diff options
| -rw-r--r-- | numpy/lib/arraypad.py | 84 | ||||
| -rw-r--r-- | numpy/lib/tests/test_arraypad.py | 33 |
2 files changed, 41 insertions, 76 deletions
diff --git a/numpy/lib/arraypad.py b/numpy/lib/arraypad.py index 62330e692..33e64708d 100644 --- a/numpy/lib/arraypad.py +++ b/numpy/lib/arraypad.py @@ -17,66 +17,6 @@ __all__ = ['pad'] # Private utility functions. -def _linear_ramp(ndim, axis, start, stop, size, reverse=False): - """ - Create a linear ramp of `size` in `axis` with `ndim`. - - This algorithm behaves like a vectorized version of `numpy.linspace`. - The resulting linear ramp is broadcastable to any array that matches the - ramp in `shape[axis]` and `ndim`. - - Parameters - ---------- - ndim : int - Number of dimensions of the resulting array. All dimensions except - the one specified by `axis` will have the size 1. - axis : int - The dimension that contains the linear ramp of `size`. - start : int or ndarray - The starting value(s) of the linear ramp. If given as an array, its - size must match `size`. - stop : int or ndarray - The stop value(s) (not included!) of the linear ramp. If given as an - array, its size must match `size`. - size : int - The number of elements in the linear ramp. If this argument is 0 the - dimensions of `ramp` will all be of length 1 except for the one given - by `axis` which will be 0. - reverse : bool - If False, increment in a positive fashion, otherwise decrement. - - Returns - ------- - ramp : ndarray - Output array of dtype np.float64 that in- or decrements along the given - `axis`. - - Examples - -------- - >>> _linear_ramp(ndim=2, axis=0, start=np.arange(3), stop=10, size=2) - array([[0. , 1. , 2. ], - [5. , 5.5, 6. ]]) - >>> _linear_ramp(ndim=3, axis=0, start=2, stop=0, size=0) - array([], shape=(0, 1, 1), dtype=float64) - """ - # Create initial ramp - ramp = np.arange(size, dtype=np.float64) - if reverse: - ramp = ramp[::-1] - - # Make sure, that ramp is broadcastable - init_shape = (1,) * axis + (size,) + (1,) * (ndim - axis - 1) - ramp = ramp.reshape(init_shape) - - if size != 0: - # And scale to given start and stop values - gain = (stop - start) / float(size) - ramp = ramp * gain - ramp += start - - return ramp - - def _round_if_needed(arr, dtype): """ Rounds arr inplace if destination dtype is integer. @@ -269,17 +209,25 @@ def _get_linear_ramps(padded, axis, width_pair, end_value_pair): """ edge_pair = _get_edges(padded, axis, width_pair) - left_ramp = _linear_ramp( - padded.ndim, axis, start=end_value_pair[0], stop=edge_pair[0], - size=width_pair[0], reverse=False + left_ramp = np.linspace( + start=end_value_pair[0], + stop=edge_pair[0].squeeze(axis), # Dimensions is replaced by linspace + num=width_pair[0], + endpoint=False, + dtype=padded.dtype, + axis=axis, ) - _round_if_needed(left_ramp, padded.dtype) - right_ramp = _linear_ramp( - padded.ndim, axis, start=end_value_pair[1], stop=edge_pair[1], - size=width_pair[1], reverse=True + right_ramp = np.linspace( + start=end_value_pair[1], + stop=edge_pair[1].squeeze(axis), # Dimension is replaced by linspace + num=width_pair[1], + endpoint=False, + dtype=padded.dtype, + axis=axis, ) - _round_if_needed(right_ramp, padded.dtype) + # Reverse linear space in appropriate dimension + right_ramp = right_ramp[_slice_at_axis(slice(None, None, -1), axis)] return left_ramp, right_ramp diff --git a/numpy/lib/tests/test_arraypad.py b/numpy/lib/tests/test_arraypad.py index b6dd3b31c..65593dd29 100644 --- a/numpy/lib/tests/test_arraypad.py +++ b/numpy/lib/tests/test_arraypad.py @@ -2,7 +2,6 @@ """ from __future__ import division, absolute_import, print_function -from itertools import chain import pytest @@ -11,6 +10,12 @@ from numpy.testing import assert_array_equal, assert_allclose, assert_equal from numpy.lib.arraypad import _as_pairs +_numeric_dtypes = ( + np.sctypes["uint"] + + np.sctypes["int"] + + np.sctypes["float"] + + np.sctypes["complex"] +) _all_modes = { 'constant': {'constant_values': 0}, 'edge': {}, @@ -738,6 +743,24 @@ class TestLinearRamp(object): assert_equal(a[0, :], 0.) assert_equal(a[-1, :], 0.) + @pytest.mark.parametrize("dtype", _numeric_dtypes) + def test_negative_difference(self, dtype): + """ + Check correct behavior of unsigned dtypes if there is a negative + difference between the edge to pad and `end_values`. Check both cases + to be independent of implementation. Test behavior for all other dtypes + in case dtype casting interferes with complex dtypes. See gh-14191. + """ + x = np.array([3], dtype=dtype) + result = np.pad(x, 3, mode="linear_ramp", end_values=0) + expected = np.array([0, 1, 2, 3, 2, 1, 0], dtype=dtype) + assert_equal(result, expected) + + x = np.array([0], dtype=dtype) + result = np.pad(x, 3, mode="linear_ramp", end_values=3) + expected = np.array([3, 2, 1, 0, 1, 2, 3], dtype=dtype) + assert_equal(result, expected) + class TestReflect(object): def test_check_simple(self): @@ -1330,13 +1353,7 @@ def test_memory_layout_persistence(mode): assert np.pad(x, 5, mode).flags["F_CONTIGUOUS"] -@pytest.mark.parametrize("dtype", chain( - # Skip "other" dtypes as they are not supported by all modes - np.sctypes["int"], - np.sctypes["uint"], - np.sctypes["float"], - np.sctypes["complex"] -)) +@pytest.mark.parametrize("dtype", _numeric_dtypes) @pytest.mark.parametrize("mode", _all_modes.keys()) def test_dtype_persistence(dtype, mode): arr = np.zeros((3, 2, 1), dtype=dtype) |