Maksimov and Kolovsky, Equation (3)

Percentage Accurate: 73.8% → 99.0%
Time: 4.2s
Alternatives: 4
Speedup: N/A×

Specification

?
\[\begin{array}{l} \\ \begin{array}{l} t_0 := \cos \left(\frac{K}{2}\right)\\ \left(\left(-2 \cdot J\right) \cdot t\_0\right) \cdot \sqrt{1 + {\left(\frac{U}{\left(2 \cdot J\right) \cdot t\_0}\right)}^{2}} \end{array} \end{array} \]
(FPCore (J K U)
 :precision binary64
 (let* ((t_0 (cos (/ K 2.0))))
   (* (* (* -2.0 J) t_0) (sqrt (+ 1.0 (pow (/ U (* (* 2.0 J) t_0)) 2.0))))))
double code(double J, double K, double U) {
	double t_0 = cos((K / 2.0));
	return ((-2.0 * J) * t_0) * sqrt((1.0 + pow((U / ((2.0 * J) * t_0)), 2.0)));
}
module fmin_fmax_functions
    implicit none
    private
    public fmax
    public fmin

    interface fmax
        module procedure fmax88
        module procedure fmax44
        module procedure fmax84
        module procedure fmax48
    end interface
    interface fmin
        module procedure fmin88
        module procedure fmin44
        module procedure fmin84
        module procedure fmin48
    end interface
contains
    real(8) function fmax88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(4) function fmax44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(8) function fmax84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmax48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
    end function
    real(8) function fmin88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(4) function fmin44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(8) function fmin84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmin48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
    end function
end module

real(8) function code(j, k, u)
use fmin_fmax_functions
    real(8), intent (in) :: j
    real(8), intent (in) :: k
    real(8), intent (in) :: u
    real(8) :: t_0
    t_0 = cos((k / 2.0d0))
    code = (((-2.0d0) * j) * t_0) * sqrt((1.0d0 + ((u / ((2.0d0 * j) * t_0)) ** 2.0d0)))
end function
public static double code(double J, double K, double U) {
	double t_0 = Math.cos((K / 2.0));
	return ((-2.0 * J) * t_0) * Math.sqrt((1.0 + Math.pow((U / ((2.0 * J) * t_0)), 2.0)));
}
def code(J, K, U):
	t_0 = math.cos((K / 2.0))
	return ((-2.0 * J) * t_0) * math.sqrt((1.0 + math.pow((U / ((2.0 * J) * t_0)), 2.0)))
function code(J, K, U)
	t_0 = cos(Float64(K / 2.0))
	return Float64(Float64(Float64(-2.0 * J) * t_0) * sqrt(Float64(1.0 + (Float64(U / Float64(Float64(2.0 * J) * t_0)) ^ 2.0))))
end
function tmp = code(J, K, U)
	t_0 = cos((K / 2.0));
	tmp = ((-2.0 * J) * t_0) * sqrt((1.0 + ((U / ((2.0 * J) * t_0)) ^ 2.0)));
end
code[J_, K_, U_] := Block[{t$95$0 = N[Cos[N[(K / 2.0), $MachinePrecision]], $MachinePrecision]}, N[(N[(N[(-2.0 * J), $MachinePrecision] * t$95$0), $MachinePrecision] * N[Sqrt[N[(1.0 + N[Power[N[(U / N[(N[(2.0 * J), $MachinePrecision] * t$95$0), $MachinePrecision]), $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \cos \left(\frac{K}{2}\right)\\
\left(\left(-2 \cdot J\right) \cdot t\_0\right) \cdot \sqrt{1 + {\left(\frac{U}{\left(2 \cdot J\right) \cdot t\_0}\right)}^{2}}
\end{array}
\end{array}

Sampling outcomes in binary64 precision:

Local Percentage Accuracy vs ?

The average percentage accuracy by input value. Horizontal axis shows value of an input variable; the variable is choosen in the title. Vertical axis is accuracy; higher is better. Red represent the original program, while blue represents Herbie's suggestion. These can be toggled with buttons below the plot. The line is an average while dots represent individual samples.

Accuracy vs Speed?

Herbie found 4 alternatives:

AlternativeAccuracySpeedup
The accuracy (vertical axis) and speed (horizontal axis) of each alternatives. Up and to the right is better. The red square shows the initial program, and each blue circle shows an alternative.The line shows the best available speed-accuracy tradeoffs.

Initial Program: 73.8% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \cos \left(\frac{K}{2}\right)\\ \left(\left(-2 \cdot J\right) \cdot t\_0\right) \cdot \sqrt{1 + {\left(\frac{U}{\left(2 \cdot J\right) \cdot t\_0}\right)}^{2}} \end{array} \end{array} \]
(FPCore (J K U)
 :precision binary64
 (let* ((t_0 (cos (/ K 2.0))))
   (* (* (* -2.0 J) t_0) (sqrt (+ 1.0 (pow (/ U (* (* 2.0 J) t_0)) 2.0))))))
double code(double J, double K, double U) {
	double t_0 = cos((K / 2.0));
	return ((-2.0 * J) * t_0) * sqrt((1.0 + pow((U / ((2.0 * J) * t_0)), 2.0)));
}
module fmin_fmax_functions
    implicit none
    private
    public fmax
    public fmin

