@stdlib/math-base-special-atan2

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atan2

Compute the angle in the plane (in radians) between the positive x-axis and the ray from (0,0) to the point (x,y).

Installation

npm install @stdlib/math-base-special-atan2

Usage

var atan2 = require( '@stdlib/math-base-special-atan2' );

atan2( y, x )

Computes the angle in the plane (in radians) between the positive x-axis and the ray from (0,0) to the point (x,y).

var v = atan2( 2.0, 2.0 ); // => atan(1.0)
// returns ~0.785

v = atan2( 6.0, 2.0 ); // => atan(3.0)
// returns ~1.249

v = atan2( -1.0, -1.0 ); // => atan(1.0) - π
// returns ~-2.356

v = atan2( 3.0, 0.0 ); // => π/2
// returns ~1.571

v = atan2( -2.0, 0.0 ); // => -π/2
// returns ~-1.571

v = atan2( 0.0, 0.0 );
// returns 0.0

v = atan2( 3.0, NaN );
// returns NaN

Examples

var randu = require( '@stdlib/random-base-randu' );
var atan2 = require( '@stdlib/math-base-special-atan2' );

var y;
var x;
var i;

for ( i = 0; i < 100; i++ ) {
    y = randu() * 100.0;
    x = randu() * 100.0;
    console.log( 'y: %d, \t x: %d, \t atan2(y,x): %d', y.toFixed( 4 ), x.toFixed( 4 ), atan2( y, x ).toFixed( 4 ) );
}

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C APIs

Usage

#include "stdlib/math/base/special/atan2.h"

stdlib_base_atan2( y, x )

Computes the angle in the plane (in radians) between the positive x-axis and the ray from (0,0) to the point (x,y).

double out = stdlib_base_atan2( 2.0, 2.0 ); 
// returns ~0.785

out = stdlib_base_atan2( 6.0, 2.0 );
// returns ~1.249

The function accepts the following arguments:

• y: [in] double - y coordinate
• x: [in] double - x coordinate

double stdlib_base_atan2( const double y, const double x );

Examples

#include "stdlib/math/base/special/atan2.h"
#include <stdlib.h>
#include <stdio.h>

int main( void ) {
    double y;
    double x;
    double v;
    int i;

    for ( i = 0; i < 100; i++ ) {
        y = ( ( (double)rand() / (double)RAND_MAX ) * 100.0 );
        x = ( ( (double)rand() / (double)RAND_MAX ) * 100.0 );
        v = stdlib_base_atan2( y, x );
        printf( "atan2(%lf, %lf) = %lf\n", y, x, v );
    }
    return 0;
}

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See Also

• @stdlib/math-base/special/atan: compute the arctangent of a double-precision floating-point number.

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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

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Copyright

Copyright © 2016-2024. The Stdlib Authors.

Changelog

0.3.0 (2024-07-28)

<section class="features">

Features

• 1cf574b - add C implementation for math/base/special/atan2

</section> <!-- /.features --> <section class="commits">

Commits

<details>

• 55ec8ed - docs: remove comment (by Athan Reines)
• 2777e4b - bench: resolve lint errors in benchmarks (by Athan Reines)
• 189c569 - docs: update related packages sections (#2194) (by stdlib-bot)
• 41d41e9 - test: include trailing newlines in Julia-generated JSON fixtures (by Philipp Burckhardt)
• 9ed7d0e - chore: add missing trailing newlines (by Philipp Burckhardt)
• a258a50 - chore: update package meta data (#2087) (by stdlib-bot, Philipp Burckhardt)
• 1cf574b - feat: add C implementation for math/base/special/atan2 (by Pushpendra Chandravanshi, stdlib-bot, Philipp Burckhardt, Pranav Goswami)

</details> </section> <!-- /.commits --> <section class="contributors">

Contributors

A total of 4 people contributed to this release. Thank you to the following contributors:

• Athan Reines
• Philipp Burckhardt
• Pranav Goswami
• Pushpendra Chandravanshi

</section> <!-- /.contributors --> </section> <!-- /.release --> <section class="release" id="v0.2.1">