32 bit or 64 bit?

Phil Hobbs pcdhSpamMeSenseless at electrooptical.net
Tue Jun 17 14:13:40 CEST 2008


ram.rachum at gmail.com wrote:
> On Jun 15, 7:43 pm, Peter Otten <__pete... at web.de> wrote:
>> ram.rac... at gmail.com wrote:
>>> On Jun 15, 6:58 pm, Christian Meesters <meest... at uni-mainz.de> wrote:
>>>>> I do need speed. Is there an option?
>>>> Mind telling us what you *actually* want to achieve? (What do you want to
>>>> calculate?)
>>>> Christian
>>> Physical simulations of objects with near-lightspeed velocity.
>> How did you determine that standard python floats are not good enough?
> 
> 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.
> 
>> Everything beyond that is unlikely to be supported by the hardware and will
>> therefore introduce a speed penalty.
>>
> 
> I have thought of that as well. However I have no choice. I must do
> these calculations. If you know of any way that is supported by the
> hardware, it will be terrific, but for now the slower things will have
> to do.

You need to change your representation.  Try redoing the algebra using 
(c-v) as the independent variable, and calculate that.

Cheers,

Phil Hobbs



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