    interface fmax
        module procedure fmax88
        module procedure fmax44
        module procedure fmax84
        module procedure fmax48
    end interface
    interface fmin
        module procedure fmin88
        module procedure fmin44
        module procedure fmin84
        module procedure fmin48
    end interface
contains
    real(8) function fmax88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(4) function fmax44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(8) function fmax84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmax48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
    end function
    real(8) function fmin88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(4) function fmin44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(8) function fmin84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmin48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
    end function
end module

real(8) function code(j, k, u)
use fmin_fmax_functions
    real(8), intent (in) :: j
    real(8), intent (in) :: k
    real(8), intent (in) :: u
    real(8) :: t_0
    t_0 = cos((k / 2.0d0))
    code = (((-2.0d0) * j) * t_0) * sqrt((1.0d0 + ((u / ((2.0d0 * j) * t_0)) ** 2.0d0)))
end function
public static double code(double J, double K, double U) {
	double t_0 = Math.cos((K / 2.0));
	return ((-2.0 * J) * t_0) * Math.sqrt((1.0 + Math.pow((U / ((2.0 * J) * t_0)), 2.0)));
}
def code(J, K, U):
	t_0 = math.cos((K / 2.0))
	return ((-2.0 * J) * t_0) * math.sqrt((1.0 + math.pow((U / ((2.0 * J) * t_0)), 2.0)))
function code(J, K, U)
	t_0 = cos(Float64(K / 2.0))
	return Float64(Float64(Float64(-2.0 * J) * t_0) * sqrt(Float64(1.0 + (Float64(U / Float64(Float64(2.0 * J) * t_0)) ^ 2.0))))
end
function tmp = code(J, K, U)
	t_0 = cos((K / 2.0));
	tmp = ((-2.0 * J) * t_0) * sqrt((1.0 + ((U / ((2.0 * J) * t_0)) ^ 2.0)));
end
code[J_, K_, U_] := Block[{t$95$0 = N[Cos[N[(K / 2.0), $MachinePrecision]], $MachinePrecision]}, N[(N[(N[(-2.0 * J), $MachinePrecision] * t$95$0), $MachinePrecision] * N[Sqrt[N[(1.0 + N[Power[N[(U / N[(N[(2.0 * J), $MachinePrecision] * t$95$0), $MachinePrecision]), $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \cos \left(\frac{K}{2}\right)\\
\left(\left(-2 \cdot J\right) \cdot t\_0\right) \cdot \sqrt{1 + {\left(\frac{U}{\left(2 \cdot J\right) \cdot t\_0}\right)}^{2}}
\end{array}
\end{array}

Alternative 1: 99.0% accurate, N/A× speedup?

\[\begin{array}{l} U_m = \left|U\right| \\ J\_m = \left|J\right| \\ J\_s = \mathsf{copysign}\left(1, J\right) \\ \begin{array}{l} t_0 := \cos \left(\frac{K}{2}\right)\\ t_1 := \left(\left(-2 \cdot J\_m\right) \cdot t\_0\right) \cdot \sqrt{1 + {\left(\frac{U\_m}{\left(2 \cdot J\_m\right) \cdot t\_0}\right)}^{2}}\\ J\_s \cdot \begin{array}{l} \mathbf{if}\;t\_1 \leq -\infty:\\ \;\;\;\;-1 \cdot U\_m\\ \mathbf{elif}\;t\_1 \leq 10^{+293}:\\ \;\;\;\;t\_1\\ \mathbf{else}:\\ \;\;\;\;U\_m\\ \end{array} \end{array} \end{array} \]
U_m = (fabs.f64 U)
J\_m = (fabs.f64 J)
J\_s = (copysign.f64 #s(literal 1 binary64) J)
(FPCore (J_s J_m K U_m)
 :precision binary64
 (let* ((t_0 (cos (/ K 2.0)))
        (t_1
         (*
          (* (* -2.0 J_m) t_0)
          (sqrt (+ 1.0 (pow (/ U_m (* (* 2.0 J_m) t_0)) 2.0))))))
   (*
    J_s
    (if (<= t_1 (- INFINITY)) (* -1.0 U_m) (if (<= t_1 1e+293) t_1 U_m)))))
U_m = fabs(U);
J\_m = fabs(J);
J\_s = copysign(1.0, J);
double code(double J_s, double J_m, double K, double U_m) {
	double t_0 = cos((K / 2.0));
	double t_1 = ((-2.0 * J_m) * t_0) * sqrt((1.0 + pow((U_m / ((2.0 * J_m) * t_0)), 2.0)));
	double tmp;
	if (t_1 <= -((double) INFINITY)) {
		tmp = -1.0 * U_m;
	} else if (t_1 <= 1e+293) {
		tmp = t_1;
	} else {
		tmp = U_m;
	}
	return J_s * tmp;
}
U_m = Math.abs(U);
J\_m = Math.abs(J);
J\_s = Math.copySign(1.0, J);
public static double code(double J_s, double J_m, double K, double U_m) {
	double t_0 = Math.cos((K / 2.0));
	double t_1 = ((-2.0 * J_m) * t_0) * Math.sqrt((1.0 + Math.pow((U_m / ((2.0 * J_m) * t_0)), 2.0)));
	double tmp;
	if (t_1 <= -Double.POSITIVE_INFINITY) {
		tmp = -1.0 * U_m;
	} else if (t_1 <= 1e+293) {
		tmp = t_1;
	} else {
		tmp = U_m;
	}
	return J_s * tmp;
}
U_m = math.fabs(U)
J\_m = math.fabs(J)
J\_s = math.copysign(1.0, J)
def code(J_s, J_m, K, U_m):
	t_0 = math.cos((K / 2.0))
	t_1 = ((-2.0 * J_m) * t_0) * math.sqrt((1.0 + math.pow((U_m / ((2.0 * J_m) * t_0)), 2.0)))
	tmp = 0
	if t_1 <= -math.inf:
		tmp = -1.0 * U_m
	elif t_1 <= 1e+293:
		tmp = t_1
	else:
		tmp = U_m
	return J_s * tmp
U_m = abs(U)
J\_m = abs(J)
J\_s = copysign(1.0, J)
function code(J_s, J_m, K, U_m)
	t_0 = cos(Float64(K / 2.0))
	t_1 = Float64(Float64(Float64(-2.0 * J_m) * t_0) * sqrt(Float64(1.0 + (Float64(U_m / Float64(Float64(2.0 * J_m) * t_0)) ^ 2.0))))
	tmp = 0.0
	if (t_1 <= Float64(-Inf))
		tmp = Float64(-1.0 * U_m);
	elseif (t_1 <= 1e+293)
		tmp = t_1;
	else
		tmp = U_m;
	end
	return Float64(J_s * tmp)
end
U_m = abs(U);
J\_m = abs(J);
J\_s = sign(J) * abs(1.0);
function tmp_2 = code(J_s, J_m, K, U_m)
	t_0 = cos((K / 2.0));
	t_1 = ((-2.0 * J_m) * t_0) * sqrt((1.0 + ((U_m / ((2.0 * J_m) * t_0)) ^ 2.0)));
	tmp = 0.0;
	if (t_1 <= -Inf)
		tmp = -1.0 * U_m;
	elseif (t_1 <= 1e+293)
		tmp = t_1;
	else
		tmp = U_m;
	end
	tmp_2 = J_s * tmp;
end
U_m = N[Abs[U], $MachinePrecision]
J\_m = N[Abs[J], $MachinePrecision]
J\_s = N[With[{TMP1 = Abs[1.0], TMP2 = Sign[J]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
code[J$95$s_, J$95$m_, K_, U$95$m_] := Block[{t$95$0 = N[Cos[N[(K / 2.0), $MachinePrecision]], $MachinePrecision]}, Block[{t$95$1 = N[(N[(N[(-2.0 * J$95$m), $MachinePrecision] * t$95$0), $MachinePrecision] * N[Sqrt[N[(1.0 + N[Power[N[(U$95$m / N[(N[(2.0 * J$95$m), $MachinePrecision] * t$95$0), $MachinePrecision]), $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]}, N[(J$95$s * If[LessEqual[t$95$1, (-Infinity)], N[(-1.0 * U$95$m), $MachinePrecision], If[LessEqual[t$95$1, 1e+293], t$95$1, U$95$m]]), $MachinePrecision]]]
\begin{array}{l}
U_m = \left|U\right|
\\
J\_m = \left|J\right|
\\
J\_s = \mathsf{copysign}\left(1, J\right)

