Toniolo and Linder, Equation (2)

Percentage Accurate: 84.3% → 98.9%
Time: 15.8s
Alternatives: 8
Speedup: 2.5×

Specification

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

\\
\sin^{-1} \left(\sqrt{\frac{1 - {\left(\frac{Om}{Omc}\right)}^{2}}{1 + 2 \cdot {\left(\frac{t}{\ell}\right)}^{2}}}\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 8 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: 84.3% accurate, 1.0× speedup?

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

\\
\sin^{-1} \left(\sqrt{\frac{1 - {\left(\frac{Om}{Omc}\right)}^{2}}{1 + 2 \cdot {\left(\frac{t}{\ell}\right)}^{2}}}\right)
\end{array}

Alternative 1: 98.9% accurate, 1.8× speedup?

\[\begin{array}{l} l_m = \left|\ell\right| \\ t_m = \left|t\right| \\ \begin{array}{l} \mathbf{if}\;\frac{t\_m}{l\_m} \leq 10^{+151}:\\ \;\;\;\;\sin^{-1} \left(\sqrt{\frac{1 - \frac{Om \cdot \frac{Om}{Omc}}{Omc}}{\mathsf{fma}\left(\frac{t\_m}{l\_m}, \frac{t\_m}{l\_m} \cdot 2, 1\right)}}\right)\\ \mathbf{else}:\\ \;\;\;\;\sin^{-1} \left(\sqrt{1 - \frac{Om}{Omc} \cdot \frac{Om}{Omc}} \cdot \frac{l\_m \cdot \sqrt{0.5}}{t\_m}\right)\\ \end{array} \end{array} \]
l_m = (fabs.f64 l)
t_m = (fabs.f64 t)
(FPCore (t_m l_m Om Omc)
 :precision binary64
 (if (<= (/ t_m l_m) 1e+151)
   (asin
    (sqrt
     (/
      (- 1.0 (/ (* Om (/ Om Omc)) Omc))
      (fma (/ t_m l_m) (* (/ t_m l_m) 2.0) 1.0))))
   (asin
    (* (sqrt (- 1.0 (* (/ Om Omc) (/ Om Omc)))) (/ (* l_m (sqrt 0.5)) t_m)))))
l_m = fabs(l);
t_m = fabs(t);
double code(double t_m, double l_m, double Om, double Omc) {
	double tmp;
	if ((t_m / l_m) <= 1e+151) {
		tmp = asin(sqrt(((1.0 - ((Om * (Om / Omc)) / Omc)) / fma((t_m / l_m), ((t_m / l_m) * 2.0), 1.0))));
	} else {
		tmp = asin((sqrt((1.0 - ((Om / Omc) * (Om / Omc)))) * ((l_m * sqrt(0.5)) / t_m)));
	}
	return tmp;
}
l_m = abs(l)
t_m = abs(t)
function code(t_m, l_m, Om, Omc)
	tmp = 0.0
	if (Float64(t_m / l_m) <= 1e+151)
		tmp = asin(sqrt(Float64(Float64(1.0 - Float64(Float64(Om * Float64(Om / Omc)) / Omc)) / fma(Float64(t_m / l_m), Float64(Float64(t_m / l_m) * 2.0), 1.0))));
	else
		tmp = asin(Float64(sqrt(Float64(1.0 - Float64(Float64(Om / Omc) * Float64(Om / Omc)))) * Float64(Float64(l_m * sqrt(0.5)) / t_m)));
	end
	return tmp
end
l_m = N[Abs[l], $MachinePrecision]
t_m = N[Abs[t], $MachinePrecision]
code[t$95$m_, l$95$m_, Om_, Omc_] := If[LessEqual[N[(t$95$m / l$95$m), $MachinePrecision], 1e+151], N[ArcSin[N[Sqrt[N[(N[(1.0 - N[(N[(Om * N[(Om / Omc), $MachinePrecision]), $MachinePrecision] / Omc), $MachinePrecision]), $MachinePrecision] / N[(N[(t$95$m / l$95$m), $MachinePrecision] * N[(N[(t$95$m / l$95$m), $MachinePrecision] * 2.0), $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]], $MachinePrecision], N[ArcSin[N[(N[Sqrt[N[(1.0 - N[(N[(Om / Omc), $MachinePrecision] * N[(Om / Omc), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * N[(N[(l$95$m * N[Sqrt[0.5], $MachinePrecision]), $MachinePrecision] / t$95$m), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]]
\begin{array}{l}
l_m = \left|\ell\right|
\\
t_m = \left|t\right|

