27 Jul
2005
27 Jul
'05
5:01 a.m.
multi-precision libraries which can handle up to 128
bit integers?
I wanted to get thousands of digits of Pi once and implemented
it using up to 1500 bit precision integers (Yeah Rite).
For this simple program I just used arrays of integers and kept
shifting carry bits to the left or right, depending on whether I was
dividing or multiplying. I got about 500 digits of Pi at the time
(1976). Today we could probably get something like 5000 digits
in 5 seconds on a PC.
I encourage you to try this yourself.
For example an array of (1,0,0,0) divided by 3 would become (0,3,3,3),
minding carries. An array of (0,0,0,5) times 6 would be (0,0,3,0).
Using these two simple tools I was able to get hundreds of digits of Pi
in 2 pages of code.
John A.
Make magazine. Issue 3 on newstands now.