32 bit or 64 bit?

Peter Pearson ppearson at nowhere.invalid
Wed Jun 18 18:12:50 CEST 2008

On Tue, 17 Jun 2008 08:13:40 -0400, Phil Hobbs wrote:
> ram.rachum at gmail.com 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.
>> I concluded that I need Python to work at a higher precision.
> You need to change your representation.  Try redoing the algebra using 
> (c-v) as the independent variable, and calculate that.

Or represent the velocity as c*tanh(b), where b is the independent
variable.  If memory serves, this is the representation in which
constant acceleration corresponds to db/dt = constant.

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