Re: How do I do very big integer computing by Mathematica?
- To: mathgroup at smc.vnet.net
- Subject: [mg115406] Re: How do I do very big integer computing by Mathematica?
- From: Dana DeLouis <dana01 at me.com>
- Date: Mon, 10 Jan 2011 02:38:25 -0500 (EST)
On Jan 9, 2:19 am, a boy <avv... at gmail.com> wrote:
> I asked how to do very-big-integer computing. For example:
> Mod[2^2^64,1342352]
> It's pity, this code causes overflow!
> is there some funtions like this: StringMod["111...111","345=94]
Hi. If I understand correctly, you're looking for the PowerMod
Function.
Double Check Power is Right to Left
FullForm[a^b^c]
Power[a,Power[b,c]]
2^3^4 == 2^(3^4)
True
Mod[2^2^64, 1342352]
General::ovfl:Overflow occurred in computation. >>
Overflow[]
PowerMod[2, 2^64, 1342352]
963840
On your above =93String Version=94, here's a general idea.
Let's assume n is a large number.
n=123456789;
Break the number (or string) into 2 or more parts. ie.
{12345, 6789};
Do the first Mod:
Mod[12345,345]
270
Append the results to the next number:
Mod[2706789,345]
264
The results check using the original =93Large=94 number:
Mod[n,345]
264
= = = = = = =
Hope this Helps!
Dana DeLouis
Mathematica 8 on Mac Pro