Function _Sign

express/MathOp.cpp:447–449

Computes sign of x eltment-wise sign(x) = 0 if x=0 sign(x) =-1 if x<0 sign(x) = 1 if x>0 */

 sign(x) = 1 if x>0
 */
VARP _Sign(VARP x) {
    return _Unary(x, UnaryOpOperation_SIGN);
}

/*Computes the trignometric inverse tangent of x element-wise.
The atan operation returns the inverse of tan, such that if y = tan(x) then, x = atan(y).