2tan (problem 3.3.2)

Percentage Accurate: 62.5% → 99.6%
Time: 13.2s
Alternatives: 9
Speedup: 207.0×

Specification

?
\[\left(\left(-10000 \leq x \land x \leq 10000\right) \land 10^{-16} \cdot \left|x\right| < \varepsilon\right) \land \varepsilon < \left|x\right|\]
\[\begin{array}{l} \\ \tan \left(x + \varepsilon\right) - \tan x \end{array} \]
(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 9 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: 62.5% 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: 99.6% accurate, 0.1× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := {\sin x}^{2}\\ t_1 := {\cos x}^{2}\\ \mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\frac{\sin x}{t\_1}, \sin x, 1\right), -0.5, \frac{\mathsf{fma}\left(\mathsf{fma}\left(t\_0, \frac{-1}{t\_1}, -1\right), t\_0, t\_0 \cdot 0.16666666666666666\right)}{t\_1}\right), -1, -0.16666666666666666\right) \cdot \varepsilon, \varepsilon, \frac{\mathsf{fma}\left(\mathsf{fma}\left(\frac{t\_0}{t\_1}, \varepsilon, \varepsilon\right), \sin x, \frac{t\_0}{\cos x}\right)}{\cos x}\right), \varepsilon, \varepsilon\right) \end{array} \end{array} \]
(FPCore (x eps)
 :precision binary64
 (let* ((t_0 (pow (sin x) 2.0)) (t_1 (pow (cos x) 2.0)))
   (fma
    (fma
     (*
      (fma
       (fma
        (fma (/ (sin x) t_1) (sin x) 1.0)
        -0.5
        (/
         (fma (fma t_0 (/ -1.0 t_1) -1.0) t_0 (* t_0 0.16666666666666666))
         t_1))
       -1.0
       -0.16666666666666666)
      eps)
     eps
     (/ (fma (fma (/ t_0 t_1) eps eps) (sin x) (/ t_0 (cos x))) (cos x)))
    eps
    eps)))
double code(double x, double eps) {
	double t_0 = pow(sin(x), 2.0);
	double t_1 = pow(cos(x), 2.0);
	return fma(fma((fma(fma(fma((sin(x) / t_1), sin(x), 1.0), -0.5, (fma(fma(t_0, (-1.0 / t_1), -1.0), t_0, (t_0 * 0.16666666666666666)) / t_1)), -1.0, -0.16666666666666666) * eps), eps, (fma(fma((t_0 / t_1), eps, eps), sin(x), (t_0 / cos(x))) / cos(x))), eps, eps);
}
function code(x, eps)
	t_0 = sin(x) ^ 2.0
	t_1 = cos(x) ^ 2.0
	return fma(fma(Float64(fma(fma(fma(Float64(sin(x) / t_1), sin(x), 1.0), -0.5, Float64(fma(fma(t_0, Float64(-1.0 / t_1), -1.0), t_0, Float64(t_0 * 0.16666666666666666)) / t_1)), -1.0, -0.16666666666666666) * eps), eps, Float64(fma(fma(Float64(t_0 / t_1), eps, eps), sin(x), Float64(t_0 / cos(x))) / cos(x))), eps, eps)
end
code[x_, eps_] := Block[{t$95$0 = N[Power[N[Sin[x], $MachinePrecision], 2.0], $MachinePrecision]}, Block[{t$95$1 = N[Power[N[Cos[x], $MachinePrecision], 2.0], $MachinePrecision]}, N[(N[(N[(N[(N[(N[(N[(N[Sin[x], $MachinePrecision] / t$95$1), $MachinePrecision] * N[Sin[x], $MachinePrecision] + 1.0), $MachinePrecision] * -0.5 + N[(N[(N[(t$95$0 * N[(-1.0 / t$95$1), $MachinePrecision] + -1.0), $MachinePrecision] * t$95$0 + N[(t$95$0 * 0.16666666666666666), $MachinePrecision]), $MachinePrecision] / t$95$1), $MachinePrecision]), $MachinePrecision] * -1.0 + -0.16666666666666666), $MachinePrecision] * eps), $MachinePrecision] * eps + N[(N[(N[(N[(t$95$0 / t$95$1), $MachinePrecision] * eps + eps), $MachinePrecision] * N[Sin[x], $MachinePrecision] + N[(t$95$0 / N[Cos[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[Cos[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * eps + eps), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := {\sin x}^{2}\\
t_1 := {\cos x}^{2}\\
\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\frac{\sin x}{t\_1}, \sin x, 1\right), -0.5, \frac{\mathsf{fma}\left(\mathsf{fma}\left(t\_0, \frac{-1}{t\_1}, -1\right), t\_0, t\_0 \cdot 0.16666666666666666\right)}{t\_1}\right), -1, -0.16666666666666666\right) \cdot \varepsilon, \varepsilon, \frac{\mathsf{fma}\left(\mathsf{fma}\left(\frac{t\_0}{t\_1}, \varepsilon, \varepsilon\right), \sin x, \frac{t\_0}{\cos x}\right)}{\cos x}\right), \varepsilon, \varepsilon\right)
\end{array}
\end{array}
Derivation
  1. Initial program 60.3%

