README
Kernel Cosine
Compute the cosine of a number on
[-π/4, π/4]
.
Installation
npm install @stdlib/math-base-special-kernel-cos
Usage
var kernelCos = require( '@stdlib/math-base-special-kernel-cos' );
kernelCos( x, y )
Computes the cosine of a number
on [-π/4, π/4]
. For increased accuracy, the number for which the cosine should be evaluated can be supplied as a double-double number (i.e., a non-evaluated sum of two double-precision floating-point numbers x
and y
).
var v = kernelCos( 0.0, 0.0 );
// returns ~1.0
v = kernelCos( 3.141592653589793/6.0, 0.0 );
// returns ~0.866
v = kernelCos( 0.785, -1.144e-17 );
// returns ~0.707
v = kernelCos( NaN, 0.0 );
// returns NaN
Notes
As components of a double-double number, the two double-precision floating-point numbers
x
andy
must satisfy
where
ulp
stands for units in the last place.
Examples
var linspace = require( '@stdlib/array-base-linspace' );
var PI = require( '@stdlib/constants-float64-pi' );
var kernelCos = require( '@stdlib/math-base-special-kernel-cos' );
var x = linspace( -PI/4.0, PI/4.0, 100 );
var i;
for ( i = 0; i < x.length; i++ ) {
console.log( 'kernelCos(%d) = %d', x[ i ], kernelCos( x[ i ], 0.0 ) );
}
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.
Copyright
Copyright © 2016-2022. The Stdlib Authors.