2tan (problem 3.3.2)

Percentage Accurate: 42.1% → 99.5%
Time: 16.2s
Alternatives: 11
Speedup: 2.0×

Specification

?
\[\begin{array}{l} \\ \tan \left(x + \varepsilon\right) - \tan x \end{array} \]
(FPCore (x eps) :precision binary64 (- (tan (+ x eps)) (tan x)))
double code(double x, double eps) {
	return tan((x + eps)) - tan(x);
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    code = tan((x + eps)) - tan(x)
end function
public static double code(double x, double eps) {
	return Math.tan((x + eps)) - Math.tan(x);
}
def code(x, eps):
	return math.tan((x + eps)) - math.tan(x)
function code(x, eps)
	return Float64(tan(Float64(x + eps)) - tan(x))
end
function tmp = code(x, eps)
	tmp = tan((x + eps)) - tan(x);
end
code[x_, eps_] := N[(N[Tan[N[(x + eps), $MachinePrecision]], $MachinePrecision] - N[Tan[x], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\tan \left(x + \varepsilon\right) - \tan x
\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 11 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: 42.1% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \tan \left(x + \varepsilon\right) - \tan x \end{array} \]
(FPCore (x eps) :precision binary64 (- (tan (+ x eps)) (tan x)))
double code(double x, double eps) {
	return tan((x + eps)) - tan(x);
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    code = tan((x + eps)) - tan(x)
end function
public static double code(double x, double eps) {
	return Math.tan((x + eps)) - Math.tan(x);
}
def code(x, eps):
	return math.tan((x + eps)) - math.tan(x)
function code(x, eps)
	return Float64(tan(Float64(x + eps)) - tan(x))
end
function tmp = code(x, eps)
	tmp = tan((x + eps)) - tan(x);
end
code[x_, eps_] := N[(N[Tan[N[(x + eps), $MachinePrecision]], $MachinePrecision] - N[Tan[x], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\tan \left(x + \varepsilon\right) - \tan x
\end{array}

Alternative 1: 99.5% accurate, 0.1× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \frac{{\sin x}^{2}}{{\cos x}^{2}}\\ t_1 := 1 + t_0\\ t_2 := \tan x + \tan \varepsilon\\ \mathbf{if}\;\varepsilon \leq -8 \cdot 10^{-5}:\\ \;\;\;\;\frac{t_2}{1 - \frac{\tan x}{\frac{1}{\tan \varepsilon}}} - \tan x\\ \mathbf{elif}\;\varepsilon \leq 5.5 \cdot 10^{-5}:\\ \;\;\;\;\mathsf{fma}\left(\varepsilon, t_1, \frac{\varepsilon \cdot \varepsilon}{\frac{\frac{\cos x}{\sin x}}{t_1}}\right) + {\varepsilon}^{3} \cdot \left(t_0 \cdot t_1 + -0.3333333333333333 \cdot \left(-1 - t_0\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{t_2}{1 - \tan x \cdot \tan \varepsilon} - \tan x\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (let* ((t_0 (/ (pow (sin x) 2.0) (pow (cos x) 2.0)))
        (t_1 (+ 1.0 t_0))
        (t_2 (+ (tan x) (tan eps))))
   (if (<= eps -8e-5)
     (- (/ t_2 (- 1.0 (/ (tan x) (/ 1.0 (tan eps))))) (tan x))
     (if (<= eps 5.5e-5)
       (+
        (fma eps t_1 (/ (* eps eps) (/ (/ (cos x) (sin x)) t_1)))
        (* (pow eps 3.0) (+ (* t_0 t_1) (* -0.3333333333333333 (- -1.0 t_0)))))
       (- (/ t_2 (- 1.0 (* (tan x) (tan eps)))) (tan x))))))
double code(double x, double eps) {
	double t_0 = pow(sin(x), 2.0) / pow(cos(x), 2.0);
	double t_1 = 1.0 + t_0;
	double t_2 = tan(x) + tan(eps);
	double tmp;
	if (eps <= -8e-5) {
		tmp = (t_2 / (1.0 - (tan(x) / (1.0 / tan(eps))))) - tan(x);
	} else if (eps <= 5.5e-5) {
		tmp = fma(eps, t_1, ((eps * eps) / ((cos(x) / sin(x)) / t_1))) + (pow(eps, 3.0) * ((t_0 * t_1) + (-0.3333333333333333 * (-1.0 - t_0))));
	} else {
		tmp = (t_2 / (1.0 - (tan(x) * tan(eps)))) - tan(x);
	}
	return tmp;
}
function code(x, eps)
	t_0 = Float64((sin(x) ^ 2.0) / (cos(x) ^ 2.0))
	t_1 = Float64(1.0 + t_0)
	t_2 = Float64(tan(x) + tan(eps))
	tmp = 0.0
	if (eps <= -8e-5)
		tmp = Float64(Float64(t_2 / Float64(1.0 - Float64(tan(x) / Float64(1.0 / tan(eps))))) - tan(x));
	elseif (eps <= 5.5e-5)
		tmp = Float64(fma(eps, t_1, Float64(Float64(eps * eps) / Float64(Float64(cos(x) / sin(x)) / t_1))) + Float64((eps ^ 3.0) * Float64(Float64(t_0 * t_1) + Float64(-0.3333333333333333 * Float64(-1.0 - t_0)))));
	else
		tmp = Float64(Float64(t_2 / Float64(1.0 - Float64(tan(x) * tan(eps)))) - tan(x));
	end
	return tmp
end
code[x_, eps_] := Block[{t$95$0 = N[(N[Power[N[Sin[x], $MachinePrecision], 2.0], $MachinePrecision] / N[Power[N[Cos[x], $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[(1.0 + t$95$0), $MachinePrecision]}, Block[{t$95$2 = N[(N[Tan[x], $MachinePrecision] + N[Tan[eps], $MachinePrecision]), $MachinePrecision]}, If[LessEqual[eps, -8e-5], N[(N[(t$95$2 / N[(1.0 - N[(N[Tan[x], $MachinePrecision] / N[(1.0 / N[Tan[eps], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[Tan[x], $MachinePrecision]), $MachinePrecision], If[LessEqual[eps, 5.5e-5], N[(N[(eps * t$95$1 + N[(N[(eps * eps), $MachinePrecision] / N[(N[(N[Cos[x], $MachinePrecision] / N[Sin[x], $MachinePrecision]), $MachinePrecision] / t$95$1), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(N[Power[eps, 3.0], $MachinePrecision] * N[(N[(t$95$0 * t$95$1), $MachinePrecision] + N[(-0.3333333333333333 * N[(-1.0 - t$95$0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[(t$95$2 / N[(1.0 - N[(N[Tan[x], $MachinePrecision] * N[Tan[eps], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[Tan[x], $MachinePrecision]), $MachinePrecision]]]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \frac{{\sin x}^{2}}{{\cos x}^{2}}\\
t_1 := 1 + t_0\\
t_2 := \tan x + \tan \varepsilon\\
\mathbf{if}\;\varepsilon \leq -8 \cdot 10^{-5}:\\
\;\;\;\;\frac{t_2}{1 - \frac{\tan x}{\frac{1}{\tan \varepsilon}}} - \tan x\\

\mathbf{elif}\;\varepsilon \leq 5.5 \cdot 10^{-5}:\\
\;\;\;\;\mathsf{fma}\left(\varepsilon, t_1, \frac{\varepsilon \cdot \varepsilon}{\frac{\frac{\cos x}{\sin x}}{t_1}}\right) + {\varepsilon}^{3} \cdot \left(t_0 \cdot t_1 + -0.3333333333333333 \cdot \left(-1 - t_0\right)\right)\\

\mathbf{else}:\\
\;\;\;\;\frac{t_2}{1 - \tan x \cdot \tan \varepsilon} - \tan x\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if eps < -8.00000000000000065e-5

    1. Initial program 65.8%

      \[\tan \left(x + \varepsilon\right) - \tan x \]
    2. Step-by-step derivation
      1. tan-sum99.7%

        \[\leadsto \color{blue}{\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon}} - \tan x \]
      2. div-inv99.7%

        \[\leadsto \color{blue}{\left(\tan x + \tan \varepsilon\right) \cdot \frac{1}{1 - \tan x \cdot \tan \varepsilon}} - \tan x \]
      3. fma-neg99.8%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\tan x + \tan \varepsilon, \frac{1}{1 - \tan x \cdot \tan \varepsilon}, -\tan x\right)} \]
    3. Applied egg-rr99.8%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\tan x + \tan \varepsilon, \frac{1}{1 - \tan x \cdot \tan \varepsilon}, -\tan x\right)} \]
    4. Step-by-step derivation
      1. fma-neg99.7%

        \[\leadsto \color{blue}{\left(\tan x + \tan \varepsilon\right) \cdot \frac{1}{1 - \tan x \cdot \tan \varepsilon} - \tan x} \]
      2. associate-*r/99.7%

        \[\leadsto \color{blue}{\frac{\left(\tan x + \tan \varepsilon\right) \cdot 1}{1 - \tan x \cdot \tan \varepsilon}} - \tan x \]
      3. *-rgt-identity99.7%

        \[\leadsto \frac{\color{blue}{\tan x + \tan \varepsilon}}{1 - \tan x \cdot \tan \varepsilon} - \tan x \]
    5. Simplified99.7%

      \[\leadsto \color{blue}{\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon} - \tan x} \]
    6. Step-by-step derivation
      1. tan-quot99.7%

        \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \color{blue}{\frac{\sin \varepsilon}{\cos \varepsilon}}} - \tan x \]
      2. clear-num99.7%

        \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \color{blue}{\frac{1}{\frac{\cos \varepsilon}{\sin \varepsilon}}}} - \tan x \]
      3. un-div-inv99.7%

        \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \color{blue}{\frac{\tan x}{\frac{\cos \varepsilon}{\sin \varepsilon}}}} - \tan x \]
      4. clear-num99.7%

        \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \frac{\tan x}{\color{blue}{\frac{1}{\frac{\sin \varepsilon}{\cos \varepsilon}}}}} - \tan x \]
      5. tan-quot99.8%

        \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \frac{\tan x}{\frac{1}{\color{blue}{\tan \varepsilon}}}} - \tan x \]
    7. Applied egg-rr99.8%