\\
\begin{array}{l}
t_0 := \cos \left(\frac{K}{2}\right)\\
t_1 := \left(\left(-2 \cdot J\_m\right) \cdot t\_0\right) \cdot \sqrt{1 + {\left(\frac{U\_m}{\left(2 \cdot J\_m\right) \cdot t\_0}\right)}^{2}}\\
J\_s \cdot \begin{array}{l}
\mathbf{if}\;t\_1 \leq -\infty:\\
\;\;\;\;-1 \cdot U\_m\\

\mathbf{elif}\;t\_1 \leq 10^{+293}:\\
\;\;\;\;t\_1\\

\mathbf{else}:\\
\;\;\;\;U\_m\\


\end{array}
\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if (*.f64 (*.f64 (*.f64 #s(literal -2 binary64) J) (cos.f64 (/.f64 K #s(literal 2 binary64)))) (sqrt.f64 (+.f64 #s(literal 1 binary64) (pow.f64 (/.f64 U (*.f64 (*.f64 #s(literal 2 binary64) J) (cos.f64 (/.f64 K #s(literal 2 binary64))))) #s(literal 2 binary64))))) < -inf.0

    1. Initial program 5.6%

      \[\left(\left(-2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)\right) \cdot \sqrt{1 + {\left(\frac{U}{\left(2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)}\right)}^{2}} \]
    2. Add Preprocessing
    3. Taylor expanded in J around 0

      \[\leadsto \color{blue}{-1 \cdot U} \]
    4. Step-by-step derivation
      1. lower-*.f6464.3

        \[\leadsto -1 \cdot \color{blue}{U} \]
    5. Applied rewrites64.3%

      \[\leadsto \color{blue}{-1 \cdot U} \]

    if -inf.0 < (*.f64 (*.f64 (*.f64 #s(literal -2 binary64) J) (cos.f64 (/.f64 K #s(literal 2 binary64)))) (sqrt.f64 (+.f64 #s(literal 1 binary64) (pow.f64 (/.f64 U (*.f64 (*.f64 #s(literal 2 binary64) J) (cos.f64 (/.f64 K #s(literal 2 binary64))))) #s(literal 2 binary64))))) < 9.9999999999999992e292

