function atan( x ) {
	return addon( x );
}
Computes the arctangent of a double-precision floating-point number.

@private
@param {number} x - input value
@returns {number} arctangent (in radians)

@example
var v = atan( 0.0 );
// returns ~0.0

@example
var PI = require( '@stdlib/constants/float64/pi' );

var v = atan( -PI/4.0 );
// returns ~-0.666

@example
var PI = require( '@stdlib/constants/float64/pi' );

var v = atan( PI/4.0 );
// returns ~0.666

@example
var v = atan( NaN );
// returns NaN