Function Acos

tensorflow/compiler/xla/client/lib/math.cc:1118–1123

acos(x) = 2 * atan(sqrt(1 - x^2) / (1 + x)) if x != -1 pi if x == -1

// acos(x) = 2 * atan(sqrt(1 - x^2) / (1 + x)) if x != -1
//           pi                                if x == -1
XlaOp Acos(XlaOp x) {
  return Select(Ne(x, FullLike(x, -1)),
                ScalarLike(x, 2.0) * Atan2(Sqrt(ScalarLike(x, 1.0) - x * x),
                                           ScalarLike(x, 1.0) + x),
                FullLike(x, M_PI));
}

// asin(x) = 2 * atan(x / (1 + sqrt(1 - x^2)))
XlaOp Asin(XlaOp x) {