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

    \[\leadsto \color{blue}{\varepsilon \cdot \left(\left(1 + \varepsilon \cdot \left(-1 \cdot \left(\varepsilon \cdot \left(\frac{1}{6} + \left(-1 \cdot \frac{{\sin x}^{2} \cdot \left(1 - -1 \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\right)}{{\cos x}^{2}} + \left(\frac{-1}{2} \cdot \left(1 - -1 \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\right) + \frac{1}{6} \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\right)\right)\right)\right) - -1 \cdot \frac{\sin x \cdot \left(1 - -1 \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\right)}{\cos x}\right)\right) - -1 \cdot \frac{{\sin x}^{2}}{{\cos x}^{2}}\right)} \]
  4. Applied rewrites100.0%

    \[\leadsto \color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\frac{\sin x}{{\cos x}^{2}}, \sin x, 1\right), -0.5, \frac{\mathsf{fma}\left(\mathsf{fma}\left({\sin x}^{2}, \frac{-1}{{\cos x}^{2}}, -1\right), {\sin x}^{2}, {\sin x}^{2} \cdot 0.16666666666666666\right)}{{\cos x}^{2}}\right), -1, -0.16666666666666666\right) \cdot \varepsilon, \varepsilon, \frac{\mathsf{fma}\left(\mathsf{fma}\left(\frac{{\sin x}^{2}}{{\cos x}^{2}}, \varepsilon, \varepsilon\right), \sin x, \frac{{\sin x}^{2}}{\cos x}\right)}{\cos x}\right), \varepsilon, \varepsilon\right)} \]
  5. Add Preprocessing

Alternative 2: 99.9% accurate, 0.6× speedup?

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

\\
\frac{\frac{\sin \varepsilon}{\cos \left(\varepsilon + x\right)}}{\cos x}
\end{array}
Derivation
  1. Initial program 60.3%

    \[\tan \left(x + \varepsilon\right) - \tan x \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. lift--.f64N/A

      \[\leadsto \color{blue}{\tan \left(x + \varepsilon\right) - \tan x} \]
    2. lift-tan.f64N/A

      \[\leadsto \color{blue}{\tan \left(x + \varepsilon\right)} - \tan x \]
    3. tan-quotN/A

      \[\leadsto \color{blue}{\frac{\sin \left(x + \varepsilon\right)}{\cos \left(x + \varepsilon\right)}} - \tan x \]
    4. lift-tan.f64N/A

      \[\leadsto \frac{\sin \left(x + \varepsilon\right)}{\cos \left(x + \varepsilon\right)} - \color{blue}{\tan x} \]
    5. tan-quotN/A

      \[\leadsto \frac{\sin \left(x + \varepsilon\right)}{\cos \left(x + \varepsilon\right)} - \color{blue}{\frac{\sin x}{\cos x}} \]
    6. frac-subN/A

      \[\leadsto \color{blue}{\frac{\sin \left(x + \varepsilon\right) \cdot \cos x - \cos \left(x + \varepsilon\right) \cdot \sin x}{\cos \left(x + \varepsilon\right) \cdot \cos x}} \]
    7. associate-/r*N/A

      \[\leadsto \color{blue}{\frac{\frac{\sin \left(x + \varepsilon\right) \cdot \cos x - \cos \left(x + \varepsilon\right) \cdot \sin x}{\cos \left(x + \varepsilon\right)}}{\cos x}} \]
    8. lower-/.f64N/A

      \[\leadsto \color{blue}{\frac{\frac{\sin \left(x + \varepsilon\right) \cdot \cos x - \cos \left(x + \varepsilon\right) \cdot \sin x}{\cos \left(x + \varepsilon\right)}}{\cos x}} \]
    9. lower-/.f64N/A

      \[\leadsto \frac{\color{blue}{\frac{\sin \left(x + \varepsilon\right) \cdot \cos x - \cos \left(x + \varepsilon\right) \cdot \sin x}{\cos \left(x + \varepsilon\right)}}}{\cos x} \]
    10. sin-diff-revN/A

      \[\leadsto \frac{\frac{\color{blue}{\sin \left(\left(x + \varepsilon\right) - x\right)}}{\cos \left(x + \varepsilon\right)}}{\cos x} \]
    11. lower-sin.f64N/A

      \[\leadsto \frac{\frac{\color{blue}{\sin \left(\left(x + \varepsilon\right) - x\right)}}{\cos \left(x + \varepsilon\right)}}{\cos x} \]
    12. lower--.f64N/A

      \[\leadsto \frac{\frac{\sin \color{blue}{\left(\left(x + \varepsilon\right) - x\right)}}{\cos \left(x + \varepsilon\right)}}{\cos x} \]
    13. lift-+.f64N/A

      \[\leadsto \frac{\frac{\sin \left(\color{blue}{\left(x + \varepsilon\right)} - x\right)}{\cos \left(x + \varepsilon\right)}}{\cos x} \]
    14. +-commutativeN/A

      \[\leadsto \frac{\frac{\sin \left(\color{blue}{\left(\varepsilon + x\right)} - x\right)}{\cos \left(x + \varepsilon\right)}}{\cos x} \]
    15. lower-+.f64N/A

      \[\leadsto \frac{\frac{\sin \left(\color{blue}{\left(\varepsilon + x\right)} - x\right)}{\cos \left(x + \varepsilon\right)}}{\cos x} \]
    16. lower-cos.f64N/A

      \[\leadsto \frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\color{blue}{\cos \left(x + \varepsilon\right)}}}{\cos x} \]
    17. lift-+.f64N/A

      \[\leadsto \frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\cos \color{blue}{\left(x + \varepsilon\right)}}}{\cos x} \]
    18. +-commutativeN/A

      \[\leadsto \frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\cos \color{blue}{\left(\varepsilon + x\right)}}}{\cos x} \]
    19. lower-+.f64N/A

      \[\leadsto \frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\cos \color{blue}{\left(\varepsilon + x\right)}}}{\cos x} \]
    20. lower-cos.f6460.4

      \[\leadsto \frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\cos \left(\varepsilon + x\right)}}{\color{blue}{\cos x}} \]
  4. Applied rewrites60.4%

    \[\leadsto \color{blue}{\frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\cos \left(\varepsilon + x\right)}}{\cos x}} \]
  5. Taylor expanded in x around 0

    \[\leadsto \frac{\frac{\color{blue}{\sin \varepsilon}}{\cos \left(\varepsilon + x\right)}}{\cos x} \]
  6. Step-by-step derivation
    1. lower-sin.f6499.9

      \[\leadsto \frac{\frac{\color{blue}{\sin \varepsilon}}{\cos \left(\varepsilon + x\right)}}{\cos x} \]
  7. Applied rewrites99.9%

    \[\leadsto \frac{\frac{\color{blue}{\sin \varepsilon}}{\cos \left(\varepsilon + x\right)}}{\cos x} \]
  8. Add Preprocessing

