Struct Differentiator 

pub struct Differentiator { /* private fields */ }

Finite-difference differentiation configuration.

Implementations

impl Differentiator

pub const fn new(step: f64) -> Differentiator

Creates a differentiator with the given sample step.

pub fn try_new(step: f64) -> Result<Differentiator, CalculusError>

Creates a differentiator from a finite positive step.

Errors

Returns CalculusError::NonFiniteStep when step is NaN or infinite, and CalculusError::NonPositiveStep when step <= 0.0.

Examples

use use_calculus::{CalculusError, Differentiator};

let differentiator = Differentiator::try_new(1.0e-4)?;
assert_eq!(differentiator, Differentiator::new(1.0e-4));

assert!(matches!(
    Differentiator::try_new(0.0),
    Err(CalculusError::NonPositiveStep(0.0))
));

pub fn validate(self) -> Result<Differentiator, CalculusError>

Validates that the stored step is finite and positive.

Errors

Returns the same error variants as Self::try_new.

pub const fn step(&self) -> f64

Returns the sample step.

pub fn derivative_at<F>( self, function: F, at: f64, ) -> Result<f64, CalculusError>

where F: FnMut(f64) -> f64,

Approximates the first derivative using the central-difference formula.

Errors

Returns CalculusError when the stored step is invalid, at is not finite, or sampled evaluations are not finite.

Examples

use use_calculus::Differentiator;

let differentiator = Differentiator::try_new(1.0e-5)?;
let slope = differentiator.derivative_at(|x| x.powi(2), 3.0)?;

assert!((slope - 6.0).abs() < 1.0e-6);

pub fn second_derivative_at<F>( self, function: F, at: f64, ) -> Result<f64, CalculusError>

where F: FnMut(f64) -> f64,

Approximates the second derivative using the central-difference formula.

Errors

Returns CalculusError when the stored step is invalid, at is not finite, or sampled evaluations are not finite.

Trait Implementations

impl Clone for Differentiator

fn clone(&self) -> Differentiator

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Differentiator

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

Formats the value using the given formatter.

impl PartialEq for Differentiator

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

Tests for self and other values to be equal, and is used by ==.

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

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

impl Copy for Differentiator

impl StructuralPartialEq for Differentiator