      \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \color{blue}{\frac{\tan x}{\frac{1}{\tan \varepsilon}}}} - \tan x \]

    if -8.00000000000000065e-5 < eps < 5.5000000000000002e-5

    1. Initial program 27.2%

      \[\tan \left(x + \varepsilon\right) - \tan x \]
    2. Taylor expanded in eps around 0 99.6%

      \[\leadsto \color{blue}{\varepsilon \cdot \left(1 - -1 \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\right) + \left(\frac{{\varepsilon}^{2} \cdot \left(\sin x \cdot \left(1 - -1 \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\right)\right)}{\cos x} + -1 \cdot \left({\varepsilon}^{3} \cdot \left(0.16666666666666666 \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}} + \left(0.16666666666666666 + \left(-1 \cdot \frac{{\sin x}^{2} \cdot \left(1 - -1 \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\right)}{{\cos x}^{2}} + -0.5 \cdot \left(1 - -1 \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\right)\right)\right)\right)\right)\right)} \]
    3. Simplified99.6%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\varepsilon, 1 + \frac{{\sin x}^{2}}{{\cos x}^{2}}, \frac{\varepsilon \cdot \varepsilon}{\frac{\frac{\cos x}{\sin x}}{1 + \frac{{\sin x}^{2}}{{\cos x}^{2}}}}\right) - {\varepsilon}^{3} \cdot \left(\left(1 + \frac{{\sin x}^{2}}{{\cos x}^{2}}\right) \cdot -0.3333333333333333 - \frac{{\sin x}^{2}}{{\cos x}^{2}} \cdot \left(1 + \frac{{\sin x}^{2}}{{\cos x}^{2}}\right)\right)} \]

    if 5.5000000000000002e-5 < eps

    1. Initial program 58.3%

      \[\tan \left(x + \varepsilon\right) - \tan x \]
    2. Step-by-step derivation
      1. tan-sum99.7%

        \[\leadsto \color{blue}{\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon}} - \tan x \]
      2. div-inv99.6%

        \[\leadsto \color{blue}{\left(\tan x + \tan \varepsilon\right) \cdot \frac{1}{1 - \tan x \cdot \tan \varepsilon}} - \tan x \]
      3. fma-neg99.6%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\tan x + \tan \varepsilon, \frac{1}{1 - \tan x \cdot \tan \varepsilon}, -\tan x\right)} \]
    3. Applied egg-rr99.6%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\tan x + \tan \varepsilon, \frac{1}{1 - \tan x \cdot \tan \varepsilon}, -\tan x\right)} \]
    4. Step-by-step derivation
      1. fma-neg99.6%

        \[\leadsto \color{blue}{\left(\tan x + \tan \varepsilon\right) \cdot \frac{1}{1 - \tan x \cdot \tan \varepsilon} - \tan x} \]
      2. associate-*r/99.7%

        \[\leadsto \color{blue}{\frac{\left(\tan x + \tan \varepsilon\right) \cdot 1}{1 - \tan x \cdot \tan \varepsilon}} - \tan x \]
      3. *-rgt-identity99.7%

        \[\leadsto \frac{\color{blue}{\tan x + \tan \varepsilon}}{1 - \tan x \cdot \tan \varepsilon} - \tan x \]
    5. Simplified99.7%

      \[\leadsto \color{blue}{\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon} - \tan x} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification99.7%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -8 \cdot 10^{-5}:\\ \;\;\;\;\frac{\tan x + \tan \varepsilon}{1 - \frac{\tan x}{\frac{1}{\tan \varepsilon}}} - \tan x\\ \mathbf{elif}\;\varepsilon \leq 5.5 \cdot 10^{-5}:\\ \;\;\;\;\mathsf{fma}\left(\varepsilon, 1 + \frac{{\sin x}^{2}}{{\cos x}^{2}}, \frac{\varepsilon \cdot \varepsilon}{\frac{\frac{\cos x}{\sin x}}{1 + \frac{{\sin x}^{2}}{{\cos x}^{2}}}}\right) + {\varepsilon}^{3} \cdot \left(\frac{{\sin x}^{2}}{{\cos x}^{2}} \cdot \left(1 + \frac{{\sin x}^{2}}{{\cos x}^{2}}\right) + -0.3333333333333333 \cdot \left(-1 - \frac{{\sin x}^{2}}{{\cos x}^{2}}\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon} - \tan x\\ \end{array} \]

Alternative 2: 99.5% accurate, 0.2× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := 1 + \frac{{\sin x}^{2}}{{\cos x}^{2}}\\ t_1 := \tan x + \tan \varepsilon\\ \mathbf{if}\;\varepsilon \leq -1.3 \cdot 10^{-7}:\\ \;\;\;\;\frac{t_1}{1 - \frac{\tan x}{\frac{1}{\tan \varepsilon}}} - \tan x\\ \mathbf{elif}\;\varepsilon \leq 4.1 \cdot 10^{-7}:\\ \;\;\;\;\mathsf{fma}\left(\varepsilon, t_0, \frac{\varepsilon \cdot \varepsilon}{\frac{\frac{\cos x}{\sin x}}{t_0}}\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{t_1}{1 - \tan x \cdot \tan \varepsilon} - \tan x\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (let* ((t_0 (+ 1.0 (/ (pow (sin x) 2.0) (pow (cos x) 2.0))))
        (t_1 (+ (tan x) (tan eps))))
   (if (<= eps -1.3e-7)
     (- (/ t_1 (- 1.0 (/ (tan x) (/ 1.0 (tan eps))))) (tan x))
     (if (<= eps 4.1e-7)
       (fma eps t_0 (/ (* eps eps) (/ (/ (cos x) (sin x)) t_0)))
       (- (/ t_1 (- 1.0 (* (tan x) (tan eps)))) (tan x))))))
double code(double x, double eps) {
	double t_0 = 1.0 + (pow(sin(x), 2.0) / pow(cos(x), 2.0));
	double t_1 = tan(x) + tan(eps);
	double tmp;
	if (eps <= -1.3e-7) {
		tmp = (t_1 / (1.0 - (tan(x) / (1.0 / tan(eps))))) - tan(x);
	} else if (eps <= 4.1e-7) {
		tmp = fma(eps, t_0, ((eps * eps) / ((cos(x) / sin(x)) / t_0)));
	} else {
		tmp = (t_1 / (1.0 - (tan(x) * tan(eps)))) - tan(x);
	}
	return tmp;
}
function code(x, eps)
	t_0 = Float64(1.0 + Float64((sin(x) ^ 2.0) / (cos(x) ^ 2.0)))
	t_1 = Float64(tan(x) + tan(eps))
	tmp = 0.0
	if (eps <= -1.3e-7)
		tmp = Float64(Float64(t_1 / Float64(1.0 - Float64(tan(x) / Float64(1.0 / tan(eps))))) - tan(x));
	elseif (eps <= 4.1e-7)
		tmp = fma(eps, t_0, Float64(Float64(eps * eps) / Float64(Float64(cos(x) / sin(x)) / t_0)));
	else
		tmp = Float64(Float64(t_1 / Float64(1.0 - Float64(tan(x) * tan(eps)))) - tan(x));
	end
	return tmp
end
code[x_, eps_] := Block[{t$95$0 = N[(1.0 + N[(N[Power[N[Sin[x], $MachinePrecision], 2.0], $MachinePrecision] / N[Power[N[Cos[x], $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[(N[Tan[x], $MachinePrecision] + N[Tan[eps], $MachinePrecision]), $MachinePrecision]}, If[LessEqual[eps, -1.3e-7], N[(N[(t$95$1 / N[(1.0 - N[(N[Tan[x], $MachinePrecision] / N[(1.0 / N[Tan[eps], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[Tan[x], $MachinePrecision]), $MachinePrecision], If[LessEqual[eps, 4.1e-7], N[(eps * t$95$0 + N[(N[(eps * eps), $MachinePrecision] / N[(N[(N[Cos[x], $MachinePrecision] / N[Sin[x], $MachinePrecision]), $MachinePrecision] / t$95$0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[(t$95$1 / N[(1.0 - N[(N[Tan[x], $MachinePrecision] * N[Tan[eps], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[Tan[x], $MachinePrecision]), $MachinePrecision]]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := 1 + \frac{{\sin x}^{2}}{{\cos x}^{2}}\\
t_1 := \tan x + \tan \varepsilon\\
\mathbf{if}\;\varepsilon \leq -1.3 \cdot 10^{-7}:\\
\;\;\;\;\frac{t_1}{1 - \frac{\tan x}{\frac{1}{\tan \varepsilon}}} - \tan x\\

\mathbf{elif}\;\varepsilon \leq 4.1 \cdot 10^{-7}:\\
\;\;\;\;\mathsf{fma}\left(\varepsilon, t_0, \frac{\varepsilon \cdot \varepsilon}{\frac{\frac{\cos x}{\sin x}}{t_0}}\right)\\

\mathbf{else}:\\
\;\;\;\;\frac{t_1}{1 - \tan x \cdot \tan \varepsilon} - \tan x\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if eps < -1.29999999999999999e-7

    1. Initial program 65.8%

      \[\tan \left(x + \varepsilon\right) - \tan x \]
    2. Step-by-step derivation
      1. tan-sum99.7%

        \[\leadsto \color{blue}{\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon}} - \tan x \]
      2. div-inv99.7%

        \[\leadsto \color{blue}{\left(\tan x + \tan \varepsilon\right) \cdot \frac{1}{1 - \tan x \cdot \tan \varepsilon}} - \tan x \]
      3. fma-neg99.8%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\tan x + \tan \varepsilon, \frac{1}{1 - \tan x \cdot \tan \varepsilon}, -\tan x\right)} \]
    3. Applied egg-rr99.8%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\tan x + \tan \varepsilon, \frac{1}{1 - \tan x \cdot \tan \varepsilon}, -\tan x\right)} \]
    4. Step-by-step derivation
      1. fma-neg99.7%

        \[\leadsto \color{blue}{\left(\tan x + \tan \varepsilon\right) \cdot \frac{1}{1 - \tan x \cdot \tan \varepsilon} - \tan x} \]
      2. associate-*r/99.7%

        \[\leadsto \color{blue}{\frac{\left(\tan x + \tan \varepsilon\right) \cdot 1}{1 - \tan x \cdot \tan \varepsilon}} - \tan x \]
      3. *-rgt-identity99.7%

        \[\leadsto \frac{\color{blue}{\tan x + \tan \varepsilon}}{1 - \tan x \cdot \tan \varepsilon} - \tan x \]
    5. Simplified99.7%

      \[\leadsto \color{blue}{\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon} - \tan x} \]
    6. Step-by-step derivation
      1. tan-quot99.7%

        \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \color{blue}{\frac{\sin \varepsilon}{\cos \varepsilon}}} - \tan x \]
      2. clear-num99.7%

        \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \color{blue}{\frac{1}{\frac{\cos \varepsilon}{\sin \varepsilon}}}} - \tan x \]
      3. un-div-inv99.7%

        \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \color{blue}{\frac{\tan x}{\frac{\cos \varepsilon}{\sin \varepsilon}}}} - \tan x \]
      4. clear-num99.7%

        \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \frac{\tan x}{\color{blue}{\frac{1}{\frac{\sin \varepsilon}{\cos \varepsilon}}}}} - \tan x \]
      5. tan-quot99.8%

        \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \frac{\tan x}{\frac{1}{\color{blue}{\tan \varepsilon}}}} - \tan x \]
    7. Applied egg-rr99.8%

