diff options
| -rw-r--r-- | numpy/core/src/umath/funcs.inc.src | 17 | ||||
| -rw-r--r-- | numpy/core/tests/test_umath.py | 25 |
2 files changed, 41 insertions, 1 deletions
diff --git a/numpy/core/src/umath/funcs.inc.src b/numpy/core/src/umath/funcs.inc.src index d8127322c..5dc58e990 100644 --- a/numpy/core/src/umath/funcs.inc.src +++ b/numpy/core/src/umath/funcs.inc.src @@ -238,7 +238,22 @@ nc_pow@c@(c@typ@ *a, c@typ@ *b, c@typ@ *r) return; } if (ar == 0. && ai == 0.) { - *r = npy_cpack@c@(0., 0.); + if (br > 0 && bi == 0) { + *r = npy_cpack@c@(0., 0.); + } + else { + /* NB: there are four complex zeros; c0 = (+-0, +-0), so that unlike + * for reals, c0**p, with `p` negative is in general + * ill-defined. + * + * c0**z with z complex is also ill-defined. + */ + *r = npy_cpack@c@(NPY_NAN, NPY_NAN); + + /* Raise invalid */ + ar = NPY_INFINITY; + ar = ar - ar; + } return; } if (bi == 0 && (n=(intp)br) == br) { diff --git a/numpy/core/tests/test_umath.py b/numpy/core/tests/test_umath.py index 2741287ec..2dace8c16 100644 --- a/numpy/core/tests/test_umath.py +++ b/numpy/core/tests/test_umath.py @@ -86,6 +86,31 @@ class TestPower(TestCase): finally: np.seterr(**err) + def test_power_zero(self): + # ticket #1271 + zero = np.array([0j]) + one = np.array([1+0j]) + cinf = np.array([complex(np.inf, 0)]) + cnan = np.array([complex(np.nan, np.nan)]) + + def assert_complex_equal(x, y): + x, y = np.asarray(x), np.asarray(y) + assert_array_equal(x.real, y.real) + assert_array_equal(x.imag, y.imag) + + # positive powers + for p in [0.33, 0.5, 1, 1.5, 2, 3, 4, 5, 6.6]: + assert_complex_equal(np.power(zero, p), zero) + + # zero power + assert_complex_equal(np.power(zero, 0), one) + assert_complex_equal(np.power(zero, 0+1j), cnan) + + # negative power + for p in [0.33, 0.5, 1, 1.5, 2, 3, 4, 5, 6.6]: + assert_complex_equal(np.power(zero, -p), cnan) + assert_complex_equal(np.power(zero, -1+0.2j), cnan) + class TestLog2(TestCase): def test_log2_values(self) : |