Add __radd__ for sptensor

pyttb/sptensor.py

@@ -2901,6 +2901,29 @@ def __add__(self, other):
         # Otherwise return negated sub
         return self.__sub__(-other)
 
+    def __radd__(self, other):
+        """
+        Right binary addition operator (+).
+
+        Parameters
+        ----------
+        other:
+            Object to add to the sparse tensor.
+
+        Examples
+        --------
+        Add a scalar value, returning a dense tensor:
+
+        >>> S = ttb.sptensor(shape=(2, 2))
+        >>> S[1, 1] = 1.0
+        >>> 1 + S
+        tensor of shape (2, 2) with order F
+        data[:, :] =
+        [[1. 1.]
+         [1. 2.]]
+        """
+        return self.__add__(other)
+
     def __pos__(self):
         """
         Unary plus operator (+).

tests/test_sptensor.py

@@ -910,6 +910,14 @@ def test_sptensor__add__(sample_sptensor):
     assert np.array_equal(subSptensor.data, sptensorInstance.to_tensor().data)
 
 
+def test_sptensor__radd__(sample_sptensor):
+    (data, sptensorInstance) = sample_sptensor
+
+    # scalar + Sptensor
+    subSptensor = 0 + sptensorInstance
+    assert np.array_equal(subSptensor.data, sptensorInstance.to_tensor().data)
+
+
 def test_sptensor_isequal(sample_sptensor):
     (data, sptensorInstance) = sample_sptensor