On Sep 7, 3:47 pm, kj <no.em...@please.post> wrote: > Is there some standardized way (e.g. some "official" module of such > limit constants) to get the smallest positive float that Python > will regard as distinct from 0.0? > > TIA! > > kj
There's sys.float_info.min: >>> import sys >>> sys.float_info sys.float_info(max=1.7976931348623157e+308, max_exp=1024, max_10_exp=308, min=2.2250738585072014e-308, min_exp=-1021, min_10_exp=-307, dig=15, mant_dig=53, epsilon=2.2204460492503131e-16, radix=2, rounds=1) >>> sys.float_info.min 2.2250738585072014e-308 But that only gives you the smallest *normal* positive float, which is 2**-1022 on most systems. The smallest positive subnormal value is usually 2**-1074. If you want something that would still work if Python ever switched to using IEEE 754 binary128 format (or some other IEEE 754 format), then sys.float_info.min * 2**(1-sys.float_info.mant_dig) will work. But on 99.99%+ of systems you'll find Python running on, it's going to be 2**-1074. Mark -- http://mail.python.org/mailman/listinfo/python-list