      \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \color{blue}{\frac{\tan x}{\frac{1}{\tan \varepsilon}}}} - \tan x \]

    if -1.29999999999999999e-7 < eps < 4.0999999999999999e-7

    1. Initial program 27.2%

      \[\tan \left(x + \varepsilon\right) - \tan x \]
    2. Taylor expanded in eps around 0 99.6%

      \[\leadsto \color{blue}{\varepsilon \cdot \left(1 - -1 \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\right) + \frac{{\varepsilon}^{2} \cdot \left(\sin x \cdot \left(1 - -1 \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\right)\right)}{\cos x}} \]
    3. Step-by-step derivation
      1. fma-def99.6%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\varepsilon, 1 - -1 \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}, \frac{{\varepsilon}^{2} \cdot \left(\sin x \cdot \left(1 - -1 \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\right)\right)}{\cos x}\right)} \]
      2. cancel-sign-sub-inv99.6%

        \[\leadsto \mathsf{fma}\left(\varepsilon, \color{blue}{1 + \left(--1\right) \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}}, \frac{{\varepsilon}^{2} \cdot \left(\sin x \cdot \left(1 - -1 \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\right)\right)}{\cos x}\right) \]
      3. metadata-eval99.6%

        \[\leadsto \mathsf{fma}\left(\varepsilon, 1 + \color{blue}{1} \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}, \frac{{\varepsilon}^{2} \cdot \left(\sin x \cdot \left(1 - -1 \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\right)\right)}{\cos x}\right) \]
      4. *-lft-identity99.6%

        \[\leadsto \mathsf{fma}\left(\varepsilon, 1 + \color{blue}{\frac{{\sin x}^{2}}{{\cos x}^{2}}}, \frac{{\varepsilon}^{2} \cdot \left(\sin x \cdot \left(1 - -1 \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\right)\right)}{\cos x}\right) \]
      5. associate-/l*99.6%

        \[\leadsto \mathsf{fma}\left(\varepsilon, 1 + \frac{{\sin x}^{2}}{{\cos x}^{2}}, \color{blue}{\frac{{\varepsilon}^{2}}{\frac{\cos x}{\sin x \cdot \left(1 - -1 \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\right)}}}\right) \]
      6. unpow299.6%

        \[\leadsto \mathsf{fma}\left(\varepsilon, 1 + \frac{{\sin x}^{2}}{{\cos x}^{2}}, \frac{\color{blue}{\varepsilon \cdot \varepsilon}}{\frac{\cos x}{\sin x \cdot \left(1 - -1 \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\right)}}\right) \]
      7. associate-/r*99.6%

        \[\leadsto \mathsf{fma}\left(\varepsilon, 1 + \frac{{\sin x}^{2}}{{\cos x}^{2}}, \frac{\varepsilon \cdot \varepsilon}{\color{blue}{\frac{\frac{\cos x}{\sin x}}{1 - -1 \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}}}}\right) \]
      8. cancel-sign-sub-inv99.6%

        \[\leadsto \mathsf{fma}\left(\varepsilon, 1 + \frac{{\sin x}^{2}}{{\cos x}^{2}}, \frac{\varepsilon \cdot \varepsilon}{\frac{\frac{\cos x}{\sin x}}{\color{blue}{1 + \left(--1\right) \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}}}}\right) \]
      9. metadata-eval99.6%

        \[\leadsto \mathsf{fma}\left(\varepsilon, 1 + \frac{{\sin x}^{2}}{{\cos x}^{2}}, \frac{\varepsilon \cdot \varepsilon}{\frac{\frac{\cos x}{\sin x}}{1 + \color{blue}{1} \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}}}\right) \]
      10. *-lft-identity99.6%

        \[\leadsto \mathsf{fma}\left(\varepsilon, 1 + \frac{{\sin x}^{2}}{{\cos x}^{2}}, \frac{\varepsilon \cdot \varepsilon}{\frac{\frac{\cos x}{\sin x}}{1 + \color{blue}{\frac{{\sin x}^{2}}{{\cos x}^{2}}}}}\right) \]
    4. Simplified99.6%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\varepsilon, 1 + \frac{{\sin x}^{2}}{{\cos x}^{2}}, \frac{\varepsilon \cdot \varepsilon}{\frac{\frac{\cos x}{\sin x}}{1 + \frac{{\sin x}^{2}}{{\cos x}^{2}}}}\right)} \]

    if 4.0999999999999999e-7 < eps

    1. Initial program 58.3%

      \[\tan \left(x + \varepsilon\right) - \tan x \]
    2. Step-by-step derivation
      1. tan-sum99.7%

        \[\leadsto \color{blue}{\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon}} - \tan x \]
      2. div-inv99.6%

        \[\leadsto \color{blue}{\left(\tan x + \tan \varepsilon\right) \cdot \frac{1}{1 - \tan x \cdot \tan \varepsilon}} - \tan x \]
      3. fma-neg99.6%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\tan x + \tan \varepsilon, \frac{1}{1 - \tan x \cdot \tan \varepsilon}, -\tan x\right)} \]
    3. Applied egg-rr99.6%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\tan x + \tan \varepsilon, \frac{1}{1 - \tan x \cdot \tan \varepsilon}, -\tan x\right)} \]
    4. Step-by-step derivation
      1. fma-neg99.6%

        \[\leadsto \color{blue}{\left(\tan x + \tan \varepsilon\right) \cdot \frac{1}{1 - \tan x \cdot \tan \varepsilon} - \tan x} \]
      2. associate-*r/99.7%

        \[\leadsto \color{blue}{\frac{\left(\tan x + \tan \varepsilon\right) \cdot 1}{1 - \tan x \cdot \tan \varepsilon}} - \tan x \]
      3. *-rgt-identity99.7%

        \[\leadsto \frac{\color{blue}{\tan x + \tan \varepsilon}}{1 - \tan x \cdot \tan \varepsilon} - \tan x \]
    5. Simplified99.7%

      \[\leadsto \color{blue}{\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon} - \tan x} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification99.6%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -1.3 \cdot 10^{-7}:\\ \;\;\;\;\frac{\tan x + \tan \varepsilon}{1 - \frac{\tan x}{\frac{1}{\tan \varepsilon}}} - \tan x\\ \mathbf{elif}\;\varepsilon \leq 4.1 \cdot 10^{-7}:\\ \;\;\;\;\mathsf{fma}\left(\varepsilon, 1 + \frac{{\sin x}^{2}}{{\cos x}^{2}}, \frac{\varepsilon \cdot \varepsilon}{\frac{\frac{\cos x}{\sin x}}{1 + \frac{{\sin x}^{2}}{{\cos x}^{2}}}}\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon} - \tan x\\ \end{array} \]

Alternative 3: 99.4% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \tan x + \tan \varepsilon\\ t_1 := 1 - \tan x \cdot \tan \varepsilon\\ \mathbf{if}\;\varepsilon \leq -3 \cdot 10^{-7}:\\ \;\;\;\;\frac{t_0}{1 - \frac{\tan x}{\frac{1}{\tan \varepsilon}}} - \tan x\\ \mathbf{elif}\;\varepsilon \leq 2.1 \cdot 10^{-7}:\\ \;\;\;\;\frac{\varepsilon \cdot \left(\cos x + \frac{{\sin x}^{2}}{\cos x}\right)}{\cos x \cdot t_1}\\ \mathbf{else}:\\ \;\;\;\;\frac{t_0}{t_1} - \tan x\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (let* ((t_0 (+ (tan x) (tan eps))) (t_1 (- 1.0 (* (tan x) (tan eps)))))
   (if (<= eps -3e-7)
     (- (/ t_0 (- 1.0 (/ (tan x) (/ 1.0 (tan eps))))) (tan x))
     (if (<= eps 2.1e-7)
       (/ (* eps (+ (cos x) (/ (pow (sin x) 2.0) (cos x)))) (* (cos x) t_1))
       (- (/ t_0 t_1) (tan x))))))
double code(double x, double eps) {
	double t_0 = tan(x) + tan(eps);
	double t_1 = 1.0 - (tan(x) * tan(eps));
	double tmp;
	if (eps <= -3e-7) {
		tmp = (t_0 / (1.0 - (tan(x) / (1.0 / tan(eps))))) - tan(x);
	} else if (eps <= 2.1e-7) {
		tmp = (eps * (cos(x) + (pow(sin(x), 2.0) / cos(x)))) / (cos(x) * t_1);
	} else {
		tmp = (t_0 / t_1) - tan(x);
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: t_0
    real(8) :: t_1
    real(8) :: tmp
    t_0 = tan(x) + tan(eps)
    t_1 = 1.0d0 - (tan(x) * tan(eps))
    if (eps <= (-3d-7)) then
        tmp = (t_0 / (1.0d0 - (tan(x) / (1.0d0 / tan(eps))))) - tan(x)
    else if (eps <= 2.1d-7) then
        tmp = (eps * (cos(x) + ((sin(x) ** 2.0d0) / cos(x)))) / (cos(x) * t_1)
    else
        tmp = (t_0 / t_1) - tan(x)
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double t_0 = Math.tan(x) + Math.tan(eps);
	double t_1 = 1.0 - (Math.tan(x) * Math.tan(eps));
	double tmp;
	if (eps <= -3e-7) {
		tmp = (t_0 / (1.0 - (Math.tan(x) / (1.0 / Math.tan(eps))))) - Math.tan(x);
	} else if (eps <= 2.1e-7) {
		tmp = (eps * (Math.cos(x) + (Math.pow(Math.sin(x), 2.0) / Math.cos(x)))) / (Math.cos(x) * t_1);
	} else {
		tmp = (t_0 / t_1) - Math.tan(x);
	}
	return tmp;
}
def code(x, eps):
	t_0 = math.tan(x) + math.tan(eps)
	t_1 = 1.0 - (math.tan(x) * math.tan(eps))
	tmp = 0
	if eps <= -3e-7:
		tmp = (t_0 / (1.0 - (math.tan(x) / (1.0 / math.tan(eps))))) - math.tan(x)
	elif eps <= 2.1e-7:
		tmp = (eps * (math.cos(x) + (math.pow(math.sin(x), 2.0) / math.cos(x)))) / (math.cos(x) * t_1)
	else:
		tmp = (t_0 / t_1) - math.tan(x)
	return tmp
function code(x, eps)
	t_0 = Float64(tan(x) + tan(eps))
	t_1 = Float64(1.0 - Float64(tan(x) * tan(eps)))
	tmp = 0.0
	if (eps <= -3e-7)
		tmp = Float64(Float64(t_0 / Float64(1.0 - Float64(tan(x) / Float64(1.0 / tan(eps))))) - tan(x));
	elseif (eps <= 2.1e-7)
		tmp = Float64(Float64(eps * Float64(cos(x) + Float64((sin(x) ^ 2.0) / cos(x)))) / Float64(cos(x) * t_1));
	else
		tmp = Float64(Float64(t_0 / t_1) - tan(x));
	end
	return tmp
end
function tmp_2 = code(x, eps)
	t_0 = tan(x) + tan(eps);
	t_1 = 1.0 - (tan(x) * tan(eps));
	tmp = 0.0;
	if (eps <= -3e-7)
		tmp = (t_0 / (1.0 - (tan(x) / (1.0 / tan(eps))))) - tan(x);
	elseif (eps <= 2.1e-7)
		tmp = (eps * (cos(x) + ((sin(x) ^ 2.0) / cos(x)))) / (cos(x) * t_1);
	else
		tmp = (t_0 / t_1) - tan(x);
	end
	tmp_2 = tmp;
end
code[x_, eps_] := Block[{t$95$0 = N[(N[Tan[x], $MachinePrecision] + N[Tan[eps], $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[(1.0 - N[(N[Tan[x], $MachinePrecision] * N[Tan[eps], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[eps, -3e-7], N[(N[(t$95$0 / N[(1.0 - N[(N[Tan[x], $MachinePrecision] / N[(1.0 / N[Tan[eps], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[Tan[x], $MachinePrecision]), $MachinePrecision], If[LessEqual[eps, 2.1e-7], N[(N[(eps * N[(N[Cos[x], $MachinePrecision] + N[(N[Power[N[Sin[x], $MachinePrecision], 2.0], $MachinePrecision] / N[Cos[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(N[Cos[x], $MachinePrecision] * t$95$1), $MachinePrecision]), $MachinePrecision], N[(N[(t$95$0 / t$95$1), $MachinePrecision] - N[Tan[x], $MachinePrecision]), $MachinePrecision]]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \tan x + \tan \varepsilon\\
t_1 := 1 - \tan x \cdot \tan \varepsilon\\
\mathbf{if}\;\varepsilon \leq -3 \cdot 10^{-7}:\\
\;\;\;\;\frac{t_0}{1 - \frac{\tan x}{\frac{1}{\tan \varepsilon}}} - \tan x\\

\mathbf{elif}\;\varepsilon \leq 2.1 \cdot 10^{-7}:\\
\;\;\;\;\frac{\varepsilon \cdot \left(\cos x + \frac{{\sin x}^{2}}{\cos x}\right)}{\cos x \cdot t_1}\\

\mathbf{else}:\\
\;\;\;\;\frac{t_0}{t_1} - \tan x\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if eps < -2.9999999999999999e-7