\\
\begin{array}{l}
\mathbf{if}\;\frac{t\_m}{l\_m} \leq 10^{+151}:\\
\;\;\;\;\sin^{-1} \left(\sqrt{\frac{1 - \frac{Om \cdot \frac{Om}{Omc}}{Omc}}{\mathsf{fma}\left(\frac{t\_m}{l\_m}, \frac{t\_m}{l\_m} \cdot 2, 1\right)}}\right)\\

\mathbf{else}:\\
\;\;\;\;\sin^{-1} \left(\sqrt{1 - \frac{Om}{Omc} \cdot \frac{Om}{Omc}} \cdot \frac{l\_m \cdot \sqrt{0.5}}{t\_m}\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (/.f64 t l) < 1.00000000000000002e151

    1. Initial program 99.2%

      \[\sin^{-1} \left(\sqrt{\frac{1 - {\left(\frac{Om}{Omc}\right)}^{2}}{1 + 2 \cdot {\left(\frac{t}{\ell}\right)}^{2}}}\right) \]
    2. Add Preprocessing
    3. Step-by-step derivation
      1. lift-+.f64N/A

        \[\leadsto \sin^{-1} \left(\sqrt{\frac{1 - {\left(\frac{Om}{Omc}\right)}^{2}}{\color{blue}{1 + 2 \cdot {\left(\frac{t}{\ell}\right)}^{2}}}}\right) \]
      2. +-commutativeN/A

        \[\leadsto \sin^{-1} \left(\sqrt{\frac{1 - {\left(\frac{Om}{Omc}\right)}^{2}}{\color{blue}{2 \cdot {\left(\frac{t}{\ell}\right)}^{2} + 1}}}\right) \]
      3. lift-*.f64N/A

        \[\leadsto \sin^{-1} \left(\sqrt{\frac{1 - {\left(\frac{Om}{Omc}\right)}^{2}}{\color{blue}{2 \cdot {\left(\frac{t}{\ell}\right)}^{2}} + 1}}\right) \]
      4. *-commutativeN/A

        \[\leadsto \sin^{-1} \left(\sqrt{\frac{1 - {\left(\frac{Om}{Omc}\right)}^{2}}{\color{blue}{{\left(\frac{t}{\ell}\right)}^{2} \cdot 2} + 1}}\right) \]
      5. lift-pow.f64N/A

        \[\leadsto \sin^{-1} \left(\sqrt{\frac{1 - {\left(\frac{Om}{Omc}\right)}^{2}}{\color{blue}{{\left(\frac{t}{\ell}\right)}^{2}} \cdot 2 + 1}}\right) \]
      6. unpow2N/A

        \[\leadsto \sin^{-1} \left(\sqrt{\frac{1 - {\left(\frac{Om}{Omc}\right)}^{2}}{\color{blue}{\left(\frac{t}{\ell} \cdot \frac{t}{\ell}\right)} \cdot 2 + 1}}\right) \]
      7. associate-*l*N/A

        \[\leadsto \sin^{-1} \left(\sqrt{\frac{1 - {\left(\frac{Om}{Omc}\right)}^{2}}{\color{blue}{\frac{t}{\ell} \cdot \left(\frac{t}{\ell} \cdot 2\right)} + 1}}\right) \]
      8. lower-fma.f64N/A

        \[\leadsto \sin^{-1} \left(\sqrt{\frac{1 - {\left(\frac{Om}{Omc}\right)}^{2}}{\color{blue}{\mathsf{fma}\left(\frac{t}{\ell}, \frac{t}{\ell} \cdot 2, 1\right)}}}\right) \]
      9. *-commutativeN/A

        \[\leadsto \sin^{-1} \left(\sqrt{\frac{1 - {\left(\frac{Om}{Omc}\right)}^{2}}{\mathsf{fma}\left(\frac{t}{\ell}, \color{blue}{2 \cdot \frac{t}{\ell}}, 1\right)}}\right) \]
      10. lower-*.f6499.2

        \[\leadsto \sin^{-1} \left(\sqrt{\frac{1 - {\left(\frac{Om}{Omc}\right)}^{2}}{\mathsf{fma}\left(\frac{t}{\ell}, \color{blue}{2 \cdot \frac{t}{\ell}}, 1\right)}}\right) \]
    4. Applied rewrites99.2%

