[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 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. 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. Peter -- http://mail.python.org/mailman/listinfo/python-list
