@stdlib/math-base-tools-evalpoly
v0.2.3TypeScript
Evaluate a polynomial using double-precision floating-point arithmetic.
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Published by The Stdlib Authors
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evalpoly
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> Evaluate a [polynomial][polynomial] using double-precision floating-point arithmetic.
A [polynomial][polynomial] in a variable x can be expressed as
where c_n, c_{n-1}, ..., c_0 are constants.
Installation
``bash`
npm install @stdlib/math-base-tools-evalpoly
Usage
`javascript`
var evalpoly = require( '@stdlib/math-base-tools-evalpoly' );
#### evalpoly( c, x )
Evaluates a [polynomial][polynomial] having coefficients c and degree n at a value x, where n = c.length-1.
`javascript`
var v = evalpoly( [ 3.0, 2.0, 1.0 ], 10 ); // => 310^0 + 210^1 + 1*10^2
// returns 123.0
The coefficients should be ordered in ascending degree, thus matching summation notation.
#### evalpoly.factory( c )
Uses code generation to in-line coefficients and return a function for evaluating a [polynomial][polynomial] using double-precision floating-point arithmetic.
`javascript
var polyval = evalpoly.factory( [ 3.0, 2.0, 1.0 ] );
var v = polyval( 10.0 ); // => 310^0 + 210^1 + 1*10^2
// returns 123.0
v = polyval( 5.0 ); // => 35^0 + 25^1 + 1*5^2
// returns 38.0
`
Notes
- For hot code paths in which coefficients are invariant, a compiled function will be more performant than evalpoly().
- While code generation can boost performance, its use may be problematic in browser contexts enforcing a strict [content security policy][mdn-csp] (CSP). If running in or targeting an environment with a CSP, avoid using code generation.
Examples
`javascript
var discreteUniform = require( '@stdlib/random-array-discrete-uniform' );
var uniform = require( '@stdlib/random-base-uniform' );
var evalpoly = require( '@stdlib/math-base-tools-evalpoly' );
// Create an array of random coefficients:
var coef = discreteUniform( 10, -100, 100 );
// Evaluate the polynomial at random values:
var v;
var i;
for ( i = 0; i < 100; i++ ) {
v = uniform( 0.0, 100.0 );
console.log( 'f(%d) = %d', v, evalpoly( coef, v ) );
}
// Generate an evalpoly function:`
var polyval = evalpoly.factory( coef );
for ( i = 0; i < 100; i++ ) {
v = uniform( -50.0, 50.0 );
console.log( 'f(%d) = %d', v, polyval( v ) );
}
*
See Also
- [@stdlib/math-base/tools/evalrational][@stdlib/math/base/tools/evalrational]: evaluate a rational function using double-precision floating-point arithmetic.
*
Notice
This package is part of [stdlib][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][stdlib], see the main project [repository][stdlib].
#### Community
[![Chat][chat-image]][chat-url]
---
License
See [LICENSE][stdlib-license].
Copyright
Copyright © 2016-2026. The Stdlib [Authors][stdlib-authors].
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[umd]: https://github.com/umdjs/umd
[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules
[deno-url]: https://github.com/stdlib-js/math-base-tools-evalpoly/tree/deno
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[umd-url]: https://github.com/stdlib-js/math-base-tools-evalpoly/tree/umd
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[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/math-base-tools-evalpoly/main/LICENSE
[polynomial]: https://en.wikipedia.org/wiki/Polynomial
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[@stdlib/math/base/tools/evalrational]: https://www.npmjs.com/package/@stdlib/math-base-tools-evalrational