    1. Initial program 65.8%

      \[\tan \left(x + \varepsilon\right) - \tan x \]
    2. Step-by-step derivation
      1. tan-sum99.7%

        \[\leadsto \color{blue}{\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon}} - \tan x \]
      2. div-inv99.7%

        \[\leadsto \color{blue}{\left(\tan x + \tan \varepsilon\right) \cdot \frac{1}{1 - \tan x \cdot \tan \varepsilon}} - \tan x \]
      3. fma-neg99.8%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\tan x + \tan \varepsilon, \frac{1}{1 - \tan x \cdot \tan \varepsilon}, -\tan x\right)} \]
    3. Applied egg-rr99.8%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\tan x + \tan \varepsilon, \frac{1}{1 - \tan x \cdot \tan \varepsilon}, -\tan x\right)} \]
    4. Step-by-step derivation
      1. fma-neg99.7%

        \[\leadsto \color{blue}{\left(\tan x + \tan \varepsilon\right) \cdot \frac{1}{1 - \tan x \cdot \tan \varepsilon} - \tan x} \]
      2. associate-*r/99.7%

        \[\leadsto \color{blue}{\frac{\left(\tan x + \tan \varepsilon\right) \cdot 1}{1 - \tan x \cdot \tan \varepsilon}} - \tan x \]
      3. *-rgt-identity99.7%

        \[\leadsto \frac{\color{blue}{\tan x + \tan \varepsilon}}{1 - \tan x \cdot \tan \varepsilon} - \tan x \]
    5. Simplified99.7%

      \[\leadsto \color{blue}{\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon} - \tan x} \]
    6. Step-by-step derivation
      1. tan-quot99.7%

        \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \color{blue}{\frac{\sin \varepsilon}{\cos \varepsilon}}} - \tan x \]
      2. clear-num99.7%

        \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \color{blue}{\frac{1}{\frac{\cos \varepsilon}{\sin \varepsilon}}}} - \tan x \]
      3. un-div-inv99.7%

        \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \color{blue}{\frac{\tan x}{\frac{\cos \varepsilon}{\sin \varepsilon}}}} - \tan x \]
      4. clear-num99.7%

        \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \frac{\tan x}{\color{blue}{\frac{1}{\frac{\sin \varepsilon}{\cos \varepsilon}}}}} - \tan x \]
      5. tan-quot99.8%

        \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \frac{\tan x}{\frac{1}{\color{blue}{\tan \varepsilon}}}} - \tan x \]
    7. Applied egg-rr99.8%

      \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \color{blue}{\frac{\tan x}{\frac{1}{\tan \varepsilon}}}} - \tan x \]

    if -2.9999999999999999e-7 < eps < 2.1e-7

    1. Initial program 27.2%

      \[\tan \left(x + \varepsilon\right) - \tan x \]
    2. Step-by-step derivation
      1. tan-sum27.7%

        \[\leadsto \color{blue}{\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon}} - \tan x \]
      2. tan-quot27.5%

        \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon} - \color{blue}{\frac{\sin x}{\cos x}} \]
      3. frac-sub27.6%

        \[\leadsto \color{blue}{\frac{\left(\tan x + \tan \varepsilon\right) \cdot \cos x - \left(1 - \tan x \cdot \tan \varepsilon\right) \cdot \sin x}{\left(1 - \tan x \cdot \tan \varepsilon\right) \cdot \cos x}} \]
    3. Applied egg-rr27.6%

      \[\leadsto \color{blue}{\frac{\left(\tan x + \tan \varepsilon\right) \cdot \cos x - \left(1 - \tan x \cdot \tan \varepsilon\right) \cdot \sin x}{\left(1 - \tan x \cdot \tan \varepsilon\right) \cdot \cos x}} \]
    4. Taylor expanded in eps around 0 99.5%

      \[\leadsto \frac{\color{blue}{\left(\cos x - -1 \cdot \frac{{\sin x}^{2}}{\cos x}\right) \cdot \varepsilon}}{\left(1 - \tan x \cdot \tan \varepsilon\right) \cdot \cos x} \]
    5. Step-by-step derivation
      1. *-commutative99.5%

        \[\leadsto \frac{\color{blue}{\varepsilon \cdot \left(\cos x - -1 \cdot \frac{{\sin x}^{2}}{\cos x}\right)}}{\left(1 - \tan x \cdot \tan \varepsilon\right) \cdot \cos x} \]
      2. cancel-sign-sub-inv99.5%

        \[\leadsto \frac{\varepsilon \cdot \color{blue}{\left(\cos x + \left(--1\right) \cdot \frac{{\sin x}^{2}}{\cos x}\right)}}{\left(1 - \tan x \cdot \tan \varepsilon\right) \cdot \cos x} \]
      3. metadata-eval99.5%

        \[\leadsto \frac{\varepsilon \cdot \left(\cos x + \color{blue}{1} \cdot \frac{{\sin x}^{2}}{\cos x}\right)}{\left(1 - \tan x \cdot \tan \varepsilon\right) \cdot \cos x} \]
      4. *-lft-identity99.5%

        \[\leadsto \frac{\varepsilon \cdot \left(\cos x + \color{blue}{\frac{{\sin x}^{2}}{\cos x}}\right)}{\left(1 - \tan x \cdot \tan \varepsilon\right) \cdot \cos x} \]
    6. Simplified99.5%

      \[\leadsto \frac{\color{blue}{\varepsilon \cdot \left(\cos x + \frac{{\sin x}^{2}}{\cos x}\right)}}{\left(1 - \tan x \cdot \tan \varepsilon\right) \cdot \cos x} \]

    if 2.1e-7 < eps

    1. Initial program 58.3%

      \[\tan \left(x + \varepsilon\right) - \tan x \]
    2. Step-by-step derivation
      1. tan-sum99.7%

        \[\leadsto \color{blue}{\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon}} - \tan x \]
      2. div-inv99.6%

        \[\leadsto \color{blue}{\left(\tan x + \tan \varepsilon\right) \cdot \frac{1}{1 - \tan x \cdot \tan \varepsilon}} - \tan x \]
      3. fma-neg99.6%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\tan x + \tan \varepsilon, \frac{1}{1 - \tan x \cdot \tan \varepsilon}, -\tan x\right)} \]
    3. Applied egg-rr99.6%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\tan x + \tan \varepsilon, \frac{1}{1 - \tan x \cdot \tan \varepsilon}, -\tan x\right)} \]
    4. Step-by-step derivation
      1. fma-neg99.6%

        \[\leadsto \color{blue}{\left(\tan x + \tan \varepsilon\right) \cdot \frac{1}{1 - \tan x \cdot \tan \varepsilon} - \tan x} \]
      2. associate-*r/99.7%

        \[\leadsto \color{blue}{\frac{\left(\tan x + \tan \varepsilon\right) \cdot 1}{1 - \tan x \cdot \tan \varepsilon}} - \tan x \]
      3. *-rgt-identity99.7%

        \[\leadsto \frac{\color{blue}{\tan x + \tan \varepsilon}}{1 - \tan x \cdot \tan \varepsilon} - \tan x \]
    5. Simplified99.7%

      \[\leadsto \color{blue}{\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon} - \tan x} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification99.6%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -3 \cdot 10^{-7}:\\ \;\;\;\;\frac{\tan x + \tan \varepsilon}{1 - \frac{\tan x}{\frac{1}{\tan \varepsilon}}} - \tan x\\ \mathbf{elif}\;\varepsilon \leq 2.1 \cdot 10^{-7}:\\ \;\;\;\;\frac{\varepsilon \cdot \left(\cos x + \frac{{\sin x}^{2}}{\cos x}\right)}{\cos x \cdot \left(1 - \tan x \cdot \tan \varepsilon\right)}\\ \mathbf{else}:\\ \;\;\;\;\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon} - \tan x\\ \end{array} \]

Alternative 4: 99.0% accurate, 0.4× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -3 \cdot 10^{-9} \lor \neg \left(\varepsilon \leq 1.75 \cdot 10^{-19}\right):\\ \;\;\;\;\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon} - \tan x\\ \mathbf{else}:\\ \;\;\;\;\varepsilon + \varepsilon \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (or (<= eps -3e-9) (not (<= eps 1.75e-19)))
   (- (/ (+ (tan x) (tan eps)) (- 1.0 (* (tan x) (tan eps)))) (tan x))
   (+ eps (* eps (/ (pow (sin x) 2.0) (pow (cos x) 2.0))))))
double code(double x, double eps) {
	double tmp;
	if ((eps <= -3e-9) || !(eps <= 1.75e-19)) {
		tmp = ((tan(x) + tan(eps)) / (1.0 - (tan(x) * tan(eps)))) - tan(x);
	} else {
		tmp = eps + (eps * (pow(sin(x), 2.0) / pow(cos(x), 2.0)));
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: tmp
    if ((eps <= (-3d-9)) .or. (.not. (eps <= 1.75d-19))) then
        tmp = ((tan(x) + tan(eps)) / (1.0d0 - (tan(x) * tan(eps)))) - tan(x)
    else
        tmp = eps + (eps * ((sin(x) ** 2.0d0) / (cos(x) ** 2.0d0)))
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if ((eps <= -3e-9) || !(eps <= 1.75e-19)) {
		tmp = ((Math.tan(x) + Math.tan(eps)) / (1.0 - (Math.tan(x) * Math.tan(eps)))) - Math.tan(x);
	} else {
		tmp = eps + (eps * (Math.pow(Math.sin(x), 2.0) / Math.pow(Math.cos(x), 2.0)));
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if (eps <= -3e-9) or not (eps <= 1.75e-19):
		tmp = ((math.tan(x) + math.tan(eps)) / (1.0 - (math.tan(x) * math.tan(eps)))) - math.tan(x)
	else:
		tmp = eps + (eps * (math.pow(math.sin(x), 2.0) / math.pow(math.cos(x), 2.0)))
	return tmp
function code(x, eps)
	tmp = 0.0
	if ((eps <= -3e-9) || !(eps <= 1.75e-19))
		tmp = Float64(Float64(Float64(tan(x) + tan(eps)) / Float64(1.0 - Float64(tan(x) * tan(eps)))) - tan(x));
	else
		tmp = Float64(eps + Float64(eps * Float64((sin(x) ^ 2.0) / (cos(x) ^ 2.0))));
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if ((eps <= -3e-9) || ~((eps <= 1.75e-19)))
		tmp = ((tan(x) + tan(eps)) / (1.0 - (tan(x) * tan(eps)))) - tan(x);
	else
		tmp = eps + (eps * ((sin(x) ^ 2.0) / (cos(x) ^ 2.0)));
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[Or[LessEqual[eps, -3e-9], N[Not[LessEqual[eps, 1.75e-19]], $MachinePrecision]], N[(N[(N[(N[Tan[x], $MachinePrecision] + N[Tan[eps], $MachinePrecision]), $MachinePrecision] / N[(1.0 - N[(N[Tan[x], $MachinePrecision] * N[Tan[eps], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[Tan[x], $MachinePrecision]), $MachinePrecision], N[(eps + N[(eps * N[(N[Power[N[Sin[x], $MachinePrecision], 2.0], $MachinePrecision] / N[Power[N[Cos[x], $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -3 \cdot 10^{-9} \lor \neg \left(\varepsilon \leq 1.75 \cdot 10^{-19}\right):\\
\;\;\;\;\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon} - \tan x\\

\mathbf{else}:\\
\;\;\;\;\varepsilon + \varepsilon \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < -2.99999999999999998e-9 or 1.75000000000000008e-19 < eps

