On Tue, 03 Jan 2017, Stephan Hoyer wrote:
> On Tue, Jan 3, 2017 at 9:00 AM, Yaroslav Halchenko <li...@onerussian.com>
> wrote:
> Sorry for coming too late to the discussion and after PR "addressing"
> the issue by issuing an error was merged [1].A I got burnt by new
> behavior while trying to build fresh pandas release on Debian (we are
> freezing for release way too soon ;) ) -- some pandas tests failed since
> they rely on previous non-erroring behavior and we gotA numpy 1.12.0~b1
> which included [1] in unstable/testing (candidate release) now.
> I quickly glanced over the discussion but I guess I have missed
> actual description of the problem being fixed here...A what was it??
> previous behavior, int**int->int made sense to me as it seemed to be
> consistent with casting Python's pow result to int, somewhat fulfilling
> desired promise for in-place operations and being inline with built-in
> pow results as far as I see it (up to casting).
> I believe this is exactly the behavior we preserved. Rather, we turned
> some cases that previously often gave wrong results (involving negative
> integer powers) into errors.
hm... testing on current master (first result is from python's pow)
$> python -c "import numpy; print('numpy version: ', numpy.__version__); a=2;
b=-2; print(pow(a,b)); print(pow(numpy.array(a), b))"
('numpy version: ', '1.13.0.dev0+02e2ea8')
0.25
Traceback (most recent call last):
File "<string>", line 1, in <module>
ValueError: Integers to negative integer powers are not allowed.
testing on Debian's packaged beta
$> python -c "import numpy; print('numpy version: ', numpy.__version__); a=2;
b=-2; print(pow(a,b)); print(pow(numpy.array(a), b))"
('numpy version: ', '1.12.0b1')
0.25
Traceback (most recent call last):
File "<string>", line 1, in <module>
ValueError: Integers to negative integer powers are not allowed.
testing on stable debian box with elderly numpy, where it does behave sensibly:
$> python -c "import numpy; print('numpy version: ', numpy.__version__); a=2;
b=-2; print(pow(a,b)); print(pow(numpy.array(a), b))"
('numpy version: ', '1.8.2')
0.25
0
what am I missing?
> The pandas test suite triggered this behavior, but not intentionally, and
> should be fixed in the next release:
> https://github.com/pandas-dev/pandas/pull/14498
I don't think that was the full set of cases, e.g.
(git)hopa/sid-i386:~exppsy/pandas[bf-i386]
$> nosetests -s -v
pandas/tests/test_expressions.py:TestExpressions.test_mixed_arithmetic_series
test_mixed_arithmetic_series (pandas.tests.test_expressions.TestExpressions)
... ERROR
======================================================================
ERROR: test_mixed_arithmetic_series
(pandas.tests.test_expressions.TestExpressions)
----------------------------------------------------------------------
Traceback (most recent call last):
File "/home/yoh/deb/gits/pkg-exppsy/pandas/pandas/tests/test_expressions.py",
line 223, in test_mixed_arithmetic_series
self.run_series(self.mixed2[col], self.mixed2[col], binary_comp=4)
File "/home/yoh/deb/gits/pkg-exppsy/pandas/pandas/tests/test_expressions.py",
line 164, in run_series
test_flex=False, **kwargs)
File "/home/yoh/deb/gits/pkg-exppsy/pandas/pandas/tests/test_expressions.py",
line 93, in run_arithmetic_test
expected = op(df, other)
File "/home/yoh/deb/gits/pkg-exppsy/pandas/pandas/core/ops.py", line 715, in
wrapper
result = wrap_results(safe_na_op(lvalues, rvalues))
File "/home/yoh/deb/gits/pkg-exppsy/pandas/pandas/core/ops.py", line 676, in
safe_na_op
return na_op(lvalues, rvalues)
File "/home/yoh/deb/gits/pkg-exppsy/pandas/pandas/core/ops.py", line 652, in
na_op
raise_on_error=True, **eval_kwargs)
File
"/home/yoh/deb/gits/pkg-exppsy/pandas/pandas/computation/expressions.py", line
210, in evaluate
**eval_kwargs)
File
"/home/yoh/deb/gits/pkg-exppsy/pandas/pandas/computation/expressions.py", line
63, in _evaluate_standard
return op(a, b)
ValueError: Integers to negative integer powers are not allowed.
and being paranoid, I have rebuilt exact current master of pandas with
master numpy in PYTHONPATH:
(git)hopa:~exppsy/pandas[master]git
$> PYTHONPATH=/home/yoh/proj/numpy nosetests -s -v
pandas/tests/test_expressions.py:TestExpressions.test_mixed_arithmetic_series
test_mixed_arithmetic_series (pandas.tests.test_expressions.TestExpressions)
... ERROR
======================================================================
ERROR: test_mixed_arithmetic_series
(pandas.tests.test_expressions.TestExpressions)
----------------------------------------------------------------------
Traceback (most recent call last):
File "/home/yoh/deb/gits/pkg-exppsy/pandas/pandas/tests/test_expressions.py",
line 223, in test_mixed_arithmetic_series
self.run_series(self.mixed2[col], self.mixed2[col], binary_comp=4)
File "/home/yoh/deb/gits/pkg-exppsy/pandas/pandas/tests/test_expressions.py",
line 164, in run_series
test_flex=False, **kwargs)
File "/home/yoh/deb/gits/pkg-exppsy/pandas/pandas/tests/test_expressions.py",
line 93, in run_arithmetic_test
expected = op(df, other)
File "/home/yoh/deb/gits/pkg-exppsy/pandas/pandas/core/ops.py", line 715, in
wrapper
result = wrap_results(safe_na_op(lvalues, rvalues))
File "/home/yoh/deb/gits/pkg-exppsy/pandas/pandas/core/ops.py", line 676, in
safe_na_op
return na_op(lvalues, rvalues)
File "/home/yoh/deb/gits/pkg-exppsy/pandas/pandas/core/ops.py", line 652, in
na_op
raise_on_error=True, **eval_kwargs)
File
"/home/yoh/deb/gits/pkg-exppsy/pandas/pandas/computation/expressions.py", line
210, in evaluate
**eval_kwargs)
File
"/home/yoh/deb/gits/pkg-exppsy/pandas/pandas/computation/expressions.py", line
63, in _evaluate_standard
return op(a, b)
ValueError: Integers to negative integer powers are not allowed.
----------------------------------------------------------------------
Ran 1 test in 0.015s
FAILED (errors=1)
$> git describe --tags
v0.19.0-303-gb957f6f
$> PYTHONPATH=/home/yoh/proj/numpy python -c "import numpy; print('numpy
version: ', numpy.__version__); a=2; b=-2; print(pow(a,b));
print(pow(numpy.array(a), b))"
('numpy version: ', '1.13.0.dev0+02e2ea8')
0.25
Traceback (most recent call last):
File "<string>", line 1, in <module>
ValueError: Integers to negative integer powers are not allowed.
--
Yaroslav O. Halchenko
Center for Open Neuroscience http://centerforopenneuroscience.org
Dartmouth College, 419 Moore Hall, Hinman Box 6207, Hanover, NH 03755
Phone: +1 (603) 646-9834 Fax: +1 (603) 646-1419
WWW: http://www.linkedin.com/in/yarik
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