Message127986
Hi,
to_integral() should behave like quantize() for negative exponents:
"Otherwise (the operand has a negative exponent) the result is the
same as using the quantize operation using the given operand as the
left-hand-operand, 1E+0 as the right-hand-operand, and the precision
of the operand as the precision setting. The rounding mode is taken
from the context, as usual."
There are some corner cases where this matters:
>>> from decimal import *
>>> c = Context(prec=1, Emin=-1, Emax=1, traps=[])
>>> d = Context(prec=4, Emin=-1, Emax=1, traps=[])
>>>
>>> c.to_integral(Decimal("999.9"))
Decimal('1000')
>>> d.quantize(Decimal("999.9"), Decimal("1e0"))
Decimal('NaN')
Indeed, decNumber returns NaN for to_integral(). This is an odd
situation, since for the result it is possible to exceed the
precision but not Emax:
>>> c = Context(prec=3, Emin=-3, Emax=3, traps=[])
>>> d = Context(prec=4, Emin=-3, Emax=3, traps=[])
>>> c.to_integral(Decimal("999.9"))
Decimal('1000')
>>> d.quantize(Decimal("999.9"), Decimal("1e0"))
Decimal('1000')
The specification is on the side of decNumber, but I wonder if this is
an oversight. |
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Date |
User |
Action |
Args |
2011-02-05 13:06:49 | skrah | set | recipients:
+ skrah, mark.dickinson |
2011-02-05 13:06:49 | skrah | set | messageid: <1296911209.51.0.925327858699.issue11128@psf.upfronthosting.co.za> |
2011-02-05 13:06:48 | skrah | link | issue11128 messages |
2011-02-05 13:06:48 | skrah | create | |
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