SPTENSOR: Infer shape from data (#243)

Co-authored-by: Danny Dunlavy <[email protected]>

pyttb/sptensor.py

@@ -174,11 +174,14 @@ def __init__(
                     raise ValueError(f"Invalid shape provided: {shape}")
                 self.shape = tuple(shape)
             return
-        if subs is None or vals is None or shape is None:
+        if subs is None or vals is None:
             raise ValueError(
                 "For non-empty sptensors subs, vals, and shape must be provided"
             )
 
+        if shape is None:
+            shape = tuple(np.max(subs, axis=0) + 1)
+
         if subs.size > 0:
             assert subs.shape[1] == len(shape) and np.all(
                 (np.max(subs, axis=0) + 1) <= shape

tests/test_sptensor.py

@@ -48,8 +48,9 @@ def test_sptensor_initialization_from_data(sample_sptensor):
     assert np.array_equal(sptensorInstance.vals, data["vals"])
     assert sptensorInstance.shape == data["shape"]
 
-    with pytest.raises(ValueError):
-        ttb.sptensor(data["subs"], data["vals"])
+    # Infer shape from data
+    another_sptensor = ttb.sptensor(data["subs"], data["vals"])
+    assert another_sptensor.isequal(sptensorInstance)
 
     with pytest.raises(AssertionError):
         shape = (3, 3, 1)