This replaces the wrapper around the runtime RNG with a pure Rust implementation of the same algorithm. This is much faster (up to 5x), and is hopefully safer.
There is still (a little) room for optimisation: testing by summing 100,000,000 random `u32`s indicates this is about ~~40-50%~~ 10% slower than the pure C implementation (running as standalone executable, not in the runtime).
(Only 6d50d55 is part of this PR, the first two are from #6058, but are required for the rt rng to be correct to compare against in the tests.)
This replaces the wrapper around the runtime RNG with a pure Rust
implementation of the same algorithm. This is faster (up to 5x), and
is hopefully safer.
There is still much room for optimisation: testing by summing 100,000,000
random `u32`s indicates this is about 40-50% slower than the pure C
implementation (running as standalone executable, not in the runtime).
As discussed on issue #4819, I have created four new traits: `Algebraic`, `Trigonometric`, `Exponential` and `Hyperbolic`, and moved the appropriate methods into them from `Real`.
~~~rust
pub trait Algebraic {
fn pow(&self, n: Self) -> Self;
fn sqrt(&self) -> Self;
fn rsqrt(&self) -> Self;
fn cbrt(&self) -> Self;
fn hypot(&self, other: Self) -> Self;
}
pub trait Trigonometric {
fn sin(&self) -> Self;
fn cos(&self) -> Self;
fn tan(&self) -> Self;
fn asin(&self) -> Self;
fn acos(&self) -> Self;
fn atan(&self) -> Self;
fn atan2(&self, other: Self) -> Self;
}
pub trait Exponential {
fn exp(&self) -> Self;
fn exp2(&self) -> Self;
fn expm1(&self) -> Self;
fn log(&self) -> Self;
fn log2(&self) -> Self;
fn log10(&self) -> Self;
}
pub trait Hyperbolic: Exponential {
fn sinh(&self) -> Self;
fn cosh(&self) -> Self;
fn tanh(&self) -> Self;
}
~~~
There was some discussion over whether we should shorten the names, for example `Trig` and `Exp`. No abbreviations have been agreed on yet, but this could be considered in the future.
Additionally, `Integer::divisible_by` has been renamed to `Integer::is_multiple_of`.
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.
r? @brson mkdir_recursive creates a directory as well as any of its
parent directories that don't exist already. Seems like a useful
thing to have in core.
(Or r? anyone who gets to it first.)
As part of the numeric trait reform (see issue #4819), I have added the following traits to `core::num` and implemented them for Rust's primitive numeric types:
~~~rust
pub trait Bitwise: Not<Self>
+ BitAnd<Self,Self>
+ BitOr<Self,Self>
+ BitXor<Self,Self>
+ Shl<Self,Self>
+ Shr<Self,Self> {}
pub trait BitCount {
fn population_count(&self) -> Self;
fn leading_zeros(&self) -> Self;
fn trailing_zeros(&self) -> Self;
}
pub trait Bounded {
fn min_value() -> Self;
fn max_value() -> Self;
}
pub trait Primitive: Num
+ NumCast
+ Bounded
+ Neg<Self>
+ Add<Self,Self>
+ Sub<Self,Self>
+ Mul<Self,Self>
+ Quot<Self,Self>
+ Rem<Self,Self> {
fn bits() -> uint;
fn bytes() -> uint;
}
pub trait Int: Integer
+ Primitive
+ Bitwise
+ BitCount {}
pub trait Float: Real
+ Signed
+ Primitive {
fn NaN() -> Self;
fn infinity() -> Self;
fn neg_infinity() -> Self;
fn neg_zero() -> Self;
fn is_NaN(&self) -> bool;
fn is_infinite(&self) -> bool;
fn is_finite(&self) -> bool;
fn mantissa_digits() -> uint;
fn digits() -> uint;
fn epsilon() -> Self;
fn min_exp() -> int;
fn max_exp() -> int;
fn min_10_exp() -> int;
fn max_10_exp() -> int;
fn mul_add(&self, a: Self, b: Self) -> Self;
fn next_after(&self, other: Self) -> Self;
}
~~~
Note: I'm not sure my implementation for `BitCount::trailing_zeros` and `BitCount::leading_zeros` is correct for uints. I also need some assistance creating appropriate unit tests for them.
More work needs to be done in implementing specialized primitive floating-point and integer methods, but I'm beginning to reach the limits of my knowledge. Please leave your suggestions/critiques/ideas on #4819 if you have them – I'd very much appreciate hearing them.
