Re: Handling calculations with many decimal places
Re: Handling calculations with many decimal places
- Subject: Re: Handling calculations with many decimal places
- From: Graham Cox <email@hidden>
- Date: Wed, 4 Nov 2009 01:29:17 +1100
On 04/11/2009, at 1:18 AM, Ian Piper wrote:
I am writing an implementation of the Brent-Salamin algorithm for
calculating pi. I want to be able to display potentially a large
number of decimal places in the result (hundreds at least). However
I am finding that even using long double values in my calculation
gives me only the first 50 or so decimal places. Is this a
limitation of long double that I am running into here?
Yes, remarkably enough, something of finite size has limits on its
precision.
Should I be using NSDecimal instead to do this kind of calculation?
If so, can anyone point me at a good example of its use as I am
struggling with how to use it?
NSDecimal may help, but it's also of finite size, so it won't help
trying to print out the digits of pi to arbitrary precision, since pi
is infinitely long. Algorithms to print the digits of pi usually emit
the digits one at a time, so they are not storing the whole value as a
single number. You'll probably need to resort to this sort of approach
if you're just trying to calculate pi. To use the resulting value of
pi in a calculation is going to be very difficult, and probably serves
no practical purpose.
--Graham
_______________________________________________
Cocoa-dev mailing list (email@hidden)
Please do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden