Merge pull request #1220 from IntelPython/multiply-scalar-gh-1219

Fixes incorrect result when multiplying real array and complex scalar

Author: ndgrigorian

dpctl/tensor/_elementwise_common.py

@@ -255,7 +255,7 @@ def _resolve_weak_types(o1_dtype, o2_dtype, dev):
             raise ValueError
         o1_kind_num = _weak_type_num_kind(o1_dtype)
         o2_kind_num = _strong_dtype_num_kind(o2_dtype)
-        if o1_kind_num > o2_kind_num:
+        if o1_kind_num > o2_kind_num or o1_kind_num == 2:
             if isinstance(o1_dtype, WeakBooleanType):
                 return dpt.bool, o2_dtype
             if isinstance(o1_dtype, WeakIntegralType):
@@ -273,7 +273,7 @@ def _resolve_weak_types(o1_dtype, o2_dtype, dev):
     ):
         o1_kind_num = _strong_dtype_num_kind(o1_dtype)
         o2_kind_num = _weak_type_num_kind(o2_dtype)
-        if o2_kind_num > o1_kind_num:
+        if o2_kind_num > o1_kind_num or o2_kind_num == 2:
             if isinstance(o2_dtype, WeakBooleanType):
                 return o1_dtype, dpt.bool
             if isinstance(o2_dtype, WeakIntegralType):

dpctl/tests/elementwise/test_multiply.py

@@ -152,3 +152,18 @@ def test_multiply_python_scalar(arr_dt):
         assert isinstance(R, dpt.usm_ndarray)
         R = dpt.multiply(sc, X)
         assert isinstance(R, dpt.usm_ndarray)
+
+
+def test_multiply_python_scalar_gh1219():
+    q = get_queue_or_skip()
+
+    X = dpt.ones(4, dtype="f4", sycl_queue=q)
+
+    r = dpt.multiply(X, 2j)
+    expected = dpt.multiply(X, dpt.asarray(2j, sycl_queue=q))
+    assert _compare_dtypes(r.dtype, expected.dtype, sycl_queue=q)
+
+    # symmetric case
+    r = dpt.multiply(2j, X)
+    expected = dpt.multiply(dpt.asarray(2j, sycl_queue=q), X)
+    assert _compare_dtypes(r.dtype, expected.dtype, sycl_queue=q)