    1. Initial program 61.9%

      \[\tan \left(x + \varepsilon\right) - \tan x \]
    2. Step-by-step derivation
      1. tan-sum99.5%

        \[\leadsto \color{blue}{\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon}} - \tan x \]
      2. div-inv99.4%

        \[\leadsto \color{blue}{\left(\tan x + \tan \varepsilon\right) \cdot \frac{1}{1 - \tan x \cdot \tan \varepsilon}} - \tan x \]
      3. fma-neg99.5%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\tan x + \tan \varepsilon, \frac{1}{1 - \tan x \cdot \tan \varepsilon}, -\tan x\right)} \]
    3. Applied egg-rr99.5%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\tan x + \tan \varepsilon, \frac{1}{1 - \tan x \cdot \tan \varepsilon}, -\tan x\right)} \]
    4. Step-by-step derivation
      1. fma-neg99.4%

        \[\leadsto \color{blue}{\left(\tan x + \tan \varepsilon\right) \cdot \frac{1}{1 - \tan x \cdot \tan \varepsilon} - \tan x} \]
      2. associate-*r/99.5%

        \[\leadsto \color{blue}{\frac{\left(\tan x + \tan \varepsilon\right) \cdot 1}{1 - \tan x \cdot \tan \varepsilon}} - \tan x \]
      3. *-rgt-identity99.5%

        \[\leadsto \frac{\color{blue}{\tan x + \tan \varepsilon}}{1 - \tan x \cdot \tan \varepsilon} - \tan x \]
    5. Simplified99.5%

      \[\leadsto \color{blue}{\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon} - \tan x} \]

    if -2.99999999999999998e-9 < eps < 1.75000000000000008e-19

    1. Initial program 26.8%

      \[\tan \left(x + \varepsilon\right) - \tan x \]
    2. Taylor expanded in eps around 0 99.6%

      \[\leadsto \color{blue}{\varepsilon \cdot \left(1 - -1 \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\right)} \]
    3. Step-by-step derivation
      1. cancel-sign-sub-inv99.6%

        \[\leadsto \varepsilon \cdot \color{blue}{\left(1 + \left(--1\right) \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\right)} \]
      2. metadata-eval99.6%

        \[\leadsto \varepsilon \cdot \left(1 + \color{blue}{1} \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\right) \]
      3. *-lft-identity99.6%

        \[\leadsto \varepsilon \cdot \left(1 + \color{blue}{\frac{{\sin x}^{2}}{{\cos x}^{2}}}\right) \]
      4. distribute-lft-in99.7%

        \[\leadsto \color{blue}{\varepsilon \cdot 1 + \varepsilon \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}} \]
      5. *-rgt-identity99.7%

        \[\leadsto \color{blue}{\varepsilon} + \varepsilon \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}} \]
    4. Simplified99.7%

      \[\leadsto \color{blue}{\varepsilon + \varepsilon \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification99.6%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -3 \cdot 10^{-9} \lor \neg \left(\varepsilon \leq 1.75 \cdot 10^{-19}\right):\\ \;\;\;\;\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon} - \tan x\\ \mathbf{else}:\\ \;\;\;\;\varepsilon + \varepsilon \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\\ \end{array} \]

Alternative 5: 99.0% accurate, 0.4× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \tan x + \tan \varepsilon\\ \mathbf{if}\;\varepsilon \leq -2 \cdot 10^{-9}:\\ \;\;\;\;\frac{t_0}{1 - \frac{\tan x}{\frac{1}{\tan \varepsilon}}} - \tan x\\ \mathbf{elif}\;\varepsilon \leq 1.75 \cdot 10^{-19}:\\ \;\;\;\;\varepsilon + \varepsilon \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\\ \mathbf{else}:\\ \;\;\;\;\frac{t_0}{1 - \tan x \cdot \tan \varepsilon} - \tan x\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (let* ((t_0 (+ (tan x) (tan eps))))
   (if (<= eps -2e-9)
     (- (/ t_0 (- 1.0 (/ (tan x) (/ 1.0 (tan eps))))) (tan x))
     (if (<= eps 1.75e-19)
       (+ eps (* eps (/ (pow (sin x) 2.0) (pow (cos x) 2.0))))
       (- (/ t_0 (- 1.0 (* (tan x) (tan eps)))) (tan x))))))
double code(double x, double eps) {
	double t_0 = tan(x) + tan(eps);
	double tmp;
	if (eps <= -2e-9) {
		tmp = (t_0 / (1.0 - (tan(x) / (1.0 / tan(eps))))) - tan(x);
	} else if (eps <= 1.75e-19) {
		tmp = eps + (eps * (pow(sin(x), 2.0) / pow(cos(x), 2.0)));
	} else {
		tmp = (t_0 / (1.0 - (tan(x) * tan(eps)))) - tan(x);
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: t_0
    real(8) :: tmp
    t_0 = tan(x) + tan(eps)
    if (eps <= (-2d-9)) then
        tmp = (t_0 / (1.0d0 - (tan(x) / (1.0d0 / tan(eps))))) - tan(x)
    else if (eps <= 1.75d-19) then
        tmp = eps + (eps * ((sin(x) ** 2.0d0) / (cos(x) ** 2.0d0)))
    else
        tmp = (t_0 / (1.0d0 - (tan(x) * tan(eps)))) - tan(x)
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double t_0 = Math.tan(x) + Math.tan(eps);
	double tmp;
	if (eps <= -2e-9) {
		tmp = (t_0 / (1.0 - (Math.tan(x) / (1.0 / Math.tan(eps))))) - Math.tan(x);
	} else if (eps <= 1.75e-19) {
		tmp = eps + (eps * (Math.pow(Math.sin(x), 2.0) / Math.pow(Math.cos(x), 2.0)));
	} else {
		tmp = (t_0 / (1.0 - (Math.tan(x) * Math.tan(eps)))) - Math.tan(x);
	}
	return tmp;
}
def code(x, eps):
	t_0 = math.tan(x) + math.tan(eps)
	tmp = 0
	if eps <= -2e-9:
		tmp = (t_0 / (1.0 - (math.tan(x) / (1.0 / math.tan(eps))))) - math.tan(x)
	elif eps <= 1.75e-19:
		tmp = eps + (eps * (math.pow(math.sin(x), 2.0) / math.pow(math.cos(x), 2.0)))
	else:
		tmp = (t_0 / (1.0 - (math.tan(x) * math.tan(eps)))) - math.tan(x)
	return tmp
function code(x, eps)
	t_0 = Float64(tan(x) + tan(eps))
	tmp = 0.0
	if (eps <= -2e-9)
		tmp = Float64(Float64(t_0 / Float64(1.0 - Float64(tan(x) / Float64(1.0 / tan(eps))))) - tan(x));
	elseif (eps <= 1.75e-19)
		tmp = Float64(eps + Float64(eps * Float64((sin(x) ^ 2.0) / (cos(x) ^ 2.0))));
	else
		tmp = Float64(Float64(t_0 / Float64(1.0 - Float64(tan(x) * tan(eps)))) - tan(x));
	end
	return tmp
end
function tmp_2 = code(x, eps)
	t_0 = tan(x) + tan(eps);
	tmp = 0.0;
	if (eps <= -2e-9)
		tmp = (t_0 / (1.0 - (tan(x) / (1.0 / tan(eps))))) - tan(x);
	elseif (eps <= 1.75e-19)
		tmp = eps + (eps * ((sin(x) ^ 2.0) / (cos(x) ^ 2.0)));
	else
		tmp = (t_0 / (1.0 - (tan(x) * tan(eps)))) - tan(x);
	end
	tmp_2 = tmp;
end
code[x_, eps_] := Block[{t$95$0 = N[(N[Tan[x], $MachinePrecision] + N[Tan[eps], $MachinePrecision]), $MachinePrecision]}, If[LessEqual[eps, -2e-9], N[(N[(t$95$0 / N[(1.0 - N[(N[Tan[x], $MachinePrecision] / N[(1.0 / N[Tan[eps], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[Tan[x], $MachinePrecision]), $MachinePrecision], If[LessEqual[eps, 1.75e-19], N[(eps + N[(eps * N[(N[Power[N[Sin[x], $MachinePrecision], 2.0], $MachinePrecision] / N[Power[N[Cos[x], $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[(t$95$0 / N[(1.0 - N[(N[Tan[x], $MachinePrecision] * N[Tan[eps], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[Tan[x], $MachinePrecision]), $MachinePrecision]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \tan x + \tan \varepsilon\\
\mathbf{if}\;\varepsilon \leq -2 \cdot 10^{-9}:\\
\;\;\;\;\frac{t_0}{1 - \frac{\tan x}{\frac{1}{\tan \varepsilon}}} - \tan x\\

\mathbf{elif}\;\varepsilon \leq 1.75 \cdot 10^{-19}:\\
\;\;\;\;\varepsilon + \varepsilon \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\\

\mathbf{else}:\\
\;\;\;\;\frac{t_0}{1 - \tan x \cdot \tan \varepsilon} - \tan x\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if eps < -2.00000000000000012e-9

    1. Initial program 65.8%

      \[\tan \left(x + \varepsilon\right) - \tan x \]
    2. Step-by-step derivation
      1. tan-sum99.7%

        \[\leadsto \color{blue}{\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon}} - \tan x \]
      2. div-inv99.7%

        \[\leadsto \color{blue}{\left(\tan x + \tan \varepsilon\right) \cdot \frac{1}{1 - \tan x \cdot \tan \varepsilon}} - \tan x \]
      3. fma-neg99.8%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\tan x + \tan \varepsilon, \frac{1}{1 - \tan x \cdot \tan \varepsilon}, -\tan x\right)} \]
    3. Applied egg-rr99.8%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\tan x + \tan \varepsilon, \frac{1}{1 - \tan x \cdot \tan \varepsilon}, -\tan x\right)} \]
    4. Step-by-step derivation
      1. fma-neg99.7%

        \[\leadsto \color{blue}{\left(\tan x + \tan \varepsilon\right) \cdot \frac{1}{1 - \tan x \cdot \tan \varepsilon} - \tan x} \]
      2. associate-*r/99.7%

        \[\leadsto \color{blue}{\frac{\left(\tan x + \tan \varepsilon\right) \cdot 1}{1 - \tan x \cdot \tan \varepsilon}} - \tan x \]
      3. *-rgt-identity99.7%

        \[\leadsto \frac{\color{blue}{\tan x + \tan \varepsilon}}{1 - \tan x \cdot \tan \varepsilon} - \tan x \]
    5. Simplified99.7%

      \[\leadsto \color{blue}{\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon} - \tan x} \]
    6. Step-by-step derivation
      1. tan-quot99.7%

        \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \color{blue}{\frac{\sin \varepsilon}{\cos \varepsilon}}} - \tan x \]
      2. clear-num99.7%

        \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \color{blue}{\frac{1}{\frac{\cos \varepsilon}{\sin \varepsilon}}}} - \tan x \]
      3. un-div-inv99.7%

        \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \color{blue}{\frac{\tan x}{\frac{\cos \varepsilon}{\sin \varepsilon}}}} - \tan x \]
      4. clear-num99.7%

        \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \frac{\tan x}{\color{blue}{\frac{1}{\frac{\sin \varepsilon}{\cos \varepsilon}}}}} - \tan x \]
      5. tan-quot99.8%

        \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \frac{\tan x}{\frac{1}{\color{blue}{\tan \varepsilon}}}} - \tan x \]
    7. Applied egg-rr99.8%

