Christian Heimes wrote:
duncan smith wrote:
Hello,
I'm trying to find a clean and reliable way of uncovering
information about 'extremal' values for floats on versions of Python
earlier than 2.6 (just 2.5 actually). I don't want to add a dependence
on 3rd party modules just for this purpose. e.g. For the smallest
positive float I'm using,
import platform
if platform.architecture()[0].startswith('64'):
TINY = 2.2250738585072014e-308
else:
TINY = 1.1754943508222875e-38
where I've extracted the values for TINY from numpy in IDLE,
>>> float(numpy.finfo(numpy.float32).tiny)
1.1754943508222875e-38
>>> float(numpy.finfo(numpy.float64).tiny)
2.2250738585072014e-308
You are confusing a 32 / 64bit build with 32 / 64bit floats. Python's
float type is build upon C's double precision float type on both 32 and
64 bit builds. The simple precision 32bit float type isn't used. The
DBL_MIN and DBL_MAX values are equal on all platforms that have full
IEEE 754 float point support. The radix may be different, though.
Christian
OK, this is the sort of confusion I suspected. I wasn't thinking
straight. The precise issue is that I'm supplying a default value of
2.2250738585072014e-308 for a parameter (finishing temperature for a
simulated annealing algorithm) in an application. I develop on
Ubuntu64, but (I am told) it's too small a value when run on a Win32
server. I assume it's being interpreted as zero and raising an
exception. Thanks.
Duncan
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