Fix convolutional_barycenter kernel for non-symmetric images

Add authorship

Author: atong01

ot/bregman.py

@@ -9,6 +9,7 @@
 #         Titouan Vayer <titouan.vayer@irisa.fr>
 #         Hicham Janati <hicham.janati@inria.fr>
 #         Mokhtar Z. Alaya <mokhtarzahdi.alaya@gmail.com>
+#         Alexander Tong <alexander.tong@yale.edu>
 #
 # License: MIT License
 
@@ -1346,12 +1347,17 @@ def convolutional_barycenter2d(A, reg, weights=None, numItermax=10000,
     err = 1
 
     # build the convolution operator
+    # this is equivalent to blurring on horizontal then vertical directions
     t = np.linspace(0, 1, A.shape[1])
     [Y, X] = np.meshgrid(t, t)
     xi1 = np.exp(-(X - Y)**2 / reg)
 
+    t = np.linspace(0, 1, A.shape[2])
+    [Y, X] = np.meshgrid(t, t)
+    xi2 = np.exp(-(X - Y)**2 / reg)
+
     def K(x):
-        return np.dot(np.dot(xi1, x), xi1)
+        return np.dot(np.dot(xi1, x), xi2)
 
     while (err > stopThr and cpt < numItermax):
 

test/test_bregman.py

@@ -351,3 +351,10 @@ def test_screenkhorn():
     # check marginals
     np.testing.assert_allclose(G_sink.sum(0), G_screen.sum(0), atol=1e-02)
     np.testing.assert_allclose(G_sink.sum(1), G_screen.sum(1), atol=1e-02)
+
+
+def test_convolutional_barycenter_non_square():
+    # test for image with height not equal width
+    A = np.ones((2, 2, 3)) / (2 * 3)
+    b = ot.bregman.convolutional_barycenter2d(A, 1e-03)
+    np.testing.assert_allclose(np.ones((2, 3)) / (2 * 3), b, atol=1e-02)