Package Exports
- @stdlib/math-base-special-kernel-cos
- @stdlib/math-base-special-kernel-cos/dist
- @stdlib/math-base-special-kernel-cos/dist/index.js
- @stdlib/math-base-special-kernel-cos/lib/index.js
This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (@stdlib/math-base-special-kernel-cos) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.
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kernelCos
Compute the cosine of a double-precision floating-point number on
[-π/4, π/4].
Installation
npm install @stdlib/math-base-special-kernel-cosUsage
var kernelCos = require( '@stdlib/math-base-special-kernel-cos' );kernelCos( x, y )
Computes the cosine of a double-precision floating-point number on [-π/4, π/4].
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 NaNNotes
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
xandy).As components of a double-double number, the two double-precision floating-point numbers
xandymust satisfy
where
ulpstands for units in the last place.
Examples
var uniform = require( '@stdlib/random-array-uniform' );
var logEachMap = require( '@stdlib/console-log-each-map' );
var PI = require( '@stdlib/constants-float64-pi' );
var kernelCos = require( '@stdlib/math-base-special-kernel-cos' );
var opts = {
'dtype': 'float64'
};
var x = uniform( 100, -PI/4.0, PI/4.0, opts );
logEachMap( 'kernelCos(%0.4f, %0.4f) = %0.4f', x, 0.0, kernelCos );C APIs
Usage
#include "stdlib/math/base/special/kernel_cos.h"stdlib_base_kernel_cos( x, y )
Computes the cosine of a double-precision floating-point number on [-π/4, π/4].
double v = stdlib_base_kernel_cos( 0.0, 0.0 );
// returns ~1.0
v = stdlib_base_kernel_cos( 3.141592653589793/6.0, 0.0 );
// returns ~0.866The function accepts the following arguments:
- x:
[in] doubleinput value (in radians, assumed to be bounded by~pi/4in magnitude). - y:
[in] doubletail ofx.
double stdlib_base_kernel_cos( const double x, const double y );Notes
- 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
xandy).
Examples
#include "stdlib/math/base/special/kernel_cos.h"
#include <stdio.h>
int main( void ) {
const double x[] = { -0.7853981633974483, -0.6108652381980153, -0.4363323129985824, -0.26179938779914946, -0.08726646259971649, 0.08726646259971649, 0.26179938779914935, 0.43633231299858233, 0.6108652381980153, 0.7853981633974483 };
double out;
int i;
for ( i = 0; i < 10; i++ ) {
out = stdlib_base_kernel_cos( x[ i ], 0.0 );
printf ( "x[ i ]: %lf, y: %lf, out: %lf\n", x[ i ], 0.0, out );
}
}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.
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