CODEWITHSUNDEEP
juliaprecisionbiginteger
Julien
Julien

Reputation: 781

Julia and big numbers

How does Julia compute big numbers?

For example, this works as expected:

julia> 10^18
1000000000000000000

But for bigger numbers, there is a problem with integers:

julia> 10^19
    -8446744073709551616 

 julia> 10^20
     7766279631452241920

But it works if a decimal number is used:

julia> 10.0^20
1.0e20

Do you know why?

Upvotes: 3

Views: 2502

Answers (1)

Gazouu
Gazouu

Reputation: 382

Check this documentation page: https://docs.julialang.org/en/release-0.4/manual/integers-and-floating-point-numbers/

As you can see, Int64 have a max length of: 2^63 - 1 ~ 1.0 * 10^19 So your 10^19 is greater than this max value. That's why there is a problem. You can try to convert your 10 to another type.

10.0^20 works because 10.0 is a float, so it has a superior max value.

If you want unlimited precision for integers, you can use BigInts:

julia> BigInt(10)^100
10000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

Upvotes: 10

Related Questions