Toniolo and Linder, Equation (3a)

Percentage Accurate: 98.5% → 98.5%
Time: 10.3s
Alternatives: 5
Speedup: N/A×

Specification

?
\[\begin{array}{l} \\ \sqrt{\frac{1}{2} \cdot \left(1 + \frac{1}{\sqrt{1 + {\left(\frac{2 \cdot \ell}{Om}\right)}^{2} \cdot \left({\sin kx}^{2} + {\sin ky}^{2}\right)}}\right)} \end{array} \]
(FPCore (l Om kx ky)
 :precision binary64
 (sqrt
  (*
   (/ 1.0 2.0)
   (+
    1.0
    (/
     1.0
     (sqrt
      (+
       1.0
       (*
        (pow (/ (* 2.0 l) Om) 2.0)
        (+ (pow (sin kx) 2.0) (pow (sin ky) 2.0))))))))))
double code(double l, double Om, double kx, double ky) {
	return sqrt(((1.0 / 2.0) * (1.0 + (1.0 / sqrt((1.0 + (pow(((2.0 * l) / Om), 2.0) * (pow(sin(kx), 2.0) + pow(sin(ky), 2.0)))))))));
}
real(8) function code(l, om, kx, ky)
    real(8), intent (in) :: l
    real(8), intent (in) :: om
    real(8), intent (in) :: kx
    real(8), intent (in) :: ky
    code = sqrt(((1.0d0 / 2.0d0) * (1.0d0 + (1.0d0 / sqrt((1.0d0 + ((((2.0d0 * l) / om) ** 2.0d0) * ((sin(kx) ** 2.0d0) + (sin(ky) ** 2.0d0)))))))))
end function
public static double code(double l, double Om, double kx, double ky) {
	return Math.sqrt(((1.0 / 2.0) * (1.0 + (1.0 / Math.sqrt((1.0 + (Math.pow(((2.0 * l) / Om), 2.0) * (Math.pow(Math.sin(kx), 2.0) + Math.pow(Math.sin(ky), 2.0)))))))));
}
def code(l, Om, kx, ky):
	return math.sqrt(((1.0 / 2.0) * (1.0 + (1.0 / math.sqrt((1.0 + (math.pow(((2.0 * l) / Om), 2.0) * (math.pow(math.sin(kx), 2.0) + math.pow(math.sin(ky), 2.0)))))))))
function code(l, Om, kx, ky)
	return sqrt(Float64(Float64(1.0 / 2.0) * Float64(1.0 + Float64(1.0 / sqrt(Float64(1.0 + Float64((Float64(Float64(2.0 * l) / Om) ^ 2.0) * Float64((sin(kx) ^ 2.0) + (sin(ky) ^ 2.0)))))))))
end
function tmp = code(l, Om, kx, ky)
	tmp = sqrt(((1.0 / 2.0) * (1.0 + (1.0 / sqrt((1.0 + ((((2.0 * l) / Om) ^ 2.0) * ((sin(kx) ^ 2.0) + (sin(ky) ^ 2.0)))))))));
end
code[l_, Om_, kx_, ky_] := N[Sqrt[N[(N[(1.0 / 2.0), $MachinePrecision] * N[(1.0 + N[(1.0 / N[Sqrt[N[(1.0 + N[(N[Power[N[(N[(2.0 * l), $MachinePrecision] / Om), $MachinePrecision], 2.0], $MachinePrecision] * N[(N[Power[N[Sin[kx], $MachinePrecision], 2.0], $MachinePrecision] + N[Power[N[Sin[ky], $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
\sqrt{\frac{1}{2} \cdot \left(1 + \frac{1}{\sqrt{1 + {\left(\frac{2 \cdot \ell}{Om}\right)}^{2} \cdot \left({\sin kx}^{2} + {\sin ky}^{2}\right)}}\right)}
\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 5 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: 98.5% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \sqrt{\frac{1}{2} \cdot \left(1 + \frac{1}{\sqrt{1 + {\left(\frac{2 \cdot \ell}{Om}\right)}^{2} \cdot \left({\sin kx}^{2} + {\sin ky}^{2}\right)}}\right)} \end{array} \]
(FPCore (l Om kx ky)
 :precision binary64
 (sqrt
  (*
   (/ 1.0 2.0)
   (+
    1.0
    (/
     1.0
     (sqrt
      (+
       1.0
       (*
        (pow (/ (* 2.0 l) Om) 2.0)
        (+ (pow (sin kx) 2.0) (pow (sin ky) 2.0))))))))))
double code(double l, double Om, double kx, double ky) {
	return sqrt(((1.0 / 2.0) * (1.0 + (1.0 / sqrt((1.0 + (pow(((2.0 * l) / Om), 2.0) * (pow(sin(kx), 2.0) + pow(sin(ky), 2.0)))))))));
}
real(8) function code(l, om, kx, ky)
    real(8), intent (in) :: l
    real(8), intent (in) :: om
    real(8), intent (in) :: kx
    real(8), intent (in) :: ky
    code = sqrt(((1.0d0 / 2.0d0) * (1.0d0 + (1.0d0 / sqrt((1.0d0 + ((((2.0d0 * l) / om) ** 2.0d0) * ((sin(kx) ** 2.0d0) + (sin(ky) ** 2.0d0)))))))))
end function
public static double code(double l, double Om, double kx, double ky) {
	return Math.sqrt(((1.0 / 2.0) * (1.0 + (1.0 / Math.sqrt((1.0 + (Math.pow(((2.0 * l) / Om), 2.0) * (Math.pow(Math.sin(kx), 2.0) + Math.pow(Math.sin(ky), 2.0)))))))));
}
def code(l, Om, kx, ky):
	return math.sqrt(((1.0 / 2.0) * (1.0 + (1.0 / math.sqrt((1.0 + (math.pow(((2.0 * l) / Om), 2.0) * (math.pow(math.sin(kx), 2.0) + math.pow(math.sin(ky), 2.0)))))))))
function code(l, Om, kx, ky)
	return sqrt(Float64(Float64(1.0 / 2.0) * Float64(1.0 + Float64(1.0 / sqrt(Float64(1.0 + Float64((Float64(Float64(2.0 * l) / Om) ^ 2.0) * Float64((sin(kx) ^ 2.0) + (sin(ky) ^ 2.0)))))))))
end
function tmp = code(l, Om, kx, ky)
	tmp = sqrt(((1.0 / 2.0) * (1.0 + (1.0 / sqrt((1.0 + ((((2.0 * l) / Om) ^ 2.0) * ((sin(kx) ^ 2.0) + (sin(ky) ^ 2.0)))))))));
end
code[l_, Om_, kx_, ky_] := N[Sqrt[N[(N[(1.0 / 2.0), $MachinePrecision] * N[(1.0 + N[(1.0 / N[Sqrt[N[(1.0 + N[(N[Power[N[(N[(2.0 * l), $MachinePrecision] / Om), $MachinePrecision], 2.0], $MachinePrecision] * N[(N[Power[N[Sin[kx], $MachinePrecision], 2.0], $MachinePrecision] + N[Power[N[Sin[ky], $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
\sqrt{\frac{1}{2} \cdot \left(1 + \frac{1}{\sqrt{1 + {\left(\frac{2 \cdot \ell}{Om}\right)}^{2} \cdot \left({\sin kx}^{2} + {\sin ky}^{2}\right)}}\right)}
\end{array}

