Jul 9, 2013 · Jul 9, 2013 · Jul 8, 2013 · Jul 8, 2013
diff --git a/doc/release/1.8.0-notes.rst b/doc/release/1.8.0-notes.rst

 Large NPZ files >2GB can be loaded on 64-bit systems.

 Binary operations with non-arrays as second argument
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

 Binary operations of the form ``<array-or-subclass> * <non-array-subclass>``
 where ``<non-array-subclass>`` declares an ``__array_priority__`` higher than
 that of ``<array-or-subclass>`` will now unconditionally return
 *NotImplemented*, giving ``<non-array-subclass>`` a chance to handle the
 operation.  Previously, `NotImplemented` would only be returned if
 ``<non-array-subclass>`` actually implemented the reversed operation, and after
 a (potentially expensive) array conversion of ``<non-array-subclass>`` had been
 attempted. (`bug <https://github.com/numpy/numpy/issues/3375>`_, `pull request
 <https://github.com/numpy/numpy/pull/3501>`_)


 New Features
 ============
diff --git a/numpy/core/src/multiarray/number.c b/numpy/core/src/multiarray/number.c
        Py_INCREF(Py_NotImplemented);
        return Py_NotImplemented;
    }

    if (!PyArray_Check(m2)) {
          /*
           * Catch priority inversion and punt, but only if it's guaranteed
           * that we were called through m1 and the other guy is not an array
           * at all. Note that some arrays need to pass through here even
           * with priorities inverted, for example: float(17) * np.matrix(...)
           *
           * See also:
           * - https://github.com/numpy/numpy/issues/3502
           * - https://github.com/numpy/numpy/issues/3503
           */
          double m1_prio = PyArray_GetPriority(m1, NPY_SCALAR_PRIORITY);
          double m2_prio = PyArray_GetPriority(m2, NPY_SCALAR_PRIORITY);
          if (m1_prio < m2_prio) {
              Py_INCREF(Py_NotImplemented);
              return Py_NotImplemented;
          }
    }

    return PyObject_CallFunction(op, "OO", m1, m2);
 }

diff --git a/numpy/core/tests/test_ufunc.py b/numpy/core/tests/test_ufunc.py
            dtype=rational);
        assert_equal(result, expected);

    def test_custom_array_like(self):
        class MyThing(object):
            __array_priority__ = 1000

            rmul_count = 0
            getitem_count = 0

            def __init__(self, shape):
                self.shape = shape

            def __len__(self):
                return self.shape[0]

            def __getitem__(self, i):
                MyThing.getitem_count += 1
                if not isinstance(i, tuple):
                    i = (i,)
                if len(i) > len(self.shape):
                    raise IndexError("boo")

                return MyThing(self.shape[len(i):])

            def __rmul__(self, other):
                MyThing.rmul_count += 1
                return self

        np.float64(5)*MyThing((3, 3))
        assert_(MyThing.rmul_count == 1, MyThing.rmul_count)
        assert_(MyThing.getitem_count <= 2, MyThing.getitem_count)

 if __name__ == "__main__":
    run_module_suite()
Original file line number	Diff line number	Diff line change
Expand Up		@@ -85,6 +85,19 @@ IO compatibility with large files

		Large NPZ files >2GB can be loaded on 64-bit systems.

		Binary operations with non-arrays as second argument
		~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

		Binary operations of the form ``<array-or-subclass> * <non-array-subclass>``
		where ``<non-array-subclass>`` declares an ``__array_priority__`` higher than
		that of ``<array-or-subclass>`` will now unconditionally return
		NotImplemented, giving ``<non-array-subclass>`` a chance to handle the
		operation. Previously, `NotImplemented` would only be returned if
		``<non-array-subclass>`` actually implemented the reversed operation, and after
		a (potentially expensive) array conversion of ``<non-array-subclass>`` had been
		attempted. (`bug <https://github.com/numpy/numpy/issues/3375>`_, `pull request
		<https://github.com/numpy/numpy/pull/3501>`_)


		New Features
		============
Expand Down
Original file line number	Diff line number	Diff line change
Expand Up		@@ -209,6 +209,26 @@ PyArray_GenericBinaryFunction(PyArrayObject m1, PyObject m2, PyObject *op)
		Py_INCREF(Py_NotImplemented);
		return Py_NotImplemented;
		}

		if (!PyArray_Check(m2)) {
		/*
		* Catch priority inversion and punt, but only if it's guaranteed
		* that we were called through m1 and the other guy is not an array
		* at all. Note that some arrays need to pass through here even
		* with priorities inverted, for example: float(17) * np.matrix(...)
Copy link Member njsmithJul 8, 2013 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. `float(17)` isn't an array so I guess there's a mistake in the comment? Copy link ContributorAuthor inducerJul 8, 2013 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. Nope, that's correct.`float(17) * np.matrix(...)` first ends up in`np.matrix.__rmul__`, which calls`np.dot`, which calls`PyArray_MatrixProduct2`, which casts`float(17)` into an array scalar an then calls this place. :)
		*
		* See also:
		* - https://github.com/numpy/numpy/issues/3502
		* - https://github.com/numpy/numpy/issues/3503
		*/
		double m1_prio = PyArray_GetPriority(m1, NPY_SCALAR_PRIORITY);
		double m2_prio = PyArray_GetPriority(m2, NPY_SCALAR_PRIORITY);
		if (m1_prio < m2_prio) {
		Py_INCREF(Py_NotImplemented);
		return Py_NotImplemented;
		}
		}

		return PyObject_CallFunction(op, "OO", m1, m2);
		}

Expand Down
Original file line number	Diff line number	Diff line change
Expand Up		@@ -834,5 +834,35 @@ def test_custom_ufunc(self):
		dtype=rational);
		assert_equal(result, expected);

		def test_custom_array_like(self):
		class MyThing(object):
		__array_priority__ = 1000

		rmul_count = 0
		getitem_count = 0

		def __init__(self, shape):
		self.shape = shape

		def __len__(self):
		return self.shape[0]

		def __getitem__(self, i):
		MyThing.getitem_count += 1
		if not isinstance(i, tuple):
		i = (i,)
		if len(i) > len(self.shape):
		raise IndexError("boo")

		return MyThing(self.shape[len(i):])

		def __rmul__(self, other):
		MyThing.rmul_count += 1
		return self

		np.float64(5)*MyThing((3, 3))
		assert_(MyThing.rmul_count == 1, MyThing.rmul_count)
		assert_(MyThing.getitem_count <= 2, MyThing.getitem_count)

		if __name__ == "__main__":
		run_module_suite()