diff options
Diffstat (limited to 'numpy/core')
| -rw-r--r-- | numpy/core/numeric.py | 10 | ||||
| -rw-r--r-- | numpy/core/tests/test_numeric.py | 12 |
2 files changed, 20 insertions, 2 deletions
diff --git a/numpy/core/numeric.py b/numpy/core/numeric.py index 066697f3e..d4d4045a0 100644 --- a/numpy/core/numeric.py +++ b/numpy/core/numeric.py @@ -2206,7 +2206,7 @@ def binary_repr(num, width=None): designated form. If the `width` value is insufficient, it will be ignored, and `num` will - be returned in binary(`num` > 0) or two's complement (`num` < 0) form + be returned in binary (`num` > 0) or two's complement (`num` < 0) form with its width equal to the minimum number of bits needed to represent the number in the designated form. This behavior is deprecated and will later raise an error. @@ -2276,10 +2276,16 @@ def binary_repr(num, width=None): else: poswidth = len(bin(-num)[2:]) - twocomp = 2**(poswidth + 1) + num + # See gh-8679: remove extra digit + # for numbers at boundaries. + if 2**(poswidth - 1) == -num: + poswidth -= 1 + + twocomp = 2**(poswidth + 1) + num binary = bin(twocomp)[2:] binwidth = len(binary) + outwidth = max(binwidth, width) warn_if_insufficient(width, binwidth) return '1' * (outwidth - binwidth) + binary diff --git a/numpy/core/tests/test_numeric.py b/numpy/core/tests/test_numeric.py index 906280e15..9f454e52e 100644 --- a/numpy/core/tests/test_numeric.py +++ b/numpy/core/tests/test_numeric.py @@ -1149,6 +1149,18 @@ class TestBinaryRepr(TestCase): assert_equal(np.binary_repr(10, width=7), '0001010') assert_equal(np.binary_repr(-5, width=7), '1111011') + def test_neg_width_boundaries(self): + # see gh-8670 + + # Ensure that the example in the issue does not + # break before proceeding to a more thorough test. + assert_equal(np.binary_repr(-128, width=8), '10000000') + + for width in range(1, 11): + num = -2**(width - 1) + exp = '1' + (width - 1) * '0' + assert_equal(np.binary_repr(num, width=width), exp) + class TestBaseRepr(TestCase): def test_base3(self): |