Alternative 1: 98.5% accurate, 0.7× speedup?

\[\begin{array}{l} kx_m = \left|kx\right| \\ [l, Om, kx_m, ky] = \mathsf{sort}([l, Om, kx_m, ky])\\ \\ \begin{array}{l} \mathbf{if}\;{\left(\frac{2 \cdot \ell}{Om}\right)}^{2} \cdot \left({\sin kx\_m}^{2} + {\sin ky}^{2}\right) \leq 10^{+15}:\\ \;\;\;\;\sqrt{\mathsf{fma}\left(\sqrt{{\left(\mathsf{fma}\left(\frac{1 - \cos \left(2 \cdot ky\right)}{2 \cdot Om} \cdot \left(\frac{\ell}{Om} \cdot \ell\right), 4, 1\right)\right)}^{-1}}, 0.5, 0.5\right)}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{0.5}\\ \end{array} \end{array} \]
kx_m = (fabs.f64 kx)
NOTE: l, Om, kx_m, and ky should be sorted in increasing order before calling this function.
(FPCore (l Om kx_m ky)
 :precision binary64
 (if (<=
      (*
       (pow (/ (* 2.0 l) Om) 2.0)
       (+ (pow (sin kx_m) 2.0) (pow (sin ky) 2.0)))
      1e+15)
   (sqrt
    (fma
     (sqrt
      (pow
       (fma (* (/ (- 1.0 (cos (* 2.0 ky))) (* 2.0 Om)) (* (/ l Om) l)) 4.0 1.0)
       -1.0))
     0.5
     0.5))
   (sqrt 0.5)))
kx_m = fabs(kx);
assert(l < Om && Om < kx_m && kx_m < ky);
double code(double l, double Om, double kx_m, double ky) {
	double tmp;
	if ((pow(((2.0 * l) / Om), 2.0) * (pow(sin(kx_m), 2.0) + pow(sin(ky), 2.0))) <= 1e+15) {
		tmp = sqrt(fma(sqrt(pow(fma((((1.0 - cos((2.0 * ky))) / (2.0 * Om)) * ((l / Om) * l)), 4.0, 1.0), -1.0)), 0.5, 0.5));
	} else {
		tmp = sqrt(0.5);
	}
	return tmp;
}
kx_m = abs(kx)
l, Om, kx_m, ky = sort([l, Om, kx_m, ky])
function code(l, Om, kx_m, ky)
	tmp = 0.0
	if (Float64((Float64(Float64(2.0 * l) / Om) ^ 2.0) * Float64((sin(kx_m) ^ 2.0) + (sin(ky) ^ 2.0))) <= 1e+15)
		tmp = sqrt(fma(sqrt((fma(Float64(Float64(Float64(1.0 - cos(Float64(2.0 * ky))) / Float64(2.0 * Om)) * Float64(Float64(l / Om) * l)), 4.0, 1.0) ^ -1.0)), 0.5, 0.5));
	else
		tmp = sqrt(0.5);
	end
	return tmp
end
kx_m = N[Abs[kx], $MachinePrecision]
NOTE: l, Om, kx_m, and ky should be sorted in increasing order before calling this function.
code[l_, Om_, kx$95$m_, ky_] := If[LessEqual[N[(N[Power[N[(N[(2.0 * l), $MachinePrecision] / Om), $MachinePrecision], 2.0], $MachinePrecision] * N[(N[Power[N[Sin[kx$95$m], $MachinePrecision], 2.0], $MachinePrecision] + N[Power[N[Sin[ky], $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], 1e+15], N[Sqrt[N[(N[Sqrt[N[Power[N[(N[(N[(N[(1.0 - N[Cos[N[(2.0 * ky), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / N[(2.0 * Om), $MachinePrecision]), $MachinePrecision] * N[(N[(l / Om), $MachinePrecision] * l), $MachinePrecision]), $MachinePrecision] * 4.0 + 1.0), $MachinePrecision], -1.0], $MachinePrecision]], $MachinePrecision] * 0.5 + 0.5), $MachinePrecision]], $MachinePrecision], N[Sqrt[0.5], $MachinePrecision]]
\begin{array}{l}
kx_m = \left|kx\right|
\\
[l, Om, kx_m, ky] = \mathsf{sort}([l, Om, kx_m, ky])\\
\\
\begin{array}{l}
\mathbf{if}\;{\left(\frac{2 \cdot \ell}{Om}\right)}^{2} \cdot \left({\sin kx\_m}^{2} + {\sin ky}^{2}\right) \leq 10^{+15}:\\
\;\;\;\;\sqrt{\mathsf{fma}\left(\sqrt{{\left(\mathsf{fma}\left(\frac{1 - \cos \left(2 \cdot ky\right)}{2 \cdot Om} \cdot \left(\frac{\ell}{Om} \cdot \ell\right), 4, 1\right)\right)}^{-1}}, 0.5, 0.5\right)}\\

