Struct FSum 

pub struct FSum { /* private fields */ }

Accumulator that represents the exact sum of f64 values and allows additional f64 values to be added without loss of precision.

Implementations

impl FSum

pub fn new() -> FSum

Constructs zeroed accumulator.

Example

use fsum::FSum;

assert_eq!(FSum::new().value(), 0.0);

pub fn with_value(initial_value: f64) -> FSum

Constructs accumulator with given initial_value.

Example

use fsum::FSum;

assert_eq!(FSum::with_value(5.0).value(), 5.0);

pub fn with_all<Bf64, InIter>(values: InIter) -> FSum

where Bf64: Borrow<f64>, InIter: IntoIterator<Item = Bf64>,

Constructs accumulator with all values from iter.

Examples

use fsum::FSum;

assert_eq!(FSum::with_all((0..10).map(|_| 0.1)).value(), 1.0);

pub fn add(&mut self, x: f64) -> &mut FSum

Increases the sum by x and returns self.

Example

use fsum::FSum;

let mut s = FSum::new();
assert_eq!(s.value(), 0.0);
s.add(1.0);
assert_eq!(s.value(), 1.0);
s.add(2.0);
assert_eq!(s.value(), 3.0);
assert_eq!(s.add(5.0).value(), 8.0);

Complexity

The complexities are:

• time: from O(1) (optimistic) to O(n) (pessimistic), where n is the number of values added so far,
• memory: O(1), but internal vector stored in self can be increased by 1 element.

Usually the time complexity is close to optimistic.

pub fn add_all<InIter, Bf64>(&mut self, values: InIter) -> &mut FSum

where Bf64: Borrow<f64>, InIter: IntoIterator<Item = Bf64>,

Increases the sum by all values from iter. Returns self.

Example

use fsum::FSum;

assert_eq!(FSum::new().add_all((0..10).map(|_| 0.1)).value(), 1.0);

pub fn value(&self) -> f64

Returns the current value of the sum.

The complexities are:

• time: from O(1) (optimistic) to O(n) (pessimistic), where n is the number of values added so far,
• memory: O(1).

Usually the time complexity is close to optimistic.

Example

use fsum::FSum;

assert_eq!(FSum::with_value(2.0).value(), 2.0);

pub fn reset(&mut self) -> &mut FSum

Sets the current sum to 0 and returns self.

pub fn set(&mut self, value: f64) -> &mut FSum

Sets the current sum to value and returns self.

Example

use fsum::FSum;

assert_eq!(FSum::new().set(1.0).value(), 1.0);

Trait Implementations

impl AddAssign<f64> for FSum

fn add_assign(&mut self, other: f64)

Performs the += operation.

impl Clone for FSum

fn clone(&self) -> FSum

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for FSum

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

Formats the value using the given formatter.

impl Default for FSum

fn default() -> FSum

Returns the “default value” for a type.

impl From<&FSum> for f64

fn from(fsum: &FSum) -> Self

Converts to this type from the input type.

impl From<FSum> for f64

fn from(fsum: FSum) -> Self

Converts to this type from the input type.

impl From<f64> for FSum

fn from(initial_value: f64) -> Self

Converts to this type from the input type.

impl SubAssign<f64> for FSum

fn sub_assign(&mut self, other: f64)

Performs the -= operation.