}
	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 {

			t.Errorf("Atan(%g) = %g, want %g", -v.in, f, -v.want)
		}
	}
	for _, pt := range branchPoints {
		if f0, f1 := Atan(pt[0]), Atan(pt[1]); !cVeryclose(f0, f1) {
			t.Errorf("Atan(%g) not continuous, got %g want %g", pt[0], f0, f1)
		}
	}
}
func TestAtanh(t *testing.T) {
	for i := 0; i < len(vc); i++ {
		if f := Atanh(vc[i]); !cVeryclose(atanh[i], f) {

	-Pi,             // atan2(-0, -Pi)
	-Pi,             // atan2(-0, -0)
	Copysign(0, -1), // atan2(-0, +0)
	Copysign(0, -1), // atan2(-0, +Pi)
	Copysign(0, -1), // atan2(-0, +Inf)
	NaN(),           // atan2(-0, NaN)
	Pi,              // atan2(+0, -Inf)
	Pi,              // atan2(+0, -Pi)
	Pi,              // atan2(+0, -0)
	0,               // atan2(+0, +0)
	0,               // atan2(+0, +Pi)
	0,               // atan2(+0, +Inf)

//	Atan2(+Inf, -Inf) = 3Pi/4
//	Atan2(-Inf, -Inf) = -3Pi/4
//	Atan2(y, +Inf) = 0
//	Atan2(y>0, -Inf) = +Pi
//	Atan2(y<0, -Inf) = -Pi
//	Atan2(+Inf, x) = +Pi/2
//	Atan2(-Inf, x) = -Pi/2
func Atan2(y, x float64) float64 {
	if haveArchAtan2 {
		return archAtan2(y, x)
	}
	return atan2(y, x)
}

func atan2(y, x float64) float64 {
	// special cases
	switch {
	case IsNaN(y) || IsNaN(x):
		return NaN()

//

// Atanh returns the inverse hyperbolic tangent of x.
//
// Special cases are:
//
//	Atanh(1) = +Inf
//	Atanh(±0) = ±0
//	Atanh(-1) = -Inf
//	Atanh(x) = NaN if x < -1 or x > 1
//	Atanh(NaN) = NaN
func Atanh(x float64) float64 {
	if haveArchAtanh {
		return archAtanh(x)
	}
	return atanh(x)
}

func atanh(x float64) float64 {
	const NearZero = 1.0 / (1 << 28) // 2**-28
	// special cases

var CoshNoVec = cosh
var SinNoVec = sin
var SinhNoVec = sinh
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

	}
	return Pi/4 + xatan((x-1)/(x+1)) + 0.5*Morebits
}

// 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)
	}

// had peak relative error 1.5e-16, rms relative error
// 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) {

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
}

func ExampleCopysign() {
	fmt.Printf("%.2f", math.Copysign(3.2, -1))
	// Output: -3.20
}

}

TEST_F(CWiseUnaryGradTest, Atanh) {
  auto x_fn = [this](const int i) { return RV({0, -0.5, 0.5, -0.1, 0.1}); };
  TestCWiseGrad<float, float>(ATANH, x_fn);
}

TEST_F(CWiseUnaryGradTest, Atanh_Complex) {
  auto x_fn = [this](const int i) {
    return CRV({{0.1, 0}, {0, 0.1}, {0.2, -0.1}, {0.1, 0.2}, {0.3, 0.4}});
  };
  TestCWiseGrad<complex64, complex64>(ATANH, x_fn);
}