\mathbf{else}:\\
\;\;\;\;\sqrt{0.5}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (*.f64 (pow.f64 (/.f64 (*.f64 #s(literal 2 binary64) l) Om) #s(literal 2 binary64)) (+.f64 (pow.f64 (sin.f64 kx) #s(literal 2 binary64)) (pow.f64 (sin.f64 ky) #s(literal 2 binary64)))) < 1e15

    1. Initial program 100.0%

      \[\sqrt{\frac{1}{2} \cdot \left(1 + \frac{1}{\sqrt{1 + {\left(\frac{2 \cdot \ell}{Om}\right)}^{2} \cdot \left({\sin kx}^{2} + {\sin ky}^{2}\right)}}\right)} \]
    2. Add Preprocessing
    3. Taylor expanded in kx around 0

      \[\leadsto \sqrt{\color{blue}{\frac{1}{2} \cdot \left(1 + \sqrt{\frac{1}{1 + 4 \cdot \frac{{\ell}^{2} \cdot {\sin ky}^{2}}{{Om}^{2}}}}\right)}} \]
    4. Step-by-step derivation
      1. +-commutativeN/A

        \[\leadsto \sqrt{\frac{1}{2} \cdot \color{blue}{\left(\sqrt{\frac{1}{1 + 4 \cdot \frac{{\ell}^{2} \cdot {\sin ky}^{2}}{{Om}^{2}}}} + 1\right)}} \]
      2. distribute-rgt-inN/A

        \[\leadsto \sqrt{\color{blue}{\sqrt{\frac{1}{1 + 4 \cdot \frac{{\ell}^{2} \cdot {\sin ky}^{2}}{{Om}^{2}}}} \cdot \frac{1}{2} + 1 \cdot \frac{1}{2}}} \]
      3. metadata-evalN/A

        \[\leadsto \sqrt{\sqrt{\frac{1}{1 + 4 \cdot \frac{{\ell}^{2} \cdot {\sin ky}^{2}}{{Om}^{2}}}} \cdot \frac{1}{2} + \color{blue}{\frac{1}{2}}} \]
      4. lower-fma.f64N/A

        \[\leadsto \sqrt{\color{blue}{\mathsf{fma}\left(\sqrt{\frac{1}{1 + 4 \cdot \frac{{\ell}^{2} \cdot {\sin ky}^{2}}{{Om}^{2}}}}, \frac{1}{2}, \frac{1}{2}\right)}} \]
    5. Applied rewrites92.7%

      \[\leadsto \sqrt{\color{blue}{\mathsf{fma}\left(\sqrt{\frac{1}{\mathsf{fma}\left(\frac{{\sin ky}^{2}}{Om} \cdot \frac{\ell \cdot \ell}{Om}, 4, 1\right)}}, 0.5, 0.5\right)}} \]
    6. Step-by-step derivation
      1. Applied rewrites97.9%

        \[\leadsto \sqrt{\mathsf{fma}\left(\sqrt{\frac{1}{\mathsf{fma}\left(\frac{{\sin ky}^{2}}{Om} \cdot \left(\frac{\ell}{Om} \cdot \ell\right), 4, 1\right)}}, 0.5, 0.5\right)} \]
      2. Step-by-step derivation
        1. Applied rewrites97.6%

          \[\leadsto \sqrt{\mathsf{fma}\left(\sqrt{\frac{1}{\mathsf{fma}\left(\frac{1 - \cos \left(2 \cdot ky\right)}{2 \cdot Om} \cdot \left(\frac{\ell}{Om} \cdot \ell\right), 4, 1\right)}}, 0.5, 0.5\right)} \]

        if 1e15 < (*.f64 (pow.f64 (/.f64 (*.f64 #s(literal 2 binary64) l) Om) #s(literal 2 binary64)) (+.f64 (pow.f64 (sin.f64 kx) #s(literal 2 binary64)) (pow.f64 (sin.f64 ky) #s(literal 2 binary64))))

        1. Initial program 95.9%

          \[\sqrt{\frac{1}{2} \cdot \left(1 + \frac{1}{\sqrt{1 + {\left(\frac{2 \cdot \ell}{Om}\right)}^{2} \cdot \left({\sin kx}^{2} + {\sin ky}^{2}\right)}}\right)} \]
        2. Add Preprocessing
        3. Taylor expanded in l around inf

          \[\leadsto \sqrt{\color{blue}{\frac{1}{2}}} \]
        4. Step-by-step derivation
          1. Applied rewrites98.7%

            \[\leadsto \sqrt{\color{blue}{0.5}} \]
        5. Recombined 2 regimes into one program.
        6. Final simplification98.1%

          \[\leadsto \begin{array}{l} \mathbf{if}\;{\left(\frac{2 \cdot \ell}{Om}\right)}^{2} \cdot \left({\sin kx}^{2} + {\sin ky}^{2}\right) \leq 10^{+15}:\\ \;\;\;\;\sqrt{\mathsf{fma}\left(\sqrt{{\left(\mathsf{fma}\left(\frac{1 - \cos \left(2 \cdot ky\right)}{2 \cdot Om} \cdot \left(\frac{\ell}{Om} \cdot \ell\right), 4, 1\right)\right)}^{-1}}, 0.5, 0.5\right)}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{0.5}\\ \end{array} \]
        7. Add Preprocessing

        Alternative 2: 95.2% accurate, 0.9× speedup?

