On Jun 15, 8:52 pm, Peter Otten <[EMAIL PROTECTED]> wrote: > [EMAIL PROTECTED] wrote: > > I have a physical system set up in which a body is supposed to > > accelerate and to get very close to lightspeed, while never really > > attaining it. After approx. 680 seconds, Python gets stuck and tells > > me the object has passed lightspeed. I put the same equations in > > Mathematica, again I get the same mistake around 680 seconds. So I > > think, I have a problem with my model! Then I pump up the > > WorkingPrecision in Mathematica to about 10. I run the same equations > > again, and it works! At least for the first 10,000 seconds, the object > > does not pass lightspeed. > > That the values are possible doesn't mean that you can trust them. >
I do not understand this comment. > > I concluded that I need Python to work at a higher precision. > > How is WorkingPrecision defined? Python floats have about 16 significant > digits in base 10, so at first glance I would guess that you switched to > a /lower/ precision. > I don't know how WorkingPrecision is defined. However, I think it's not lower, it's higher. > But I've come to agree with Christian that it would be good to show your > model to a physics and/or numerical maths expert. Perhaps you can find a > way for the errors to cancel out rather than accumulate. I might try that. -- http://mail.python.org/mailman/listinfo/python-list
