datatable.math.atan2()

datatable.math.

atan2

(

x

,

y

)

source

The inverse trigonometric tangent of y/x, taking into account the signs of x and y to produce the correct result.

If (x,y) is a point in a Cartesian plane, then arctan2(y, x) returns the radian measure of an angle formed by two rays: one starting at the origin and passing through point (0,1), and the other starting at the origin and passing through point (x,y). The angle is assumed positive if the rotation from the first ray to the second occurs counter-clockwise, and negative otherwise.

As a special case, arctan2(0, 0) == 0, and arctan2(0, -1) == tau/2.

See also

• arctan(x) – inverse tangent function.