        \[\begin{array}{l} kx_m = \left|kx\right| \\ [l, Om, kx_m, ky] = \mathsf{sort}([l, Om, kx_m, ky])\\ \\ \begin{array}{l} \mathbf{if}\;{\left(\frac{2 \cdot \ell}{Om}\right)}^{2} \cdot \left({\sin kx\_m}^{2} + {\sin ky}^{2}\right) \leq 0.02:\\ \;\;\;\;1\\ \mathbf{else}:\\ \;\;\;\;\sqrt{\mathsf{fma}\left(\frac{Om}{\sin ky \cdot \ell}, -0.25, 0.5\right)}\\ \end{array} \end{array} \]
        kx_m = (fabs.f64 kx)
        NOTE: l, Om, kx_m, and ky should be sorted in increasing order before calling this function.
        (FPCore (l Om kx_m ky)
         :precision binary64
         (if (<=
              (*
               (pow (/ (* 2.0 l) Om) 2.0)
               (+ (pow (sin kx_m) 2.0) (pow (sin ky) 2.0)))
              0.02)
           1.0
           (sqrt (fma (/ Om (* (sin ky) l)) -0.25 0.5))))
        kx_m = fabs(kx);
        assert(l < Om && Om < kx_m && kx_m < ky);
        double code(double l, double Om, double kx_m, double ky) {
        	double tmp;
        	if ((pow(((2.0 * l) / Om), 2.0) * (pow(sin(kx_m), 2.0) + pow(sin(ky), 2.0))) <= 0.02) {
        		tmp = 1.0;
        	} else {
        		tmp = sqrt(fma((Om / (sin(ky) * l)), -0.25, 0.5));
        	}
        	return tmp;
        }
        
        kx_m = abs(kx)
        l, Om, kx_m, ky = sort([l, Om, kx_m, ky])
        function code(l, Om, kx_m, ky)
        	tmp = 0.0
        	if (Float64((Float64(Float64(2.0 * l) / Om) ^ 2.0) * Float64((sin(kx_m) ^ 2.0) + (sin(ky) ^ 2.0))) <= 0.02)
        		tmp = 1.0;
        	else
        		tmp = sqrt(fma(Float64(Om / Float64(sin(ky) * l)), -0.25, 0.5));
        	end
        	return tmp
        end
        
        kx_m = N[Abs[kx], $MachinePrecision]
        NOTE: l, Om, kx_m, and ky should be sorted in increasing order before calling this function.
        code[l_, Om_, kx$95$m_, ky_] := If[LessEqual[N[(N[Power[N[(N[(2.0 * l), $MachinePrecision] / Om), $MachinePrecision], 2.0], $MachinePrecision] * N[(N[Power[N[Sin[kx$95$m], $MachinePrecision], 2.0], $MachinePrecision] + N[Power[N[Sin[ky], $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], 0.02], 1.0, N[Sqrt[N[(N[(Om / N[(N[Sin[ky], $MachinePrecision] * l), $MachinePrecision]), $MachinePrecision] * -0.25 + 0.5), $MachinePrecision]], $MachinePrecision]]
        
        \begin{array}{l}
        kx_m = \left|kx\right|
        \\
        [l, Om, kx_m, ky] = \mathsf{sort}([l, Om, kx_m, ky])\\
        \\
        \begin{array}{l}
        \mathbf{if}\;{\left(\frac{2 \cdot \ell}{Om}\right)}^{2} \cdot \left({\sin kx\_m}^{2} + {\sin ky}^{2}\right) \leq 0.02:\\
        \;\;\;\;1\\
        
        \mathbf{else}:\\
        \;\;\;\;\sqrt{\mathsf{fma}\left(\frac{Om}{\sin ky \cdot \ell}, -0.25, 0.5\right)}\\
        
        
        \end{array}
        \end{array}
        
        Derivation
        1. Split input into 2 regimes
        2. if (*.f64 (pow.f64 (/.f64 (*.f64 #s(literal 2 binary64) l) Om) #s(literal 2 binary64)) (+.f64 (pow.f64 (sin.f64 kx) #s(literal 2 binary64)) (pow.f64 (sin.f64 ky) #s(literal 2 binary64)))) < 0.0200000000000000004

          1. Initial program 100.0%

            \[\sqrt{\frac{1}{2} \cdot \left(1 + \frac{1}{\sqrt{1 + {\left(\frac{2 \cdot \ell}{Om}\right)}^{2} \cdot \left({\sin kx}^{2} + {\sin ky}^{2}\right)}}\right)} \]
          2. Add Preprocessing
          3. Applied rewrites100.0%

            \[\leadsto \color{blue}{{\left({\left(\mathsf{fma}\left({\left(\mathsf{fma}\left(\mathsf{fma}\left(\sin ky, \sin ky, {\sin kx}^{2}\right), {\left(\frac{\ell \cdot 2}{Om}\right)}^{2}, 1\right)\right)}^{-0.5}, 0.5, 0.5\right)\right)}^{0.25}\right)}^{2}} \]
          4. Taylor expanded in kx around 0

            \[\leadsto {\left({\left(\mathsf{fma}\left({\left(\mathsf{fma}\left(\color{blue}{{\sin ky}^{2}}, {\left(\frac{\ell \cdot 2}{Om}\right)}^{2}, 1\right)\right)}^{\frac{-1}{2}}, \frac{1}{2}, \frac{1}{2}\right)\right)}^{\frac{1}{4}}\right)}^{2} \]
          5. Step-by-step derivation
            1. lower-pow.f64N/A

              \[\leadsto {\left({\left(\mathsf{fma}\left({\left(\mathsf{fma}\left(\color{blue}{{\sin ky}^{2}}, {\left(\frac{\ell \cdot 2}{Om}\right)}^{2}, 1\right)\right)}^{\frac{-1}{2}}, \frac{1}{2}, \frac{1}{2}\right)\right)}^{\frac{1}{4}}\right)}^{2} \]
            2. lower-sin.f6499.8

              \[\leadsto {\left({\left(\mathsf{fma}\left({\left(\mathsf{fma}\left({\color{blue}{\sin ky}}^{2}, {\left(\frac{\ell \cdot 2}{Om}\right)}^{2}, 1\right)\right)}^{-0.5}, 0.5, 0.5\right)\right)}^{0.25}\right)}^{2} \]
          6. Applied rewrites99.8%

            \[\leadsto {\left({\left(\mathsf{fma}\left({\left(\mathsf{fma}\left(\color{blue}{{\sin ky}^{2}}, {\left(\frac{\ell \cdot 2}{Om}\right)}^{2}, 1\right)\right)}^{-0.5}, 0.5, 0.5\right)\right)}^{0.25}\right)}^{2} \]
          7. Taylor expanded in l around 0

            \[\leadsto \color{blue}{1} \]
          8. Step-by-step derivation
            1. Applied rewrites98.9%

              \[\leadsto \color{blue}{1} \]

            if 0.0200000000000000004 < (*.f64 (pow.f64 (/.f64 (*.f64 #s(literal 2 binary64) l) Om) #s(literal 2 binary64)) (+.f64 (pow.f64 (sin.f64 kx) #s(literal 2 binary64)) (pow.f64 (sin.f64 ky) #s(literal 2 binary64))))

