}

// Atan returns the arctangent, in radians, of x.
//
// Special cases are:
//
//	Atan(±0) = ±0
//	Atan(±Inf) = ±Pi/2
func Atan(x float64) float64 {
	if haveArchAtan {
		return archAtan(x)
	}
	return atan(x)
}

func atan(x float64) float64 {
	if x == 0 {
		return x
	}
	if x > 0 {
		return satan(x)
	}
	return -satan(-x)

// 2.9e-17.  See also clog().

// Atan returns the inverse tangent of x.
func Atan(x complex128) complex128 {
	switch re, im := real(x), imag(x); {
	case im == 0:
		return complex(math.Atan(re), im)
	case re == 0 && math.Abs(im) <= 1:
		return complex(re, math.Atanh(im))
	case math.IsInf(im, 0) || math.IsInf(re, 0):
		if math.IsNaN(re) {
			return complex(math.NaN(), math.Copysign(0, im))
		}

	}
	sign := false
	if x < 0 {
		x = -x
		sign = true
	}
	if x > 1 {
		return NaN() // special case
	}

	temp := Sqrt(1 - x*x)
	if x > 0.7 {
		temp = Pi/2 - satan(temp/x)
	} else {
		temp = satan(x / temp)
	}

	if sign {
		temp = -temp
	}
	return temp
}

// Acos returns the arccosine, in radians, of x.
//
// Special case is:
//
//	Acos(x) = NaN if x < -1 or x > 1

			}
		}
		switch {
		case IsInf(y, 0):
			return Copysign(3*Pi/4, y)
		default:
			return Copysign(Pi, y)
		}
	case IsInf(y, 0):
		return Copysign(Pi/2, y)
	}

	// Call atan and determine the quadrant.
	q := Atan(y / x)
	if x < 0 {
		if q <= 0 {
			return q + Pi
		}
		return q - Pi
	}
	return q

GLOBL ·atanxmone<> + 0(SB), RODATA, $8

// Atan returns the arctangent, in radians, of the argument.
//
// Special cases are:
//      Atan(±0) = ±0
//      Atan(±Inf) = ±Pi/2Pi
// The algorithm used is minimax polynomial approximation
// with coefficients determined with a Remez exchange algorithm.

TEXT	·atanAsm(SB), NOSPLIT, $0-16
	FMOVD	x+0(FP), F0
	//special case Atan(±0) = ±0
	FMOVD   $(0.0), F1
	FCMPU   F0, F1

var TanhNoVec = tanh
var Log1pNovec = log1p
var AtanhNovec = atanh
var AcosNovec = acos
var AcoshNovec = acosh
var AsinNovec = asin
var AsinhNovec = asinh
var ErfNovec = erf
var ErfcNovec = erfc
var AtanNovec = atan
var Atan2Novec = atan2
var CbrtNovec = cbrt
var LogNovec = log
var TanNovec = tan
var ExpNovec = exp
var Expm1Novec = expm1
var PowNovec = pow
var HypotNovec = hypot

		}
	}
}
func TestAtan(t *testing.T) {
	for i := 0; i < len(vc); i++ {
		if f := Atan(vc[i]); !cVeryclose(atan[i], f) {
			t.Errorf("Atan(%g) = %g, want %g", vc[i], f, atan[i])
		}
	}
	for _, v := range atanSC {
		if f := Atan(v.in); !cAlike(v.want, f) {
			t.Errorf("Atan(%g) = %g, want %g", v.in, f, v.want)
		}
		if math.IsNaN(imag(v.in)) || math.IsNaN(imag(v.want)) {

}

TEST_F(CWiseUnaryGradTest, Atan) {
  auto x_fn = [this](const int i) { return RV({0, -1, 1, -2, 2, -3, 3}); };
  TestCWiseGrad<float, float>(ATAN, x_fn);
}

TEST_F(CWiseUnaryGradTest, Atan_Complex) {
  auto x_fn = [this](const int i) {
    return CRV({{1, 0}, {0, 1}, {2, -1}, {1, 2}, {3, 4}});
  };
  // TODO(kbsriram)
  // Add test when the atan kernel supports complex numbers

	if !HasVX {
		t.Skipf("no vector support")
	}
	for i := 0; i < len(vf); i++ {
		if f := AtanNovec(vf[i]); !veryclose(atan[i], f) {
			t.Errorf("Atan(%g) = %g, want %g", vf[i], f, atan[i])
		}
	}
	for i := 0; i < len(vfatanSC); i++ {
		if f := AtanNovec(vfatanSC[i]); !alike(atanSC[i], f) {
			t.Errorf("Atan(%g) = %g, want %g", vfatanSC[i], f, atanSC[i])
		}
	}
}

func TestAtan2Novec(t *testing.T) {
	if !HasVX {

func ExampleAsin() {
	fmt.Printf("%.2f", math.Asin(0))
	// Output: 0.00
}

func ExampleAsinh() {
	fmt.Printf("%.2f", math.Asinh(0))
	// Output: 0.00
}

func ExampleAtan() {
	fmt.Printf("%.2f", math.Atan(0))
	// Output: 0.00
}

func ExampleAtan2() {
	fmt.Printf("%.2f", math.Atan2(0, 0))
	// Output: 0.00
}

func ExampleAtanh() {
	fmt.Printf("%.2f", math.Atanh(0))
	// Output: 0.00
}