atan2d

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

Installation

npm install @stdlib/math-base-special-atan2d

Usage

var atan2d = require( '@stdlib/math-base-special-atan2d' );

atan2d( y, x )

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

var v = atan2d( 2.0, 2.0 ); // => atand(1.0)
// returns ~45.0

v = atan2d( 6.0, 2.0 ); // => atand(3.0)
// returns ~71.565

v = atan2d( -1.0, -1.0 ); // => atand(1.0) - 180.0
// returns ~-135.0

v = atan2d( 3.0, 0.0 );
// returns 90.0

v = atan2d( -2.0, 0.0 );
// returns -90.0

v = atan2d( 0.0, 0.0 );
// returns 0.0

v = atan2d( 3.0, NaN );
// returns NaN

Examples

var uniform = require( '@stdlib/random-array-uniform' );
var logEachMap = require( '@stdlib/console-log-each-map' );
var atan2d = require( '@stdlib/math-base-special-atan2d' );

var x = uniform( 100, 0.0, 100.0 );
var y = uniform( 100, 0.0, 100.0 );

logEachMap( 'y: %0.4f, x: %0.4f, atan2d(y,x): %0.4f', y, x, atan2d );

C APIs

Usage

#include "stdlib/math/base/special/atan2d.h"

stdlib_base_atan2d( y, x )

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

double out = stdlib_base_atan2d( 2.0, 2.0 );
// returns ~45.0

out = stdlib_base_atan2d( 6.0, 2.0 );
// returns ~71.565

The function accepts the following arguments:

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

double stdlib_base_atan2d( const double y, const double x );

Examples

#include "stdlib/math/base/special/atan2d.h"
#include <stdlib.h>
#include <stdio.h>

static double random_uniform( const double min, const double max ) {
    double v = (double)rand() / ( (double)RAND_MAX + 1.0 );
    return min + ( v*(max-min) );
}

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

    for ( i = 0; i < 100; i++ ) {
        y = random_uniform( 0.0, 100.0 );
        x = random_uniform( 0.0, 100.0 );
        v = stdlib_base_atan2d( y, x );
        printf( "atan2d(%lf, %lf) = %lf\n", y, x, v );
    }
}

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 © 2016-2026. The Stdlib Authors.