            1. Initial program 96.0%

              \[\sqrt{\frac{1}{2} \cdot \left(1 + \frac{1}{\sqrt{1 + {\left(\frac{2 \cdot \ell}{Om}\right)}^{2} \cdot \left({\sin kx}^{2} + {\sin ky}^{2}\right)}}\right)} \]
            2. Add Preprocessing
            3. Taylor expanded in kx around 0

              \[\leadsto \sqrt{\color{blue}{\frac{1}{2} \cdot \left(1 + \sqrt{\frac{1}{1 + 4 \cdot \frac{{\ell}^{2} \cdot {\sin ky}^{2}}{{Om}^{2}}}}\right)}} \]
            4. Step-by-step derivation
              1. +-commutativeN/A

                \[\leadsto \sqrt{\frac{1}{2} \cdot \color{blue}{\left(\sqrt{\frac{1}{1 + 4 \cdot \frac{{\ell}^{2} \cdot {\sin ky}^{2}}{{Om}^{2}}}} + 1\right)}} \]
              2. distribute-rgt-inN/A

                \[\leadsto \sqrt{\color{blue}{\sqrt{\frac{1}{1 + 4 \cdot \frac{{\ell}^{2} \cdot {\sin ky}^{2}}{{Om}^{2}}}} \cdot \frac{1}{2} + 1 \cdot \frac{1}{2}}} \]
              3. metadata-evalN/A

                \[\leadsto \sqrt{\sqrt{\frac{1}{1 + 4 \cdot \frac{{\ell}^{2} \cdot {\sin ky}^{2}}{{Om}^{2}}}} \cdot \frac{1}{2} + \color{blue}{\frac{1}{2}}} \]
              4. lower-fma.f64N/A

                \[\leadsto \sqrt{\color{blue}{\mathsf{fma}\left(\sqrt{\frac{1}{1 + 4 \cdot \frac{{\ell}^{2} \cdot {\sin ky}^{2}}{{Om}^{2}}}}, \frac{1}{2}, \frac{1}{2}\right)}} \]
            5. Applied rewrites77.3%

              \[\leadsto \sqrt{\color{blue}{\mathsf{fma}\left(\sqrt{\frac{1}{\mathsf{fma}\left(\frac{{\sin ky}^{2}}{Om} \cdot \frac{\ell \cdot \ell}{Om}, 4, 1\right)}}, 0.5, 0.5\right)}} \]
            6. Taylor expanded in l around -inf

              \[\leadsto \sqrt{\frac{1}{2} + \color{blue}{\frac{-1}{4} \cdot \frac{Om}{\ell \cdot \sin ky}}} \]
            7. Step-by-step derivation
              1. Applied rewrites85.4%

                \[\leadsto \sqrt{\mathsf{fma}\left(\frac{Om}{\sin ky \cdot \ell}, \color{blue}{-0.25}, 0.5\right)} \]
            8. Recombined 2 regimes into one program.
            9. Add Preprocessing

            Alternative 3: 98.3% accurate, 1.1× speedup?

            \[\begin{array}{l} kx_m = \left|kx\right| \\ [l, Om, kx_m, ky] = \mathsf{sort}([l, Om, kx_m, ky])\\ \\ \begin{array}{l} \mathbf{if}\;{\left(\frac{2 \cdot \ell}{Om}\right)}^{2} \cdot \left({\sin kx\_m}^{2} + {\sin ky}^{2}\right) \leq 0.02:\\ \;\;\;\;1\\ \mathbf{else}:\\ \;\;\;\;\sqrt{0.5}\\ \end{array} \end{array} \]
            kx_m = (fabs.f64 kx)
            NOTE: l, Om, kx_m, and ky should be sorted in increasing order before calling this function.
            (FPCore (l Om kx_m ky)
             :precision binary64
             (if (<=
                  (*
                   (pow (/ (* 2.0 l) Om) 2.0)
                   (+ (pow (sin kx_m) 2.0) (pow (sin ky) 2.0)))
                  0.02)
               1.0
               (sqrt 0.5)))
            kx_m = fabs(kx);
            assert(l < Om && Om < kx_m && kx_m < ky);
            double code(double l, double Om, double kx_m, double ky) {
            	double tmp;
            	if ((pow(((2.0 * l) / Om), 2.0) * (pow(sin(kx_m), 2.0) + pow(sin(ky), 2.0))) <= 0.02) {
            		tmp = 1.0;
            	} else {
            		tmp = sqrt(0.5);
            	}
            	return tmp;
            }
            
            kx_m = abs(kx)
            NOTE: l, Om, kx_m, and ky should be sorted in increasing order before calling this function.
            real(8) function code(l, om, kx_m, ky)
                real(8), intent (in) :: l
                real(8), intent (in) :: om
                real(8), intent (in) :: kx_m
                real(8), intent (in) :: ky
                real(8) :: tmp
                if (((((2.0d0 * l) / om) ** 2.0d0) * ((sin(kx_m) ** 2.0d0) + (sin(ky) ** 2.0d0))) <= 0.02d0) then
                    tmp = 1.0d0
                else
                    tmp = sqrt(0.5d0)
                end if
                code = tmp
            end function
            
            kx_m = Math.abs(kx);
            assert l < Om && Om < kx_m && kx_m < ky;
            public static double code(double l, double Om, double kx_m, double ky) {
            	double tmp;
            	if ((Math.pow(((2.0 * l) / Om), 2.0) * (Math.pow(Math.sin(kx_m), 2.0) + Math.pow(Math.sin(ky), 2.0))) <= 0.02) {
            		tmp = 1.0;
            	} else {
            		tmp = Math.sqrt(0.5);
            	}
            	return tmp;
            }
            
            kx_m = math.fabs(kx)
            [l, Om, kx_m, ky] = sort([l, Om, kx_m, ky])
            def code(l, Om, kx_m, ky):
            	tmp = 0
            	if (math.pow(((2.0 * l) / Om), 2.0) * (math.pow(math.sin(kx_m), 2.0) + math.pow(math.sin(ky), 2.0))) <= 0.02:
            		tmp = 1.0
            	else:
            		tmp = math.sqrt(0.5)
            	return tmp
            