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

        \[\leadsto \sin^{-1} \left(\sqrt{\frac{1 - \color{blue}{{\left(\frac{Om}{Omc}\right)}^{2}}}{\mathsf{fma}\left(\frac{t}{\ell}, 2 \cdot \frac{t}{\ell}, 1\right)}}\right) \]
      2. unpow2N/A

        \[\leadsto \sin^{-1} \left(\sqrt{\frac{1 - \color{blue}{\frac{Om}{Omc} \cdot \frac{Om}{Omc}}}{\mathsf{fma}\left(\frac{t}{\ell}, 2 \cdot \frac{t}{\ell}, 1\right)}}\right) \]
      3. lift-/.f64N/A

        \[\leadsto \sin^{-1} \left(\sqrt{\frac{1 - \frac{Om}{Omc} \cdot \color{blue}{\frac{Om}{Omc}}}{\mathsf{fma}\left(\frac{t}{\ell}, 2 \cdot \frac{t}{\ell}, 1\right)}}\right) \]
      4. associate-*r/N/A

        \[\leadsto \sin^{-1} \left(\sqrt{\frac{1 - \color{blue}{\frac{\frac{Om}{Omc} \cdot Om}{Omc}}}{\mathsf{fma}\left(\frac{t}{\ell}, 2 \cdot \frac{t}{\ell}, 1\right)}}\right) \]
      5. lower-/.f64N/A

        \[\leadsto \sin^{-1} \left(\sqrt{\frac{1 - \color{blue}{\frac{\frac{Om}{Omc} \cdot Om}{Omc}}}{\mathsf{fma}\left(\frac{t}{\ell}, 2 \cdot \frac{t}{\ell}, 1\right)}}\right) \]
      6. lower-*.f6499.2

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

      \[\leadsto \sin^{-1} \left(\sqrt{\frac{1 - \color{blue}{\frac{\frac{Om}{Omc} \cdot Om}{Omc}}}{\mathsf{fma}\left(\frac{t}{\ell}, 2 \cdot \frac{t}{\ell}, 1\right)}}\right) \]

    if 1.00000000000000002e151 < (/.f64 t l)

    1. Initial program 48.1%

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

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

        \[\leadsto \sin^{-1} \color{blue}{\left(\sqrt{1 - \frac{{Om}^{2}}{{Omc}^{2}}} \cdot \frac{\ell \cdot \sqrt{\frac{1}{2}}}{t}\right)} \]
      2. lower-*.f64N/A

        \[\leadsto \sin^{-1} \color{blue}{\left(\sqrt{1 - \frac{{Om}^{2}}{{Omc}^{2}}} \cdot \frac{\ell \cdot \sqrt{\frac{1}{2}}}{t}\right)} \]
      3. lower-sqrt.f64N/A

        \[\leadsto \sin^{-1} \left(\color{blue}{\sqrt{1 - \frac{{Om}^{2}}{{Omc}^{2}}}} \cdot \frac{\ell \cdot \sqrt{\frac{1}{2}}}{t}\right) \]
      4. lower--.f64N/A

        \[\leadsto \sin^{-1} \left(\sqrt{\color{blue}{1 - \frac{{Om}^{2}}{{Omc}^{2}}}} \cdot \frac{\ell \cdot \sqrt{\frac{1}{2}}}{t}\right) \]
      5. lower-/.f64N/A

        \[\leadsto \sin^{-1} \left(\sqrt{1 - \color{blue}{\frac{{Om}^{2}}{{Omc}^{2}}}} \cdot \frac{\ell \cdot \sqrt{\frac{1}{2}}}{t}\right) \]
      6. unpow2N/A

