Merge pull request #29 from scikit-tda/single-point-same-bug

Fixes #28

Author: ctralie

persim/bottleneck.py

@@ -85,7 +85,7 @@ def bottleneck(dgm1, dgm2, matching=False):
         for i in range(N):
             graph["%s" % i] = {j for j in range(N) if D[i, j] <= d}
         res = HopcroftKarp(graph).maximum_matching()
-        if len(res) == 2 * N and d < bdist:
+        if len(res) == 2 * N and d <= bdist:
             bdist = d
             matching = res
             ds = ds[0:idx]

test/test_distances.py

@@ -96,6 +96,17 @@ def test_matching_to_self(self):
         dist = bottleneck(pd, pd)
         assert dist == 0
 
+    def test_single_point_same(self):
+        dgm = np.array([[0.11371516, 4.45734882]])
+        dist = bottleneck(dgm, dgm)
+        assert dist == 0
+    
+    def test_2x2_bisect_bug(self):
+        dgm1 = np.array([[6, 9], [6, 8]])
+        dgm2 = np.array([[4, 10], [9, 10]])
+        dist = bottleneck(dgm1, dgm2)
+        assert dist == 2
+
 class TestWasserstein:
     def test_single(self):
         d = wasserstein(
@@ -130,6 +141,11 @@ def test_matching_to_self(self):
         dist = wasserstein(pd, pd)
         assert dist == 0
 
+    def test_single_point_same(self):
+        dgm = np.array([[0.11371516, 4.45734882]])
+        dist = wasserstein(dgm, dgm)
+        assert dist == 0
+
 
 class TestSliced:
     def test_single(self):
@@ -170,6 +186,10 @@ def test_different_size(self):
         # These are very loose bounds
         assert d == pytest.approx(0.314, 0.1)
 
+    def test_single_point_same(self):
+        dgm = np.array([[0.11371516, 4.45734882]])
+        dist = sliced_wasserstein(dgm, dgm)
+        assert dist == 0
 
 class TestHeat:
     def test_compare(self):
@@ -186,6 +206,11 @@ def test_compare(self):
         # These are very loose bounds
         assert d1 < d2
 
+    def test_single_point_same(self):
+        dgm = np.array([[0.11371516, 4.45734882]])
+        dist = heat(dgm, dgm)
+        assert dist == 0
+
 
 class TestModifiedGromovHausdorff:
     def test_single_point(self):