Both expm1 and ln1p have been renamed to exp_m1 and ln_1p in order to be consistent with the underscore usage elsewhere.
The exp_m1 method is used for increased accuracy when doing floating point calculations, so this has been moved from the more general 'Exponential' trait into 'Float'.
After discussions on IRC and #4819, we have decided to revert this change. This is due to the traits expressing different ideas and because hyperbolic functions are not trivially implementable from exponential functions for floating-point types.
The Hyperbolic Functions are trivially implemented in terms of `exp`, so it's simpler to group them the Exponential trait. In the future these would have default implementations.
This is a temporary trait until we have default methods. We don't want to encumber all implementors of Ord by requiring them to implement these functions, but at the same time we want to be able to take advantage of the speed of the specific numeric functions (like the `fmin` and `fmax` intrinsics).
Having three traits for primitive ints/uints seemed rather excessive. If users wish to specify between them they can simply combine Int with either the Signed and Unsigned traits. For example: fn foo<T: Int + Signed>() { … }
This brings them in line with the quot and rem traits, and is be better for large Integer types like BigInt and BigUint because they don't need to be copied unnecessarily.
'Natural' normally means 'positive integer' in mathematics. It is therefore strange to implement it on signed integer types. 'Integer' is probably a better choice.
This adds the following methods to ints and uints:
- div
- modulo
- div_mod
- quot_rem
- gcd
- lcm
- divisible_by
- is_even
- is_odd
I have not implemented Natural for BigInt and BigUInt because they're a little over my head.
This restores the trait that was lost in 216e85fadf. It will eventually be broken up into a more fine-grained trait hierarchy in the future once a design can be agreed upon.