    1. Initial program 99.8%

      \[\left(\left(-2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)\right) \cdot \sqrt{1 + {\left(\frac{U}{\left(2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)}\right)}^{2}} \]
    2. Add Preprocessing

    if 9.9999999999999992e292 < (*.f64 (*.f64 (*.f64 #s(literal -2 binary64) J) (cos.f64 (/.f64 K #s(literal 2 binary64)))) (sqrt.f64 (+.f64 #s(literal 1 binary64) (pow.f64 (/.f64 U (*.f64 (*.f64 #s(literal 2 binary64) J) (cos.f64 (/.f64 K #s(literal 2 binary64))))) #s(literal 2 binary64)))))

    1. Initial program 13.3%

      \[\left(\left(-2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)\right) \cdot \sqrt{1 + {\left(\frac{U}{\left(2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)}\right)}^{2}} \]
    2. Add Preprocessing
    3. Taylor expanded in U around -inf

      \[\leadsto \color{blue}{U} \]
    4. Step-by-step derivation
      1. Applied rewrites45.5%

        \[\leadsto \color{blue}{U} \]
    5. Recombined 3 regimes into one program.
    6. Add Preprocessing

    Alternative 2: 97.5% accurate, N/A× speedup?

    \[\begin{array}{l} U_m = \left|U\right| \\ J\_m = \left|J\right| \\ J\_s = \mathsf{copysign}\left(1, J\right) \\ \begin{array}{l} t_0 := \cos \left(\frac{K}{2}\right)\\ t_1 := \left(-2 \cdot J\_m\right) \cdot t\_0\\ t_2 := t\_1 \cdot \sqrt{1 + {\left(\frac{U\_m}{\left(2 \cdot J\_m\right) \cdot t\_0}\right)}^{2}}\\ J\_s \cdot \begin{array}{l} \mathbf{if}\;t\_2 \leq -\infty:\\ \;\;\;\;-1 \cdot U\_m\\ \mathbf{elif}\;t\_2 \leq 10^{+293}:\\ \;\;\;\;t\_1 \cdot \cosh \sinh^{-1} \left(\frac{\frac{U\_m}{2 \cdot J\_m}}{t\_0}\right)\\ \mathbf{else}:\\ \;\;\;\;U\_m\\ \end{array} \end{array} \end{array} \]
    U_m = (fabs.f64 U)
    J\_m = (fabs.f64 J)
    J\_s = (copysign.f64 #s(literal 1 binary64) J)
    (FPCore (J_s J_m K U_m)
     :precision binary64
     (let* ((t_0 (cos (/ K 2.0)))
            (t_1 (* (* -2.0 J_m) t_0))
            (t_2 (* t_1 (sqrt (+ 1.0 (pow (/ U_m (* (* 2.0 J_m) t_0)) 2.0))))))
       (*
        J_s
        (if (<= t_2 (- INFINITY))
          (* -1.0 U_m)
          (if (<= t_2 1e+293)
            (* t_1 (cosh (asinh (/ (/ U_m (* 2.0 J_m)) t_0))))
            U_m)))))
    U_m = fabs(U);
    J\_m = fabs(J);
    J\_s = copysign(1.0, J);
    double code(double J_s, double J_m, double K, double U_m) {
    	double t_0 = cos((K / 2.0));
    	double t_1 = (-2.0 * J_m) * t_0;
    	double t_2 = t_1 * sqrt((1.0 + pow((U_m / ((2.0 * J_m) * t_0)), 2.0)));
    	double tmp;
    	if (t_2 <= -((double) INFINITY)) {
    		tmp = -1.0 * U_m;
    	} else if (t_2 <= 1e+293) {
    		tmp = t_1 * cosh(asinh(((U_m / (2.0 * J_m)) / t_0)));
    	} else {
    		tmp = U_m;
    	}
    	return J_s * tmp;
    }
    
    U_m = math.fabs(U)
    J\_m = math.fabs(J)
    J\_s = math.copysign(1.0, J)
    def code(J_s, J_m, K, U_m):
    	t_0 = math.cos((K / 2.0))
    	t_1 = (-2.0 * J_m) * t_0
    	t_2 = t_1 * math.sqrt((1.0 + math.pow((U_m / ((2.0 * J_m) * t_0)), 2.0)))
    	tmp = 0
    	if t_2 <= -math.inf:
    		tmp = -1.0 * U_m
    	elif t_2 <= 1e+293:
    		tmp = t_1 * math.cosh(math.asinh(((U_m / (2.0 * J_m)) / t_0)))
    	else:
    		tmp = U_m
    	return J_s * tmp
    
    U_m = abs(U)
    J\_m = abs(J)
    J\_s = copysign(1.0, J)
    function code(J_s, J_m, K, U_m)
    	t_0 = cos(Float64(K / 2.0))
    	t_1 = Float64(Float64(-2.0 * J_m) * t_0)
    	t_2 = Float64(t_1 * sqrt(Float64(1.0 + (Float64(U_m / Float64(Float64(2.0 * J_m) * t_0)) ^ 2.0))))
    	tmp = 0.0
    	if (t_2 <= Float64(-Inf))
    		tmp = Float64(-1.0 * U_m);
    	elseif (t_2 <= 1e+293)
    		tmp = Float64(t_1 * cosh(asinh(Float64(Float64(U_m / Float64(2.0 * J_m)) / t_0))));
    	else
    		tmp = U_m;
    	end
    	return Float64(J_s * tmp)
    end
    
