diff options
Diffstat (limited to 'numpy/core')
| -rw-r--r-- | numpy/core/code_generators/generate_umath.py | 6 | ||||
| -rw-r--r-- | numpy/core/code_generators/ufunc_docstrings.py | 64 | ||||
| -rw-r--r-- | numpy/core/tests/test_umath.py | 11 |
3 files changed, 80 insertions, 1 deletions
diff --git a/numpy/core/code_generators/generate_umath.py b/numpy/core/code_generators/generate_umath.py index 21dab54c5..c8bb557d3 100644 --- a/numpy/core/code_generators/generate_umath.py +++ b/numpy/core/code_generators/generate_umath.py @@ -370,6 +370,12 @@ defdict = { TD(inexact, f='pow', astype={'e':'f'}), TD(O, f='npy_ObjectPower'), ), +'float_power': + Ufunc(2, 1, None, + docstrings.get('numpy.core.umath.float_power'), + None, + TD('dgDG', f='pow'), + ), 'absolute': Ufunc(1, 1, None, docstrings.get('numpy.core.umath.absolute'), diff --git a/numpy/core/code_generators/ufunc_docstrings.py b/numpy/core/code_generators/ufunc_docstrings.py index 0d506102f..dd4cf1ea8 100644 --- a/numpy/core/code_generators/ufunc_docstrings.py +++ b/numpy/core/code_generators/ufunc_docstrings.py @@ -2543,7 +2543,8 @@ add_newdoc('numpy.core.umath', 'power', First array elements raised to powers from second array, element-wise. Raise each base in `x1` to the positionally-corresponding power in - `x2`. `x1` and `x2` must be broadcastable to the same shape. + `x2`. `x1` and `x2` must be broadcastable to the same shape. Note that an + integer type raised to a negative integer power will raise a ValueError. Parameters ---------- @@ -2557,6 +2558,10 @@ add_newdoc('numpy.core.umath', 'power', y : ndarray The bases in `x1` raised to the exponents in `x2`. + See Also + -------- + float_power : power function that promotes integers to float + Examples -------- Cube each element in a list. @@ -2585,6 +2590,63 @@ add_newdoc('numpy.core.umath', 'power', """) +add_newdoc('numpy.core.umath', 'float_power', + """ + First array elements raised to powers from second array, element-wise. + + Raise each base in `x1` to the positionally-corresponding power in `x2`. + `x1` and `x2` must be broadcastable to the same shape. This differs from + the power function in that integers, float16, and float32 are promoted to + floats with a minimum precision of float64 so that the result is always + inexact. The intent is that the function will return a usable result for + negative powers and seldom overflow for positive powers. + + .. versionadded:: 1.12.0 + + Parameters + ---------- + x1 : array_like + The bases. + x2 : array_like + The exponents. + + Returns + ------- + y : ndarray + The bases in `x1` raised to the exponents in `x2`. + + See Also + -------- + power : power function that preserves type + + Examples + -------- + Cube each element in a list. + + >>> x1 = range(6) + >>> x1 + [0, 1, 2, 3, 4, 5] + >>> np.float_power(x1, 3) + array([ 0., 1., 8., 27., 64., 125.]) + + Raise the bases to different exponents. + + >>> x2 = [1.0, 2.0, 3.0, 3.0, 2.0, 1.0] + >>> np.float_power(x1, x2) + array([ 0., 1., 8., 27., 16., 5.]) + + The effect of broadcasting. + + >>> x2 = np.array([[1, 2, 3, 3, 2, 1], [1, 2, 3, 3, 2, 1]]) + >>> x2 + array([[1, 2, 3, 3, 2, 1], + [1, 2, 3, 3, 2, 1]]) + >>> np.float_power(x1, x2) + array([[ 0., 1., 8., 27., 16., 5.], + [ 0., 1., 8., 27., 16., 5.]]) + + """) + add_newdoc('numpy.core.umath', 'radians', """ Convert angles from degrees to radians. diff --git a/numpy/core/tests/test_umath.py b/numpy/core/tests/test_umath.py index 4538c53ac..4c0243559 100644 --- a/numpy/core/tests/test_umath.py +++ b/numpy/core/tests/test_umath.py @@ -465,6 +465,17 @@ class TestPower(TestCase): assert_raises(ValueError, np.power, one, minusone) +class TestFloat_power(TestCase): + def test_type_conversion(self): + arg_type = '?bhilBHILefdgFDG' + res_type = 'ddddddddddddgDDG' + for dtin, dtout in zip(arg_type, res_type): + msg = "dtin: %s, dtout: %s" % (dtin, dtout) + arg = np.ones(1, dtype=dtin) + res = np.float_power(arg, arg) + assert_(res.dtype.name == np.dtype(dtout).name, msg) + + class TestLog2(TestCase): def test_log2_values(self): x = [1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024] |