        \[\leadsto \sin^{-1} \left(\sqrt{1 - \frac{\color{blue}{Om \cdot Om}}{{Omc}^{2}}} \cdot \frac{\ell \cdot \sqrt{\frac{1}{2}}}{t}\right) \]
      7. lower-*.f64N/A

        \[\leadsto \sin^{-1} \left(\sqrt{1 - \frac{\color{blue}{Om \cdot Om}}{{Omc}^{2}}} \cdot \frac{\ell \cdot \sqrt{\frac{1}{2}}}{t}\right) \]
      8. unpow2N/A

        \[\leadsto \sin^{-1} \left(\sqrt{1 - \frac{Om \cdot Om}{\color{blue}{Omc \cdot Omc}}} \cdot \frac{\ell \cdot \sqrt{\frac{1}{2}}}{t}\right) \]
      9. lower-*.f64N/A

        \[\leadsto \sin^{-1} \left(\sqrt{1 - \frac{Om \cdot Om}{\color{blue}{Omc \cdot Omc}}} \cdot \frac{\ell \cdot \sqrt{\frac{1}{2}}}{t}\right) \]
      10. lower-/.f64N/A

        \[\leadsto \sin^{-1} \left(\sqrt{1 - \frac{Om \cdot Om}{Omc \cdot Omc}} \cdot \color{blue}{\frac{\ell \cdot \sqrt{\frac{1}{2}}}{t}}\right) \]
      11. lower-*.f64N/A

        \[\leadsto \sin^{-1} \left(\sqrt{1 - \frac{Om \cdot Om}{Omc \cdot Omc}} \cdot \frac{\color{blue}{\ell \cdot \sqrt{\frac{1}{2}}}}{t}\right) \]
      12. lower-sqrt.f6488.4

        \[\leadsto \sin^{-1} \left(\sqrt{1 - \frac{Om \cdot Om}{Omc \cdot Omc}} \cdot \frac{\ell \cdot \color{blue}{\sqrt{0.5}}}{t}\right) \]
    5. Applied rewrites88.4%

      \[\leadsto \sin^{-1} \color{blue}{\left(\sqrt{1 - \frac{Om \cdot Om}{Omc \cdot Omc}} \cdot \frac{\ell \cdot \sqrt{0.5}}{t}\right)} \]
    6. Step-by-step derivation
      1. Applied rewrites99.6%

        \[\leadsto \sin^{-1} \left(\sqrt{1 - \frac{Om}{Omc} \cdot \frac{Om}{Omc}} \cdot \frac{\ell \cdot \sqrt{0.5}}{t}\right) \]
    7. Recombined 2 regimes into one program.
    8. Final simplification99.3%

      \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{t}{\ell} \leq 10^{+151}:\\ \;\;\;\;\sin^{-1} \left(\sqrt{\frac{1 - \frac{Om \cdot \frac{Om}{Omc}}{Omc}}{\mathsf{fma}\left(\frac{t}{\ell}, \frac{t}{\ell} \cdot 2, 1\right)}}\right)\\ \mathbf{else}:\\ \;\;\;\;\sin^{-1} \left(\sqrt{1 - \frac{Om}{Omc} \cdot \frac{Om}{Omc}} \cdot \frac{\ell \cdot \sqrt{0.5}}{t}\right)\\ \end{array} \]
    9. Add Preprocessing

    Alternative 2: 97.9% accurate, 1.3× speedup?

