Struct stats_ci::utils::KahanSum

pub struct KahanSum<T: Float> { /* private fields */ }

Kahan compensated summation register.

This is a register that can be used to sum a sequence of floating point numbers with a better precision than a naive summation.

See https://en.wikipedia.org/wiki/Kahan_summation_algorithm

Examples

let repetitions = 10_000;
let mut naive = 0.0_f32;
let mut sum = KahanSum::new(0.0_f32);
(1..=repetitions).for_each(|_| {
    sum += 0.1;
    naive += 0.1;
});
assert_eq!(sum.sum(), repetitions as f32 * 0.1);
assert_ne!(naive, repetitions as f32 * 0.1);

Implementations

impl<T: Float> KahanSum<T>

pub fn new(value: T) -> Self

Create a new KahanSum register with the given initial value

Arguments

• value - the initial value

pub fn value(&self) -> T

Return the current value of the sum

Trait Implementations

impl<T: Float, X> Add<X> for KahanSum<T>where Self: AddAssign<X>,

type Output = KahanSum<T>

The resulting type after applying the + operator.

fn add(self, rhs: X) -> Self::Output

Performs the + operation.

impl<T: Float> AddAssign<KahanSum<T>> for KahanSum<T>

fn add_assign(&mut self, rhs: Self)

Performs the += operation.

impl<T: Float> AddAssign<T> for KahanSum<T>

fn add_assign(&mut self, rhs: T)

Performs the += operation.

impl<T: Clone + Float> Clone for KahanSum<T>

fn clone(&self) -> KahanSum<T>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: Debug + Float> Debug for KahanSum<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T: Float> Default for KahanSum<T>

fn default() -> Self

Returns the “default value” for a type.

impl<T: Float + Display> Display for KahanSum<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T: Float> From<T> for KahanSum<T>

fn from(value: T) -> Self

Converts to this type from the input type.

impl<T: Float> PartialEq<KahanSum<T>> for KahanSum<T>

fn eq(&self, other: &Self) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<T: Copy + Float> Copy for KahanSum<T>