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[REF] float_utils: moved in its own python module 

bzr revid: odo@openerp.com-20111216160426-gya8d1d1zymcz8os
This commit is contained in:
Olivier Dony 2011-12-16 17:04:26 +01:00
parent 6add700d7a
commit 9ddd05fb3a
4 changed files with 114 additions and 93 deletions
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2
openerp/addons/base/res/res_currency.py
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@ -24,7 +24,7 @@ import netsvc
from osv import fields, osv
import tools
from tools.misc import currency, float_round, float_is_zero, float_compare
from tools import float_round, float_is_zero, float_compare
from tools.translate import _
CURRENCY_DISPLAY_PATTERN = re.compile(r'(\w+)\s*(?:\((.*)\))?')

1
openerp/tools/__init__.py
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@ -31,6 +31,7 @@ from amount_to_text_en import *
from pdf_utils import *
from yaml_import import *
from sql import *
from float_utils import *
#.apidoc title: Tools

112
openerp/tools/float_utils.py Normal file
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@ -0,0 +1,112 @@
# -*- coding: utf-8 -*-
##############################################################################
#
# OpenERP, Open Source Business Applications
# Copyright (c) 2011 OpenERP S.A. <http://openerp.com>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
#
##############################################################################
def _float_check_precision(precision_digits=None, precision_rounding=None):
assert (precision_digits is not None or precision_rounding is not None) and \
not (precision_digits and precision_rounding),\
"exactly one of precision_digits and precision_rounding must be specified"
if precision_digits is not None:
return 10 ** -precision_digits
return precision_rounding
def float_round(value, precision_digits=None, precision_rounding=None):
"""Return ``value`` rounded to ``precision_digits``
decimal digits, minimizing IEEE-754 floating point representation
errors.
Precision must be given by ``precision_digits`` or ``precision_rounding``,
not both!
To illustrate how this is different from the default round() builtin,
here is an example (depends on Python version, here is for v2.7.2 x64)::
>>> round_float(2.675)
2.68
>>> round(2.675,2)
2.67
:param float value: the value to round
:param int precision_digits: number of decimal digits to round to.
:param float precision_rounding: decimal number representing the minimum
non-zero value at the desired precision (for example, 0.01 for a
2-digit precision).
:return: rounded float
"""
rounding_factor = _float_check_precision(precision_digits=precision_digits,
precision_rounding=precision_rounding)
if rounding_factor == 0: return 0.0
# Then round to integer wrt. rounding factor
return round(value / rounding_factor) * rounding_factor
def float_is_zero(value, precision_digits=None, precision_rounding=None):
"""Returns true if ``value`` is small enough to be treated as
zero at the given precision.
Precision must be given by ``precision_digits`` or ``precision_rounding``,
not both!
Warning: ``float_is_zero(value1-value2)`` is not always equivalent to
``float_compare(value1,value2) == 0``, as the former will round after
computing the difference, while the latter will round before, giving
different results for e.g. 0.006 and 0.002 at 2 digits precision.
:param int precision_digits: number of decimal digits to round to.
:param float precision_rounding: decimal number representing the minimum
non-zero value at the desired precision (for example, 0.01 for a
2-digit precision).
:param float value: value to compare with currency's zero
:return: True if ``value`` is considered 0
"""
rounding_factor = _float_check_precision(precision_digits=precision_digits,
precision_rounding=precision_rounding)
return abs(float_round(value, precision_rounding=rounding_factor)) < rounding_factor
def float_compare(value1, value2, precision_digits=None, precision_rounding=None):
"""Compare ``value1`` and ``value2`` after rounding them according to the
given precision. A value is considered lower/greater than another value
if their rounded value is different. This is not the same as having a
non-zero difference!
For example 1.432 and 1.431 are equal at 2 digits precision,
so this method would return 0
However 0.006 and 0.002 are considered different (returns 1) because
they respectively round to 0.01 and 0.0, even though
0.006-0.002 = 0.004 which would be considered zero at 2 digits precision.
Precision must be given by ``precision_digits`` or ``precision_rounding``,
not both!
:param int precision_digits: number of decimal digits to round to.
:param float precision_rounding: decimal number representing the minimum
non-zero value at the desired precision (for example, 0.01 for a
2-digit precision).
:param float value1: first value to compare
:param float value2: second value to compare
:return: (resp.) -1, 0 or 1, if ``value1`` is (resp.) lower than,
equal to, or greater than ``value2``, at the given precision.
"""
rounding_factor = _float_check_precision(precision_digits=precision_digits,
precision_rounding=precision_rounding)
value1 = float_round(value1, precision_rounding=rounding_factor)
value2 = float_round(value2, precision_rounding=rounding_factor)
delta = value1 - value2
if float_is_zero(delta, precision_rounding=rounding_factor): return 0
return -1 if delta < 0.0 else 1