    \[\begin{array}{l} l_m = \left|\ell\right| \\ t_m = \left|t\right| \\ \begin{array}{l} \mathbf{if}\;{\left(\frac{t\_m}{l\_m}\right)}^{2} \leq 2 \cdot 10^{+33}:\\ \;\;\;\;\sin^{-1} \left(\frac{1}{\sqrt{-\mathsf{fma}\left(\frac{t\_m \cdot \frac{t\_m}{l\_m}}{l\_m}, -2, -1\right)}}\right)\\ \mathbf{else}:\\ \;\;\;\;\sin^{-1} \left(\frac{l\_m \cdot \sqrt{0.5}}{t\_m}\right)\\ \end{array} \end{array} \]
    l_m = (fabs.f64 l)
    t_m = (fabs.f64 t)
    (FPCore (t_m l_m Om Omc)
     :precision binary64
     (if (<= (pow (/ t_m l_m) 2.0) 2e+33)
       (asin (/ 1.0 (sqrt (- (fma (/ (* t_m (/ t_m l_m)) l_m) -2.0 -1.0)))))
       (asin (/ (* l_m (sqrt 0.5)) t_m))))
    l_m = fabs(l);
    t_m = fabs(t);
    double code(double t_m, double l_m, double Om, double Omc) {
    	double tmp;
    	if (pow((t_m / l_m), 2.0) <= 2e+33) {
    		tmp = asin((1.0 / sqrt(-fma(((t_m * (t_m / l_m)) / l_m), -2.0, -1.0))));
    	} else {
    		tmp = asin(((l_m * sqrt(0.5)) / t_m));
    	}
    	return tmp;
    }
    
    l_m = abs(l)
    t_m = abs(t)
    function code(t_m, l_m, Om, Omc)
    	tmp = 0.0
    	if ((Float64(t_m / l_m) ^ 2.0) <= 2e+33)
    		tmp = asin(Float64(1.0 / sqrt(Float64(-fma(Float64(Float64(t_m * Float64(t_m / l_m)) / l_m), -2.0, -1.0)))));
    	else
    		tmp = asin(Float64(Float64(l_m * sqrt(0.5)) / t_m));
    	end
    	return tmp
    end
    
    l_m = N[Abs[l], $MachinePrecision]
    t_m = N[Abs[t], $MachinePrecision]
    code[t$95$m_, l$95$m_, Om_, Omc_] := If[LessEqual[N[Power[N[(t$95$m / l$95$m), $MachinePrecision], 2.0], $MachinePrecision], 2e+33], N[ArcSin[N[(1.0 / N[Sqrt[(-N[(N[(N[(t$95$m * N[(t$95$m / l$95$m), $MachinePrecision]), $MachinePrecision] / l$95$m), $MachinePrecision] * -2.0 + -1.0), $MachinePrecision])], $MachinePrecision]), $MachinePrecision]], $MachinePrecision], N[ArcSin[N[(N[(l$95$m * N[Sqrt[0.5], $MachinePrecision]), $MachinePrecision] / t$95$m), $MachinePrecision]], $MachinePrecision]]
    
    \begin{array}{l}
    l_m = \left|\ell\right|
    \\
    t_m = \left|t\right|
    
    \\
    \begin{array}{l}
    \mathbf{if}\;{\left(\frac{t\_m}{l\_m}\right)}^{2} \leq 2 \cdot 10^{+33}:\\
    \;\;\;\;\sin^{-1} \left(\frac{1}{\sqrt{-\mathsf{fma}\left(\frac{t\_m \cdot \frac{t\_m}{l\_m}}{l\_m}, -2, -1\right)}}\right)\\
    
    \mathbf{else}:\\
    \;\;\;\;\sin^{-1} \left(\frac{l\_m \cdot \sqrt{0.5}}{t\_m}\right)\\
    
    
    \end{array}
    \end{array}
    
    Derivation
    1. Split input into 2 regimes
    2. if (pow.f64 (/.f64 t l) #s(literal 2 binary64)) < 1.9999999999999999e33

      1. Initial program 98.2%

        \[\sin^{-1} \left(\sqrt{\frac{1 - {\left(\frac{Om}{Omc}\right)}^{2}}{1 + 2 \cdot {\left(\frac{t}{\ell}\right)}^{2}}}\right) \]
      2. Add Preprocessing
      3. Step-by-step derivation
        1. lift-sqrt.f64N/A

          \[\leadsto \sin^{-1} \color{blue}{\left(\sqrt{\frac{1 - {\left(\frac{Om}{Omc}\right)}^{2}}{1 + 2 \cdot {\left(\frac{t}{\ell}\right)}^{2}}}\right)} \]
        2. lift-/.f64N/A

