matplotlib · dopplershift · Dec 22, 2019 · Dec 20, 2019 · Dec 22, 2019
diff --git a/examples/axes_grid1/demo_axes_hbox_divider.py b/examples/axes_grid1/demo_axes_hbox_divider.py
@@ -5,6 +5,7 @@
 
 Hbox Divider to arrange subplots.
 """
+
 import numpy as np
 import matplotlib.pyplot as plt
 from mpl_toolkits.axes_grid1.axes_divider import HBoxDivider
@@ -13,19 +14,12 @@
 
 def make_heights_equal(fig, rect, ax1, ax2, pad):
     # pad in inches
-
-    h1, v1 = Size.AxesX(ax1), Size.AxesY(ax1)
-    h2, v2 = Size.AxesX(ax2), Size.AxesY(ax2)
-
-    pad_v = Size.Scaled(1)
-    pad_h = Size.Fixed(pad)
-
-    my_divider = HBoxDivider(fig, rect,
-                             horizontal=[h1, pad_h, h2],
-                             vertical=[v1, pad_v, v2])
-
-    ax1.set_axes_locator(my_divider.new_locator(0))
-    ax2.set_axes_locator(my_divider.new_locator(2))
+    divider = HBoxDivider(
+        fig, rect,
+        horizontal=[Size.AxesX(ax1), Size.Fixed(pad), Size.AxesX(ax2)],
+        vertical=[Size.AxesY(ax1), Size.Scaled(1), Size.AxesY(ax2)])
+    ax1.set_axes_locator(divider.new_locator(0))
+    ax2.set_axes_locator(divider.new_locator(2))
 
 
 if __name__ == "__main__":
@@ -37,11 +31,13 @@ def make_heights_equal(fig, rect, ax1, ax2, pad):
     ax1.imshow(arr1)
     ax2.imshow(arr2)
 
-    rect = 111  # subplot param for combined axes
-    make_heights_equal(fig, rect, ax1, ax2, pad=0.5)  # pad in inches
-
-    for ax in [ax1, ax2]:
-        ax.locator_params(nbins=4)
+    pad = 0.5  # inches.
+    divider = HBoxDivider(
+        fig, 111,  # Position of combined axes.
+        horizontal=[Size.AxesX(ax1), Size.Fixed(pad), Size.AxesX(ax2)],
+        vertical=[Size.AxesY(ax1), Size.Scaled(1), Size.AxesY(ax2)])
+    ax1.set_axes_locator(divider.new_locator(0))
+    ax2.set_axes_locator(divider.new_locator(2))
 
     # annotate
     ax3 = plt.axes([0.5, 0.5, 0.001, 0.001], frameon=False)

diff --git a/lib/mpl_toolkits/axes_grid1/axes_divider.py b/lib/mpl_toolkits/axes_grid1/axes_divider.py
@@ -597,26 +597,22 @@ def _determine_karray(equivalent_sizes, appended_sizes,
                           total_appended_size):
 
         n = len(equivalent_sizes)
-        A = np.mat(np.zeros((n + 1, n + 1)))
+        eq_rs, eq_as = np.asarray(equivalent_sizes).T
+        ap_rs, ap_as = np.asarray(appended_sizes).T
+        A = np.zeros((n + 1, n + 1))
         B = np.zeros(n + 1)
-        # AxK = B
+        np.fill_diagonal(A[:n, :n], eq_rs)
+        A[:n, -1] = -1
+        A[-1, :-1] = ap_rs
+        B[:n] = -eq_as
+        B[-1] = total_appended_size - sum(ap_as)
 
-        # populated A
-        for i, (r, a) in enumerate(equivalent_sizes):
-            A[i, i] = r
-            A[i, -1] = -1
-            B[i] = -a
-        A[-1, :-1] = [r for r, a in appended_sizes]
-        B[-1] = total_appended_size - sum([a for rs, a in appended_sizes])
-
-        karray_H = (A.I*np.mat(B).T).A1
+        karray_H = np.linalg.solve(A, B)  # A @ K = B
         karray = karray_H[:-1]
         H = karray_H[-1]
 
         if H > max_equivalent_size:
-            karray = ((max_equivalent_size -
-                      np.array([a for r, a in equivalent_sizes]))
-                      / np.array([r for r, a in equivalent_sizes]))
+            karray = (max_equivalent_size - eq_as) / eq_rs
         return karray
 
     @staticmethod

diff --git a/lib/mpl_toolkits/tests/test_axes_grid1.py b/lib/mpl_toolkits/tests/test_axes_grid1.py
@@ -12,9 +12,10 @@
     image_comparison, remove_ticks_and_titles)
 
 from mpl_toolkits.axes_grid1 import (
-    host_subplot, make_axes_locatable, AxesGrid, ImageGrid)
+    axes_size as Size, host_subplot, make_axes_locatable, AxesGrid, ImageGrid)
 from mpl_toolkits.axes_grid1.anchored_artists import (
     AnchoredSizeBar, AnchoredDirectionArrows)
+from mpl_toolkits.axes_grid1.axes_divider import HBoxDivider
 from mpl_toolkits.axes_grid1.inset_locator import (
     zoomed_inset_axes, mark_inset, inset_axes, BboxConnectorPatch)
 
@@ -461,3 +462,26 @@ def on_pick(event):
     assert big in event_rects
     if click_on == "small":
         assert small in event_rects
+
+
+def test_hbox_divider():
+    arr1 = np.arange(20).reshape((4, 5))
+    arr2 = np.arange(20).reshape((5, 4))
+
+    fig, (ax1, ax2) = plt.subplots(1, 2)
+    ax1.imshow(arr1)
+    ax2.imshow(arr2)
+
+    pad = 0.5  # inches.
+    divider = HBoxDivider(
+        fig, 111,  # Position of combined axes.
+        horizontal=[Size.AxesX(ax1), Size.Fixed(pad), Size.AxesX(ax2)],
+        vertical=[Size.AxesY(ax1), Size.Scaled(1), Size.AxesY(ax2)])
+    ax1.set_axes_locator(divider.new_locator(0))
+    ax2.set_axes_locator(divider.new_locator(2))
+
+    fig.canvas.draw()
+    p1 = ax1.get_position()
+    p2 = ax2.get_position()
+    assert p1.height == p2.height
+    assert p2.width / p1.width == pytest.approx((4 / 5) ** 2)