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@stdlib/math-base-tools-evalrational-compile
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We believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js.
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When you use stdlib, you can be absolutely certain that you are using the most thorough, rigorous, well-written, studied, documented, tested, measured, and high-quality code out there.
To join us in bringing numerical computing to the web, get started by checking us out on GitHub, and please consider financially supporting stdlib. We greatly appreciate your continued support!
Compile a module for evaluating a rational function.
npm install @stdlib/math-base-tools-evalrational-compile
var compile = require( '@stdlib/math-base-tools-evalrational-compile' );
Compiles a module string
containing an exported function which evaluates a rational function having coefficients P
and Q
.
var P = [ 3.0, 2.0, 1.0 ];
var Q = [ -1.0, -2.0, -3.0 ];
var str = compile( P, Q );
// returns <string>
In the example above, the output string
would correspond to the following module:
'use strict';
// MAIN //
/**
* Evaluates a rational function (i.e., the ratio of two polynomials described by the coefficients stored in \\(P\\) and \\(Q\\)).
*
* ## Notes
*
* - Coefficients should be sorted in ascending degree.
* - The implementation uses [Horner's rule][horners-method] for efficient computation.
*
* [horners-method]: https://en.wikipedia.org/wiki/Horner%27s_method
*
* @private
* @param {number} x - value at which to evaluate the rational function
* @returns {number} evaluated rational function
*/
function evalrational( x ) {
var ax;
var s1;
var s2;
if ( x === 0.0 ) {
return -3.0;
}
if ( x < 0.0 ) {
ax = -x;
} else {
ax = x;
}
if ( ax <= 1.0 ) {
s1 = 3.0 + (x * (2.0 + (x * 1.0))); // eslint-disable-line max-len
s2 = -1.0 + (x * (-2.0 + (x * -3.0))); // eslint-disable-line max-len
} else {
x = 1.0 / x;
s1 = 1.0 + (x * (2.0 + (x * 3.0))); // eslint-disable-line max-len
s2 = -3.0 + (x * (-2.0 + (x * -1.0))); // eslint-disable-line max-len
}
return s1 / s2;
}
// EXPORTS //
module.exports = evalrational;
The coefficients should be ordered in ascending degree, thus matching summation notation.
var randu = require( '@stdlib/random-base-randu' );
var round = require( '@stdlib/math-base-special-round' );
var Float64Array = require( '@stdlib/array-float64' );
var compile = require( '@stdlib/math-base-tools-evalrational-compile' );
var sign;
var str;
var P;
var Q;
var i;
// Create two arrays of random coefficients...
P = new Float64Array( 10 );
Q = new Float64Array( 10 );
for ( i = 0; i < P.length; i++ ) {
if ( randu() < 0.5 ) {
sign = -1.0;
} else {
sign = 1.0;
}
P[ i ] = sign * round( randu()*100.0 );
Q[ i ] = sign * round( randu()*100.0 );
}
// Compile a module for evaluating a rational function:
str = compile( P, Q );
console.log( str );
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.
See LICENSE.
Copyright © 2016-2024. The Stdlib Authors.
FAQs
Compile a module for evaluating a rational function.
The npm package @stdlib/math-base-tools-evalrational-compile receives a total of 37 weekly downloads. As such, @stdlib/math-base-tools-evalrational-compile popularity was classified as not popular.
We found that @stdlib/math-base-tools-evalrational-compile demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 4 open source maintainers collaborating on the project.
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