          \[\leadsto \sin^{-1} \left(\sqrt{\color{blue}{\frac{1 - {\left(\frac{Om}{Omc}\right)}^{2}}{1 + 2 \cdot {\left(\frac{t}{\ell}\right)}^{2}}}}\right) \]
        3. clear-numN/A

          \[\leadsto \sin^{-1} \left(\sqrt{\color{blue}{\frac{1}{\frac{1 + 2 \cdot {\left(\frac{t}{\ell}\right)}^{2}}{1 - {\left(\frac{Om}{Omc}\right)}^{2}}}}}\right) \]
        4. sqrt-divN/A

          \[\leadsto \sin^{-1} \color{blue}{\left(\frac{\sqrt{1}}{\sqrt{\frac{1 + 2 \cdot {\left(\frac{t}{\ell}\right)}^{2}}{1 - {\left(\frac{Om}{Omc}\right)}^{2}}}}\right)} \]
        5. metadata-evalN/A

          \[\leadsto \sin^{-1} \left(\frac{\color{blue}{1}}{\sqrt{\frac{1 + 2 \cdot {\left(\frac{t}{\ell}\right)}^{2}}{1 - {\left(\frac{Om}{Omc}\right)}^{2}}}}\right) \]
        6. lower-/.f64N/A

          \[\leadsto \sin^{-1} \color{blue}{\left(\frac{1}{\sqrt{\frac{1 + 2 \cdot {\left(\frac{t}{\ell}\right)}^{2}}{1 - {\left(\frac{Om}{Omc}\right)}^{2}}}}\right)} \]
        7. lower-sqrt.f64N/A

          \[\leadsto \sin^{-1} \left(\frac{1}{\color{blue}{\sqrt{\frac{1 + 2 \cdot {\left(\frac{t}{\ell}\right)}^{2}}{1 - {\left(\frac{Om}{Omc}\right)}^{2}}}}}\right) \]
        8. frac-2negN/A

          \[\leadsto \sin^{-1} \left(\frac{1}{\sqrt{\color{blue}{\frac{\mathsf{neg}\left(\left(1 + 2 \cdot {\left(\frac{t}{\ell}\right)}^{2}\right)\right)}{\mathsf{neg}\left(\left(1 - {\left(\frac{Om}{Omc}\right)}^{2}\right)\right)}}}}\right) \]
        9. lower-/.f64N/A

          \[\leadsto \sin^{-1} \left(\frac{1}{\sqrt{\color{blue}{\frac{\mathsf{neg}\left(\left(1 + 2 \cdot {\left(\frac{t}{\ell}\right)}^{2}\right)\right)}{\mathsf{neg}\left(\left(1 - {\left(\frac{Om}{Omc}\right)}^{2}\right)\right)}}}}\right) \]
      4. Applied rewrites79.9%

        \[\leadsto \sin^{-1} \color{blue}{\left(\frac{1}{\sqrt{\frac{\mathsf{fma}\left(\frac{t \cdot t}{\ell \cdot \ell}, -2, -1\right)}{\mathsf{fma}\left(Om, \frac{Om}{Omc \cdot Omc}, -1\right)}}}\right)} \]
      5. Taylor expanded in Om around 0

        \[\leadsto \sin^{-1} \left(\frac{1}{\sqrt{\color{blue}{-1 \cdot \left(-2 \cdot \frac{{t}^{2}}{{\ell}^{2}} - 1\right)}}}\right) \]
      6. Step-by-step derivation
        1. mul-1-negN/A

          \[\leadsto \sin^{-1} \left(\frac{1}{\sqrt{\color{blue}{\mathsf{neg}\left(\left(-2 \cdot \frac{{t}^{2}}{{\ell}^{2}} - 1\right)\right)}}}\right) \]
        2. lower-neg.f64N/A

          \[\leadsto \sin^{-1} \left(\frac{1}{\sqrt{\color{blue}{\mathsf{neg}\left(\left(-2 \cdot \frac{{t}^{2}}{{\ell}^{2}} - 1\right)\right)}}}\right) \]
        3. sub-negN/A

