diff options
Diffstat (limited to 'numpy/lib/tests/test_stride_tricks.py')
| -rw-r--r-- | numpy/lib/tests/test_stride_tricks.py | 109 |
1 files changed, 107 insertions, 2 deletions
diff --git a/numpy/lib/tests/test_stride_tricks.py b/numpy/lib/tests/test_stride_tricks.py index 10d7a19ab..efec5d24d 100644 --- a/numpy/lib/tests/test_stride_tricks.py +++ b/numpy/lib/tests/test_stride_tricks.py @@ -6,8 +6,10 @@ from numpy.testing import ( ) from numpy.lib.stride_tricks import ( as_strided, broadcast_arrays, _broadcast_shape, broadcast_to, - broadcast_shapes, + broadcast_shapes, sliding_window_view, ) +import pytest + def assert_shapes_correct(input_shapes, expected_shape): # Broadcast a list of arrays with the given input shapes and check the @@ -394,6 +396,109 @@ def test_as_strided(): assert_equal(a.dtype, a_view.dtype) assert_array_equal([r] * 3, a_view) + +class TestSlidingWindowView: + def test_1d(self): + arr = np.arange(5) + arr_view = sliding_window_view(arr, 2) + expected = np.array([[0, 1], + [1, 2], + [2, 3], + [3, 4]]) + assert_array_equal(arr_view, expected) + + def test_2d(self): + i, j = np.ogrid[:3, :4] + arr = 10*i + j + shape = (2, 2) + arr_view = sliding_window_view(arr, shape) + expected = np.array([[[[0, 1], [10, 11]], + [[1, 2], [11, 12]], + [[2, 3], [12, 13]]], + [[[10, 11], [20, 21]], + [[11, 12], [21, 22]], + [[12, 13], [22, 23]]]]) + assert_array_equal(arr_view, expected) + + def test_2d_with_axis(self): + i, j = np.ogrid[:3, :4] + arr = 10*i + j + arr_view = sliding_window_view(arr, 3, 0) + expected = np.array([[[0, 10, 20], + [1, 11, 21], + [2, 12, 22], + [3, 13, 23]]]) + assert_array_equal(arr_view, expected) + + def test_2d_repeated_axis(self): + i, j = np.ogrid[:3, :4] + arr = 10*i + j + arr_view = sliding_window_view(arr, (2, 3), (1, 1)) + expected = np.array([[[[0, 1, 2], + [1, 2, 3]]], + [[[10, 11, 12], + [11, 12, 13]]], + [[[20, 21, 22], + [21, 22, 23]]]]) + assert_array_equal(arr_view, expected) + + def test_2d_without_axis(self): + i, j = np.ogrid[:4, :4] + arr = 10*i + j + shape = (2, 3) + arr_view = sliding_window_view(arr, shape) + expected = np.array([[[[0, 1, 2], [10, 11, 12]], + [[1, 2, 3], [11, 12, 13]]], + [[[10, 11, 12], [20, 21, 22]], + [[11, 12, 13], [21, 22, 23]]], + [[[20, 21, 22], [30, 31, 32]], + [[21, 22, 23], [31, 32, 33]]]]) + assert_array_equal(arr_view, expected) + + def test_errors(self): + i, j = np.ogrid[:4, :4] + arr = 10*i + j + with pytest.raises(ValueError, match='cannot contain negative values'): + sliding_window_view(arr, (-1, 3)) + with pytest.raises( + ValueError, + match='must provide window_shape for all dimensions of `x`'): + sliding_window_view(arr, (1,)) + with pytest.raises( + ValueError, + match='Must provide matching length window_shape and axis'): + sliding_window_view(arr, (1, 3, 4), axis=(0, 1)) + with pytest.raises( + ValueError, + match='window shape cannot be larger than input array'): + sliding_window_view(arr, (5, 5)) + + def test_writeable(self): + arr = np.arange(5) + view = sliding_window_view(arr, 2, writeable=False) + assert_(not view.flags.writeable) + with pytest.raises( + ValueError, + match='assignment destination is read-only'): + view[0, 0] = 3 + view = sliding_window_view(arr, 2, writeable=True) + assert_(view.flags.writeable) + view[0, 1] = 3 + assert_array_equal(arr, np.array([0, 3, 2, 3, 4])) + + def test_subok(self): + class MyArray(np.ndarray): + pass + + arr = np.arange(5).view(MyArray) + assert_(not isinstance(sliding_window_view(arr, 2, + subok=False), + MyArray)) + assert_(isinstance(sliding_window_view(arr, 2, subok=True), MyArray)) + # Default behavior + assert_(not isinstance(sliding_window_view(arr, 2), MyArray)) + + def as_strided_writeable(): arr = np.ones(10) view = as_strided(arr, writeable=False) @@ -496,7 +601,7 @@ def test_writeable(): # check: no warning emitted assert_equal(result.flags.writeable, True) result[:] = 0 - + # keep readonly input readonly original.flags.writeable = False _, result = broadcast_arrays(0, original) |