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Normalized Hermite Polynomial

$Build Status$

Evaluate a normalized Hermite polynomial using double-precision floating-point arithmetic.

The normalized (aka "probabilist") Hermite polynomials are given by

$$He_{n}(x)=(-1)^{n} e^{\frac{x^2}{2}} \frac{\mathrm d^{n}}{\mathrm d x^{n}} e^{-\frac{x^2}{2}}$$

Installation

npm install @stdlib/math-base-tools-normhermitepoly

Alternatively,

To load the package in a website via a script tag without installation and bundlers, use the ES Module available on the esm branch (see README).
If you are using Deno, visit the deno branch (see README for usage intructions).
For use in Observable, or in browser/node environments, use the Universal Module Definition (UMD) build available on the umd branch (see README).

The branches.md file summarizes the available branches and displays a diagram illustrating their relationships.

To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.

Usage

var normhermitepoly = require( '@stdlib/math-base-tools-normhermitepoly' );

normhermitepoly( n, x )

Evaluates a normalized Hermite polynomial of degree n using double-precision floating-point arithmetic.

var v = normhermitepoly( 1, 1.0 );
// returns 1.0

v = normhermitepoly( 1, 0.5 );
// returns 0.5

v = normhermitepoly( 0, 0.5 );
// returns 1.0

v = normhermitepoly( 2, 0.5 );
// returns -0.75

v = normhermitepoly( -1, 0.5 );
// returns NaN

normhermitepoly.factory( n )

Returns a function for evaluating a normalized Hermite polynomial of degree n using double-precision floating-point arithmetic.

var polyval = normhermitepoly.factory( 2 );

var v = polyval( 0.5 );
// returns -0.75

Examples

var uniform = require( '@stdlib/random-array-uniform' );
var zeros = require( '@stdlib/array-zeros' );
var dmap = require( '@stdlib/strided-base-dmap' );
var logEach = require( '@stdlib/console-log-each' );
var normhermitepoly = require( '@stdlib/math-base-tools-normhermitepoly' );

// Generate random values at which to evaluate a polynomial:
var x = uniform( 10, -50.0, 50.0, {
    'dtype': 'float64'
});

// Create a polynomial function of degree 1:
var f = normhermitepoly.factory( 1 );

// Allocate an output array:
var y = zeros( x.length, 'float64' );

// Evaluate the polynomial:
dmap( x.length, x, 1, y, 1, f );
logEach( 'He_%d(%.3f) = %.3f', 1, x, y );

// Create a polynomial function of degree 2:
f = normhermitepoly.factory( 2 );

// Allocate an output array:
y = zeros( x.length, 'float64' );

// Evaluate the polynomial:
dmap( x.length, x, 1, y, 1, f );
logEach( 'He_%d(%.3f) = %.3f', 2, x, y );

// Create a polynomial function of degree 3:
f = normhermitepoly.factory( 3 );

// Allocate an output array:
y = zeros( x.length, 'float64' );

// Evaluate the polynomial:
dmap( x.length, x, 1, y, 1, f );
logEach( 'He_%d(%.3f) = %.3f', 3, x, y );

Notice

This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.

Community

License

See LICENSE.

stdlib-js/math-base-tools-normhermitepoly