@stdlib/math-base-special-sici

Sine and cosine integrals.


Keywords
stdlib, stdmath, mathematics, math, special, function, sine, sin, cosine, cos, integral, sici, number, javascript, node, node-js, nodejs
License
Apache-2.0
Install
npm install @stdlib/math-base-special-sici@0.0.5

Documentation

sici

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Compute the sine and cosine integrals.

The sine integral is defined as

Sine integral.

and the cosine integral is defined as

Cosine integral.

where γ is the Euler-Mascheroni constant.

Installation

npm install @stdlib/math-base-special-sici

Usage

var sici = require( '@stdlib/math-base-special-sici' );

sici( [out,] x )

Computes the sine and cosine integrals.

var v = sici( 3.0 );
// returns [ ~1.849, ~0.12 ]

v = sici( 0.0 );
// returns [ 0.0, -Infinity ]

v = sici( -9.0 );
// returns [ ~-1.665, ~0.055 ]

v = sici( NaN );
// returns [ NaN, NaN ]

By default, the function returns the sine and cosine integrals as a two-element array. To avoid unnecessary memory allocation, the function supports providing an output (destination) object.

var Float64Array = require( '@stdlib/array-float64' );

var out = new Float64Array( 2 );

var v = sici( out, 3.0 );
// returns <Float64Array>[ ~1.849, ~0.12 ]

var bool = ( v === out );
// returns true

Examples

var randu = require( '@stdlib/random-base-randu' );
var sici = require( '@stdlib/math-base-special-sici' );

var x;
var y;
var i;

for ( i = 0; i < 100; i++ ) {
    x = randu() * 100.0;
    y = sici( x );
    console.log( 'si(%d) = %d, ci(%d) = %d', x, y[ 0 ], x, y[ 1 ] );
}

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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License

See LICENSE.

Copyright

Copyright © 2016-2021. The Stdlib Authors.