I have also added an `Orderable` trait:
~~~rust
pub trait Orderable: Ord {
fn min(&self, other: &Self) -> Self;
fn max(&self, other: &Self) -> Self;
fn clamp(&self, mn: &Self, mx: &Self) -> Self;
}
~~~
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).
r? @brson
Unwinding through macros now happens as a call to the trait function `FailWithCause::fail_with()`, which consumes self, allowing to use a more generic failure object in the future.
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>() { … }
r? @graydon
Sorry, this pull request is a few different things at once, but I tried to make them separate commits.
First, as before, this should do file searching the way that's described in the doc now.
Second, there's also some preliminary work on the install command (really just tests for it).
As part of the numeric trait reform (see issue #4819), I have added the following traits to `core::num` and implemented them for floating point types:
~~~rust
pub trait Round {
fn floor(&self) -> Self;
fn ceil(&self) -> Self;
fn round(&self) -> Self;
fn trunc(&self) -> Self;
fn fract(&self) -> Self;
}
pub trait Fractional: Num
+ Ord
+ Round
+ Quot<Self,Self> {
fn recip(&self) -> Self;
}
pub trait Real: Signed
+ Fractional {
// Common Constants
fn pi() -> Self;
fn two_pi() -> Self;
fn frac_pi_2() -> Self;
fn frac_pi_3() -> Self;
fn frac_pi_4() -> Self;
fn frac_pi_6() -> Self;
fn frac_pi_8() -> Self;
fn frac_1_pi() -> Self;
fn frac_2_pi() -> Self;
fn frac_2_sqrtpi() -> Self;
fn sqrt2() -> Self;
fn frac_1_sqrt2() -> Self;
fn e() -> Self;
fn log2_e() -> Self;
fn log10_e() -> Self;
fn log_2() -> Self;
fn log_10() -> Self;
// Exponential functions
fn pow(&self, n: Self) -> Self;
fn exp(&self) -> Self;
fn exp2(&self) -> Self;
fn expm1(&self) -> Self;
fn ldexp(&self, n: int) -> Self;
fn log(&self) -> Self;
fn log2(&self) -> Self;
fn log10(&self) -> Self;
fn log_radix(&self) -> Self;
fn ilog_radix(&self) -> int;
fn sqrt(&self) -> Self;
fn rsqrt(&self) -> Self;
fn cbrt(&self) -> Self;
// Angular conversions
fn to_degrees(&self) -> Self;
fn to_radians(&self) -> Self;
// Triganomic functions
fn hypot(&self, other: Self) -> Self;
fn sin(&self) -> Self;
fn cos(&self) -> Self;
fn tan(&self) -> Self;
// Inverse triganomic functions
fn asin(&self) -> Self;
fn acos(&self) -> Self;
fn atan(&self) -> Self;
fn atan2(&self, other: Self) -> Self;
// Hyperbolic triganomic functions
fn sinh(&self) -> Self;
fn cosh(&self) -> Self;
fn tanh(&self) -> Self;
}
/// Methods that are harder to implement and not commonly used.
pub trait RealExt: Real {
// Gamma functions
fn lgamma(&self) -> (int, Self);
fn tgamma(&self) -> Self;
// Bessel functions
fn j0(&self) -> Self;
fn j1(&self) -> Self;
fn jn(&self, n: int) -> Self;
fn y0(&self) -> Self;
fn y1(&self) -> Self;
fn yn(&self, n: int) -> Self;
}
~~~
The constants in `Real` could be [associated items](http://smallcultfollowing.com/babysteps/blog/2013/04/03/associated-items-continued/) in the future (see issue #5527). At the moment I have left the constants in `{float|f32|f64}::consts` in case folks need to access these at compile time. There are also instances of `int` in `Real` and `RealExt`. In the future these could be replaced with an associated `INTEGER` type on `Real`.
`Natural` has also been renamed to `Integer`. This is because `Natural` normally means 'positive integer' in mathematics. It is therefore strange to implement it on signed integer types. `Integer` is probably a better choice.
I have also switched some of the `Integer` methods to take borrowed pointers as arguments. 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.
There has also been considerable discussion on the mailing list and IRC about the renaming of the `Div` and `Modulo` traits to `Quot` and `Rem`. Depending on the outcome of these discussions they might be renamed again.
Unwinding through macros now happens as a call to the trait function `FailWithCause::fail_with()`, which consumes self, allowing to use a more generic failure object in the future.
