Added test_reshape, fixed error uncovered by it (including ones in copying)

Author: oleksandr-pavlyk

dpctl/tensor/_copy_utils.py

@@ -129,7 +129,9 @@ def copy_same_dtype(dst, src):
         return
 
     if (dst.flags & 1) and (src.flags & 1):
-        dst.usm_data.copy_from_device(src.usm_data)
+        dst_mem = dpm.as_usm_memory(dst)
+        src_mem = dpm.as_usm_memory(src)
+        dst_mem.copy_from_device(src_mem)
         return
 
     # simplify strides

dpctl/tensor/_reshape.py

@@ -1,4 +1,4 @@
-import collections.abc
+import operator
 
 import numpy as np
 
@@ -59,14 +59,27 @@ def reshaped_strides(old_sh, old_sts, new_sh, order="C"):
 def reshape(X, newshape, order="C"):
     if type(X) is not dpt.usm_ndarray:
         raise TypeError
-    if X.size != np.prod(newshape):
-        raise ValueError("Can not reshape into {}".format(newshape))
-    if not isinstance(newshape, collections.abc.Sized):
+    if not isinstance(newshape, (list, tuple)):
         newshape = (newshape,)
     if order not in ["C", "F"]:
-        return ValueError(
+        raise ValueError(
             f"Keyword 'order' not recognized. Expecting 'C' or 'F', got {order}"
         )
+    newshape = [operator.index(d) for d in newshape]
+    negative_ones_count = 0
+    for i in range(len(newshape)):
+        if newshape[i] == -1:
+            negative_ones_count = negative_ones_count + 1
+        if (newshape[i] < -1) or negative_ones_count > 1:
+            raise ValueError(
+                "Target shape should have at most 1 negative "
+                "value which can only be -1"
+            )
+    if negative_ones_count:
+        v = X.size // (-np.prod(newshape))
+        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 newsts is None:
         # must perform a copy

dpctl/tests/test_usm_ndarray_ctor.py

@@ -775,3 +775,22 @@ def test_ctor_invalid():
     m = dpm.MemoryUSMShared(64)
     with pytest.raises(ValueError):
         dpt.usm_ndarray((4,), dtype="u1", buffer=m, strides={"not": "valid"})
+
+
+def test_reshape():
+    X = dpt.usm_ndarray((5, 5), "i4")
+    # can be done as views
+    Y = dpt.reshape(X, (25,))
+    assert Y.shape == (25,)
+    Z = X[::2, ::2]
+    # requires a copy
+    W = dpt.reshape(Z, (Z.size,), order="F")
+    assert W.shape == (Z.size,)
+    with pytest.raises(TypeError):
+        dpt.reshape("invalid")
+    with pytest.raises(ValueError):
+        dpt.reshape(Z, (2, 2, 2, 2, 2))
+    with pytest.raises(ValueError):
+        dpt.reshape(Z, Z.shape, order="invalid")
+    W = dpt.reshape(Z, (-1,), order="C")
+    assert W.shape == (Z.size,)