Should large exponentials not yield Inf?

[Palli]

@nil

julia> 456^789
0

This results in wrong values inside functions

This is right(!) in some technical (modular) sense. Modular arithmetic is the default for machine integers, and they can’t be Inf. So Int^Int, CAN’T result in Inf, if, given that it results in Int. I would argue it should result in Float64, similar to division, for the same reasons (at least for signed integers), when the power is (possibly) negative. Right now, power returns Int for purity reasons, that arguably do not apply to it, only the other operators.

@Sukera

Julia integers are machine integers, ^ on integers does integer exponentiation. Checking for overflow & throwing an error/giving a warning would prevent a lot of optimizations like vectorization to take place.

I’m not sure a lot of code relies on integer exponentiation, but it it does then plan b could be to check for overflow and throw an error, and I’m not sure it will be slow or prevent optimization. Because I think there’s no such assembly instruction.

Discussion about integer overflow

Because of overflows, and getting rid of them with this idea would be a great option: Doesn’t need to be.* That was about changing the default, but the default type for integers doesn’t need to change, only the non-default option, so we do not have to wait for Julia 2.0 (only if we change the default later, what I’m not proposing now). The question is what should replace the default integers, and I’m a bit conflicted, BigInt or SaferIntegers.jl. The argument for the former is that it’s al…

Make a^b return Float64 when b is signed integer