Alternative 3: 99.9% accurate, 0.6× speedup?

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

\\
\frac{\sin \varepsilon}{\cos \left(\varepsilon + x\right) \cdot \cos x}
\end{array}
Derivation
  1. Initial program 60.3%

    \[\tan \left(x + \varepsilon\right) - \tan x \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. lift--.f64N/A

      \[\leadsto \color{blue}{\tan \left(x + \varepsilon\right) - \tan x} \]
    2. lift-tan.f64N/A

      \[\leadsto \color{blue}{\tan \left(x + \varepsilon\right)} - \tan x \]
    3. tan-quotN/A

      \[\leadsto \color{blue}{\frac{\sin \left(x + \varepsilon\right)}{\cos \left(x + \varepsilon\right)}} - \tan x \]
    4. lift-tan.f64N/A

      \[\leadsto \frac{\sin \left(x + \varepsilon\right)}{\cos \left(x + \varepsilon\right)} - \color{blue}{\tan x} \]
    5. tan-quotN/A

      \[\leadsto \frac{\sin \left(x + \varepsilon\right)}{\cos \left(x + \varepsilon\right)} - \color{blue}{\frac{\sin x}{\cos x}} \]
    6. frac-subN/A

      \[\leadsto \color{blue}{\frac{\sin \left(x + \varepsilon\right) \cdot \cos x - \cos \left(x + \varepsilon\right) \cdot \sin x}{\cos \left(x + \varepsilon\right) \cdot \cos x}} \]
    7. associate-/r*N/A

      \[\leadsto \color{blue}{\frac{\frac{\sin \left(x + \varepsilon\right) \cdot \cos x - \cos \left(x + \varepsilon\right) \cdot \sin x}{\cos \left(x + \varepsilon\right)}}{\cos x}} \]
    8. lower-/.f64N/A

      \[\leadsto \color{blue}{\frac{\frac{\sin \left(x + \varepsilon\right) \cdot \cos x - \cos \left(x + \varepsilon\right) \cdot \sin x}{\cos \left(x + \varepsilon\right)}}{\cos x}} \]
    9. lower-/.f64N/A

      \[\leadsto \frac{\color{blue}{\frac{\sin \left(x + \varepsilon\right) \cdot \cos x - \cos \left(x + \varepsilon\right) \cdot \sin x}{\cos \left(x + \varepsilon\right)}}}{\cos x} \]
    10. sin-diff-revN/A

      \[\leadsto \frac{\frac{\color{blue}{\sin \left(\left(x + \varepsilon\right) - x\right)}}{\cos \left(x + \varepsilon\right)}}{\cos x} \]
    11. lower-sin.f64N/A

      \[\leadsto \frac{\frac{\color{blue}{\sin \left(\left(x + \varepsilon\right) - x\right)}}{\cos \left(x + \varepsilon\right)}}{\cos x} \]
    12. lower--.f64N/A

      \[\leadsto \frac{\frac{\sin \color{blue}{\left(\left(x + \varepsilon\right) - x\right)}}{\cos \left(x + \varepsilon\right)}}{\cos x} \]
    13. lift-+.f64N/A

      \[\leadsto \frac{\frac{\sin \left(\color{blue}{\left(x + \varepsilon\right)} - x\right)}{\cos \left(x + \varepsilon\right)}}{\cos x} \]
    14. +-commutativeN/A

      \[\leadsto \frac{\frac{\sin \left(\color{blue}{\left(\varepsilon + x\right)} - x\right)}{\cos \left(x + \varepsilon\right)}}{\cos x} \]
    15. lower-+.f64N/A

      \[\leadsto \frac{\frac{\sin \left(\color{blue}{\left(\varepsilon + x\right)} - x\right)}{\cos \left(x + \varepsilon\right)}}{\cos x} \]
    16. lower-cos.f64N/A

      \[\leadsto \frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\color{blue}{\cos \left(x + \varepsilon\right)}}}{\cos x} \]
    17. lift-+.f64N/A

      \[\leadsto \frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\cos \color{blue}{\left(x + \varepsilon\right)}}}{\cos x} \]
    18. +-commutativeN/A

      \[\leadsto \frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\cos \color{blue}{\left(\varepsilon + x\right)}}}{\cos x} \]
    19. lower-+.f64N/A

      \[\leadsto \frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\cos \color{blue}{\left(\varepsilon + x\right)}}}{\cos x} \]
    20. lower-cos.f6460.4

      \[\leadsto \frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\cos \left(\varepsilon + x\right)}}{\color{blue}{\cos x}} \]
  4. Applied rewrites60.4%

    \[\leadsto \color{blue}{\frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\cos \left(\varepsilon + x\right)}}{\cos x}} \]
  5. Taylor expanded in x around inf