          \[\leadsto \sin^{-1} \left(\frac{1}{\sqrt{\mathsf{neg}\left(\color{blue}{\left(-2 \cdot \frac{{t}^{2}}{{\ell}^{2}} + \left(\mathsf{neg}\left(1\right)\right)\right)}\right)}}\right) \]
        4. *-commutativeN/A

          \[\leadsto \sin^{-1} \left(\frac{1}{\sqrt{\mathsf{neg}\left(\left(\color{blue}{\frac{{t}^{2}}{{\ell}^{2}} \cdot -2} + \left(\mathsf{neg}\left(1\right)\right)\right)\right)}}\right) \]
        5. metadata-evalN/A

          \[\leadsto \sin^{-1} \left(\frac{1}{\sqrt{\mathsf{neg}\left(\left(\frac{{t}^{2}}{{\ell}^{2}} \cdot -2 + \color{blue}{-1}\right)\right)}}\right) \]
        6. lower-fma.f64N/A

          \[\leadsto \sin^{-1} \left(\frac{1}{\sqrt{\mathsf{neg}\left(\color{blue}{\mathsf{fma}\left(\frac{{t}^{2}}{{\ell}^{2}}, -2, -1\right)}\right)}}\right) \]
        7. lower-/.f64N/A

          \[\leadsto \sin^{-1} \left(\frac{1}{\sqrt{\mathsf{neg}\left(\mathsf{fma}\left(\color{blue}{\frac{{t}^{2}}{{\ell}^{2}}}, -2, -1\right)\right)}}\right) \]
        8. unpow2N/A

          \[\leadsto \sin^{-1} \left(\frac{1}{\sqrt{\mathsf{neg}\left(\mathsf{fma}\left(\frac{\color{blue}{t \cdot t}}{{\ell}^{2}}, -2, -1\right)\right)}}\right) \]
        9. lower-*.f64N/A

          \[\leadsto \sin^{-1} \left(\frac{1}{\sqrt{\mathsf{neg}\left(\mathsf{fma}\left(\frac{\color{blue}{t \cdot t}}{{\ell}^{2}}, -2, -1\right)\right)}}\right) \]
        10. unpow2N/A

          \[\leadsto \sin^{-1} \left(\frac{1}{\sqrt{\mathsf{neg}\left(\mathsf{fma}\left(\frac{t \cdot t}{\color{blue}{\ell \cdot \ell}}, -2, -1\right)\right)}}\right) \]
        11. lower-*.f6484.2

          \[\leadsto \sin^{-1} \left(\frac{1}{\sqrt{-\mathsf{fma}\left(\frac{t \cdot t}{\color{blue}{\ell \cdot \ell}}, -2, -1\right)}}\right) \]
      7. Applied rewrites84.2%

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

          \[\leadsto \sin^{-1} \left(\frac{1}{\sqrt{-\mathsf{fma}\left(\frac{\frac{t}{\ell} \cdot t}{\ell}, -2, -1\right)}}\right) \]

        if 1.9999999999999999e33 < (pow.f64 (/.f64 t l) #s(literal 2 binary64))

        1. Initial program 68.4%

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

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

            \[\leadsto \sin^{-1} \color{blue}{\left(\sqrt{1 - \frac{{Om}^{2}}{{Omc}^{2}}} \cdot \frac{\ell \cdot \sqrt{\frac{1}{2}}}{t}\right)} \]
          2. lower-*.f64N/A

            \[\leadsto \sin^{-1} \color{blue}{\left(\sqrt{1 - \frac{{Om}^{2}}{{Omc}^{2}}} \cdot \frac{\ell \cdot \sqrt{\frac{1}{2}}}{t}\right)} \]
          3. lower-sqrt.f64N/A

            \[\leadsto \sin^{-1} \left(\color{blue}{\sqrt{1 - \frac{{Om}^{2}}{{Omc}^{2}}}} \cdot \frac{\ell \cdot \sqrt{\frac{1}{2}}}{t}\right) \]
          4. lower--.f64N/A

            \[\leadsto \sin^{-1} \left(\sqrt{\color{blue}{1 - \frac{{Om}^{2}}{{Omc}^{2}}}} \cdot \frac{\ell \cdot \sqrt{\frac{1}{2}}}{t}\right) \]
          5. lower-/.f64N/A