    U_m = abs(U);
    J\_m = abs(J);
    J\_s = sign(J) * abs(1.0);
    function tmp_2 = code(J_s, J_m, K, U_m)
    	t_0 = cos((K / 2.0));
    	t_1 = (-2.0 * J_m) * t_0;
    	t_2 = t_1 * sqrt((1.0 + ((U_m / ((2.0 * J_m) * t_0)) ^ 2.0)));
    	tmp = 0.0;
    	if (t_2 <= -Inf)
    		tmp = -1.0 * U_m;
    	elseif (t_2 <= 1e+293)
    		tmp = t_1 * cosh(asinh(((U_m / (2.0 * J_m)) / t_0)));
    	else
    		tmp = U_m;
    	end
    	tmp_2 = J_s * tmp;
    end
    
    U_m = N[Abs[U], $MachinePrecision]
    J\_m = N[Abs[J], $MachinePrecision]
    J\_s = N[With[{TMP1 = Abs[1.0], TMP2 = Sign[J]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
    code[J$95$s_, J$95$m_, K_, U$95$m_] := Block[{t$95$0 = N[Cos[N[(K / 2.0), $MachinePrecision]], $MachinePrecision]}, Block[{t$95$1 = N[(N[(-2.0 * J$95$m), $MachinePrecision] * t$95$0), $MachinePrecision]}, Block[{t$95$2 = N[(t$95$1 * N[Sqrt[N[(1.0 + N[Power[N[(U$95$m / N[(N[(2.0 * J$95$m), $MachinePrecision] * t$95$0), $MachinePrecision]), $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]}, N[(J$95$s * If[LessEqual[t$95$2, (-Infinity)], N[(-1.0 * U$95$m), $MachinePrecision], If[LessEqual[t$95$2, 1e+293], N[(t$95$1 * N[Cosh[N[ArcSinh[N[(N[(U$95$m / N[(2.0 * J$95$m), $MachinePrecision]), $MachinePrecision] / t$95$0), $MachinePrecision]], $MachinePrecision]], $MachinePrecision]), $MachinePrecision], U$95$m]]), $MachinePrecision]]]]
    
    \begin{array}{l}
    U_m = \left|U\right|
    \\
    J\_m = \left|J\right|
    \\
    J\_s = \mathsf{copysign}\left(1, J\right)
    
    \\
    \begin{array}{l}
    t_0 := \cos \left(\frac{K}{2}\right)\\
    t_1 := \left(-2 \cdot J\_m\right) \cdot t\_0\\
    t_2 := t\_1 \cdot \sqrt{1 + {\left(\frac{U\_m}{\left(2 \cdot J\_m\right) \cdot t\_0}\right)}^{2}}\\
    J\_s \cdot \begin{array}{l}
    \mathbf{if}\;t\_2 \leq -\infty:\\
    \;\;\;\;-1 \cdot U\_m\\
    
    \mathbf{elif}\;t\_2 \leq 10^{+293}:\\
    \;\;\;\;t\_1 \cdot \cosh \sinh^{-1} \left(\frac{\frac{U\_m}{2 \cdot J\_m}}{t\_0}\right)\\
    
    \mathbf{else}:\\
    \;\;\;\;U\_m\\
    
    
    \end{array}
    \end{array}
    \end{array}
    
    Derivation
    1. Split input into 3 regimes
    2. if (*.f64 (*.f64 (*.f64 #s(literal -2 binary64) J) (cos.f64 (/.f64 K #s(literal 2 binary64)))) (sqrt.f64 (+.f64 #s(literal 1 binary64) (pow.f64 (/.f64 U (*.f64 (*.f64 #s(literal 2 binary64) J) (cos.f64 (/.f64 K #s(literal 2 binary64))))) #s(literal 2 binary64))))) < -inf.0

      1. Initial program 5.6%

        \[\left(\left(-2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)\right) \cdot \sqrt{1 + {\left(\frac{U}{\left(2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)}\right)}^{2}} \]
      2. Add Preprocessing
      3. Taylor expanded in J around 0

        \[\leadsto \color{blue}{-1 \cdot U} \]
      4. Step-by-step derivation
        1. lower-*.f6464.3

          \[\leadsto -1 \cdot \color{blue}{U} \]
      5. Applied rewrites64.3%

        \[\leadsto \color{blue}{-1 \cdot U} \]

      if -inf.0 < (*.f64 (*.f64 (*.f64 #s(literal -2 binary64) J) (cos.f64 (/.f64 K #s(literal 2 binary64)))) (sqrt.f64 (+.f64 #s(literal 1 binary64) (pow.f64 (/.f64 U (*.f64 (*.f64 #s(literal 2 binary64) J) (cos.f64 (/.f64 K #s(literal 2 binary64))))) #s(literal 2 binary64))))) < 9.9999999999999992e292

      1. Initial program 99.8%

        \[\left(\left(-2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)\right) \cdot \sqrt{1 + {\left(\frac{U}{\left(2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)}\right)}^{2}} \]
      2. Add Preprocessing
      3. Step-by-step derivation
        1. lift-sqrt.f64N/A

          \[\leadsto \left(\left(-2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)\right) \cdot \color{blue}{\sqrt{1 + {\left(\frac{U}{\left(2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)}\right)}^{2}}} \]
        2. lift-+.f64N/A

          \[\leadsto \left(\left(-2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)\right) \cdot \sqrt{\color{blue}{1 + {\left(\frac{U}{\left(2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)}\right)}^{2}}} \]
        3. lift-pow.f64N/A

          \[\leadsto \left(\left(-2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)\right) \cdot \sqrt{1 + \color{blue}{{\left(\frac{U}{\left(2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)}\right)}^{2}}} \]
        4. lift-/.f64N/A