    \[\leadsto \color{blue}{\frac{\sin \varepsilon}{\cos x \cdot \cos \left(\varepsilon + x\right)}} \]
  6. Step-by-step derivation
    1. lower-/.f64N/A

      \[\leadsto \color{blue}{\frac{\sin \varepsilon}{\cos x \cdot \cos \left(\varepsilon + x\right)}} \]
    2. lower-sin.f64N/A

      \[\leadsto \frac{\color{blue}{\sin \varepsilon}}{\cos x \cdot \cos \left(\varepsilon + x\right)} \]
    3. *-commutativeN/A

      \[\leadsto \frac{\sin \varepsilon}{\color{blue}{\cos \left(\varepsilon + x\right) \cdot \cos x}} \]
    4. lower-*.f64N/A

      \[\leadsto \frac{\sin \varepsilon}{\color{blue}{\cos \left(\varepsilon + x\right) \cdot \cos x}} \]
    5. lower-cos.f64N/A

      \[\leadsto \frac{\sin \varepsilon}{\color{blue}{\cos \left(\varepsilon + x\right)} \cdot \cos x} \]
    6. lower-+.f64N/A

      \[\leadsto \frac{\sin \varepsilon}{\cos \color{blue}{\left(\varepsilon + x\right)} \cdot \cos x} \]
    7. lower-cos.f6499.9

      \[\leadsto \frac{\sin \varepsilon}{\cos \left(\varepsilon + x\right) \cdot \color{blue}{\cos x}} \]
  7. Applied rewrites99.9%

    \[\leadsto \color{blue}{\frac{\sin \varepsilon}{\cos \left(\varepsilon + x\right) \cdot \cos x}} \]
  8. Add Preprocessing

Alternative 4: 99.0% accurate, 0.9× speedup?

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

\\
\frac{\frac{\varepsilon}{\cos x}}{\cos x}
\end{array}
Derivation
  1. Initial program 60.3%

    \[\tan \left(x + \varepsilon\right) - \tan x \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. lift--.f64N/A

      \[\leadsto \color{blue}{\tan \left(x + \varepsilon\right) - \tan x} \]
    2. lift-tan.f64N/A

      \[\leadsto \color{blue}{\tan \left(x + \varepsilon\right)} - \tan x \]
    3. tan-quotN/A

      \[\leadsto \color{blue}{\frac{\sin \left(x + \varepsilon\right)}{\cos \left(x + \varepsilon\right)}} - \tan x \]
    4. lift-tan.f64N/A

      \[\leadsto \frac{\sin \left(x + \varepsilon\right)}{\cos \left(x + \varepsilon\right)} - \color{blue}{\tan x} \]
    5. tan-quotN/A

      \[\leadsto \frac{\sin \left(x + \varepsilon\right)}{\cos \left(x + \varepsilon\right)} - \color{blue}{\frac{\sin x}{\cos x}} \]
    6. frac-subN/A

      \[\leadsto \color{blue}{\frac{\sin \left(x + \varepsilon\right) \cdot \cos x - \cos \left(x + \varepsilon\right) \cdot \sin x}{\cos \left(x + \varepsilon\right) \cdot \cos x}} \]
    7. associate-/r*N/A

      \[\leadsto \color{blue}{\frac{\frac{\sin \left(x + \varepsilon\right) \cdot \cos x - \cos \left(x + \varepsilon\right) \cdot \sin x}{\cos \left(x + \varepsilon\right)}}{\cos x}} \]
    8. lower-/.f64N/A

      \[\leadsto \color{blue}{\frac{\frac{\sin \left(x + \varepsilon\right) \cdot \cos x - \cos \left(x + \varepsilon\right) \cdot \sin x}{\cos \left(x + \varepsilon\right)}}{\cos x}} \]
    9. lower-/.f64N/A

      \[\leadsto \frac{\color{blue}{\frac{\sin \left(x + \varepsilon\right) \cdot \cos x - \cos \left(x + \varepsilon\right) \cdot \sin x}{\cos \left(x + \varepsilon\right)}}}{\cos x} \]
    10. sin-diff-revN/A

      \[\leadsto \frac{\frac{\color{blue}{\sin \left(\left(x + \varepsilon\right) - x\right)}}{\cos \left(x + \varepsilon\right)}}{\cos x} \]
    11. lower-sin.f64N/A

      \[\leadsto \frac{\frac{\color{blue}{\sin \left(\left(x + \varepsilon\right) - x\right)}}{\cos \left(x + \varepsilon\right)}}{\cos x} \]
    12. lower--.f64N/A

      \[\leadsto \frac{\frac{\sin \color{blue}{\left(\left(x + \varepsilon\right) - x\right)}}{\cos \left(x + \varepsilon\right)}}{\cos x} \]
    13. lift-+.f64N/A

      \[\leadsto \frac{\frac{\sin \left(\color{blue}{\left(x + \varepsilon\right)} - x\right)}{\cos \left(x + \varepsilon\right)}}{\cos x} \]
    14. +-commutativeN/A

      \[\leadsto \frac{\frac{\sin \left(\color{blue}{\left(\varepsilon + x\right)} - x\right)}{\cos \left(x + \varepsilon\right)}}{\cos x} \]
    15. lower-+.f64N/A

      \[\leadsto \frac{\frac{\sin \left(\color{blue}{\left(\varepsilon + x\right)} - x\right)}{\cos \left(x + \varepsilon\right)}}{\cos x} \]
    16. lower-cos.f64N/A

      \[\leadsto \frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\color{blue}{\cos \left(x + \varepsilon\right)}}}{\cos x} \]
    17. lift-+.f64N/A

      \[\leadsto \frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\cos \color{blue}{\left(x + \varepsilon\right)}}}{\cos x} \]
    18. +-commutativeN/A