92
openerp/tools/misc.py
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@ -1200,96 +1200,4 @@ class UnquoteEvalContext(defaultdict):
def __missing__(self, key):
return unquote(key)
def _float_check_precision(precision_digits=None, precision_rounding=None):
assert (precision_digits is not None or precision_rounding is not None) and \
not (precision_digits and precision_rounding),\
"exactly one of precision_digits and precision_rounding must be specified"
if precision_digits is not None:
return 10 ** -precision_digits
return precision_rounding
def float_round(value, precision_digits=None, precision_rounding=None):
"""Return ``value`` rounded to ``precision_digits``
decimal digits, minimizing IEEE-754 floating point representation
errors.
Precision must be given by ``precision_digits`` or ``precision_rounding``,
not both!
To illustrate how this is different from the default round() builtin,
here is an example (depends on Python version, here is for v2.7.2 x64)::
>>> round_float(2.675)
2.68
>>> round(2.675,2)
2.67
:param float value: the value to round
:param int precision_digits: number of decimal digits to round to.
:param float precision_rounding: decimal number representing the minimum
non-zero value at the desired precision (for example, 0.01 for a
2-digit precision).
:return: rounded float
"""
rounding_factor = _float_check_precision(precision_digits=precision_digits,
precision_rounding=precision_rounding)
if rounding_factor == 0: return 0.0
# Then round to integer wrt. rounding factor
return round(value / rounding_factor) * rounding_factor
def float_is_zero(value, precision_digits=None, precision_rounding=None):
"""Returns true if ``value`` is small enough to be treated as
zero at the given precision.
Precision must be given by ``precision_digits`` or ``precision_rounding``,
not both!
Warning: ``float_is_zero(value1-value2)`` is not always equivalent to
``float_compare(value1,value2) == 0``, as the former will round after
computing the difference, while the latter will round before, giving
different results for e.g. 0.006 and 0.002 at 2 digits precision.
:param int precision_digits: number of decimal digits to round to.
:param float precision_rounding: decimal number representing the minimum
non-zero value at the desired precision (for example, 0.01 for a
2-digit precision).
:param float value: value to compare with currency's zero
:return: True if ``value`` is considered 0
"""
rounding_factor = _float_check_precision(precision_digits=precision_digits,
precision_rounding=precision_rounding)
return abs(float_round(value, precision_rounding=rounding_factor)) < rounding_factor
def float_compare(value1, value2, precision_digits=None, precision_rounding=None):
"""Compare ``value1`` and ``value2`` after rounding them according to the
given precision. A value is considered lower/greater than another value
if their rounded value is different. This is not the same as having a
non-zero difference!
For example 1.432 and 1.431 are equal at 2 digits precision,
so this method would return 0
However 0.006 and 0.002 are considered different (returns 1) because
they respectively round to 0.01 and 0.0, even though
0.006-0.002 = 0.004 which would be considered zero at 2 digits precision.
Precision must be given by ``precision_digits`` or ``precision_rounding``,
not both!
:param int precision_digits: number of decimal digits to round to.
:param float precision_rounding: decimal number representing the minimum
non-zero value at the desired precision (for example, 0.01 for a
2-digit precision).
:param float value1: first value to compare
:param float value2: second value to compare
:return: (resp.) -1, 0 or 1, if ``value1`` is (resp.) lower than,
equal to, or greater than ``value2``, at the given precision.
"""
rounding_factor = _float_check_precision(precision_digits=precision_digits,
precision_rounding=precision_rounding)
value1 = float_round(value1, precision_rounding=rounding_factor)
value2 = float_round(value2, precision_rounding=rounding_factor)
delta = value1 - value2
if float_is_zero(delta, precision_rounding=rounding_factor): return 0
return -1 if delta < 0.0 else 1
# vim:expandtab:smartindent:tabstop=4:softtabstop=4:shiftwidth=4: