Struct peroxide::numerical::spline::CubicSpline

pub struct CubicSpline { /* fields omitted */ }

Cubic Spline (Natural)

Description

Implement traits of Natural cubic splines, by Arne Morten Kvarving.

Type

(&Vec, &Vec) -> Cubic Spline

Examples

#[macro_use]
extern crate peroxide;
use peroxide::fuga::*;

fn main() {
    let x = c!(0.9, 1.3, 1.9, 2.1);
    let y = c!(1.3, 1.5, 1.85, 2.1);

    let s = CubicSpline::from_nodes(x, y);

    let new_x = c!(1, 1.5, 2.0);

    // Generate Cubic polynomial
    for t in new_x.iter() {
        s.polynomial(*t).print();
    }
    // -0.2347x^3 + 0.6338x^2 - 0.0329x + 0.9873
    // 0.9096x^3 - 3.8292x^2 + 5.7691x - 1.5268
    // -2.2594x^3 + 14.2342x^2 - 28.5513x + 20.2094

    // Evaluation
    for t in new_x.iter() {
        s.eval(*t).print();
    }
}

Implementations

impl CubicSpline

pub fn from_nodes(node_x: Vec<f64>, node_y: Vec<f64>) -> Self

Examples

#[macro_use]
extern crate peroxide;
use peroxide::fuga::*;

fn main() {
    let x = c!(0.9, 1.3, 1.9, 2.1);
    let y = c!(1.3, 1.5, 1.85, 2.1);

    let s = CubicSpline::from_nodes(x, y);

    for i in 0 .. 4 {
        println!("{}", s.eval(i as f64 / 2.0));
    }
}

pub fn eval<T>(&self, x: T) -> f64 where
    T: Into<f64> + Copy, 

Evaluate cubic spline with value

Examples

#[macro_use]
extern crate peroxide;
use peroxide::fuga::*;

fn main() {
    let x = c!(0.9, 1.3, 1.9, 2.1);
    let y = c!(1.3, 1.5, 1.85, 2.1);

    let s = CubicSpline::from_nodes(x, y);

    s.eval(2.0);
}

pub fn polynomial<T>(&self, x: T) -> &Polynomial where
    T: Into<f64> + Copy, 

Returns a reference the Polynomial at the given point x.

Examples

#[macro_use]
extern crate peroxide;
use peroxide::fuga::*;

fn main() {
    let x = c!(0.9, 1.3, 1.9, 2.1);
    let y = c!(1.3, 1.5, 1.85, 2.1);

    let s = CubicSpline::from_nodes(x, y);

    let p = s.polynomial(2.0);
    let v = p.eval(1.9);

    assert_eq!((v * 100.0).round() / 100.0, 1.85)
}

If x is outside of the range of polynomials, the first or last polynomial will be returned, depending if x is lower of the first interpolation point or higher of the last interpolation point.

pub fn extend_with_nodes(&mut self, node_x: Vec<f64>, node_y: Vec<f64>)

Extends the spline with the given nodes.

The method ensures that the transition between each polynomial is smooth and that the spline interpolation of the new nodes is calculated around x = 0 in order to avoid that successive spline extensions with large x values become inaccurate.

pub fn number_of_polynomials(&self) -> usize

Returns the number of polynimials that describe the CubicSpline

Examples

#[macro_use]
extern crate peroxide;
use peroxide::fuga::*;

fn main() {
    let x = c!(0.9, 1.3, 1.9, 2.1);
    let y = c!(1.3, 1.5, 1.85, 2.1);

    let s = CubicSpline::from_nodes(x, y);

    assert_eq!(s.number_of_polynomials(), 3);
}

Trait Implementations

impl Calculus for CubicSpline

fn diff(&self) -> Self

fn integral(&self) -> Self

impl Clone for CubicSpline

fn clone(&self) -> CubicSpline

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for CubicSpline

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

Formats the value using the given formatter.

impl Default for CubicSpline

fn default() -> CubicSpline

Returns the “default value” for a type.

impl From<Vec<(Range<f64>, Polynomial), Global>> for CubicSpline

fn from(polynomials: Vec<(Range<f64>, Polynomial)>) -> Self

Performs the conversion.

impl Index<usize> for CubicSpline

type Output = (Range<f64>, Polynomial)

The returned type after indexing.

fn index(&self, index: usize) -> &Self::Output

Performs the indexing (container[index]) operation.

impl Into<Vec<(Range<f64>, Polynomial), Global>> for CubicSpline

fn into(self) -> Vec<(Range<f64>, Polynomial)>

Performs the conversion.

impl Into<Vec<Polynomial, Global>> for CubicSpline

fn into(self) -> Vec<Polynomial>

Performs the conversion.

impl Environment for CubicSpline