feat: add live plotting of updates (#166)

* feat: add live plotting of updates

* style: make plotting vars lowercase

---------

Co-authored-by: John Halloran <jhalloran@oxy.edu>

Author: john-halloran

src/diffpy/snmf/main.py

@@ -12,6 +12,7 @@
     init_weights=init_weights_file,
     init_components=init_components_file,
     init_stretch=init_stretch_file,
+    show_plots=True,
 )
 
 print("Done")

src/diffpy/snmf/plotter.py

@@ -0,0 +1,55 @@
+import matplotlib.pyplot as plt
+import numpy as np
+
+
+class SNMFPlotter:
+    def __init__(self, figsize=(12, 4)):
+        plt.ion()
+        self.fig, self.axes = plt.subplots(1, 3, figsize=figsize)
+        titles = ["Components", "Weights (rows as series)", "Stretch (rows as series)"]
+        for ax, t in zip(self.axes, titles):
+            ax.set_title(t)
+        self.lines = {"components": [], "weights": [], "stretch": []}
+        self._layout_done = False
+        plt.show()
+
+    def _ensure_lines(self, ax, key, n_series):
+        cur = self.lines[key]
+        if len(cur) != n_series:
+            ax.cla()
+            ax.set_title(ax.get_title())
+            self.lines[key] = [ax.plot([], [])[0] for _ in range(n_series)]
+        return self.lines[key]
+
+    def _update_series(self, ax, key, data_2d):
+        # Expect rows = separate series for components
+        data_2d = np.atleast_2d(data_2d)
+        n_series, n_pts = data_2d.shape
+        lines = self._ensure_lines(ax, key, n_series)
+        x = np.arange(n_pts)
+        for ln, y in zip(lines, data_2d):
+            ln.set_data(x, y)
+        ax.relim()
+        ax.autoscale_view()
+
+    def update(self, components, weights, stretch, update_tag=None):
+        # Components: transpose before plotting
+        c = np.asarray(components).T
+        self._update_series(self.axes[0], "components", c)
+
+        w = np.asarray(weights)
+        self._update_series(self.axes[1], "weights", w)
+
+        s = np.asarray(stretch)
+        self._update_series(self.axes[2], "stretch", s)
+
+        if update_tag is not None:
+            self.fig.suptitle(f"Updated: {update_tag}", fontsize=14)
+
+        if not self._layout_done:
+            self.fig.tight_layout()
+            self._layout_done = True
+
+        self.fig.canvas.draw()
+        self.fig.canvas.flush_events()
+        plt.pause(0.001)

src/diffpy/snmf/snmf_class.py

@@ -1,5 +1,6 @@
 import cvxpy as cp
 import numpy as np
+from plotter import SNMFPlotter
 from scipy.optimize import minimize
 from scipy.sparse import coo_matrix, diags
 
@@ -73,6 +74,7 @@ def __init__(
         tol=5e-7,
         n_components=None,
         random_state=None,
+        show_plots=False,
     ):
         """Initialize an instance of SNMF and run the optimization.
 
@@ -112,6 +114,8 @@ def __init__(
         random_state : int  Optional  Default = None
             The seed for the initial guesses at the matrices (A, X, and Y) created by
             the decomposition.
+        show_plots : boolean Optional  Default = False
+            Enables plotting at each step of the decomposition.
         """
 
         self.source_matrix = source_matrix
@@ -123,6 +127,7 @@ def __init__(
         self.signal_length, self.n_signals = source_matrix.shape
         self.num_updates = 0
         self._rng = np.random.default_rng(random_state)
+        self.plotter = SNMFPlotter() if show_plots else None
 
         # Enforce exclusive specification of n_components or init_weights
         if (n_components is None and init_weights is None) or (
@@ -236,6 +241,13 @@ def normalize_results(self):
             print(f"Objective function after normalize_components: {self.objective_function:.5e}")
             self._objective_history.append(self.objective_function)
             self.objective_difference = self._objective_history[-2] - self._objective_history[-1]
+            if self.plotter is not None:
+                self.plotter.update(
+                    components=self.components,
+                    weights=self.weights,
+                    stretch=self.stretch,
+                    update_tag="normalize components",
+                )
             if self.objective_difference < self.objective_function * self.tol and outiter >= 7:
                 break
 
@@ -252,6 +264,10 @@ def outer_loop(self):
             if self.objective_function < self.best_objective:
                 self.best_objective = self.objective_function
                 self.best_matrices = [self.components.copy(), self.weights.copy(), self.stretch.copy()]
+            if self.plotter is not None:
+                self.plotter.update(
+                    components=self.components, weights=self.weights, stretch=self.stretch, update_tag="components"
+                )
 
             self.update_weights()
             self.residuals = self.get_residual_matrix()
@@ -262,6 +278,10 @@ def outer_loop(self):
             if self.objective_function < self.best_objective:
                 self.best_objective = self.objective_function
                 self.best_matrices = [self.components.copy(), self.weights.copy(), self.stretch.copy()]
+            if self.plotter is not None:
+                self.plotter.update(
+                    components=self.components, weights=self.weights, stretch=self.stretch, update_tag="weights"
+                )
 
             self.objective_difference = self._objective_history[-2] - self._objective_history[-1]
             if self._objective_history[-3] - self.objective_function < self.objective_difference * 1e-3:
@@ -276,6 +296,10 @@ def outer_loop(self):
         if self.objective_function < self.best_objective:
             self.best_objective = self.objective_function
             self.best_matrices = [self.components.copy(), self.weights.copy(), self.stretch.copy()]
+        if self.plotter is not None:
+            self.plotter.update(
+                components=self.components, weights=self.weights, stretch=self.stretch, update_tag="stretch"
+            )
 
     def get_residual_matrix(self, components=None, weights=None, stretch=None):
         # Initialize residual matrix as negative of source_matrix