      \[\leadsto \frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\cos \color{blue}{\left(\varepsilon + x\right)}}}{\cos x} \]
    19. lower-+.f64N/A

      \[\leadsto \frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\cos \color{blue}{\left(\varepsilon + x\right)}}}{\cos x} \]
    20. lower-cos.f6460.4

      \[\leadsto \frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\cos \left(\varepsilon + x\right)}}{\color{blue}{\cos x}} \]
  4. Applied rewrites60.4%

    \[\leadsto \color{blue}{\frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\cos \left(\varepsilon + x\right)}}{\cos x}} \]
  5. Taylor expanded in eps around 0

    \[\leadsto \frac{\color{blue}{\frac{\varepsilon}{\cos x}}}{\cos x} \]
  6. Step-by-step derivation
    1. lower-/.f64N/A

      \[\leadsto \frac{\color{blue}{\frac{\varepsilon}{\cos x}}}{\cos x} \]
    2. lower-cos.f6499.2

      \[\leadsto \frac{\frac{\varepsilon}{\color{blue}{\cos x}}}{\cos x} \]
  7. Applied rewrites99.2%

    \[\leadsto \frac{\color{blue}{\frac{\varepsilon}{\cos x}}}{\cos x} \]
  8. Add Preprocessing

Alternative 5: 99.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \frac{\varepsilon}{{\cos x}^{2}} \end{array} \]
(FPCore (x eps) :precision binary64 (/ eps (pow (cos x) 2.0)))
double code(double x, double eps) {
	return eps / pow(cos(x), 2.0);
}
real(8) function code(x, eps)
    real(8), intent (in) :: x
    real(8), intent (in) :: eps
    code = eps / (cos(x) ** 2.0d0)
end function
public static double code(double x, double eps) {
	return eps / Math.pow(Math.cos(x), 2.0);
}
def code(x, eps):
	return eps / math.pow(math.cos(x), 2.0)
function code(x, eps)
	return Float64(eps / (cos(x) ^ 2.0))
end
function tmp = code(x, eps)
	tmp = eps / (cos(x) ^ 2.0);
end
code[x_, eps_] := N[(eps / N[Power[N[Cos[x], $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{\varepsilon}{{\cos x}^{2}}
\end{array}
Derivation
  1. Initial program 60.3%

    \[\tan \left(x + \varepsilon\right) - \tan x \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. lift--.f64N/A

      \[\leadsto \color{blue}{\tan \left(x + \varepsilon\right) - \tan x} \]
    2. lift-tan.f64N/A

      \[\leadsto \color{blue}{\tan \left(x + \varepsilon\right)} - \tan x \]
    3. tan-quotN/A

      \[\leadsto \color{blue}{\frac{\sin \left(x + \varepsilon\right)}{\cos \left(x + \varepsilon\right)}} - \tan x \]
    4. lift-tan.f64N/A

      \[\leadsto \frac{\sin \left(x + \varepsilon\right)}{\cos \left(x + \varepsilon\right)} - \color{blue}{\tan x} \]
    5. tan-quotN/A

      \[\leadsto \frac{\sin \left(x + \varepsilon\right)}{\cos \left(x + \varepsilon\right)} - \color{blue}{\frac{\sin x}{\cos x}} \]
    6. frac-subN/A

      \[\leadsto \color{blue}{\frac{\sin \left(x + \varepsilon\right) \cdot \cos x - \cos \left(x + \varepsilon\right) \cdot \sin x}{\cos \left(x + \varepsilon\right) \cdot \cos x}} \]
    7. associate-/r*N/A

      \[\leadsto \color{blue}{\frac{\frac{\sin \left(x + \varepsilon\right) \cdot \cos x - \cos \left(x + \varepsilon\right) \cdot \sin x}{\cos \left(x + \varepsilon\right)}}{\cos x}} \]
    8. lower-/.f64N/A

      \[\leadsto \color{blue}{\frac{\frac{\sin \left(x + \varepsilon\right) \cdot \cos x - \cos \left(x + \varepsilon\right) \cdot \sin x}{\cos \left(x + \varepsilon\right)}}{\cos x}} \]
    9. lower-/.f64N/A

      \[\leadsto \frac{\color{blue}{\frac{\sin \left(x + \varepsilon\right) \cdot \cos x - \cos \left(x + \varepsilon\right) \cdot \sin x}{\cos \left(x + \varepsilon\right)}}}{\cos x} \]
    10. sin-diff-revN/A

      \[\leadsto \frac{\frac{\color{blue}{\sin \left(\left(x + \varepsilon\right) - x\right)}}{\cos \left(x + \varepsilon\right)}}{\cos x} \]
    11. lower-sin.f64N/A

      \[\leadsto \frac{\frac{\color{blue}{\sin \left(\left(x + \varepsilon\right) - x\right)}}{\cos \left(x + \varepsilon\right)}}{\cos x} \]
    12. lower--.f64N/A

      \[\leadsto \frac{\frac{\sin \color{blue}{\left(\left(x + \varepsilon\right) - x\right)}}{\cos \left(x + \varepsilon\right)}}{\cos x} \]
    13. lift-+.f64N/A

      \[\leadsto \frac{\frac{\sin \left(\color{blue}{\left(x + \varepsilon\right)} - x\right)}{\cos \left(x + \varepsilon\right)}}{\cos x} \]
    14. +-commutativeN/A

      \[\leadsto \frac{\frac{\sin \left(\color{blue}{\left(\varepsilon + x\right)} - x\right)}{\cos \left(x + \varepsilon\right)}}{\cos x} \]
    15. lower-+.f64N/A

