[FIX] product,float_utils: perform ceiling via float_round with new rounding_method UP
Modified product ceiling() to use float_round() with special mode for rounding UP (away from zero), avoiding pathological cases where float representations errors were ceiling to the superior unit. Also added correspding tests for rounding_method=UP Fixes issue #1125, and replaces PR #1126.
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@ -20,9 +20,6 @@
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##############################################################################
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##############################################################################
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from openerp import tools
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from openerp import tools
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import math
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def rounding(f, r):
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def rounding(f, r):
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# TODO for trunk: log deprecation warning
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# TODO for trunk: log deprecation warning
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# _logger.warning("Deprecated rounding method, please use tools.float_round to round floats.")
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# _logger.warning("Deprecated rounding method, please use tools.float_round to round floats.")
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@ -32,4 +29,4 @@ def rounding(f, r):
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def ceiling(f, r):
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def ceiling(f, r):
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if not r:
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if not r:
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return f
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return f
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return math.ceil(f / r) * r
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return tools.float_round(f, precision_rounding=r, rounding_method='UP')
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@ -198,8 +198,8 @@
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-
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-
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!python {model: res.currency}: |
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!python {model: res.currency}: |
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from tools import float_compare, float_is_zero, float_round, float_repr
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from tools import float_compare, float_is_zero, float_round, float_repr
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def try_round(amount, expected, precision_digits=3, float_round=float_round, float_repr=float_repr):
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def try_round(amount, expected, precision_digits=3, float_round=float_round, float_repr=float_repr, rounding_method='HALF-UP'):
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result = float_repr(float_round(amount, precision_digits=precision_digits),
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result = float_repr(float_round(amount, precision_digits=precision_digits, rounding_method=rounding_method),
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precision_digits=precision_digits)
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precision_digits=precision_digits)
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assert result == expected, 'Rounding error: got %s, expected %s' % (result, expected)
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assert result == expected, 'Rounding error: got %s, expected %s' % (result, expected)
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try_round(2.6745, '2.675')
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try_round(2.6745, '2.675')
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@ -213,6 +213,15 @@
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try_round(457.4554, '457.455')
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try_round(457.4554, '457.455')
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try_round(-457.4554, '-457.455')
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try_round(-457.4554, '-457.455')
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# Try some rounding value with rounding method UP instead of HALF-UP
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# We use 8.175 because when normalizing 8.175 with precision_digits=3 it gives
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# us 8175,0000000001234 as value, and if not handle correctly the rounding UP
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# value will be incorrect (should be 8,175 and not 8,176)
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try_round(8.175, '8.175', rounding_method='UP')
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try_round(8.1751, '8.176', rounding_method='UP')
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try_round(-8.175, '-8.175', rounding_method='UP')
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try_round(-8.1751, '-8.175', rounding_method='UP')
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# Extended float range test, inspired by Cloves Almeida's test on bug #882036.
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# Extended float range test, inspired by Cloves Almeida's test on bug #882036.
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fractions = [.0, .015, .01499, .675, .67499, .4555, .4555, .45555]
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fractions = [.0, .015, .01499, .675, .67499, .4555, .4555, .45555]
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expecteds = ['.00', '.02', '.01', '.68', '.67', '.46', '.456', '.4556']
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expecteds = ['.00', '.02', '.01', '.68', '.67', '.46', '.456', '.4556']
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@ -29,10 +29,11 @@ def _float_check_precision(precision_digits=None, precision_rounding=None):
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return 10 ** -precision_digits
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return 10 ** -precision_digits
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return precision_rounding
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return precision_rounding
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def float_round(value, precision_digits=None, precision_rounding=None):
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def float_round(value, precision_digits=None, precision_rounding=None, rounding_method='HALF-UP'):
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"""Return ``value`` rounded to ``precision_digits``
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"""Return ``value`` rounded to ``precision_digits`` decimal digits,
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decimal digits, minimizing IEEE-754 floating point representation
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minimizing IEEE-754 floating point representation errors, and applying
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errors, and applying HALF-UP (away from zero) tie-breaking rule.
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the tie-breaking rule selected with ``rounding_method``, by default
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HALF-UP (away from zero).
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Precision must be given by ``precision_digits`` or ``precision_rounding``,
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Precision must be given by ``precision_digits`` or ``precision_rounding``,
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not both!
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not both!
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@ -41,6 +42,9 @@ def float_round(value, precision_digits=None, precision_rounding=None):
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:param float precision_rounding: decimal number representing the minimum
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:param float precision_rounding: decimal number representing the minimum
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non-zero value at the desired precision (for example, 0.01 for a
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non-zero value at the desired precision (for example, 0.01 for a
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2-digit precision).
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2-digit precision).
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:param rounding_method: the rounding method used: 'HALF-UP' or 'UP', the first
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one rounding up to the closest number with the rule that number>=0.5 is
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rounded up to 1, and the latest one always rounding up.
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:return: rounded float
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:return: rounded float
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"""
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"""
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rounding_factor = _float_check_precision(precision_digits=precision_digits,
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rounding_factor = _float_check_precision(precision_digits=precision_digits,
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@ -52,7 +56,7 @@ def float_round(value, precision_digits=None, precision_rounding=None):
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# we normalize the value before rounding it as an integer, and de-normalize
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# we normalize the value before rounding it as an integer, and de-normalize
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# after rounding: e.g. float_round(1.3, precision_rounding=.5) == 1.5
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# after rounding: e.g. float_round(1.3, precision_rounding=.5) == 1.5
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# TIE-BREAKING: HALF-UP
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# TIE-BREAKING: HALF-UP (for normal rounding)
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# We want to apply HALF-UP tie-breaking rules, i.e. 0.5 rounds away from 0.
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# We want to apply HALF-UP tie-breaking rules, i.e. 0.5 rounds away from 0.
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# Due to IEE754 float/double representation limits, the approximation of the
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# Due to IEE754 float/double representation limits, the approximation of the
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# real value may be slightly below the tie limit, resulting in an error of
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# real value may be slightly below the tie limit, resulting in an error of
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@ -66,8 +70,19 @@ def float_round(value, precision_digits=None, precision_rounding=None):
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normalized_value = value / rounding_factor # normalize
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normalized_value = value / rounding_factor # normalize
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epsilon_magnitude = math.log(abs(normalized_value), 2)
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epsilon_magnitude = math.log(abs(normalized_value), 2)
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epsilon = 2**(epsilon_magnitude-53)
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epsilon = 2**(epsilon_magnitude-53)
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normalized_value += cmp(normalized_value,0) * epsilon
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if rounding_method == 'HALF-UP':
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rounded_value = round(normalized_value) # round to integer
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normalized_value += cmp(normalized_value,0) * epsilon
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rounded_value = round(normalized_value) # round to integer
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# TIE-BREAKING: UP (for ceiling operations)
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# When rounding the value up, we instead subtract the epsilon value
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# as the the approximation of the real value may be slightly *above* the
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# tie limit, this would result in incorrectly rounding up to the next number
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elif rounding_method == 'UP':
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normalized_value -= cmp(normalized_value,0) * epsilon
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rounded_value = math.ceil(normalized_value) # ceil to integer
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result = rounded_value * rounding_factor # de-normalize
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result = rounded_value * rounding_factor # de-normalize
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return result
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return result
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