      \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \color{blue}{\frac{\tan x}{\frac{1}{\tan \varepsilon}}}} - \tan x \]

    if -2.00000000000000012e-9 < eps < 1.75000000000000008e-19

    1. Initial program 26.8%

      \[\tan \left(x + \varepsilon\right) - \tan x \]
    2. Taylor expanded in eps around 0 99.6%

      \[\leadsto \color{blue}{\varepsilon \cdot \left(1 - -1 \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\right)} \]
    3. Step-by-step derivation
      1. cancel-sign-sub-inv99.6%

        \[\leadsto \varepsilon \cdot \color{blue}{\left(1 + \left(--1\right) \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\right)} \]
      2. metadata-eval99.6%

        \[\leadsto \varepsilon \cdot \left(1 + \color{blue}{1} \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\right) \]
      3. *-lft-identity99.6%

        \[\leadsto \varepsilon \cdot \left(1 + \color{blue}{\frac{{\sin x}^{2}}{{\cos x}^{2}}}\right) \]
      4. distribute-lft-in99.7%

        \[\leadsto \color{blue}{\varepsilon \cdot 1 + \varepsilon \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}} \]
      5. *-rgt-identity99.7%

        \[\leadsto \color{blue}{\varepsilon} + \varepsilon \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}} \]
    4. Simplified99.7%

      \[\leadsto \color{blue}{\varepsilon + \varepsilon \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}} \]

    if 1.75000000000000008e-19 < eps

    1. Initial program 58.1%

      \[\tan \left(x + \varepsilon\right) - \tan x \]
    2. Step-by-step derivation
      1. tan-sum99.2%

        \[\leadsto \color{blue}{\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon}} - \tan x \]
      2. div-inv99.1%

        \[\leadsto \color{blue}{\left(\tan x + \tan \varepsilon\right) \cdot \frac{1}{1 - \tan x \cdot \tan \varepsilon}} - \tan x \]
      3. fma-neg99.2%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\tan x + \tan \varepsilon, \frac{1}{1 - \tan x \cdot \tan \varepsilon}, -\tan x\right)} \]
    3. Applied egg-rr99.2%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\tan x + \tan \varepsilon, \frac{1}{1 - \tan x \cdot \tan \varepsilon}, -\tan x\right)} \]
    4. Step-by-step derivation
      1. fma-neg99.1%

        \[\leadsto \color{blue}{\left(\tan x + \tan \varepsilon\right) \cdot \frac{1}{1 - \tan x \cdot \tan \varepsilon} - \tan x} \]
      2. associate-*r/99.2%

        \[\leadsto \color{blue}{\frac{\left(\tan x + \tan \varepsilon\right) \cdot 1}{1 - \tan x \cdot \tan \varepsilon}} - \tan x \]
      3. *-rgt-identity99.2%

        \[\leadsto \frac{\color{blue}{\tan x + \tan \varepsilon}}{1 - \tan x \cdot \tan \varepsilon} - \tan x \]
    5. Simplified99.2%

      \[\leadsto \color{blue}{\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon} - \tan x} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification99.6%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -2 \cdot 10^{-9}:\\ \;\;\;\;\frac{\tan x + \tan \varepsilon}{1 - \frac{\tan x}{\frac{1}{\tan \varepsilon}}} - \tan x\\ \mathbf{elif}\;\varepsilon \leq 1.75 \cdot 10^{-19}:\\ \;\;\;\;\varepsilon + \varepsilon \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\\ \mathbf{else}:\\ \;\;\;\;\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon} - \tan x\\ \end{array} \]

Alternative 6: 77.9% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -6 \cdot 10^{-6}:\\ \;\;\;\;\tan \varepsilon\\ \mathbf{elif}\;\varepsilon \leq 1.75 \cdot 10^{-19}:\\ \;\;\;\;\varepsilon + \varepsilon \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\\ \mathbf{else}:\\ \;\;\;\;\frac{\tan x + \tan \varepsilon}{1 - \frac{\tan x}{\frac{1}{\varepsilon} + \varepsilon \cdot -0.3333333333333333}} - \tan x\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (<= eps -6e-6)
   (tan eps)
   (if (<= eps 1.75e-19)
     (+ eps (* eps (/ (pow (sin x) 2.0) (pow (cos x) 2.0))))
     (-
      (/
       (+ (tan x) (tan eps))
       (- 1.0 (/ (tan x) (+ (/ 1.0 eps) (* eps -0.3333333333333333)))))
      (tan x)))))
double code(double x, double eps) {
	double tmp;
	if (eps <= -6e-6) {
		tmp = tan(eps);
	} else if (eps <= 1.75e-19) {
		tmp = eps + (eps * (pow(sin(x), 2.0) / pow(cos(x), 2.0)));
	} else {
		tmp = ((tan(x) + tan(eps)) / (1.0 - (tan(x) / ((1.0 / eps) + (eps * -0.3333333333333333))))) - tan(x);
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: tmp
    if (eps <= (-6d-6)) then
        tmp = tan(eps)
    else if (eps <= 1.75d-19) then
        tmp = eps + (eps * ((sin(x) ** 2.0d0) / (cos(x) ** 2.0d0)))
    else
        tmp = ((tan(x) + tan(eps)) / (1.0d0 - (tan(x) / ((1.0d0 / eps) + (eps * (-0.3333333333333333d0)))))) - tan(x)
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if (eps <= -6e-6) {
		tmp = Math.tan(eps);
	} else if (eps <= 1.75e-19) {
		tmp = eps + (eps * (Math.pow(Math.sin(x), 2.0) / Math.pow(Math.cos(x), 2.0)));
	} else {
		tmp = ((Math.tan(x) + Math.tan(eps)) / (1.0 - (Math.tan(x) / ((1.0 / eps) + (eps * -0.3333333333333333))))) - Math.tan(x);
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if eps <= -6e-6:
		tmp = math.tan(eps)
	elif eps <= 1.75e-19:
		tmp = eps + (eps * (math.pow(math.sin(x), 2.0) / math.pow(math.cos(x), 2.0)))
	else:
		tmp = ((math.tan(x) + math.tan(eps)) / (1.0 - (math.tan(x) / ((1.0 / eps) + (eps * -0.3333333333333333))))) - math.tan(x)
	return tmp
function code(x, eps)
	tmp = 0.0
	if (eps <= -6e-6)
		tmp = tan(eps);
	elseif (eps <= 1.75e-19)
		tmp = Float64(eps + Float64(eps * Float64((sin(x) ^ 2.0) / (cos(x) ^ 2.0))));
	else
		tmp = Float64(Float64(Float64(tan(x) + tan(eps)) / Float64(1.0 - Float64(tan(x) / Float64(Float64(1.0 / eps) + Float64(eps * -0.3333333333333333))))) - tan(x));
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if (eps <= -6e-6)
		tmp = tan(eps);
	elseif (eps <= 1.75e-19)
		tmp = eps + (eps * ((sin(x) ^ 2.0) / (cos(x) ^ 2.0)));
	else
		tmp = ((tan(x) + tan(eps)) / (1.0 - (tan(x) / ((1.0 / eps) + (eps * -0.3333333333333333))))) - tan(x);
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[LessEqual[eps, -6e-6], N[Tan[eps], $MachinePrecision], If[LessEqual[eps, 1.75e-19], N[(eps + N[(eps * N[(N[Power[N[Sin[x], $MachinePrecision], 2.0], $MachinePrecision] / N[Power[N[Cos[x], $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[(N[(N[Tan[x], $MachinePrecision] + N[Tan[eps], $MachinePrecision]), $MachinePrecision] / N[(1.0 - N[(N[Tan[x], $MachinePrecision] / N[(N[(1.0 / eps), $MachinePrecision] + N[(eps * -0.3333333333333333), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[Tan[x], $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -6 \cdot 10^{-6}:\\
\;\;\;\;\tan \varepsilon\\

\mathbf{elif}\;\varepsilon \leq 1.75 \cdot 10^{-19}:\\
\;\;\;\;\varepsilon + \varepsilon \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\\

\mathbf{else}:\\
\;\;\;\;\frac{\tan x + \tan \varepsilon}{1 - \frac{\tan x}{\frac{1}{\varepsilon} + \varepsilon \cdot -0.3333333333333333}} - \tan x\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if eps < -6.0000000000000002e-6

    1. Initial program 65.8%

      \[\tan \left(x + \varepsilon\right) - \tan x \]
    2. Taylor expanded in x around 0 66.6%

      \[\leadsto \color{blue}{\frac{\sin \varepsilon}{\cos \varepsilon}} \]
    3. Step-by-step derivation
      1. tan-quot66.9%

        \[\leadsto \color{blue}{\tan \varepsilon} \]
      2. expm1-log1p-u53.2%

        \[\leadsto \color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\tan \varepsilon\right)\right)} \]
      3. expm1-udef52.6%

        \[\leadsto \color{blue}{e^{\mathsf{log1p}\left(\tan \varepsilon\right)} - 1} \]
    4. Applied egg-rr52.6%

      \[\leadsto \color{blue}{e^{\mathsf{log1p}\left(\tan \varepsilon\right)} - 1} \]
    5. Step-by-step derivation
      1. expm1-def53.2%

        \[\leadsto \color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\tan \varepsilon\right)\right)} \]
      2. expm1-log1p66.9%

        \[\leadsto \color{blue}{\tan \varepsilon} \]
    6. Simplified66.9%

      \[\leadsto \color{blue}{\tan \varepsilon} \]

    if -6.0000000000000002e-6 < eps < 1.75000000000000008e-19

    1. Initial program 26.8%

      \[\tan \left(x + \varepsilon\right) - \tan x \]
    2. Taylor expanded in eps around 0 99.6%

      \[\leadsto \color{blue}{\varepsilon \cdot \left(1 - -1 \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\right)} \]
    3. Step-by-step derivation
      1. cancel-sign-sub-inv99.6%

        \[\leadsto \varepsilon \cdot \color{blue}{\left(1 + \left(--1\right) \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\right)} \]
      2. metadata-eval99.6%

        \[\leadsto \varepsilon \cdot \left(1 + \color{blue}{1} \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\right) \]
      3. *-lft-identity99.6%

        \[\leadsto \varepsilon \cdot \left(1 + \color{blue}{\frac{{\sin x}^{2}}{{\cos x}^{2}}}\right) \]
      4. distribute-lft-in99.7%

        \[\leadsto \color{blue}{\varepsilon \cdot 1 + \varepsilon \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}} \]
      5. *-rgt-identity99.7%

        \[\leadsto \color{blue}{\varepsilon} + \varepsilon \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}} \]
    4. Simplified99.7%

      \[\leadsto \color{blue}{\varepsilon + \varepsilon \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}} \]

    if 1.75000000000000008e-19 < eps

    1. Initial program 58.1%

      \[\tan \left(x + \varepsilon\right) - \tan x \]
    2. Step-by-step derivation
      1. tan-sum99.2%

        \[\leadsto \color{blue}{\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon}} - \tan x \]
      2. div-inv99.1%

        \[\leadsto \color{blue}{\left(\tan x + \tan \varepsilon\right) \cdot \frac{1}{1 - \tan x \cdot \tan \varepsilon}} - \tan x \]
      3. fma-neg99.2%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\tan x + \tan \varepsilon, \frac{1}{1 - \tan x \cdot \tan \varepsilon}, -\tan x\right)} \]
    3. Applied egg-rr99.2%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\tan x + \tan \varepsilon, \frac{1}{1 - \tan x \cdot \tan \varepsilon}, -\tan x\right)} \]
    4. Step-by-step derivation
      1. fma-neg99.1%

        \[\leadsto \color{blue}{\left(\tan x + \tan \varepsilon\right) \cdot \frac{1}{1 - \tan x \cdot \tan \varepsilon} - \tan x} \]
      2. associate-*r/99.2%

        \[\leadsto \color{blue}{\frac{\left(\tan x + \tan \varepsilon\right) \cdot 1}{1 - \tan x \cdot \tan \varepsilon}} - \tan x \]
      3. *-rgt-identity99.2%

        \[\leadsto \frac{\color{blue}{\tan x + \tan \varepsilon}}{1 - \tan x \cdot \tan \varepsilon} - \tan x \]
    5. Simplified99.2%

      \[\leadsto \color{blue}{\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon} - \tan x} \]
    6. Step-by-step derivation
      1. tan-quot99.2%