      \[\leadsto \frac{\frac{\sin \left(\color{blue}{\left(\varepsilon + x\right)} - x\right)}{\cos \left(x + \varepsilon\right)}}{\cos x} \]
    16. lower-cos.f64N/A

      \[\leadsto \frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\color{blue}{\cos \left(x + \varepsilon\right)}}}{\cos x} \]
    17. lift-+.f64N/A

      \[\leadsto \frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\cos \color{blue}{\left(x + \varepsilon\right)}}}{\cos x} \]
    18. +-commutativeN/A

      \[\leadsto \frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\cos \color{blue}{\left(\varepsilon + x\right)}}}{\cos x} \]
    19. lower-+.f64N/A

      \[\leadsto \frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\cos \color{blue}{\left(\varepsilon + x\right)}}}{\cos x} \]
    20. lower-cos.f6460.4

      \[\leadsto \frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\cos \left(\varepsilon + x\right)}}{\color{blue}{\cos x}} \]
  4. Applied rewrites60.4%

    \[\leadsto \color{blue}{\frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\cos \left(\varepsilon + x\right)}}{\cos x}} \]
  5. Taylor expanded in eps around 0

    \[\leadsto \color{blue}{\frac{\varepsilon}{{\cos x}^{2}}} \]
  6. Step-by-step derivation
    1. lower-/.f64N/A

      \[\leadsto \color{blue}{\frac{\varepsilon}{{\cos x}^{2}}} \]
    2. lower-pow.f64N/A

      \[\leadsto \frac{\varepsilon}{\color{blue}{{\cos x}^{2}}} \]
    3. lower-cos.f6499.2

      \[\leadsto \frac{\varepsilon}{{\color{blue}{\cos x}}^{2}} \]
  7. Applied rewrites99.2%

    \[\leadsto \color{blue}{\frac{\varepsilon}{{\cos x}^{2}}} \]
  8. Add Preprocessing

Alternative 6: 98.2% accurate, 1.5× speedup?

\[\begin{array}{l} \\ \frac{\frac{\varepsilon}{\cos x}}{\mathsf{fma}\left(x \cdot x, -0.5, 1\right)} \end{array} \]
(FPCore (x eps) :precision binary64 (/ (/ eps (cos x)) (fma (* x x) -0.5 1.0)))
double code(double x, double eps) {
	return (eps / cos(x)) / fma((x * x), -0.5, 1.0);
}
function code(x, eps)
	return Float64(Float64(eps / cos(x)) / fma(Float64(x * x), -0.5, 1.0))
end
code[x_, eps_] := N[(N[(eps / N[Cos[x], $MachinePrecision]), $MachinePrecision] / N[(N[(x * x), $MachinePrecision] * -0.5 + 1.0), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{\frac{\varepsilon}{\cos x}}{\mathsf{fma}\left(x \cdot x, -0.5, 1\right)}
\end{array}
Derivation
  1. Initial program 60.3%

    \[\tan \left(x + \varepsilon\right) - \tan x \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. lift--.f64N/A

      \[\leadsto \color{blue}{\tan \left(x + \varepsilon\right) - \tan x} \]
    2. lift-tan.f64N/A

      \[\leadsto \color{blue}{\tan \left(x + \varepsilon\right)} - \tan x \]
    3. tan-quotN/A

      \[\leadsto \color{blue}{\frac{\sin \left(x + \varepsilon\right)}{\cos \left(x + \varepsilon\right)}} - \tan x \]
    4. lift-tan.f64N/A

      \[\leadsto \frac{\sin \left(x + \varepsilon\right)}{\cos \left(x + \varepsilon\right)} - \color{blue}{\tan x} \]
    5. tan-quotN/A

      \[\leadsto \frac{\sin \left(x + \varepsilon\right)}{\cos \left(x + \varepsilon\right)} - \color{blue}{\frac{\sin x}{\cos x}} \]
    6. frac-subN/A

      \[\leadsto \color{blue}{\frac{\sin \left(x + \varepsilon\right) \cdot \cos x - \cos \left(x + \varepsilon\right) \cdot \sin x}{\cos \left(x + \varepsilon\right) \cdot \cos x}} \]
    7. associate-/r*N/A

      \[\leadsto \color{blue}{\frac{\frac{\sin \left(x + \varepsilon\right) \cdot \cos x - \cos \left(x + \varepsilon\right) \cdot \sin x}{\cos \left(x + \varepsilon\right)}}{\cos x}} \]
    8. lower-/.f64N/A

      \[\leadsto \color{blue}{\frac{\frac{\sin \left(x + \varepsilon\right) \cdot \cos x - \cos \left(x + \varepsilon\right) \cdot \sin x}{\cos \left(x + \varepsilon\right)}}{\cos x}} \]
    9. lower-/.f64N/A

      \[\leadsto \frac{\color{blue}{\frac{\sin \left(x + \varepsilon\right) \cdot \cos x - \cos \left(x + \varepsilon\right) \cdot \sin x}{\cos \left(x + \varepsilon\right)}}}{\cos x} \]
    10. sin-diff-revN/A

      \[\leadsto \frac{\frac{\color{blue}{\sin \left(\left(x + \varepsilon\right) - x\right)}}{\cos \left(x + \varepsilon\right)}}{\cos x} \]
    11. lower-sin.f64N/A

      \[\leadsto \frac{\frac{\color{blue}{\sin \left(\left(x + \varepsilon\right) - x\right)}}{\cos \left(x + \varepsilon\right)}}{\cos x} \]
    12. lower--.f64N/A

      \[\leadsto \frac{\frac{\sin \color{blue}{\left(\left(x + \varepsilon\right) - x\right)}}{\cos \left(x + \varepsilon\right)}}{\cos x} \]
    13. lift-+.f64N/A

