Rho factor failure

[DagurB]

pollard in content/number-theory/Factor.h goes in an infinite loop when trying to factor 13090697986362792343ull = 2351473519 * 5567019097

[simonlindholm]

Uh oh. Have you investigated why this happens?

[DagurB]

Uh oh. Have you investigated why this happens?

Haven't yet. I'll be busy until after the EWPC awards ceremony. I'll look at it after that

[Matistjati]

I think the failure is because this is greater than Miller Rabin's max safe value.

[simonlindholm]

Seems to exceed the max value of modmul. The Miller Rabin itself is fine as long as you use a modmul that works across the whole u64 range. Worth documenting, perhaps.