        \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \color{blue}{\frac{\sin \varepsilon}{\cos \varepsilon}}} - \tan x \]
      2. clear-num99.2%

        \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \color{blue}{\frac{1}{\frac{\cos \varepsilon}{\sin \varepsilon}}}} - \tan x \]
      3. un-div-inv99.2%

        \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \color{blue}{\frac{\tan x}{\frac{\cos \varepsilon}{\sin \varepsilon}}}} - \tan x \]
      4. clear-num99.2%

        \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \frac{\tan x}{\color{blue}{\frac{1}{\frac{\sin \varepsilon}{\cos \varepsilon}}}}} - \tan x \]
      5. tan-quot99.2%

        \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \frac{\tan x}{\frac{1}{\color{blue}{\tan \varepsilon}}}} - \tan x \]
    7. Applied egg-rr99.2%

      \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \color{blue}{\frac{\tan x}{\frac{1}{\tan \varepsilon}}}} - \tan x \]
    8. Taylor expanded in eps around 0 61.4%

      \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \frac{\tan x}{\color{blue}{\frac{1}{\varepsilon} + -0.3333333333333333 \cdot \varepsilon}}} - \tan x \]
    9. Step-by-step derivation
      1. *-commutative5.8%

        \[\leadsto \frac{1}{\frac{1}{\varepsilon} + \color{blue}{\varepsilon \cdot -0.3333333333333333}} \]
    10. Simplified61.4%

      \[\leadsto \frac{\tan x + \tan \varepsilon}{1 - \frac{\tan x}{\color{blue}{\frac{1}{\varepsilon} + \varepsilon \cdot -0.3333333333333333}}} - \tan x \]
  3. Recombined 3 regimes into one program.
  4. Final simplification80.9%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -6 \cdot 10^{-6}:\\ \;\;\;\;\tan \varepsilon\\ \mathbf{elif}\;\varepsilon \leq 1.75 \cdot 10^{-19}:\\ \;\;\;\;\varepsilon + \varepsilon \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\\ \mathbf{else}:\\ \;\;\;\;\frac{\tan x + \tan \varepsilon}{1 - \frac{\tan x}{\frac{1}{\varepsilon} + \varepsilon \cdot -0.3333333333333333}} - \tan x\\ \end{array} \]

Alternative 7: 78.1% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -1.45 \cdot 10^{-6}:\\ \;\;\;\;\tan \varepsilon\\ \mathbf{elif}\;\varepsilon \leq 1.2 \cdot 10^{-5}:\\ \;\;\;\;\varepsilon \cdot \left(1 + \frac{{\sin x}^{2}}{{\cos x}^{2}}\right)\\ \mathbf{else}:\\ \;\;\;\;\tan \varepsilon\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (<= eps -1.45e-6)
   (tan eps)
   (if (<= eps 1.2e-5)
     (* eps (+ 1.0 (/ (pow (sin x) 2.0) (pow (cos x) 2.0))))
     (tan eps))))
double code(double x, double eps) {
	double tmp;
	if (eps <= -1.45e-6) {
		tmp = tan(eps);
	} else if (eps <= 1.2e-5) {
		tmp = eps * (1.0 + (pow(sin(x), 2.0) / pow(cos(x), 2.0)));
	} else {
		tmp = tan(eps);
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: tmp
    if (eps <= (-1.45d-6)) then
        tmp = tan(eps)
    else if (eps <= 1.2d-5) then
        tmp = eps * (1.0d0 + ((sin(x) ** 2.0d0) / (cos(x) ** 2.0d0)))
    else
        tmp = tan(eps)
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if (eps <= -1.45e-6) {
		tmp = Math.tan(eps);
	} else if (eps <= 1.2e-5) {
		tmp = eps * (1.0 + (Math.pow(Math.sin(x), 2.0) / Math.pow(Math.cos(x), 2.0)));
	} else {
		tmp = Math.tan(eps);
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if eps <= -1.45e-6:
		tmp = math.tan(eps)
	elif eps <= 1.2e-5:
		tmp = eps * (1.0 + (math.pow(math.sin(x), 2.0) / math.pow(math.cos(x), 2.0)))
	else:
		tmp = math.tan(eps)
	return tmp
function code(x, eps)
	tmp = 0.0
	if (eps <= -1.45e-6)
		tmp = tan(eps);
	elseif (eps <= 1.2e-5)
		tmp = Float64(eps * Float64(1.0 + Float64((sin(x) ^ 2.0) / (cos(x) ^ 2.0))));
	else
		tmp = tan(eps);
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if (eps <= -1.45e-6)
		tmp = tan(eps);
	elseif (eps <= 1.2e-5)
		tmp = eps * (1.0 + ((sin(x) ^ 2.0) / (cos(x) ^ 2.0)));
	else
		tmp = tan(eps);
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[LessEqual[eps, -1.45e-6], N[Tan[eps], $MachinePrecision], If[LessEqual[eps, 1.2e-5], N[(eps * N[(1.0 + N[(N[Power[N[Sin[x], $MachinePrecision], 2.0], $MachinePrecision] / N[Power[N[Cos[x], $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[Tan[eps], $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -1.45 \cdot 10^{-6}:\\
\;\;\;\;\tan \varepsilon\\

\mathbf{elif}\;\varepsilon \leq 1.2 \cdot 10^{-5}:\\
\;\;\;\;\varepsilon \cdot \left(1 + \frac{{\sin x}^{2}}{{\cos x}^{2}}\right)\\

\mathbf{else}:\\
\;\;\;\;\tan \varepsilon\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < -1.4500000000000001e-6 or 1.2e-5 < eps

    1. Initial program 62.0%

      \[\tan \left(x + \varepsilon\right) - \tan x \]
    2. Taylor expanded in x around 0 63.5%

      \[\leadsto \color{blue}{\frac{\sin \varepsilon}{\cos \varepsilon}} \]
    3. Step-by-step derivation
      1. tan-quot63.8%

        \[\leadsto \color{blue}{\tan \varepsilon} \]
      2. expm1-log1p-u51.4%

        \[\leadsto \color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\tan \varepsilon\right)\right)} \]
      3. expm1-udef51.0%

        \[\leadsto \color{blue}{e^{\mathsf{log1p}\left(\tan \varepsilon\right)} - 1} \]
    4. Applied egg-rr51.0%

      \[\leadsto \color{blue}{e^{\mathsf{log1p}\left(\tan \varepsilon\right)} - 1} \]
    5. Step-by-step derivation
      1. expm1-def51.4%

        \[\leadsto \color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\tan \varepsilon\right)\right)} \]
      2. expm1-log1p63.8%

        \[\leadsto \color{blue}{\tan \varepsilon} \]
    6. Simplified63.8%

      \[\leadsto \color{blue}{\tan \varepsilon} \]

    if -1.4500000000000001e-6 < eps < 1.2e-5

    1. Initial program 27.2%

      \[\tan \left(x + \varepsilon\right) - \tan x \]
    2. Step-by-step derivation
      1. tan-sum27.7%

        \[\leadsto \color{blue}{\frac{\tan x + \tan \varepsilon}{1 - \tan x \cdot \tan \varepsilon}} - \tan x \]
      2. div-inv27.7%

        \[\leadsto \color{blue}{\left(\tan x + \tan \varepsilon\right) \cdot \frac{1}{1 - \tan x \cdot \tan \varepsilon}} - \tan x \]
      3. fma-neg27.7%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\tan x + \tan \varepsilon, \frac{1}{1 - \tan x \cdot \tan \varepsilon}, -\tan x\right)} \]
    3. Applied egg-rr27.7%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\tan x + \tan \varepsilon, \frac{1}{1 - \tan x \cdot \tan \varepsilon}, -\tan x\right)} \]
    4. Taylor expanded in eps around 0 99.3%

      \[\leadsto \color{blue}{\varepsilon \cdot \left(1 + \frac{{\sin x}^{2}}{{\cos x}^{2}}\right)} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification80.9%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -1.45 \cdot 10^{-6}:\\ \;\;\;\;\tan \varepsilon\\ \mathbf{elif}\;\varepsilon \leq 1.2 \cdot 10^{-5}:\\ \;\;\;\;\varepsilon \cdot \left(1 + \frac{{\sin x}^{2}}{{\cos x}^{2}}\right)\\ \mathbf{else}:\\ \;\;\;\;\tan \varepsilon\\ \end{array} \]

Alternative 8: 78.1% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\varepsilon \leq -5.8 \cdot 10^{-6}:\\ \;\;\;\;\tan \varepsilon\\ \mathbf{elif}\;\varepsilon \leq 2.9 \cdot 10^{-6}:\\ \;\;\;\;\varepsilon + \varepsilon \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\\ \mathbf{else}:\\ \;\;\;\;\tan \varepsilon\\ \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (if (<= eps -5.8e-6)
   (tan eps)
   (if (<= eps 2.9e-6)
     (+ eps (* eps (/ (pow (sin x) 2.0) (pow (cos x) 2.0))))
     (tan eps))))
double code(double x, double eps) {
	double tmp;
	if (eps <= -5.8e-6) {
		tmp = tan(eps);
	} else if (eps <= 2.9e-6) {
		tmp = eps + (eps * (pow(sin(x), 2.0) / pow(cos(x), 2.0)));
	} else {
		tmp = tan(eps);
	}
	return tmp;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    real(8) :: tmp
    if (eps <= (-5.8d-6)) then
        tmp = tan(eps)
    else if (eps <= 2.9d-6) then
        tmp = eps + (eps * ((sin(x) ** 2.0d0) / (cos(x) ** 2.0d0)))
    else
        tmp = tan(eps)
    end if
    code = tmp
end function
public static double code(double x, double eps) {
	double tmp;
	if (eps <= -5.8e-6) {
		tmp = Math.tan(eps);
	} else if (eps <= 2.9e-6) {
		tmp = eps + (eps * (Math.pow(Math.sin(x), 2.0) / Math.pow(Math.cos(x), 2.0)));
	} else {
		tmp = Math.tan(eps);
	}
	return tmp;
}
def code(x, eps):
	tmp = 0
	if eps <= -5.8e-6:
		tmp = math.tan(eps)
	elif eps <= 2.9e-6:
		tmp = eps + (eps * (math.pow(math.sin(x), 2.0) / math.pow(math.cos(x), 2.0)))
	else:
		tmp = math.tan(eps)
	return tmp
function code(x, eps)
	tmp = 0.0
	if (eps <= -5.8e-6)
		tmp = tan(eps);
	elseif (eps <= 2.9e-6)
		tmp = Float64(eps + Float64(eps * Float64((sin(x) ^ 2.0) / (cos(x) ^ 2.0))));
	else
		tmp = tan(eps);
	end
	return tmp
end
function tmp_2 = code(x, eps)
	tmp = 0.0;
	if (eps <= -5.8e-6)
		tmp = tan(eps);
	elseif (eps <= 2.9e-6)
		tmp = eps + (eps * ((sin(x) ^ 2.0) / (cos(x) ^ 2.0)));
	else
		tmp = tan(eps);
	end
	tmp_2 = tmp;
end
code[x_, eps_] := If[LessEqual[eps, -5.8e-6], N[Tan[eps], $MachinePrecision], If[LessEqual[eps, 2.9e-6], N[(eps + N[(eps * N[(N[Power[N[Sin[x], $MachinePrecision], 2.0], $MachinePrecision] / N[Power[N[Cos[x], $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[Tan[eps], $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\varepsilon \leq -5.8 \cdot 10^{-6}:\\
\;\;\;\;\tan \varepsilon\\