      \[\leadsto \frac{\frac{\sin \left(\color{blue}{\left(x + \varepsilon\right)} - x\right)}{\cos \left(x + \varepsilon\right)}}{\cos x} \]
    14. +-commutativeN/A

      \[\leadsto \frac{\frac{\sin \left(\color{blue}{\left(\varepsilon + x\right)} - x\right)}{\cos \left(x + \varepsilon\right)}}{\cos x} \]
    15. lower-+.f64N/A

      \[\leadsto \frac{\frac{\sin \left(\color{blue}{\left(\varepsilon + x\right)} - x\right)}{\cos \left(x + \varepsilon\right)}}{\cos x} \]
    16. lower-cos.f64N/A

      \[\leadsto \frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\color{blue}{\cos \left(x + \varepsilon\right)}}}{\cos x} \]
    17. lift-+.f64N/A

      \[\leadsto \frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\cos \color{blue}{\left(x + \varepsilon\right)}}}{\cos x} \]
    18. +-commutativeN/A

      \[\leadsto \frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\cos \color{blue}{\left(\varepsilon + x\right)}}}{\cos x} \]
    19. lower-+.f64N/A

      \[\leadsto \frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\cos \color{blue}{\left(\varepsilon + x\right)}}}{\cos x} \]
    20. lower-cos.f6460.4

      \[\leadsto \frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\cos \left(\varepsilon + x\right)}}{\color{blue}{\cos x}} \]
  4. Applied rewrites60.4%

    \[\leadsto \color{blue}{\frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\cos \left(\varepsilon + x\right)}}{\cos x}} \]
  5. Taylor expanded in x around 0

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

      \[\leadsto \frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\cos \left(\varepsilon + x\right)}}{\color{blue}{\frac{-1}{2} \cdot {x}^{2} + 1}} \]
    2. *-commutativeN/A

      \[\leadsto \frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\cos \left(\varepsilon + x\right)}}{\color{blue}{{x}^{2} \cdot \frac{-1}{2}} + 1} \]
    3. lower-fma.f64N/A

      \[\leadsto \frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\cos \left(\varepsilon + x\right)}}{\color{blue}{\mathsf{fma}\left({x}^{2}, \frac{-1}{2}, 1\right)}} \]
    4. unpow2N/A

      \[\leadsto \frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\cos \left(\varepsilon + x\right)}}{\mathsf{fma}\left(\color{blue}{x \cdot x}, \frac{-1}{2}, 1\right)} \]
    5. lower-*.f6460.0

      \[\leadsto \frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\cos \left(\varepsilon + x\right)}}{\mathsf{fma}\left(\color{blue}{x \cdot x}, -0.5, 1\right)} \]
  7. Applied rewrites60.0%

    \[\leadsto \frac{\frac{\sin \left(\left(\varepsilon + x\right) - x\right)}{\cos \left(\varepsilon + x\right)}}{\color{blue}{\mathsf{fma}\left(x \cdot x, -0.5, 1\right)}} \]
  8. Taylor expanded in eps around 0

    \[\leadsto \frac{\color{blue}{\frac{\varepsilon}{\cos x}}}{\mathsf{fma}\left(x \cdot x, \frac{-1}{2}, 1\right)} \]
  9. Step-by-step derivation
    1. lower-/.f64N/A

      \[\leadsto \frac{\color{blue}{\frac{\varepsilon}{\cos x}}}{\mathsf{fma}\left(x \cdot x, \frac{-1}{2}, 1\right)} \]
    2. lower-cos.f6498.5

      \[\leadsto \frac{\frac{\varepsilon}{\color{blue}{\cos x}}}{\mathsf{fma}\left(x \cdot x, -0.5, 1\right)} \]
  10. Applied rewrites98.5%

    \[\leadsto \frac{\color{blue}{\frac{\varepsilon}{\cos x}}}{\mathsf{fma}\left(x \cdot x, -0.5, 1\right)} \]
  11. Add Preprocessing

Alternative 7: 97.8% accurate, 12.2× speedup?

\[\begin{array}{l} \\ \mathsf{fma}\left(\varepsilon \cdot \varepsilon, 0.3333333333333333, 1\right) \cdot \varepsilon \end{array} \]
(FPCore (x eps)
 :precision binary64
 (* (fma (* eps eps) 0.3333333333333333 1.0) eps))
double code(double x, double eps) {
	return fma((eps * eps), 0.3333333333333333, 1.0) * eps;
}
function code(x, eps)
	return Float64(fma(Float64(eps * eps), 0.3333333333333333, 1.0) * eps)
end
code[x_, eps_] := N[(N[(N[(eps * eps), $MachinePrecision] * 0.3333333333333333 + 1.0), $MachinePrecision] * eps), $MachinePrecision]
\begin{array}{l}

\\
\mathsf{fma}\left(\varepsilon \cdot \varepsilon, 0.3333333333333333, 1\right) \cdot \varepsilon
\end{array}
Derivation
  1. Initial program 60.3%

    \[\tan \left(x + \varepsilon\right) - \tan x \]
  2. Add Preprocessing
  3. Taylor expanded in x around 0

    \[\leadsto \color{blue}{\frac{\sin \varepsilon}{\cos \varepsilon}} \]
  4. Step-by-step derivation
    1. lower-/.f64N/A

      \[\leadsto \color{blue}{\frac{\sin \varepsilon}{\cos \varepsilon}} \]
    2. lower-sin.f64N/A

      \[\leadsto \frac{\color{blue}{\sin \varepsilon}}{\cos \varepsilon} \]
    3. lower-cos.f6497.9

      \[\leadsto \frac{\sin \varepsilon}{\color{blue}{\cos \varepsilon}} \]
  5. Applied rewrites97.9%

