Fix time in plots (#136)

Closes #120.

Fix annotated time shown in plot.py

goalie/plot.py

@@ -1,6 +1,7 @@
 """
 Driver functions for plotting solution data.
 """
+
 from firedrake.pyplot import tricontourf, triplot  # noqa
 import matplotlib.pyplot as plt
 
@@ -42,8 +43,8 @@ def plot_snapshots(solutions, time_partition, field, label, **kwargs):
             tc.append(tricontourf(sol, axes=ax, **kwargs))
             if not steady:
                 time = (
-                    i * P.end_time / cols
-                    + j * P.num_timesteps_per_export[i] * P.timesteps[i]
+                    P.subintervals[i][0]
+                    + (j + 1) * P.timesteps[i] * P.num_timesteps_per_export[i]
                 )
                 ax.annotate(f"t={time:.2f}", (0.05, 0.05), color="white")
         tcs.append(tc)
@@ -80,8 +81,8 @@ def plot_indicator_snapshots(indicators, time_partition, field, **kwargs):
             tc.append(tricontourf(indi, axes=ax, **kwargs))
             if not steady:
                 time = (
-                    i * P.end_time / cols
-                    + j * P.num_timesteps_per_export[i] * P.timesteps[i]
+                    P.subintervals[i][0]
+                    + (j + 1) * P.timesteps[i] * P.num_timesteps_per_export[i]
                 )
                 ax.annotate(f"t={time:.2f}", (0.05, 0.05), color="white")
         tcs.append(tc)