# Trait sp_arithmetic::per_things::PerThing[−][src]

``````pub trait PerThing: Sized + Saturating + Copy + Default + Eq + PartialEq + Ord + PartialOrd + Bounded + Debug + Div<Output = Self> + Mul<Output = Self> + Pow<usize, Output = Self> {
type Inner: BaseArithmetic + Unsigned + Copy + Into<u128> + Debug;
type Upper: BaseArithmetic + Copy + From<Self::Inner> + TryInto<Self::Inner> + UniqueSaturatedInto<Self::Inner> + Unsigned + Debug;

const ACCURACY: Self::Inner;
Show 18 methods
fn deconstruct(self) -> Self::Inner;
fn from_parts(parts: Self::Inner) -> Self;
fn from_float(x: f64) -> Self;
fn from_rational<N>(p: N, q: N) -> Self    where        N: Clone + Ord + TryInto<Self::Inner> + TryInto<Self::Upper> + Div<N, Output = N> + Rem<N, Output = N> + Add<N, Output = N> + Unsigned,        Self::Inner: Into<N>;

fn zero() -> Self { ... }
fn is_zero(&self) -> bool { ... }
fn one() -> Self { ... }
fn is_one(&self) -> bool { ... }
fn from_percent(x: Self::Inner) -> Self { ... }
fn square(self) -> Self { ... }
fn left_from_one(self) -> Self { ... }
fn mul_floor<N>(self, b: N) -> N    where        N: Clone + UniqueSaturatedInto<Self::Inner> + Rem<N, Output = N> + Div<N, Output = N> + Mul<N, Output = N> + Add<N, Output = N> + Unsigned,        Self::Inner: Into<N>,
{ ... }
fn mul_ceil<N>(self, b: N) -> N    where        N: Clone + UniqueSaturatedInto<Self::Inner> + Rem<N, Output = N> + Div<N, Output = N> + Mul<N, Output = N> + Add<N, Output = N> + Unsigned,        Self::Inner: Into<N>,
{ ... }
fn saturating_reciprocal_mul<N>(self, b: N) -> N    where        N: Clone + UniqueSaturatedInto<Self::Inner> + Rem<N, Output = N> + Div<N, Output = N> + Mul<N, Output = N> + Add<N, Output = N> + Saturating + Unsigned,        Self::Inner: Into<N>,
{ ... }
fn saturating_reciprocal_mul_floor<N>(self, b: N) -> N    where        N: Clone + UniqueSaturatedInto<Self::Inner> + Rem<N, Output = N> + Div<N, Output = N> + Mul<N, Output = N> + Add<N, Output = N> + Saturating + Unsigned,        Self::Inner: Into<N>,
{ ... }
fn saturating_reciprocal_mul_ceil<N>(self, b: N) -> N    where        N: Clone + UniqueSaturatedInto<Self::Inner> + Rem<N, Output = N> + Div<N, Output = N> + Mul<N, Output = N> + Add<N, Output = N> + Saturating + Unsigned,        Self::Inner: Into<N>,
{ ... }
fn from_fraction(x: f64) -> Self { ... }
fn from_rational_approximation<N>(p: N, q: N) -> Self    where        N: Clone + Ord + TryInto<Self::Inner> + TryInto<Self::Upper> + Div<N, Output = N> + Rem<N, Output = N> + Add<N, Output = N> + Unsigned + Zero + One,        Self::Inner: Into<N>,
{ ... }
}``````
Expand description

Something that implements a fixed point ration with an arbitrary granularity `X`, as parts per `X`.

## Associated Types

The data type used to build this per-thingy.

A data type larger than `Self::Inner`, used to avoid overflow in some computations. It must be able to compute `ACCURACY^2`.

## Associated Constants

The accuracy of this type.

## Required methods

Consume self and return the number of parts per thing.

Build this type from a number of parts per thing.

Converts a fraction into `Self`.

Approximate the fraction `p/q` into a per-thing fraction. This will never overflow.

The computation of this approximation is performed in the generic type `N`. Given `M` as the data type that can hold the maximum value of this per-thing (e.g. u32 for perbill), this can only work if `N == M` or `N: From<M> + TryInto<M>`.

Note that this always rounds down, i.e.

``````// 989/100 is technically closer to 99%.
assert_eq!(
Percent::from_rational(989u64, 1000),
Percent::from_parts(98),
);``````

## Provided methods

Equivalent to `Self::from_parts(0)`.

Return `true` if this is nothing.

Equivalent to `Self::from_parts(Self::ACCURACY)`.

Return `true` if this is one.

Build this type from a percent. Equivalent to `Self::from_parts(x * Self::ACCURACY / 100)` but more accurate and can cope with potential type overflows.

Return the product of multiplication of this value by itself.

Return the part left when `self` is saturating-subtracted from `Self::one()`.

Multiplication that always rounds down to a whole number. The standard `Mul` rounds to the nearest whole number.

``````// round to nearest
assert_eq!(Percent::from_percent(34) * 10u64, 3);
assert_eq!(Percent::from_percent(36) * 10u64, 4);

// round down
assert_eq!(Percent::from_percent(34).mul_floor(10u64), 3);
assert_eq!(Percent::from_percent(36).mul_floor(10u64), 3);``````

Multiplication that always rounds the result up to a whole number. The standard `Mul` rounds to the nearest whole number.

``````// round to nearest
assert_eq!(Percent::from_percent(34) * 10u64, 3);
assert_eq!(Percent::from_percent(36) * 10u64, 4);

// round up
assert_eq!(Percent::from_percent(34).mul_ceil(10u64), 4);
assert_eq!(Percent::from_percent(36).mul_ceil(10u64), 4);``````

Saturating multiplication by the reciprocal of `self`. The result is rounded to the nearest whole number and saturates at the numeric bounds instead of overflowing.

``assert_eq!(Percent::from_percent(50).saturating_reciprocal_mul(10u64), 20);``

Saturating multiplication by the reciprocal of `self`. The result is rounded down to the nearest whole number and saturates at the numeric bounds instead of overflowing.

``````// round to nearest
assert_eq!(Percent::from_percent(60).saturating_reciprocal_mul(10u64), 17);
// round down
assert_eq!(Percent::from_percent(60).saturating_reciprocal_mul_floor(10u64), 16);``````

Saturating multiplication by the reciprocal of `self`. The result is rounded up to the nearest whole number and saturates at the numeric bounds instead of overflowing.

``````// round to nearest
assert_eq!(Percent::from_percent(61).saturating_reciprocal_mul(10u64), 16);
// round up
assert_eq!(Percent::from_percent(61).saturating_reciprocal_mul_ceil(10u64), 17);``````
👎 Deprecated:

Same as `Self::from_float`.
Same as `Self::from_rational`.