WIP: floordiv, mod, divmod #943

[westurner]

• Closes floordiv (and divmod, modulo, math.floor) raise DimensionalityError #943
• Executed black -t py36 . && isort -rc . && flake8 with no errors
• The change is fully covered by automated unit tests
• Documented in docs/ as appropriate
• Added an entry to the CHANGES file

...

This is surely the wrong way to do this:
The hasattr(obj, 'dimensionless') check is probably not correct?

IDK how to get math.floor to return a quantity. Modifying __float__ to return a non-Quantity float results in further errors.

Why is floordiv returning 10.0 in TestQuantityBasicMath.test_nparray?

@pytest.mark.parametrize might make it easier to identify the test failures by creating named test cases for each combination. There's probably a historical or a technical reason for the current approach?

This is already beyond my level of comprehension of the pint internal API. I'd be grateful for any help or "just move" https://stackoverflow.com/questions/14947789/github-clone-from-pull-request

[westurner]

The e.g. __divmod__ / __rdivmod__ variants could likely be solved with a decorator that swaps self and other and a proto-function?

[westurner]

Here's the output from `pytest ./test_quantity.py`:

$ pytest test_quantity.py 
==================================================================== test session starts =====================================================================
platform linux -- Python 3.6.8, pytest-5.3.0, py-1.8.0, pluggy-0.12.0
rootdir: /home/wturner/-wrk/-ce37/woodworking/src/pint
collected 436 items                                                                                                                                          

test_quantity.py .....................................FFF............................................................................................. [ 30%]
...................................................................................................................................................... [ 64%]
...................................................................................................................................................... [ 99%]
...                                                                                                                                                    [100%]

========================================================================== FAILURES ==========================================================================
______________________________________________________________ TestQuantityBasicMath.test_float ______________________________________________________________

self = <pint.testsuite.test_quantity.TestQuantityBasicMath testMethod=test_float>

    def test_float(self):
>       self._test_numeric(1.0, self._test_not_inplace)

test_quantity.py:798: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
test_quantity.py:794: in _test_numeric
    self._test_quantity_divmod()
test_quantity.py:785: in _test_quantity_divmod
    self._test_quantity_divmod_one("10*meter", 3)
test_quantity.py:752: in _test_quantity_divmod_one
    self.assertEqual(q, math.floor(q))
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <Quantity(3, 'meter')>

    def __float__(self):
        if self.dimensionless:
            return float(self._convert_magnitude_not_inplace(UnitsContainer()))
        # else: # ( for math.floor !? )
        #     return float(self._magnitude)
>       raise DimensionalityError(self._units, "dimensionless")
E       pint.errors.DimensionalityError: Cannot convert from 'meter' to 'dimensionless'

../quantity.py:669: DimensionalityError
____________________________________________________________ TestQuantityBasicMath.test_fraction _____________________________________________________________

self = <pint.testsuite.test_quantity.TestQuantityBasicMath testMethod=test_fraction>

    def test_fraction(self):
        import fractions
    
>       self._test_numeric(fractions.Fraction(1, 1), self._test_not_inplace)

test_quantity.py:803: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
test_quantity.py:794: in _test_numeric
    self._test_quantity_divmod()
test_quantity.py:785: in _test_quantity_divmod
    self._test_quantity_divmod_one("10*meter", 3)
test_quantity.py:752: in _test_quantity_divmod_one
    self.assertEqual(q, math.floor(q))
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <Quantity(3, 'meter')>

    def __float__(self):
        if self.dimensionless:
            return float(self._convert_magnitude_not_inplace(UnitsContainer()))
        # else: # ( for math.floor !? )
        #     return float(self._magnitude)
>       raise DimensionalityError(self._units, "dimensionless")
E       pint.errors.DimensionalityError: Cannot convert from 'meter' to 'dimensionless'

../quantity.py:669: DimensionalityError
_____________________________________________________________ TestQuantityBasicMath.test_nparray _____________________________________________________________

self = <pint.testsuite.test_quantity.TestQuantityBasicMath testMethod=test_nparray>