          \[\leadsto \left(\left(-2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)\right) \cdot \sqrt{1 + {\color{blue}{\left(\frac{U}{\left(2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)}\right)}}^{2}} \]
        5. lift-*.f64N/A

          \[\leadsto \left(\left(-2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)\right) \cdot \sqrt{1 + {\left(\frac{U}{\color{blue}{\left(2 \cdot J\right)} \cdot \cos \left(\frac{K}{2}\right)}\right)}^{2}} \]
        6. lift-*.f64N/A

          \[\leadsto \left(\left(-2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)\right) \cdot \sqrt{1 + {\left(\frac{U}{\color{blue}{\left(2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)}}\right)}^{2}} \]
        7. lift-/.f64N/A

          \[\leadsto \left(\left(-2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)\right) \cdot \sqrt{1 + {\left(\frac{U}{\left(2 \cdot J\right) \cdot \cos \color{blue}{\left(\frac{K}{2}\right)}}\right)}^{2}} \]
        8. lift-cos.f64N/A

          \[\leadsto \left(\left(-2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)\right) \cdot \sqrt{1 + {\left(\frac{U}{\left(2 \cdot J\right) \cdot \color{blue}{\cos \left(\frac{K}{2}\right)}}\right)}^{2}} \]
        9. +-commutativeN/A

          \[\leadsto \left(\left(-2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)\right) \cdot \sqrt{\color{blue}{{\left(\frac{U}{\left(2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)}\right)}^{2} + 1}} \]
        10. unpow2N/A

          \[\leadsto \left(\left(-2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)\right) \cdot \sqrt{\color{blue}{\frac{U}{\left(2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)} \cdot \frac{U}{\left(2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)}} + 1} \]
        11. cosh-asinh-revN/A

          \[\leadsto \left(\left(-2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)\right) \cdot \color{blue}{\cosh \sinh^{-1} \left(\frac{U}{\left(2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)}\right)} \]
        12. lower-cosh.f64N/A

          \[\leadsto \left(\left(-2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)\right) \cdot \color{blue}{\cosh \sinh^{-1} \left(\frac{U}{\left(2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)}\right)} \]
        13. lower-asinh.f64N/A

          \[\leadsto \left(\left(-2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)\right) \cdot \cosh \color{blue}{\sinh^{-1} \left(\frac{U}{\left(2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)}\right)} \]
      4. Applied rewrites97.9%

        \[\leadsto \left(\left(-2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)\right) \cdot \color{blue}{\cosh \sinh^{-1} \left(\frac{\frac{U}{2 \cdot J}}{\cos \left(\frac{K}{2}\right)}\right)} \]

      if 9.9999999999999992e292 < (*.f64 (*.f64 (*.f64 #s(literal -2 binary64) J) (cos.f64 (/.f64 K #s(literal 2 binary64)))) (sqrt.f64 (+.f64 #s(literal 1 binary64) (pow.f64 (/.f64 U (*.f64 (*.f64 #s(literal 2 binary64) J) (cos.f64 (/.f64 K #s(literal 2 binary64))))) #s(literal 2 binary64)))))

      1. Initial program 13.3%

        \[\left(\left(-2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)\right) \cdot \sqrt{1 + {\left(\frac{U}{\left(2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)}\right)}^{2}} \]
      2. Add Preprocessing
      3. Taylor expanded in U around -inf

        \[\leadsto \color{blue}{U} \]
      4. Step-by-step derivation
        1. Applied rewrites45.5%

          \[\leadsto \color{blue}{U} \]
      5. Recombined 3 regimes into one program.
      6. Add Preprocessing

      Alternative 3: 51.0% accurate, N/A× speedup?

      \[\begin{array}{l} U_m = \left|U\right| \\ J\_m = \left|J\right| \\ J\_s = \mathsf{copysign}\left(1, J\right) \\ J\_s \cdot \begin{array}{l} \mathbf{if}\;\cos \left(\frac{K}{2}\right) \leq -2 \cdot 10^{-310}:\\ \;\;\;\;U\_m\\ \mathbf{else}:\\ \;\;\;\;-1 \cdot U\_m\\ \end{array} \end{array} \]
      U_m = (fabs.f64 U)
      J\_m = (fabs.f64 J)
      J\_s = (copysign.f64 #s(literal 1 binary64) J)
      (FPCore (J_s J_m K U_m)
       :precision binary64
       (* J_s (if (<= (cos (/ K 2.0)) -2e-310) U_m (* -1.0 U_m))))
      U_m = fabs(U);
      J\_m = fabs(J);
      J\_s = copysign(1.0, J);
      double code(double J_s, double J_m, double K, double U_m) {
      	double tmp;
      	if (cos((K / 2.0)) <= -2e-310) {
      		tmp = U_m;
      	} else {
      		tmp = -1.0 * U_m;
      	}
      	return J_s * tmp;
      }
      
