gospline

README

gospline

Golang cubic spline library

This library generates a cubic spline for given points.

Usage

Create a cubic spline

s := gospline.NewCubicSpline([]float64{0, 1, 2, 3}, []float64{0, 0.5, 2, 1.5})

Get an interpolated value

s.At(3.5)

Get an array of interpolated values

s.Range(0, 3, 0.25)

Supported boundaries

First derivation boundary: gospline.NewClampedCubicSpline

Second derivation boundary: gospline.NewNaturalCubicSpline

Installation

Just go get github.com/cnkei/gospline

Documentation

Index

• Constants
• type Spline
  • func NewClampedCubicSpline(x, y []float64, f0, fn float64) Spline
  • func NewCubicSpline(x, y []float64) Spline
  • func NewMonotoneSpline(x, y []float64) Spline
  • func NewNaturalCubicSpline(x, y []float64, f0, fn float64) Spline

Constants

const (
	CubicFirstDeriv boundary = iota
	CubicSecondDeriv
	CubicThirdDeriv
	CubicPeriodic
)

bounday types

Types

type Spline

type Spline interface {
	// At returns interpolated value at x
	// 0 <= x <= 1
	At(x float64) float64

	// Range returns interpolated values in [start, end] with step
	Range(start, end, step float64) []float64
}

Spline interface for interpolation functions

func NewClampedCubicSpline

func NewClampedCubicSpline(x, y []float64, f0, fn float64) Spline

NewClampedCubicSpline returns cubic spline with natural boundary the boundaries are:

f0: f'(x[0])
fn: f'(x[len(x)-1])

func NewCubicSpline

func NewCubicSpline(x, y []float64) Spline

NewCubicSpline returns cubic spline with natural boundary the whole array must be in ascending order

func NewMonotoneSpline

func NewMonotoneSpline(x, y []float64) Spline

NewMonotoneSpline returns cubic monotone hermite spline the whole array must be in ascending order

func NewNaturalCubicSpline

func NewNaturalCubicSpline(x, y []float64, f0, fn float64) Spline

NewNaturalCubicSpline returns cubic spline with natural boundary the boundaries are:

f0: f''(x[0])
fn: f''(x[len(x)-1])