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| author | Mark Dickinson <mdickinson@enthought.com> | 2011-03-12 11:12:52 (GMT) |
|---|---|---|
| committer | Mark Dickinson <mdickinson@enthought.com> | 2011-03-12 11:12:52 (GMT) |
| commit | 37a79fb75b8f6d1833caee16c777d07b9338938f (patch) | |
| tree | 5cb83acd730e2ac26c763ecf5d1928af5da172fc | |
| parent | abd4a0556142e971c22d23243bacd3f0ad6d2299 (diff) | |
| download | cpython-37a79fb75b8f6d1833caee16c777d07b9338938f.zip cpython-37a79fb75b8f6d1833caee16c777d07b9338938f.tar.gz cpython-37a79fb75b8f6d1833caee16c777d07b9338938f.tar.bz2 | |
Issue 11131: Fix sign of zero result on decimal.Decimal plus and minus operations in ROUND_FLOOR rounding mode.
| -rw-r--r-- | Lib/decimal.py | 19 | ||||
| -rw-r--r-- | Lib/test/decimaltestdata/extra.decTest | 70 | ||||
| -rw-r--r-- | Misc/NEWS | 3 |
3 files changed, 84 insertions, 8 deletions
diff --git a/Lib/decimal.py b/Lib/decimal.py index c61b549..5e53d8e 100644 --- a/Lib/decimal.py +++ b/Lib/decimal.py @@ -1040,14 +1040,16 @@ class Decimal(object): if ans: return ans - if not self: - # -Decimal('0') is Decimal('0'), not Decimal('-0') + if context is None: + context = getcontext() + + if not self and context.rounding != ROUND_FLOOR: + # -Decimal('0') is Decimal('0'), not Decimal('-0'), except + # in ROUND_FLOOR rounding mode. ans = self.copy_abs() else: ans = self.copy_negate() - if context is None: - context = getcontext() return ans._fix(context) def __pos__(self, context=None): @@ -1060,14 +1062,15 @@ class Decimal(object): if ans: return ans - if not self: - # + (-0) = 0 + if context is None: + context = getcontext() + + if not self and context.rounding != ROUND_FLOOR: + # + (-0) = 0, except in ROUND_FLOOR rounding mode. ans = self.copy_abs() else: ans = Decimal(self) - if context is None: - context = getcontext() return ans._fix(context) def __abs__(self, round=True, context=None): diff --git a/Lib/test/decimaltestdata/extra.decTest b/Lib/test/decimaltestdata/extra.decTest index fce8435..fe8b77a 100644 --- a/Lib/test/decimaltestdata/extra.decTest +++ b/Lib/test/decimaltestdata/extra.decTest @@ -2745,3 +2745,73 @@ pwmx437 power 17 1728 1729 -> 1 pwmx438 power 18 1728 1729 -> 1 pwmx439 power 19 1728 1729 -> 456 pwmx440 power 20 1728 1729 -> 1 + +-- plus and minus zero in various rounding modes (see issue 11131) +extended: 1 +precision: 9 +maxexponent: 384 +minexponent: -383 + +rounding: half_even +plux1000 plus 0.0 -> 0.0 +plux1001 plus -0.0 -> 0.0 +minx1000 minus 0.0 -> 0.0 +minx1001 minus -0.0 -> 0.0 +absx1000 abs 0.0 -> 0.0 +absx1001 abs -0.0 -> 0.0 + +rounding: half_up +plux1010 plus 0.0 -> 0.0 +minx1010 minus 0.0 -> 0.0 +plux1011 plus -0.0 -> 0.0 +minx1011 minus -0.0 -> 0.0 +absx1010 abs 0.0 -> 0.0 +absx1011 abs -0.0 -> 0.0 + +rounding: ceiling +plux1020 plus 0.0 -> 0.0 +minx1020 minus 0.0 -> 0.0 +plux1021 plus -0.0 -> 0.0 +minx1021 minus -0.0 -> 0.0 +absx1020 abs 0.0 -> 0.0 +absx1021 abs -0.0 -> 0.0 + +rounding: floor +plux1030 plus 0.0 -> 0.0 +minx1030 minus 0.0 -> -0.0 +plux1031 plus -0.0 -> -0.0 +minx1031 minus -0.0 -> 0.0 +absx1030 abs 0.0 -> 0.0 +absx1031 abs -0.0 -> 0.0 + +rounding: down +plux1040 plus 0.0 -> 0.0 +minx1040 minus 0.0 -> 0.0 +plux1041 plus -0.0 -> 0.0 +minx1041 minus -0.0 -> 0.0 +absx1040 abs 0.0 -> 0.0 +absx1041 abs -0.0 -> 0.0 + +rounding: up +plux1050 plus 0.0 -> 0.0 +minx1050 minus 0.0 -> 0.0 +plux1051 plus -0.0 -> 0.0 +minx1051 minus -0.0 -> 0.0 +absx1050 abs 0.0 -> 0.0 +absx1051 abs -0.0 -> 0.0 + +rounding: half_down +plux1060 plus 0.0 -> 0.0 +minx1060 minus 0.0 -> 0.0 +plux1061 plus -0.0 -> 0.0 +minx1061 minus -0.0 -> 0.0 +absx1060 abs 0.0 -> 0.0 +absx1061 abs -0.0 -> 0.0 + +rounding: 05up +plux1070 plus 0.0 -> 0.0 +minx1070 minus 0.0 -> 0.0 +plux1071 plus -0.0 -> 0.0 +minx1071 minus -0.0 -> 0.0 +absx1070 abs 0.0 -> 0.0 +absx1071 abs -0.0 -> 0.0 @@ -40,6 +40,9 @@ Core and Builtins Library ------- +- Issue #11131: Fix sign of zero in decimal.Decimal plus and minus + operations when the rounding mode is ROUND_FLOOR. + - Issue #5622: Fix curses.wrapper to raise correct exception if curses initialization fails. |