diff options
| -rw-r--r-- | numpy/core/src/npysort/selection.c.src | 8 | ||||
| -rw-r--r-- | numpy/core/tests/test_multiarray.py | 11 |
2 files changed, 13 insertions, 6 deletions
diff --git a/numpy/core/src/npysort/selection.c.src b/numpy/core/src/npysort/selection.c.src index b11753367..073b5847f 100644 --- a/numpy/core/src/npysort/selection.c.src +++ b/numpy/core/src/npysort/selection.c.src @@ -176,12 +176,8 @@ static npy_intp @name@median5_@suff@( } } else { - if (@TYPE@_LT(v[IDX(2)], v[IDX(1)])) { - return 1; - } - else { - return 2; - } + /* v[1] and v[2] swapped into order above */ + return 2; } } diff --git a/numpy/core/tests/test_multiarray.py b/numpy/core/tests/test_multiarray.py index 77da5543d..ee773ef4a 100644 --- a/numpy/core/tests/test_multiarray.py +++ b/numpy/core/tests/test_multiarray.py @@ -1141,6 +1141,17 @@ class TestMethods(TestCase): assert_array_equal(d[np.argpartition(d, -6, kind=k)], np.partition(d, 41, kind=k)) + # median of 3 killer, O(n^2) on pure median 3 pivot quickselect + # exercises the median of median of 5 code used to keep O(n) + d = np.arange(1000000) + x = np.roll(d, d.size // 2) + mid = x.size // 2 + 1 + assert_equal(np.partition(x, mid)[mid], mid) + d = np.arange(1000001) + x = np.roll(d, d.size // 2 + 1) + mid = x.size // 2 + 1 + assert_equal(np.partition(x, mid)[mid], mid) + # equal elements d = np.arange((47)) % 7 tgt = np.sort(np.arange((47)) % 7) |