\mathbf{elif}\;\varepsilon \leq 2.9 \cdot 10^{-6}:\\
\;\;\;\;\varepsilon + \varepsilon \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\\

\mathbf{else}:\\
\;\;\;\;\tan \varepsilon\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if eps < -5.8000000000000004e-6 or 2.9000000000000002e-6 < eps

    1. Initial program 62.0%

      \[\tan \left(x + \varepsilon\right) - \tan x \]
    2. Taylor expanded in x around 0 63.5%

      \[\leadsto \color{blue}{\frac{\sin \varepsilon}{\cos \varepsilon}} \]
    3. Step-by-step derivation
      1. tan-quot63.8%

        \[\leadsto \color{blue}{\tan \varepsilon} \]
      2. expm1-log1p-u51.4%

        \[\leadsto \color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\tan \varepsilon\right)\right)} \]
      3. expm1-udef51.0%

        \[\leadsto \color{blue}{e^{\mathsf{log1p}\left(\tan \varepsilon\right)} - 1} \]
    4. Applied egg-rr51.0%

      \[\leadsto \color{blue}{e^{\mathsf{log1p}\left(\tan \varepsilon\right)} - 1} \]
    5. Step-by-step derivation
      1. expm1-def51.4%

        \[\leadsto \color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\tan \varepsilon\right)\right)} \]
      2. expm1-log1p63.8%

        \[\leadsto \color{blue}{\tan \varepsilon} \]
    6. Simplified63.8%

      \[\leadsto \color{blue}{\tan \varepsilon} \]

    if -5.8000000000000004e-6 < eps < 2.9000000000000002e-6

    1. Initial program 27.2%

      \[\tan \left(x + \varepsilon\right) - \tan x \]
    2. Taylor expanded in eps around 0 99.3%

      \[\leadsto \color{blue}{\varepsilon \cdot \left(1 - -1 \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\right)} \]
    3. Step-by-step derivation
      1. cancel-sign-sub-inv99.3%

        \[\leadsto \varepsilon \cdot \color{blue}{\left(1 + \left(--1\right) \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\right)} \]
      2. metadata-eval99.3%

        \[\leadsto \varepsilon \cdot \left(1 + \color{blue}{1} \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\right) \]
      3. *-lft-identity99.3%

        \[\leadsto \varepsilon \cdot \left(1 + \color{blue}{\frac{{\sin x}^{2}}{{\cos x}^{2}}}\right) \]
      4. distribute-lft-in99.3%

        \[\leadsto \color{blue}{\varepsilon \cdot 1 + \varepsilon \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}} \]
      5. *-rgt-identity99.3%

        \[\leadsto \color{blue}{\varepsilon} + \varepsilon \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}} \]
    4. Simplified99.3%

      \[\leadsto \color{blue}{\varepsilon + \varepsilon \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification80.9%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\varepsilon \leq -5.8 \cdot 10^{-6}:\\ \;\;\;\;\tan \varepsilon\\ \mathbf{elif}\;\varepsilon \leq 2.9 \cdot 10^{-6}:\\ \;\;\;\;\varepsilon + \varepsilon \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\\ \mathbf{else}:\\ \;\;\;\;\tan \varepsilon\\ \end{array} \]

Alternative 9: 58.2% accurate, 2.0× speedup?

\[\begin{array}{l} \\ \tan \varepsilon \end{array} \]
(FPCore (x eps) :precision binary64 (tan eps))
double code(double x, double eps) {
	return tan(eps);
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    code = tan(eps)
end function
public static double code(double x, double eps) {
	return Math.tan(eps);
}
def code(x, eps):
	return math.tan(eps)
function code(x, eps)
	return tan(eps)
end
function tmp = code(x, eps)
	tmp = tan(eps);
end
code[x_, eps_] := N[Tan[eps], $MachinePrecision]
\begin{array}{l}

\\
\tan \varepsilon
\end{array}
Derivation
  1. Initial program 45.3%

    \[\tan \left(x + \varepsilon\right) - \tan x \]
  2. Taylor expanded in x around 0 62.0%

    \[\leadsto \color{blue}{\frac{\sin \varepsilon}{\cos \varepsilon}} \]
  3. Step-by-step derivation
    1. tan-quot62.2%

      \[\leadsto \color{blue}{\tan \varepsilon} \]
    2. expm1-log1p-u55.7%

      \[\leadsto \color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\tan \varepsilon\right)\right)} \]
    3. expm1-udef29.3%

      \[\leadsto \color{blue}{e^{\mathsf{log1p}\left(\tan \varepsilon\right)} - 1} \]
  4. Applied egg-rr29.3%

    \[\leadsto \color{blue}{e^{\mathsf{log1p}\left(\tan \varepsilon\right)} - 1} \]
  5. Step-by-step derivation
    1. expm1-def55.7%

      \[\leadsto \color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\tan \varepsilon\right)\right)} \]
    2. expm1-log1p62.2%

      \[\leadsto \color{blue}{\tan \varepsilon} \]
  6. Simplified62.2%

    \[\leadsto \color{blue}{\tan \varepsilon} \]
  7. Final simplification62.2%

    \[\leadsto \tan \varepsilon \]

Alternative 10: 32.0% accurate, 22.8× speedup?

\[\begin{array}{l} \\ \frac{1}{\frac{1}{\varepsilon} + \varepsilon \cdot -0.3333333333333333} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (/ 1.0 (+ (/ 1.0 eps) (* eps -0.3333333333333333))))
double code(double x, double eps) {
	return 1.0 / ((1.0 / eps) + (eps * -0.3333333333333333));
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    code = 1.0d0 / ((1.0d0 / eps) + (eps * (-0.3333333333333333d0)))
end function
public static double code(double x, double eps) {
	return 1.0 / ((1.0 / eps) + (eps * -0.3333333333333333));
}
def code(x, eps):
	return 1.0 / ((1.0 / eps) + (eps * -0.3333333333333333))
function code(x, eps)
	return Float64(1.0 / Float64(Float64(1.0 / eps) + Float64(eps * -0.3333333333333333)))
end
function tmp = code(x, eps)
	tmp = 1.0 / ((1.0 / eps) + (eps * -0.3333333333333333));
end
code[x_, eps_] := N[(1.0 / N[(N[(1.0 / eps), $MachinePrecision] + N[(eps * -0.3333333333333333), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{1}{\frac{1}{\varepsilon} + \varepsilon \cdot -0.3333333333333333}
\end{array}
Derivation
  1. Initial program 45.3%

    \[\tan \left(x + \varepsilon\right) - \tan x \]
  2. Taylor expanded in x around 0 62.0%

    \[\leadsto \color{blue}{\frac{\sin \varepsilon}{\cos \varepsilon}} \]
  3. Step-by-step derivation
    1. tan-quot62.2%

      \[\leadsto \color{blue}{\tan \varepsilon} \]
    2. add-sqr-sqrt32.0%

      \[\leadsto \color{blue}{\sqrt{\tan \varepsilon} \cdot \sqrt{\tan \varepsilon}} \]
    3. pow232.0%

      \[\leadsto \color{blue}{{\left(\sqrt{\tan \varepsilon}\right)}^{2}} \]
  4. Applied egg-rr32.0%

    \[\leadsto \color{blue}{{\left(\sqrt{\tan \varepsilon}\right)}^{2}} \]
  5. Step-by-step derivation
    1. sqrt-pow262.2%

      \[\leadsto \color{blue}{{\tan \varepsilon}^{\left(\frac{2}{2}\right)}} \]
    2. metadata-eval62.2%

      \[\leadsto {\tan \varepsilon}^{\color{blue}{1}} \]
    3. metadata-eval62.2%

      \[\leadsto {\tan \varepsilon}^{\color{blue}{\left(--1\right)}} \]
    4. pow-flip62.1%

      \[\leadsto \color{blue}{\frac{1}{{\tan \varepsilon}^{-1}}} \]
    5. inv-pow62.1%

      \[\leadsto \frac{1}{\color{blue}{\frac{1}{\tan \varepsilon}}} \]
  6. Applied egg-rr62.1%

    \[\leadsto \color{blue}{\frac{1}{\frac{1}{\tan \varepsilon}}} \]
  7. Taylor expanded in eps around 0 31.2%

    \[\leadsto \frac{1}{\color{blue}{\frac{1}{\varepsilon} + -0.3333333333333333 \cdot \varepsilon}} \]
  8. Step-by-step derivation
    1. *-commutative31.2%

      \[\leadsto \frac{1}{\frac{1}{\varepsilon} + \color{blue}{\varepsilon \cdot -0.3333333333333333}} \]
  9. Simplified31.2%

    \[\leadsto \frac{1}{\color{blue}{\frac{1}{\varepsilon} + \varepsilon \cdot -0.3333333333333333}} \]
  10. Final simplification31.2%

    \[\leadsto \frac{1}{\frac{1}{\varepsilon} + \varepsilon \cdot -0.3333333333333333} \]

Alternative 11: 31.6% accurate, 205.0× speedup?

\[\begin{array}{l} \\ \varepsilon \end{array} \]
(FPCore (x eps) :precision binary64 eps)
double code(double x, double eps) {
	return eps;
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    code = eps
end function
public static double code(double x, double eps) {
	return eps;
}
def code(x, eps):
	return eps
function code(x, eps)
	return eps
end
function tmp = code(x, eps)
	tmp = eps;
end
code[x_, eps_] := eps
\begin{array}{l}

\\
\varepsilon
\end{array}
Derivation
  1. Initial program 45.3%

    \[\tan \left(x + \varepsilon\right) - \tan x \]
  2. Taylor expanded in x around 0 62.0%

    \[\leadsto \color{blue}{\frac{\sin \varepsilon}{\cos \varepsilon}} \]
  3. Taylor expanded in eps around 0 30.6%

    \[\leadsto \color{blue}{\varepsilon} \]
  4. Final simplification30.6%

    \[\leadsto \varepsilon \]

Developer target: 76.9% accurate, 0.7× speedup?

\[\begin{array}{l} \\ \frac{\sin \varepsilon}{\cos x \cdot \cos \left(x + \varepsilon\right)} \end{array} \]
(FPCore (x eps) :precision binary64 (/ (sin eps) (* (cos x) (cos (+ x eps)))))
double code(double x, double eps) {
	return sin(eps) / (cos(x) * cos((x + eps)));
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    code = sin(eps) / (cos(x) * cos((x + eps)))
end function
public static double code(double x, double eps) {
	return Math.sin(eps) / (Math.cos(x) * Math.cos((x + eps)));
}
def code(x, eps):
	return math.sin(eps) / (math.cos(x) * math.cos((x + eps)))
function code(x, eps)
	return Float64(sin(eps) / Float64(cos(x) * cos(Float64(x + eps))))
end
function tmp = code(x, eps)
	tmp = sin(eps) / (cos(x) * cos((x + eps)));
end
code[x_, eps_] := N[(N[Sin[eps], $MachinePrecision] / N[(N[Cos[x], $MachinePrecision] * N[Cos[N[(x + eps), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{\sin \varepsilon}{\cos x \cdot \cos \left(x + \varepsilon\right)}
\end{array}

Reproduce

?
herbie shell --seed 2023256 
(FPCore (x eps)
  :name "2tan (problem 3.3.2)"
  :precision binary64

  :herbie-target
  (/ (sin eps) (* (cos x) (cos (+ x eps))))

  (- (tan (+ x eps)) (tan x)))