            kx_m = abs(kx)
            l, Om, kx_m, ky = sort([l, Om, kx_m, ky])
            function code(l, Om, kx_m, ky)
            	tmp = 0.0
            	if (Float64((Float64(Float64(2.0 * l) / Om) ^ 2.0) * Float64((sin(kx_m) ^ 2.0) + (sin(ky) ^ 2.0))) <= 0.02)
            		tmp = 1.0;
            	else
            		tmp = sqrt(0.5);
            	end
            	return tmp
            end
            
            kx_m = abs(kx);
            l, Om, kx_m, ky = num2cell(sort([l, Om, kx_m, ky])){:}
            function tmp_2 = code(l, Om, kx_m, ky)
            	tmp = 0.0;
            	if (((((2.0 * l) / Om) ^ 2.0) * ((sin(kx_m) ^ 2.0) + (sin(ky) ^ 2.0))) <= 0.02)
            		tmp = 1.0;
            	else
            		tmp = sqrt(0.5);
            	end
            	tmp_2 = tmp;
            end
            
            kx_m = N[Abs[kx], $MachinePrecision]
            NOTE: l, Om, kx_m, and ky should be sorted in increasing order before calling this function.
            code[l_, Om_, kx$95$m_, ky_] := If[LessEqual[N[(N[Power[N[(N[(2.0 * l), $MachinePrecision] / Om), $MachinePrecision], 2.0], $MachinePrecision] * N[(N[Power[N[Sin[kx$95$m], $MachinePrecision], 2.0], $MachinePrecision] + N[Power[N[Sin[ky], $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], 0.02], 1.0, N[Sqrt[0.5], $MachinePrecision]]
            
            \begin{array}{l}
            kx_m = \left|kx\right|
            \\
            [l, Om, kx_m, ky] = \mathsf{sort}([l, Om, kx_m, ky])\\
            \\
            \begin{array}{l}
            \mathbf{if}\;{\left(\frac{2 \cdot \ell}{Om}\right)}^{2} \cdot \left({\sin kx\_m}^{2} + {\sin ky}^{2}\right) \leq 0.02:\\
            \;\;\;\;1\\
            
            \mathbf{else}:\\
            \;\;\;\;\sqrt{0.5}\\
            
            
            \end{array}
            \end{array}
            
            Derivation
            1. Split input into 2 regimes
            2. if (*.f64 (pow.f64 (/.f64 (*.f64 #s(literal 2 binary64) l) Om) #s(literal 2 binary64)) (+.f64 (pow.f64 (sin.f64 kx) #s(literal 2 binary64)) (pow.f64 (sin.f64 ky) #s(literal 2 binary64)))) < 0.0200000000000000004

              1. Initial program 100.0%

                \[\sqrt{\frac{1}{2} \cdot \left(1 + \frac{1}{\sqrt{1 + {\left(\frac{2 \cdot \ell}{Om}\right)}^{2} \cdot \left({\sin kx}^{2} + {\sin ky}^{2}\right)}}\right)} \]
              2. Add Preprocessing
              3. Applied rewrites100.0%

                \[\leadsto \color{blue}{{\left({\left(\mathsf{fma}\left({\left(\mathsf{fma}\left(\mathsf{fma}\left(\sin ky, \sin ky, {\sin kx}^{2}\right), {\left(\frac{\ell \cdot 2}{Om}\right)}^{2}, 1\right)\right)}^{-0.5}, 0.5, 0.5\right)\right)}^{0.25}\right)}^{2}} \]
              4. Taylor expanded in kx around 0

                \[\leadsto {\left({\left(\mathsf{fma}\left({\left(\mathsf{fma}\left(\color{blue}{{\sin ky}^{2}}, {\left(\frac{\ell \cdot 2}{Om}\right)}^{2}, 1\right)\right)}^{\frac{-1}{2}}, \frac{1}{2}, \frac{1}{2}\right)\right)}^{\frac{1}{4}}\right)}^{2} \]
              5. Step-by-step derivation
                1. lower-pow.f64N/A

                  \[\leadsto {\left({\left(\mathsf{fma}\left({\left(\mathsf{fma}\left(\color{blue}{{\sin ky}^{2}}, {\left(\frac{\ell \cdot 2}{Om}\right)}^{2}, 1\right)\right)}^{\frac{-1}{2}}, \frac{1}{2}, \frac{1}{2}\right)\right)}^{\frac{1}{4}}\right)}^{2} \]
                2. lower-sin.f6499.8

                  \[\leadsto {\left({\left(\mathsf{fma}\left({\left(\mathsf{fma}\left({\color{blue}{\sin ky}}^{2}, {\left(\frac{\ell \cdot 2}{Om}\right)}^{2}, 1\right)\right)}^{-0.5}, 0.5, 0.5\right)\right)}^{0.25}\right)}^{2} \]
              6. Applied rewrites99.8%

                \[\leadsto {\left({\left(\mathsf{fma}\left({\left(\mathsf{fma}\left(\color{blue}{{\sin ky}^{2}}, {\left(\frac{\ell \cdot 2}{Om}\right)}^{2}, 1\right)\right)}^{-0.5}, 0.5, 0.5\right)\right)}^{0.25}\right)}^{2} \]
              7. Taylor expanded in l around 0

                \[\leadsto \color{blue}{1} \]
              8. Step-by-step derivation
                1. Applied rewrites98.9%

                  \[\leadsto \color{blue}{1} \]

                if 0.0200000000000000004 < (*.f64 (pow.f64 (/.f64 (*.f64 #s(literal 2 binary64) l) Om) #s(literal 2 binary64)) (+.f64 (pow.f64 (sin.f64 kx) #s(literal 2 binary64)) (pow.f64 (sin.f64 ky) #s(literal 2 binary64))))

