_real_view and _imag_view now set flags correctly (#1355)

- these properties were setting the flags of the output to the flags of the input, which is incorrect, as the output is almost never contiguous
- added tests for this behavior

Author: ndgrigorian

dpctl/tensor/_usmarray.pyx

@@ -662,7 +662,7 @@ cdef class usm_ndarray:
         """
         if self.nd_ < 2:
             raise ValueError(
-                "array.mT requires array to have at least 2-dimensons."
+                "array.mT requires array to have at least 2 dimensions."
             )
         return _m_transpose(self)
 
@@ -1216,14 +1216,14 @@ cdef usm_ndarray _real_view(usm_ndarray ary):
     offset_elems = ary.get_offset() * 2
     r = usm_ndarray.__new__(
         usm_ndarray,
-        _make_int_tuple(ary.nd_, ary.shape_),
+        _make_int_tuple(ary.nd_, ary.shape_) if ary.nd_ > 0 else tuple(),
         dtype=_make_typestr(r_typenum_),
         strides=tuple(2 * si for si in ary.strides),
         buffer=ary.base_,
         offset=offset_elems,
         order=('C' if (ary.flags_ & USM_ARRAY_C_CONTIGUOUS) else 'F')
     )
-    r.flags_ = ary.flags_
+    r.flags_ |= (ary.flags_ & USM_ARRAY_WRITABLE)
     r.array_namespace_ = ary.array_namespace_
     return r
 
@@ -1248,14 +1248,14 @@ cdef usm_ndarray _imag_view(usm_ndarray ary):
     offset_elems = 2 * ary.get_offset() + 1
     r = usm_ndarray.__new__(
         usm_ndarray,
-        _make_int_tuple(ary.nd_, ary.shape_),
+        _make_int_tuple(ary.nd_, ary.shape_) if ary.nd_ > 0 else tuple(),
         dtype=_make_typestr(r_typenum_),
         strides=tuple(2 * si for si in ary.strides),
         buffer=ary.base_,
         offset=offset_elems,
         order=('C' if (ary.flags_ & USM_ARRAY_C_CONTIGUOUS) else 'F')
     )
-    r.flags_ = ary.flags_
+    r.flags_ |= (ary.flags_ & USM_ARRAY_WRITABLE)
     r.array_namespace_ = ary.array_namespace_
     return r
 

dpctl/tests/test_usm_ndarray_ctor.py

@@ -1438,17 +1438,26 @@ def test_real_imag_views():
     n, m = 2, 3
     try:
         X = dpt.usm_ndarray((n, m), "c8")
+        X_scalar = dpt.usm_ndarray((), dtype="c8")
     except dpctl.SyclDeviceCreationError:
         pytest.skip("No SYCL devices available")
     Xnp_r = np.arange(n * m, dtype="f4").reshape((n, m))
     Xnp_i = np.arange(n * m, 2 * n * m, dtype="f4").reshape((n, m))
     Xnp = Xnp_r + 1j * Xnp_i
     X[:] = Xnp
-    assert np.array_equal(dpt.to_numpy(X.real), Xnp.real)
+    X_real = X.real
+    X_imag = X.imag
+    assert np.array_equal(dpt.to_numpy(X_real), Xnp.real)
     assert np.array_equal(dpt.to_numpy(X.imag), Xnp.imag)
+    assert not X_real.flags["C"] and not X_real.flags["F"]
+    assert not X_imag.flags["C"] and not X_imag.flags["F"]
+    assert X_real.strides == X_imag.strides
     assert np.array_equal(dpt.to_numpy(X[1:].real), Xnp[1:].real)
     assert np.array_equal(dpt.to_numpy(X[1:].imag), Xnp[1:].imag)
 
+    X_scalar[...] = complex(n * m, 2 * n * m)
+    assert X_scalar.real and X_scalar.imag
+
 
 @pytest.mark.parametrize(
     "dtype",