Array ufunc multiplication

CHANGES

@@ -10,6 +10,9 @@ Pint Changelog
 - Add `dim_sort` function to _formatter_helpers.
 - Add `dim_order` and `default_sort_func` properties to FullFormatter.
   (PR #1926, fixes Issue #1841)
+- Fixed bug causing operations between arrays of quantity scalars and quantity holding
+  array resulting in incorrect units.
+  (PR #1677)
 - Fix LaTeX siuntix formatting when using non_int_type=decimal.Decimal.
 - Fix converting to offset units of higher dimension e.g. gauge pressure
   (PR #1949)

pint/facets/numpy/numpy_func.py

@@ -284,6 +284,17 @@ def implement_func(func_type, func_str, input_units=None, output_unit=None):
 
     @implements(func_str, func_type)
     def implementation(*args, **kwargs):
+        if func_str in ["multiply", "true_divide", "divide", "floor_divide"] and any(
+            [
+                not _is_quantity(arg) and _is_sequence_with_quantity_elements(arg)
+                for arg in args
+            ]
+        ):
+            # the sequence may contain different units, so fall back to element-wise
+            return np.array(
+                [func(*func_args) for func_args in zip(*args)], dtype=object
+            )
+
         first_input_units = _get_first_input_units(args, kwargs)
         if input_units == "all_consistent":
             # Match all input args/kwargs to same units

pint/testsuite/test_issues.py

@@ -888,6 +888,26 @@ def test_issue_1300(self):
         m = module_registry.Measurement(1, 0.1, "meter")
         assert m.default_format == "~P"
 
+    @helpers.requires_numpy()
+    def test_issue1674(self, module_registry):
+        Q_ = module_registry.Quantity
+        arr_of_q = np.array([Q_(2, "m"), Q_(4, "m")], dtype="object")
+        q_arr = Q_(np.array([1, 2]), "m")
+
+        helpers.assert_quantity_equal(
+            arr_of_q * q_arr, np.array([Q_(2, "m^2"), Q_(8, "m^2")], dtype="object")
+        )
+        helpers.assert_quantity_equal(
+            arr_of_q / q_arr, np.array([Q_(2, ""), Q_(2, "")], dtype="object")
+        )
+
+        arr_of_q = np.array([Q_(2, "m"), Q_(4, "s")], dtype="object")
+        q_arr = Q_(np.array([1, 2]), "m")
+
+        helpers.assert_quantity_equal(
+            arr_of_q * q_arr, np.array([Q_(2, "m^2"), Q_(8, "m s")], dtype="object")
+        )
+
     @helpers.requires_babel()
     def test_issue_1400(self, sess_registry):
         q1 = 3.1 * sess_registry.W