self.iterable_data["t_rad"][-1:]
+            ),
             line_color=self.plasma_colorscale[self.current_iteration - 1],
+            line_shape="hv",
             row=1,
             col=1,
             name=self.current_iteration,
@@ -344,8 +349,9 @@ def update_plasma_plots(self):
         # add a dilution factor vs shell velocity trace to the plasma plot
         self.plasma_plot.add_scatter(
             x=velocity_km_s,
-            y=self.iterable_data["w"],
+            y=np.append(self.iterable_data["w"], self.iterable_data["w"][-1:]),
             line_color=self.plasma_colorscale[self.current_iteration - 1],
+            line_shape="hv",
             row=1,
             col=2,
             legendgroup=f"group-{self.current_iteration}",

tardis/visualization/tools/tests/test_convergence_plot.py

@@ -1,4 +1,5 @@
 """Tests for Convergence Plots."""
+
 from copy import deepcopy
 
 import pytest
@@ -143,7 +144,9 @@ def test_update_plasma_plots(convergence_plots):
         # check values for t_rad subplot
         assert convergence_plots.plasma_plot.data[index].xaxis == "x"
         assert convergence_plots.plasma_plot.data[index].yaxis == "y"
-        assert convergence_plots.plasma_plot.data[index].y == tuple(t_rad_val)
+        assert (
+            convergence_plots.plasma_plot.data[index].y[:-1] == tuple(t_rad_val)
+        ).all()
         assert convergence_plots.plasma_plot.data[index].x == tuple(
             velocity.to(u.km / u.s).value
         )
@@ -152,7 +155,9 @@ def test_update_plasma_plots(convergence_plots):
         # check values for w subplot
         assert convergence_plots.plasma_plot.data[index].xaxis == "x2"
         assert convergence_plots.plasma_plot.data[index].yaxis == "y2"
-        assert convergence_plots.plasma_plot.data[index].y == tuple(w_val)
+        assert (
+            convergence_plots.plasma_plot.data[index].y[:-1] == tuple(w_val)
+        ).all()
         assert convergence_plots.plasma_plot.data[index].x == tuple(
             velocity.to(u.km / u.s).value
         )