Prime number testing

[Rahul]

Hi.
Thanks for all the info from all people.
Sorry for posting incorrect code.
Change some lines.
import math
(instead of importing sqrt from math)

and these two also

sqrt=math.sqrt(x)
sqrt=sqrt+1

Some clarifications :

> Looking at this and assuming that 2**61 -1 is prime, you find that
> this will do (2**61-1) or about 2**60 divisions.  If you assume you
> can perform 10**9 divisions per sec, then this will take about 36
> years. That's why your function is slow.

I am diving upto square root.That is upto about 2**30 or around one
billion times.Assuming a modest speed of 0.1 million divisons per
second this should take 100000 secs or three hours.Though still slow.


I will look up knuth and also the links suggested.
Thanks for the illumination

Rahul