codekingpro/portable-devtools

1import numpy as np
2from numpy.lib import array_utils
3from numpy.testing import assert_equal
4
5
6class TestByteBounds:
7    def test_byte_bounds(self):
8        # pointer difference matches size * itemsize
9        # due to contiguity
10        a = np.arange(12).reshape(3, 4)
11        low, high = array_utils.byte_bounds(a)
12        assert_equal(high - low, a.size * a.itemsize)
13
14    def test_unusual_order_positive_stride(self):
15        a = np.arange(12).reshape(3, 4)
16        b = a.T
17        low, high = array_utils.byte_bounds(b)
18        assert_equal(high - low, b.size * b.itemsize)
19
20    def test_unusual_order_negative_stride(self):
21        a = np.arange(12).reshape(3, 4)
22        b = a.T[::-1]
23        low, high = array_utils.byte_bounds(b)
24        assert_equal(high - low, b.size * b.itemsize)
25
26    def test_strided(self):
27        a = np.arange(12)
28        b = a[::2]
29        low, high = array_utils.byte_bounds(b)
30        # the largest pointer address is lost (even numbers only in the
31        # stride), and compensate addresses for striding by 2
32        assert_equal(high - low, b.size * 2 * b.itemsize - b.itemsize)
33