It's possible we should back off to just issuing a deprecation warning in
1.12?
On Jan 3, 2017 1:47 PM, "Yaroslav Halchenko" <li...@onerussian.com> wrote:
>
> 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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