                1. Initial program 96.0%

                  \[\sqrt{\frac{1}{2} \cdot \left(1 + \frac{1}{\sqrt{1 + {\left(\frac{2 \cdot \ell}{Om}\right)}^{2} \cdot \left({\sin kx}^{2} + {\sin ky}^{2}\right)}}\right)} \]
                2. Add Preprocessing
                3. Taylor expanded in l around inf

                  \[\leadsto \sqrt{\color{blue}{\frac{1}{2}}} \]
                4. Step-by-step derivation
                  1. Applied rewrites97.8%

                    \[\leadsto \sqrt{\color{blue}{0.5}} \]
                5. Recombined 2 regimes into one program.
                6. Add Preprocessing

                Alternative 4: 93.4% accurate, 1.6× speedup?

                \[\begin{array}{l} kx_m = \left|kx\right| \\ [l, Om, kx_m, ky] = \mathsf{sort}([l, Om, kx_m, ky])\\ \\ \sqrt{\mathsf{fma}\left(\sqrt{{\left(\mathsf{fma}\left(\frac{{\sin ky}^{2}}{Om} \cdot \left(\frac{\ell}{Om} \cdot \ell\right), 4, 1\right)\right)}^{-1}}, 0.5, 0.5\right)} \end{array} \]
                kx_m = (fabs.f64 kx)
                NOTE: l, Om, kx_m, and ky should be sorted in increasing order before calling this function.
                (FPCore (l Om kx_m ky)
                 :precision binary64
                 (sqrt
                  (fma
                   (sqrt (pow (fma (* (/ (pow (sin ky) 2.0) Om) (* (/ l Om) l)) 4.0 1.0) -1.0))
                   0.5
                   0.5)))
                kx_m = fabs(kx);
                assert(l < Om && Om < kx_m && kx_m < ky);
                double code(double l, double Om, double kx_m, double ky) {
                	return sqrt(fma(sqrt(pow(fma(((pow(sin(ky), 2.0) / Om) * ((l / Om) * l)), 4.0, 1.0), -1.0)), 0.5, 0.5));
                }
                
                kx_m = abs(kx)
                l, Om, kx_m, ky = sort([l, Om, kx_m, ky])
                function code(l, Om, kx_m, ky)
                	return sqrt(fma(sqrt((fma(Float64(Float64((sin(ky) ^ 2.0) / Om) * Float64(Float64(l / Om) * l)), 4.0, 1.0) ^ -1.0)), 0.5, 0.5))
                end
                
                kx_m = N[Abs[kx], $MachinePrecision]
                NOTE: l, Om, kx_m, and ky should be sorted in increasing order before calling this function.
                code[l_, Om_, kx$95$m_, ky_] := N[Sqrt[N[(N[Sqrt[N[Power[N[(N[(N[(N[Power[N[Sin[ky], $MachinePrecision], 2.0], $MachinePrecision] / Om), $MachinePrecision] * N[(N[(l / Om), $MachinePrecision] * l), $MachinePrecision]), $MachinePrecision] * 4.0 + 1.0), $MachinePrecision], -1.0], $MachinePrecision]], $MachinePrecision] * 0.5 + 0.5), $MachinePrecision]], $MachinePrecision]
                
                \begin{array}{l}
                kx_m = \left|kx\right|
                \\
                [l, Om, kx_m, ky] = \mathsf{sort}([l, Om, kx_m, ky])\\
                \\
                \sqrt{\mathsf{fma}\left(\sqrt{{\left(\mathsf{fma}\left(\frac{{\sin ky}^{2}}{Om} \cdot \left(\frac{\ell}{Om} \cdot \ell\right), 4, 1\right)\right)}^{-1}}, 0.5, 0.5\right)}
                \end{array}
                
                Derivation
                1. Initial program 98.0%

                  \[\sqrt{\frac{1}{2} \cdot \left(1 + \frac{1}{\sqrt{1 + {\left(\frac{2 \cdot \ell}{Om}\right)}^{2} \cdot \left({\sin kx}^{2} + {\sin ky}^{2}\right)}}\right)} \]
                2. Add Preprocessing
                3. Taylor expanded in kx around 0

                  \[\leadsto \sqrt{\color{blue}{\frac{1}{2} \cdot \left(1 + \sqrt{\frac{1}{1 + 4 \cdot \frac{{\ell}^{2} \cdot {\sin ky}^{2}}{{Om}^{2}}}}\right)}} \]
                4. Step-by-step derivation
                  1. +-commutativeN/A

                    \[\leadsto \sqrt{\frac{1}{2} \cdot \color{blue}{\left(\sqrt{\frac{1}{1 + 4 \cdot \frac{{\ell}^{2} \cdot {\sin ky}^{2}}{{Om}^{2}}}} + 1\right)}} \]
                  2. distribute-rgt-inN/A

                    \[\leadsto \sqrt{\color{blue}{\sqrt{\frac{1}{1 + 4 \cdot \frac{{\ell}^{2} \cdot {\sin ky}^{2}}{{Om}^{2}}}} \cdot \frac{1}{2} + 1 \cdot \frac{1}{2}}} \]
                  3. metadata-evalN/A

                    \[\leadsto \sqrt{\sqrt{\frac{1}{1 + 4 \cdot \frac{{\ell}^{2} \cdot {\sin ky}^{2}}{{Om}^{2}}}} \cdot \frac{1}{2} + \color{blue}{\frac{1}{2}}} \]
                  4. lower-fma.f64N/A

                    \[\leadsto \sqrt{\color{blue}{\mathsf{fma}\left(\sqrt{\frac{1}{1 + 4 \cdot \frac{{\ell}^{2} \cdot {\sin ky}^{2}}{{Om}^{2}}}}, \frac{1}{2}, \frac{1}{2}\right)}} \]
                5. Applied rewrites85.9%

                  \[\leadsto \sqrt{\color{blue}{\mathsf{fma}\left(\sqrt{\frac{1}{\mathsf{fma}\left(\frac{{\sin ky}^{2}}{Om} \cdot \frac{\ell \cdot \ell}{Om}, 4, 1\right)}}, 0.5, 0.5\right)}} \]
                6. Step-by-step derivation
                  1. Applied rewrites89.3%

                    \[\leadsto \sqrt{\mathsf{fma}\left(\sqrt{\frac{1}{\mathsf{fma}\left(\frac{{\sin ky}^{2}}{Om} \cdot \left(\frac{\ell}{Om} \cdot \ell\right), 4, 1\right)}}, 0.5, 0.5\right)} \]
                  2. Final simplification89.3%

                    \[\leadsto \sqrt{\mathsf{fma}\left(\sqrt{{\left(\mathsf{fma}\left(\frac{{\sin ky}^{2}}{Om} \cdot \left(\frac{\ell}{Om} \cdot \ell\right), 4, 1\right)\right)}^{-1}}, 0.5, 0.5\right)} \]
                  3. Add Preprocessing