    @helpers.requires_numpy()
    def test_nparray(self):
>       self._test_numeric(np.ones((1, 3)), self._test_inplace)

test_quantity.py:807: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
test_quantity.py:792: in _test_numeric
    self._test_quantity_floordiv(unit, self._test_not_inplace)
test_quantity.py:725: in _test_quantity_floordiv
    func(op.ifloordiv, unit * 10, 3, 3 * unit, unit)
test_quantity.py:650: in _test_not_inplace
    self.assertQuantityAlmostEqual(value1, value1_cpy)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <pint.testsuite.test_quantity.TestQuantityBasicMath testMethod=test_nparray>, first = array([[3., 3., 3.]]), second = array([[10., 10., 10.]])
rtol = 1e-07, atol = 0, msg = 'Comparing array([[3., 3., 3.]]) and array([[10., 10., 10.]]). '

    def assertQuantityAlmostEqual(self, first, second, rtol=1e-07, atol=0, msg=None):
        if msg is None:
            msg = "Comparing %r and %r. " % (first, second)
    
        m1, m2 = self._get_comparable_magnitudes(first, second, msg)
    
        if isinstance(m1, ndarray) or isinstance(m2, ndarray):
>           np.testing.assert_allclose(m1, m2, rtol=rtol, atol=atol, err_msg=msg)
E           AssertionError: 
E           Not equal to tolerance rtol=1e-07, atol=0
E           Comparing array([[3., 3., 3.]]) and array([[10., 10., 10.]]). 
E           Mismatch: 100%
E           Max absolute difference: 7.
E           Max relative difference: 0.7
E            x: array([[3., 3., 3.]])
E            y: array([[10., 10., 10.]])

__init__.py:114: AssertionError
====================================================================== warnings summary ======================================================================
pint/testsuite/test_quantity.py::TestQuantity::test_convert_numpy
  /home/wturner/-wrk/-ce37/woodworking/src/pint/pint/quantity.py:200: BehaviorChangeWarning: The way Pint handles NumPy operations has changed with the
  implementation of NEP 18. Unimplemented NumPy operations will now fail instead of making
  assumptions about units. Some functions, eg concat, will now return Quanties with units, where
  they returned ndarrays previously. See https://github.com/hgrecco/pint/pull/905.
  
  To hide this warning, wrap your first creation of an array Quantity with
  warnings.catch_warnings(), like the following:
  
  import numpy as np
  import warnings
  from pint import Quantity
  
  with warnings.catch_warnings():
      warnings.simplefilter("ignore")
      Quantity([])
  
  To disable the new behavior, see
  https://www.numpy.org/neps/nep-0018-array-function-protocol.html#implementation
  
    warnings.warn(array_function_change_msg, BehaviorChangeWarning)

pint/testsuite/test_quantity.py::TestCompareZero::test_equal_zero_NP
pint/testsuite/test_quantity.py::TestCompareZero::test_equal_zero_NP
  /home/wturner/-wrk/-ce37/woodworking/src/pint/pint/compat.py:143: DeprecationWarning: elementwise comparison failed; this will raise an error in the future.
    out = first == second

-- Docs: https://docs.pytest.org/en/latest/warnings.html
========================================================= 3 failed, 433 passed, 3 warnings in 5.58s ==========================================================
#  pytest test_quantity.py 

[jthielen]

@westurner Now that #954 is merged, @pytest.mark.parametrize should be available to use here.

[westurner]

• Merge in __ceil__ and __floor__ from @eevleevs
  https://github.com/westurner/pint/pull/1/files

[hgrecco]

@westurner Any chance of getting this fixed in the upcoming days? It would be great to include this in 0.10

[westurner]

I am away from the computer for the next day. Please feel free to pull and modify. The previous questions in the PR and, I'm not sure that the hasattr() check approach is correct, and the `__r*__` methods could probably just swap arguments and call the same @classmethod / @staticmethod?

…

On Mon, Dec 30, 2019, 5:03 PM Hernan Grecco ***@***.***> wrote: @westurner <https://github.com/westurner> Any chance of getting this fixed in the upcoming days? It would be great to include this in 0.10 — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#946?email_source=notifications&email_token=AAAMNS5YPQWWU6PCLDRTTX3Q3J45VA5CNFSM4J6HV4PKYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOEH3MU3Y#issuecomment-569821807>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAAMNS5H277VEQE45L764ZDQ3J45VANCNFSM4J6HV4PA> .

[tecki]

Please do not merge this PR. I is wrong, as I commented at the corresponding issue.

[jules-ch]

Closing