Question #260626 on Yade changed: https://answers.launchpad.net/yade/+question/260626
Bruno Chareyre proposed the following answer: @Jan The fact that two floats are converted to the same string with "print" does not imply that they are equal. Before printing a number, python is rounding and truncating. Real number representation is still a mystery to me, I know just enough to know that it is never as simple as one expects. For instance, this is not a bug: >>> x=0.1; y=0.2 >>> x+y 0.30000000000000004 >>> print x+y 0.3 This being said, your conclusion may be right (I'm still not 100% sure) even though the proof was flawn, since a variant of your script with "all" digits displayed gives this: 0.2017354310946590789654919717577286064624786376953125 0.2017354310946590789654919717577286064624786376953125 0.2017354310946590789654919717577286064624786376953125 0.2017354310946590789654919717577286064624786376953125 ___ import random; r=random.random from decimal import Decimal #see https://docs.python.org/2/tutorial/floatingpoint.html O.bodies.append(sphere((r(),r(),r()),1)) base = '/tmp/a.' for ext in 'yade','xml': print Decimal(O.bodies[0].state.pos[0]) O.save(base+ext) O.reset() O.load(base+ext) print Decimal(O.bodies[0].state.pos[0]) -- You received this question notification because you are a member of yade-users, which is an answer contact for Yade. _______________________________________________ Mailing list: https://launchpad.net/~yade-users Post to : [email protected] Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
