Subj : Re: sqrt algo
To   : comp.programming
From : Sc0rpi0
Date : Fri Jul 15 2005 11:58 pm

CBFalconer:

>>>> Here is an iterative one (from the ancient Egypt, I have been told):
>>>>
>>>> current_estimate = 0.5*(previous_estimate + number/previous_estimate)
>>>>
>>>> You'll have to terminate it when you are "close enough".  (It
>>>> converges quite quickly, the number itself may serve as the first
>>>> estimate.)
>>>
>>> In which case you might as well take 1.
>> 
>> I suspect you've misunderstood the relative precedence of + and /
>> in the above formula. :)
> 
> I don't think so.  You can plug either 'number' or '1' as
> 'previous_estimate' into the above formula, and you will get the
> same result for 'current_estimate'.

Not always same...
first_est=1 is better cause number can be 0 in sqrt() in this case ;P

first_est=1
cur_est=0.5*(1+0/1)

first_est=number:
cur_est=0.5*(0+0/0 ?)

-- 
Sc0rpi0
I hated going to weddings.
All the grandmas would poke me saying "You're next".
They stopped that when I started doing it to them at funerals.

.