SimpleUpdateGen: add simple .plot() method

quimb/tensor/tensor_arbgeom_tebd.py

@@ -685,6 +685,49 @@ def compute_energy(self):
             **self.compute_energy_opts
         )
 
+    @default_to_neutral_style
+    def plot(
+        self,
+        zoom="auto",
+        xscale="symlog",
+        xscale_linthresh=20,
+        hlines=()
+    ):
+        import numpy as np
+        import matplotlib.pyplot as plt
+        from matplotlib.colors import hsv_to_rgb
+
+        fig, ax = plt.subplots()
+
+        xs = np.array(self.its)
+        ys = np.array(self.energies)
+
+        ax.plot(xs, ys, '.-')
+        ax.set_xlabel("Iteration")
+        ax.set_ylabel("Energy")
+
+        if xscale == "symlog":
+            ax.set_xscale(xscale, linthresh=xscale_linthresh)
+            ax.axvline(xscale_linthresh, color=(.5, .5, .5), ls="-", lw=0.5)
+        else:
+            ax.set_xscale(xscale)
+
+        if hlines:
+            hlines = dict(hlines)
+            for i, (label, value) in enumerate(hlines.items()):
+                color = hsv_to_rgb([(0.1 * i) % 1.0, 0.9, 0.9])
+                ax.axhline(value, color=color, ls="--", label=label)
+                ax.text(1, value, label, color=color, va="bottom", ha="left")
+
+        if zoom is not None:
+            if zoom == "auto":
+                zoom = min(50, ys.size // 2)
+
+            iax = ax.inset_axes([0.5, 0.5, 0.5, 0.5])
+            iax.plot(xs[-zoom:], ys[-zoom:], ".-")
+
+        return fig, ax
+
     def __repr__(self):
         s = "<{}(n={}, tau={}, D={})>"
         return s.format(