      U_m =     private
      J\_m =     private
      J\_s =     private
      module fmin_fmax_functions
          implicit none
          private
          public fmax
          public fmin
      
          interface fmax
              module procedure fmax88
              module procedure fmax44
              module procedure fmax84
              module procedure fmax48
          end interface
          interface fmin
              module procedure fmin88
              module procedure fmin44
              module procedure fmin84
              module procedure fmin48
          end interface
      contains
          real(8) function fmax88(x, y) result (res)
              real(8), intent (in) :: x
              real(8), intent (in) :: y
              res = merge(y, merge(x, max(x, y), y /= y), x /= x)
          end function
          real(4) function fmax44(x, y) result (res)
              real(4), intent (in) :: x
              real(4), intent (in) :: y
              res = merge(y, merge(x, max(x, y), y /= y), x /= x)
          end function
          real(8) function fmax84(x, y) result(res)
              real(8), intent (in) :: x
              real(4), intent (in) :: y
              res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
          end function
          real(8) function fmax48(x, y) result(res)
              real(4), intent (in) :: x
              real(8), intent (in) :: y
              res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
          end function
          real(8) function fmin88(x, y) result (res)
              real(8), intent (in) :: x
              real(8), intent (in) :: y
              res = merge(y, merge(x, min(x, y), y /= y), x /= x)
          end function
          real(4) function fmin44(x, y) result (res)
              real(4), intent (in) :: x
              real(4), intent (in) :: y
              res = merge(y, merge(x, min(x, y), y /= y), x /= x)
          end function
          real(8) function fmin84(x, y) result(res)
              real(8), intent (in) :: x
              real(4), intent (in) :: y
              res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
          end function
          real(8) function fmin48(x, y) result(res)
              real(4), intent (in) :: x
              real(8), intent (in) :: y
              res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
          end function
      end module
      
      real(8) function code(j_s, j_m, k, u_m)
      use fmin_fmax_functions
          real(8), intent (in) :: j_s
          real(8), intent (in) :: j_m
          real(8), intent (in) :: k
          real(8), intent (in) :: u_m
          real(8) :: tmp
          if (cos((k / 2.0d0)) <= (-2d-310)) then
              tmp = u_m
          else
              tmp = (-1.0d0) * u_m
          end if
          code = j_s * tmp
      end function
      
      U_m = Math.abs(U);
      J\_m = Math.abs(J);
      J\_s = Math.copySign(1.0, J);
      public static double code(double J_s, double J_m, double K, double U_m) {
      	double tmp;
      	if (Math.cos((K / 2.0)) <= -2e-310) {
      		tmp = U_m;
      	} else {
      		tmp = -1.0 * U_m;
      	}
      	return J_s * tmp;
      }
      
      U_m = math.fabs(U)
      J\_m = math.fabs(J)
      J\_s = math.copysign(1.0, J)
      def code(J_s, J_m, K, U_m):
      	tmp = 0
      	if math.cos((K / 2.0)) <= -2e-310:
      		tmp = U_m
      	else:
      		tmp = -1.0 * U_m
      	return J_s * tmp
      
      U_m = abs(U)
      J\_m = abs(J)
      J\_s = copysign(1.0, J)
      function code(J_s, J_m, K, U_m)
      	tmp = 0.0
      	if (cos(Float64(K / 2.0)) <= -2e-310)
      		tmp = U_m;
      	else
      		tmp = Float64(-1.0 * U_m);
      	end
      	return Float64(J_s * tmp)
      end
      
      U_m = abs(U);
      J\_m = abs(J);
      J\_s = sign(J) * abs(1.0);
      function tmp_2 = code(J_s, J_m, K, U_m)
      	tmp = 0.0;
      	if (cos((K / 2.0)) <= -2e-310)
      		tmp = U_m;
      	else
      		tmp = -1.0 * U_m;
      	end
      	tmp_2 = J_s * tmp;
      end
      
      U_m = N[Abs[U], $MachinePrecision]
      J\_m = N[Abs[J], $MachinePrecision]
      J\_s = N[With[{TMP1 = Abs[1.0], TMP2 = Sign[J]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
      code[J$95$s_, J$95$m_, K_, U$95$m_] := N[(J$95$s * If[LessEqual[N[Cos[N[(K / 2.0), $MachinePrecision]], $MachinePrecision], -2e-310], U$95$m, N[(-1.0 * U$95$m), $MachinePrecision]]), $MachinePrecision]
      
      \begin{array}{l}
      U_m = \left|U\right|
      \\
      J\_m = \left|J\right|
      \\
      J\_s = \mathsf{copysign}\left(1, J\right)
      
      \\
      J\_s \cdot \begin{array}{l}
      \mathbf{if}\;\cos \left(\frac{K}{2}\right) \leq -2 \cdot 10^{-310}:\\
      \;\;\;\;U\_m\\
      
      \mathbf{else}:\\
      \;\;\;\;-1 \cdot U\_m\\
      
      
      \end{array}
      \end{array}
      
      Derivation
      1. Split input into 2 regimes
      2. if (cos.f64 (/.f64 K #s(literal 2 binary64))) < -1.999999999999994e-310

        1. Initial program 62.5%

          \[\left(\left(-2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)\right) \cdot \sqrt{1 + {\left(\frac{U}{\left(2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)}\right)}^{2}} \]
        2. Add Preprocessing
        3. Taylor expanded in U around -inf

          \[\leadsto \color{blue}{U} \]
        4. Step-by-step derivation
          1. Applied rewrites29.7%

            \[\leadsto \color{blue}{U} \]

          if -1.999999999999994e-310 < (cos.f64 (/.f64 K #s(literal 2 binary64)))

          1. Initial program 71.3%

            \[\left(\left(-2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)\right) \cdot \sqrt{1 + {\left(\frac{U}{\left(2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)}\right)}^{2}} \]
          2. Add Preprocessing
          3. Taylor expanded in J around 0

            \[\leadsto \color{blue}{-1 \cdot U} \]
          4. Step-by-step derivation
            1. lower-*.f6426.9

              \[\leadsto -1 \cdot \color{blue}{U} \]
          5. Applied rewrites26.9%

            \[\leadsto \color{blue}{-1 \cdot U} \]
        5. Recombined 2 regimes into one program.
        6. Add Preprocessing