                  Alternative 5: 62.9% accurate, 581.0× speedup?

                  \[\begin{array}{l} kx_m = \left|kx\right| \\ [l, Om, kx_m, ky] = \mathsf{sort}([l, Om, kx_m, ky])\\ \\ 1 \end{array} \]
                  kx_m = (fabs.f64 kx)
                  NOTE: l, Om, kx_m, and ky should be sorted in increasing order before calling this function.
                  (FPCore (l Om kx_m ky) :precision binary64 1.0)
                  kx_m = fabs(kx);
                  assert(l < Om && Om < kx_m && kx_m < ky);
                  double code(double l, double Om, double kx_m, double ky) {
                  	return 1.0;
                  }
                  
                  kx_m = abs(kx)
                  NOTE: l, Om, kx_m, and ky should be sorted in increasing order before calling this function.
                  real(8) function code(l, om, kx_m, ky)
                      real(8), intent (in) :: l
                      real(8), intent (in) :: om
                      real(8), intent (in) :: kx_m
                      real(8), intent (in) :: ky
                      code = 1.0d0
                  end function
                  
                  kx_m = Math.abs(kx);
                  assert l < Om && Om < kx_m && kx_m < ky;
                  public static double code(double l, double Om, double kx_m, double ky) {
                  	return 1.0;
                  }
                  
                  kx_m = math.fabs(kx)
                  [l, Om, kx_m, ky] = sort([l, Om, kx_m, ky])
                  def code(l, Om, kx_m, ky):
                  	return 1.0
                  
                  kx_m = abs(kx)
                  l, Om, kx_m, ky = sort([l, Om, kx_m, ky])
                  function code(l, Om, kx_m, ky)
                  	return 1.0
                  end
                  
                  kx_m = abs(kx);
                  l, Om, kx_m, ky = num2cell(sort([l, Om, kx_m, ky])){:}
                  function tmp = code(l, Om, kx_m, ky)
                  	tmp = 1.0;
                  end
                  
                  kx_m = N[Abs[kx], $MachinePrecision]
                  NOTE: l, Om, kx_m, and ky should be sorted in increasing order before calling this function.
                  code[l_, Om_, kx$95$m_, ky_] := 1.0
                  
                  \begin{array}{l}
                  kx_m = \left|kx\right|
                  \\
                  [l, Om, kx_m, ky] = \mathsf{sort}([l, Om, kx_m, ky])\\
                  \\
                  1
                  \end{array}
                  
                  Derivation
                  1. Initial program 98.0%

                    \[\sqrt{\frac{1}{2} \cdot \left(1 + \frac{1}{\sqrt{1 + {\left(\frac{2 \cdot \ell}{Om}\right)}^{2} \cdot \left({\sin kx}^{2} + {\sin ky}^{2}\right)}}\right)} \]
                  2. Add Preprocessing
                  3. Applied rewrites97.3%

                    \[\leadsto \color{blue}{{\left({\left(\mathsf{fma}\left({\left(\mathsf{fma}\left(\mathsf{fma}\left(\sin ky, \sin ky, {\sin kx}^{2}\right), {\left(\frac{\ell \cdot 2}{Om}\right)}^{2}, 1\right)\right)}^{-0.5}, 0.5, 0.5\right)\right)}^{0.25}\right)}^{2}} \]
                  4. Taylor expanded in kx around 0

                    \[\leadsto {\left({\left(\mathsf{fma}\left({\left(\mathsf{fma}\left(\color{blue}{{\sin ky}^{2}}, {\left(\frac{\ell \cdot 2}{Om}\right)}^{2}, 1\right)\right)}^{\frac{-1}{2}}, \frac{1}{2}, \frac{1}{2}\right)\right)}^{\frac{1}{4}}\right)}^{2} \]
                  5. Step-by-step derivation
                    1. lower-pow.f64N/A

                      \[\leadsto {\left({\left(\mathsf{fma}\left({\left(\mathsf{fma}\left(\color{blue}{{\sin ky}^{2}}, {\left(\frac{\ell \cdot 2}{Om}\right)}^{2}, 1\right)\right)}^{\frac{-1}{2}}, \frac{1}{2}, \frac{1}{2}\right)\right)}^{\frac{1}{4}}\right)}^{2} \]
                    2. lower-sin.f6488.3

                      \[\leadsto {\left({\left(\mathsf{fma}\left({\left(\mathsf{fma}\left({\color{blue}{\sin ky}}^{2}, {\left(\frac{\ell \cdot 2}{Om}\right)}^{2}, 1\right)\right)}^{-0.5}, 0.5, 0.5\right)\right)}^{0.25}\right)}^{2} \]
                  6. Applied rewrites88.3%

                    \[\leadsto {\left({\left(\mathsf{fma}\left({\left(\mathsf{fma}\left(\color{blue}{{\sin ky}^{2}}, {\left(\frac{\ell \cdot 2}{Om}\right)}^{2}, 1\right)\right)}^{-0.5}, 0.5, 0.5\right)\right)}^{0.25}\right)}^{2} \]
                  7. Taylor expanded in l around 0

                    \[\leadsto \color{blue}{1} \]
                  8. Step-by-step derivation
                    1. Applied rewrites61.0%

                      \[\leadsto \color{blue}{1} \]
                    2. Add Preprocessing

                    Reproduce

                    ?
                    herbie shell --seed 2024326 
                    (FPCore (l Om kx ky)
                      :name "Toniolo and Linder, Equation (3a)"
                      :precision binary64
                      (sqrt (* (/ 1.0 2.0) (+ 1.0 (/ 1.0 (sqrt (+ 1.0 (* (pow (/ (* 2.0 l) Om) 2.0) (+ (pow (sin kx) 2.0) (pow (sin ky) 2.0))))))))))