diff --git a/src/icosagon/data.py b/src/icosagon/data.py
index 7e39db7..70963ec 100644
--- a/src/icosagon/data.py
+++ b/src/icosagon/data.py
@@ -14,6 +14,7 @@ from typing import List, \
     Type
 from .decode import DEDICOMDecoder, \
     BilinearDecoder
+import numpy as np
 
 
 def _equal(x: torch.Tensor, y: torch.Tensor):
@@ -23,15 +24,29 @@ def _equal(x: torch.Tensor, y: torch.Tensor):
     if not x.is_sparse:
         return (x == y)
 
+    # if x.shape != y.shape:
+        # return torch.tensor(0, dtype=torch.uint8)
+
+    return ((x - y).coalesce().values() == 0)
+
     x = x.coalesce()
-    indices_x = list(map(tuple, x.indices().transpose(0, 1)))
-    order_x = sorted(range(len(indices_x)), key=lambda idx: indices_x[idx])
+    indices_x = np.empty(x.indices().shape[1], dtype=np.object)
+    indices_x[:] = list(map(tuple, x.indices().transpose(0, 1)))
+    order_x = np.argsort(indices_x)
+    #order_x = sorted(range(len(indices_x)), key=lambda idx: indices_x[idx])
 
     y = y.coalesce()
-    indices_y = list(map(tuple, y.indices().transpose(0, 1)))
-    order_y = sorted(range(len(indices_y)), key=lambda idx: indices_y[idx])
+    indices_y = np.empty(y.indices().shape[1], dtype=np.object)
+    indices_y[:] = list(map(tuple, y.indices().transpose(0, 1)))
+    order_y = np.argsort(indices_y)
+    # order_y = sorted(range(len(indices_y)), key=lambda idx: indices_y[idx])
+
+    # print(indices_x.shape, indices_y.shape)
+
+    if not len(indices_x) == len(indices_y):
+        return torch.tensor(0, dtype=torch.uint8)
 
-    if not indices_x == indices_y:
+    if not np.all(indices_x[order_x] == indices_y[order_y]):
         return torch.tensor(0, dtype=torch.uint8)
 
     return (x.values()[order_x] == y.values()[order_y])
diff --git a/tests/icosagon/test_data.py b/tests/icosagon/test_data.py
index 08ded89..57060e9 100644
--- a/tests/icosagon/test_data.py
+++ b/tests/icosagon/test_data.py
@@ -16,11 +16,15 @@ def test_equal_01():
     x = torch.rand((10, 10))
     y = torch.rand((10, 10)).round().to_sparse()
 
+    print('x == x ?')
     assert torch.all(_equal(x, x))
+    print('y == y ?')
     assert torch.all(_equal(y, y))
+    print('x == y ?')
     with pytest.raises(ValueError):
         _equal(x, y)
 
+    print('y == z ?')
     z = torch.rand((10, 10)).round().to_sparse()
     assert not torch.all(_equal(y, z))
 
@@ -71,7 +75,7 @@ def test_relation_family_03():
     d.add_node_type('B', 5)
 
     fam = RelationFamily(d, 'A-B', 0, 1, True, DEDICOMDecoder)
-    
+
     fam.add_relation_type('A-B', torch.rand((10, 5)).round())
 
     assert torch.all(fam.relation_types[0].adjacency_matrix.transpose(0, 1) == \