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

    \[\leadsto \varepsilon \cdot \color{blue}{\left(1 + \frac{1}{3} \cdot {\varepsilon}^{2}\right)} \]
  7. Step-by-step derivation
    1. Applied rewrites97.9%

      \[\leadsto \mathsf{fma}\left(\varepsilon \cdot \varepsilon, 0.3333333333333333, 1\right) \cdot \color{blue}{\varepsilon} \]
    2. Add Preprocessing

    Alternative 8: 97.8% accurate, 207.0× 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 60.3%

      \[\tan \left(x + \varepsilon\right) - \tan x \]
    2. Add Preprocessing
    3. Taylor expanded in x around 0

      \[\leadsto \color{blue}{\frac{\sin \varepsilon}{\cos \varepsilon}} \]
    4. Step-by-step derivation
      1. lower-/.f64N/A

        \[\leadsto \color{blue}{\frac{\sin \varepsilon}{\cos \varepsilon}} \]
      2. lower-sin.f64N/A

        \[\leadsto \frac{\color{blue}{\sin \varepsilon}}{\cos \varepsilon} \]
      3. lower-cos.f6497.9

        \[\leadsto \frac{\sin \varepsilon}{\color{blue}{\cos \varepsilon}} \]
    5. Applied rewrites97.9%

      \[\leadsto \color{blue}{\frac{\sin \varepsilon}{\cos \varepsilon}} \]
    6. Step-by-step derivation
      1. Applied rewrites3.6%

        \[\leadsto \tan \left(\left(\varepsilon + \mathsf{PI}\left(\right)\right) + \mathsf{PI}\left(\right)\right) \]
      2. Taylor expanded in eps around 0

        \[\leadsto \frac{\sin \left(2 \cdot \mathsf{PI}\left(\right)\right)}{\color{blue}{\cos \left(2 \cdot \mathsf{PI}\left(\right)\right)}} \]
      3. Step-by-step derivation
        1. Applied rewrites5.6%

          \[\leadsto 0 \]
        2. Taylor expanded in eps around 0

          \[\leadsto \varepsilon \cdot \left(1 - -1 \cdot \frac{{\sin \left(2 \cdot \mathsf{PI}\left(\right)\right)}^{2}}{{\cos \left(2 \cdot \mathsf{PI}\left(\right)\right)}^{2}}\right) + \color{blue}{\frac{\sin \left(2 \cdot \mathsf{PI}\left(\right)\right)}{\cos \left(2 \cdot \mathsf{PI}\left(\right)\right)}} \]
        3. Applied rewrites97.9%

          \[\leadsto \varepsilon \]
        4. Add Preprocessing

        Alternative 9: 5.5% accurate, 207.0× speedup?

        \[\begin{array}{l} \\ 0 \end{array} \]
        (FPCore (x eps) :precision binary64 0.0)
        double code(double x, double eps) {
        	return 0.0;
        }
        
        real(8) function code(x, eps)
            real(8), intent (in) :: x
            real(8), intent (in) :: eps
            code = 0.0d0
        end function
        
        public static double code(double x, double eps) {
        	return 0.0;
        }
        
        def code(x, eps):
        	return 0.0
        
        function code(x, eps)
        	return 0.0
        end
        
        function tmp = code(x, eps)
        	tmp = 0.0;
        end
        
        code[x_, eps_] := 0.0
        
        \begin{array}{l}
        
        \\
        0
        \end{array}
        
        Derivation
        1. Initial program 60.3%

          \[\tan \left(x + \varepsilon\right) - \tan x \]
        2. Add Preprocessing
        3. Taylor expanded in x around 0

          \[\leadsto \color{blue}{\frac{\sin \varepsilon}{\cos \varepsilon}} \]
        4. Step-by-step derivation
          1. lower-/.f64N/A

            \[\leadsto \color{blue}{\frac{\sin \varepsilon}{\cos \varepsilon}} \]
          2. lower-sin.f64N/A

            \[\leadsto \frac{\color{blue}{\sin \varepsilon}}{\cos \varepsilon} \]
          3. lower-cos.f6497.9

            \[\leadsto \frac{\sin \varepsilon}{\color{blue}{\cos \varepsilon}} \]
        5. Applied rewrites97.9%

          \[\leadsto \color{blue}{\frac{\sin \varepsilon}{\cos \varepsilon}} \]
        6. Step-by-step derivation
          1. Applied rewrites3.6%

            \[\leadsto \tan \left(\left(\varepsilon + \mathsf{PI}\left(\right)\right) + \mathsf{PI}\left(\right)\right) \]
          2. Taylor expanded in eps around 0

            \[\leadsto \frac{\sin \left(2 \cdot \mathsf{PI}\left(\right)\right)}{\color{blue}{\cos \left(2 \cdot \mathsf{PI}\left(\right)\right)}} \]
          3. Step-by-step derivation
            1. Applied rewrites5.6%

              \[\leadsto 0 \]
            2. Add Preprocessing

            Developer Target 1: 99.0% accurate, 1.0× speedup?

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

            Reproduce

            ?
            herbie shell --seed 2024326 
            (FPCore (x eps)
              :name "2tan (problem 3.3.2)"
              :precision binary64
              :pre (and (and (and (<= -10000.0 x) (<= x 10000.0)) (< (* 1e-16 (fabs x)) eps)) (< eps (fabs x)))
            
              :alt
              (! :herbie-platform default (+ eps (* eps (tan x) (tan x))))
            
              (- (tan (+ x eps)) (tan x)))