README.md

atan2f

Compute the angle in the plane (in radians) between the positive x-axis and the ray from (0,0) to the point (x,y) of a single-precision floating-point number.

Usage

var atan2f = require( '@stdlib/math/base/special/atan2f' );

atan2f( 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) of a single-precision floating-point number.

var v = atan2f( 2.0, 2.0 ); // => atanf(1.0)
// returns ~0.785

v = atan2f( 6.0, 2.0 ); // => atanf(3.0)
// returns ~1.249

v = atan2f( -1.0, -1.0 ); // => atanf(1.0) - π
// returns ~-2.356

v = atan2f( 3.0, 0.0 ); // => π/2
// returns ~1.571

v = atan2f( -2.0, 0.0 ); // => -π/2
// returns ~-1.571

v = atan2f( 0.0, 0.0 );
// returns 0.0

v = atan2f( 3.0, NaN );
// returns NaN

Examples

var randu = require( '@stdlib/random/base/randu' );
var atan2f = require( '@stdlib/math/base/special/atan2f' );

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 atan2f(y,x): %d', y.toFixed( 4 ), x.toFixed( 4 ), atan2f( y, x ).toFixed( 4 ) );
}

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C APIs

Usage

#include "stdlib/math/base/special/atan2f.h"

stdlib_base_atan2f( 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) of a single-precision floating-point number.

double out = stdlib_base_atan2f( 2.0, 2.0 );
// returns ~0.785

out = stdlib_base_atan2f( 6.0, 2.0 );
// returns ~1.249

The function accepts the following arguments:

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

float stdlib_base_atan2f( const float y, const float x );

Examples

#include "stdlib/math/base/special/atan2f.h"
#include <stdlib.h>
#include <stdio.h>

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

    for ( i = 0; i < 100; i++ ) {
        y = ( ( (float)rand() / (float)RAND_MAX ) * 100.0 );
        x = ( ( (float)rand() / (float)RAND_MAX ) * 100.0 );
        v = stdlib_base_atan2f( y, x );
        printf( "atan2f(%f, %f) = %f\n", y, x, v );
    }
    return 0;
}

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See Also

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