Large number division

science_man_88 · 2022-07-20, 20:31

Code:

div(n,x)=if(n<=10^znorder(Mod(10,x)),return(n),return(n%(10^znorder(Mod(10,x)))+div(floor(n/(10^znorder(Mod(10,x)))),x)))

paulunderwood · 2022-07-20, 20:46

Quote:

Originally Posted by science_man_88

Code:

div(n,x)=if(n<=10^znorder(Mod(10,x)),return(n),return(n%(10^znorder(Mod(10,x)))+div(floor(n/(10^znorder(Mod(10,x)))),x)))

WB sm88.

I never know if to use my or local, but your code can be made better by:

Code:

div(n,x)=local(tz=10^znorder(Mod(10,x)));if(n<=tz,return(n),return(n%tz+div(floor(n/tz),x)))

I think znorder requires factorisation,

science_man_88 · 2022-07-20, 20:54

Quote:

Originally Posted by paulunderwood

WB sm88.

I never know if to use my or local, but your code can be made better by:

Code:

div(n,x)=local(tz=10^znorder(Mod(10,x)));if(n<=tz,return(n),return(n%tz+div(floor(n/tz),x)))

I think znorder requires factorisation,

Probably but x is prime in that use case no factorization overlap.

2022-07-20, 20:31	#1
science_man_88 "Forget I exist" Jul 2009 Dartmouth NS 20E2₁₆ Posts	Large number division Code: div(n,x)=if(n<=10^znorder(Mod(10,x)),return(n),return(n%(10^znorder(Mod(10,x)))+div(floor(n/(10^znorder(Mod(10,x)))),x))) Implementation of the first step of https://math.stackexchange.com/quest...152669#3152669

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