        Alternative 4: 13.7% accurate, N/A× speedup?

        \[\begin{array}{l} U_m = \left|U\right| \\ J\_m = \left|J\right| \\ J\_s = \mathsf{copysign}\left(1, J\right) \\ J\_s \cdot U\_m \end{array} \]
        U_m = (fabs.f64 U)
        J\_m = (fabs.f64 J)
        J\_s = (copysign.f64 #s(literal 1 binary64) J)
        (FPCore (J_s J_m K U_m) :precision binary64 (* J_s U_m))
        U_m = fabs(U);
        J\_m = fabs(J);
        J\_s = copysign(1.0, J);
        double code(double J_s, double J_m, double K, double U_m) {
        	return J_s * U_m;
        }
        
        U_m =     private
        J\_m =     private
        J\_s =     private
        module fmin_fmax_functions
            implicit none
            private
            public fmax
            public fmin
        
            interface fmax
                module procedure fmax88
                module procedure fmax44
                module procedure fmax84
                module procedure fmax48
            end interface
            interface fmin
                module procedure fmin88
                module procedure fmin44
                module procedure fmin84
                module procedure fmin48
            end interface
        contains
            real(8) function fmax88(x, y) result (res)
                real(8), intent (in) :: x
                real(8), intent (in) :: y
                res = merge(y, merge(x, max(x, y), y /= y), x /= x)
            end function
            real(4) function fmax44(x, y) result (res)
                real(4), intent (in) :: x
                real(4), intent (in) :: y
                res = merge(y, merge(x, max(x, y), y /= y), x /= x)
            end function
            real(8) function fmax84(x, y) result(res)
                real(8), intent (in) :: x
                real(4), intent (in) :: y
                res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
            end function
            real(8) function fmax48(x, y) result(res)
                real(4), intent (in) :: x
                real(8), intent (in) :: y
                res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
            end function
            real(8) function fmin88(x, y) result (res)
                real(8), intent (in) :: x
                real(8), intent (in) :: y
                res = merge(y, merge(x, min(x, y), y /= y), x /= x)
            end function
            real(4) function fmin44(x, y) result (res)
                real(4), intent (in) :: x
                real(4), intent (in) :: y
                res = merge(y, merge(x, min(x, y), y /= y), x /= x)
            end function
            real(8) function fmin84(x, y) result(res)
                real(8), intent (in) :: x
                real(4), intent (in) :: y
                res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
            end function
            real(8) function fmin48(x, y) result(res)
                real(4), intent (in) :: x
                real(8), intent (in) :: y
                res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
            end function
        end module
        
        real(8) function code(j_s, j_m, k, u_m)
        use fmin_fmax_functions
            real(8), intent (in) :: j_s
            real(8), intent (in) :: j_m
            real(8), intent (in) :: k
            real(8), intent (in) :: u_m
            code = j_s * u_m
        end function
        
        U_m = Math.abs(U);
        J\_m = Math.abs(J);
        J\_s = Math.copySign(1.0, J);
        public static double code(double J_s, double J_m, double K, double U_m) {
        	return J_s * U_m;
        }
        
        U_m = math.fabs(U)
        J\_m = math.fabs(J)
        J\_s = math.copysign(1.0, J)
        def code(J_s, J_m, K, U_m):
        	return J_s * U_m
        
        U_m = abs(U)
        J\_m = abs(J)
        J\_s = copysign(1.0, J)
        function code(J_s, J_m, K, U_m)
        	return Float64(J_s * U_m)
        end
        
        U_m = abs(U);
        J\_m = abs(J);
        J\_s = sign(J) * abs(1.0);
        function tmp = code(J_s, J_m, K, U_m)
        	tmp = J_s * U_m;
        end
        
        U_m = N[Abs[U], $MachinePrecision]
        J\_m = N[Abs[J], $MachinePrecision]
        J\_s = N[With[{TMP1 = Abs[1.0], TMP2 = Sign[J]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
        code[J$95$s_, J$95$m_, K_, U$95$m_] := N[(J$95$s * U$95$m), $MachinePrecision]
        
        \begin{array}{l}
        U_m = \left|U\right|
        \\
        J\_m = \left|J\right|
        \\
        J\_s = \mathsf{copysign}\left(1, J\right)
        
        \\
        J\_s \cdot U\_m
        \end{array}
        
        Derivation
        1. Initial program 68.9%

          \[\left(\left(-2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)\right) \cdot \sqrt{1 + {\left(\frac{U}{\left(2 \cdot J\right) \cdot \cos \left(\frac{K}{2}\right)}\right)}^{2}} \]
        2. Add Preprocessing
        3. Taylor expanded in U around -inf

          \[\leadsto \color{blue}{U} \]
        4. Step-by-step derivation
          1. Applied rewrites26.4%

            \[\leadsto \color{blue}{U} \]
          2. Add Preprocessing

          Reproduce

          ?
          herbie shell --seed 2025064 
          (FPCore (J K U)
            :name "Maksimov and Kolovsky, Equation (3)"
            :precision binary64
            (* (* (* -2.0 J) (cos (/ K 2.0))) (sqrt (+ 1.0 (pow (/ U (* (* 2.0 J) (cos (/ K 2.0)))) 2.0)))))