Fixes #729

The generated reshaped_strides routine is meant for non-empty arrays,
and so empty ones must be handled differently.

Tests added as well.

Author: oleksandr-pavlyk

dpctl/tensor/_reshape.py

@@ -104,7 +104,10 @@ def reshape(X, newshape, order="C"):
         newshape = [v if d == -1 else d for d in newshape]
     if X.size != np.prod(newshape):
         raise ValueError("Can not reshape into {}".format(newshape))
-    newsts = reshaped_strides(X.shape, X.strides, newshape, order=order)
+    if X.size:
+        newsts = reshaped_strides(X.shape, X.strides, newshape, order=order)
+    else:
+        newsts = (1,) * len(newshape)
     if newsts is None:
         # must perform a copy
         flat_res = dpt.usm_ndarray(

dpctl/tests/test_usm_ndarray_ctor.py

@@ -816,6 +816,32 @@ def test_reshape():
     Y = dpt.reshape(X, X.shape)
     assert Y.flags == X.flags
 
+    A = dpt.usm_ndarray((0,), "i4")
+    A1 = dpt.reshape(A, (0,))
+    assert A1.shape == (0,)
+    A2 = dpt.reshape(
+        A,
+        (
+            2,
+            0,
+        ),
+    )
+    assert A2.shape == (
+        2,
+        0,
+    )
+    A3 = dpt.reshape(A, (0, 2))
+    assert A3.shape == (
+        0,
+        2,
+    )
+    A4 = dpt.reshape(A, (1, 0, 2))
+    assert A4.shape == (
+        1,
+        0,
+        2,
+    )
+
 
 def test_transpose():
     n, m = 2, 3