            \[\leadsto \sin^{-1} \left(\sqrt{1 - \color{blue}{\frac{{Om}^{2}}{{Omc}^{2}}}} \cdot \frac{\ell \cdot \sqrt{\frac{1}{2}}}{t}\right) \]
          6. unpow2N/A

            \[\leadsto \sin^{-1} \left(\sqrt{1 - \frac{\color{blue}{Om \cdot Om}}{{Omc}^{2}}} \cdot \frac{\ell \cdot \sqrt{\frac{1}{2}}}{t}\right) \]
          7. lower-*.f64N/A

            \[\leadsto \sin^{-1} \left(\sqrt{1 - \frac{\color{blue}{Om \cdot Om}}{{Omc}^{2}}} \cdot \frac{\ell \cdot \sqrt{\frac{1}{2}}}{t}\right) \]
          8. unpow2N/A

            \[\leadsto \sin^{-1} \left(\sqrt{1 - \frac{Om \cdot Om}{\color{blue}{Omc \cdot Omc}}} \cdot \frac{\ell \cdot \sqrt{\frac{1}{2}}}{t}\right) \]
          9. lower-*.f64N/A

            \[\leadsto \sin^{-1} \left(\sqrt{1 - \frac{Om \cdot Om}{\color{blue}{Omc \cdot Omc}}} \cdot \frac{\ell \cdot \sqrt{\frac{1}{2}}}{t}\right) \]
          10. lower-/.f64N/A

            \[\leadsto \sin^{-1} \left(\sqrt{1 - \frac{Om \cdot Om}{Omc \cdot Omc}} \cdot \color{blue}{\frac{\ell \cdot \sqrt{\frac{1}{2}}}{t}}\right) \]
          11. lower-*.f64N/A

            \[\leadsto \sin^{-1} \left(\sqrt{1 - \frac{Om \cdot Om}{Omc \cdot Omc}} \cdot \frac{\color{blue}{\ell \cdot \sqrt{\frac{1}{2}}}}{t}\right) \]
          12. lower-sqrt.f6487.3

            \[\leadsto \sin^{-1} \left(\sqrt{1 - \frac{Om \cdot Om}{Omc \cdot Omc}} \cdot \frac{\ell \cdot \color{blue}{\sqrt{0.5}}}{t}\right) \]
        5. Applied rewrites87.3%

          \[\leadsto \sin^{-1} \color{blue}{\left(\sqrt{1 - \frac{Om \cdot Om}{Omc \cdot Omc}} \cdot \frac{\ell \cdot \sqrt{0.5}}{t}\right)} \]
        6. Taylor expanded in Om around 0

          \[\leadsto \sin^{-1} \left(\frac{\ell \cdot \sqrt{\frac{1}{2}}}{\color{blue}{t}}\right) \]
        7. Step-by-step derivation
          1. Applied rewrites98.8%

            \[\leadsto \sin^{-1} \left(\frac{\ell \cdot \sqrt{0.5}}{\color{blue}{t}}\right) \]
        8. Recombined 2 regimes into one program.
        9. Final simplification97.9%

          \[\leadsto \begin{array}{l} \mathbf{if}\;{\left(\frac{t}{\ell}\right)}^{2} \leq 2 \cdot 10^{+33}:\\ \;\;\;\;\sin^{-1} \left(\frac{1}{\sqrt{-\mathsf{fma}\left(\frac{t \cdot \frac{t}{\ell}}{\ell}, -2, -1\right)}}\right)\\ \mathbf{else}:\\ \;\;\;\;\sin^{-1} \left(\frac{\ell \cdot \sqrt{0.5}}{t}\right)\\ \end{array} \]
        10. Add Preprocessing

        Reproduce

        ?
        herbie shell --seed 2024226 
        (FPCore (t l Om Omc)
          :name "Toniolo and Linder, Equation (2)"
          :precision binary64
          (asin (sqrt (/ (- 1.0 (pow (/ Om Omc) 2.0)) (+ 1.0 (* 2.0 (pow (/ t l) 2.0)))))))