2nthrt (problem 3.4.6)

?

Percentage Accurate: 37.3% → 90.4%
Time: 26.0s
Precision: binary64
Cost: 73288

?

\[{\left(x + 1\right)}^{\left(\frac{1}{n}\right)} - {x}^{\left(\frac{1}{n}\right)} \]
\[\begin{array}{l} t_0 := {x}^{\left(\frac{1}{n}\right)}\\ t_1 := {\left(x + 1\right)}^{\left(\frac{1}{n}\right)} - t_0\\ \mathbf{if}\;t_1 \leq -\infty:\\ \;\;\;\;1 - t_0\\ \mathbf{elif}\;t_1 \leq 0:\\ \;\;\;\;\mathsf{fma}\left(0.5, \frac{{\left(\mathsf{log1p}\left(x\right)\right)}^{2}}{n \cdot n}, \frac{\mathsf{log1p}\left(x\right) - \log x}{n}\right) + \frac{{\log x}^{2}}{n \cdot n} \cdot -0.5\\ \mathbf{elif}\;t_1 \leq \infty:\\ \;\;\;\;e^{\frac{x}{n}} - t_0\\ \mathbf{else}:\\ \;\;\;\;\frac{t_0}{x \cdot n}\\ \end{array} \]
(FPCore (x n)
 :precision binary64
 (- (pow (+ x 1.0) (/ 1.0 n)) (pow x (/ 1.0 n))))
(FPCore (x n)
 :precision binary64
 (let* ((t_0 (pow x (/ 1.0 n))) (t_1 (- (pow (+ x 1.0) (/ 1.0 n)) t_0)))
   (if (<= t_1 (- INFINITY))
     (- 1.0 t_0)
     (if (<= t_1 0.0)
       (+
        (fma 0.5 (/ (pow (log1p x) 2.0) (* n n)) (/ (- (log1p x) (log x)) n))
        (* (/ (pow (log x) 2.0) (* n n)) -0.5))
       (if (<= t_1 INFINITY) (- (exp (/ x n)) t_0) (/ t_0 (* x n)))))))
double code(double x, double n) {
	return pow((x + 1.0), (1.0 / n)) - pow(x, (1.0 / n));
}
double code(double x, double n) {
	double t_0 = pow(x, (1.0 / n));
	double t_1 = pow((x + 1.0), (1.0 / n)) - t_0;
	double tmp;
	if (t_1 <= -((double) INFINITY)) {
		tmp = 1.0 - t_0;
	} else if (t_1 <= 0.0) {
		tmp = fma(0.5, (pow(log1p(x), 2.0) / (n * n)), ((log1p(x) - log(x)) / n)) + ((pow(log(x), 2.0) / (n * n)) * -0.5);
	} else if (t_1 <= ((double) INFINITY)) {
		tmp = exp((x / n)) - t_0;
	} else {
		tmp = t_0 / (x * n);
	}
	return tmp;
}
function code(x, n)
	return Float64((Float64(x + 1.0) ^ Float64(1.0 / n)) - (x ^ Float64(1.0 / n)))
end
function code(x, n)
	t_0 = x ^ Float64(1.0 / n)
	t_1 = Float64((Float64(x + 1.0) ^ Float64(1.0 / n)) - t_0)
	tmp = 0.0
	if (t_1 <= Float64(-Inf))
		tmp = Float64(1.0 - t_0);
	elseif (t_1 <= 0.0)
		tmp = Float64(fma(0.5, Float64((log1p(x) ^ 2.0) / Float64(n * n)), Float64(Float64(log1p(x) - log(x)) / n)) + Float64(Float64((log(x) ^ 2.0) / Float64(n * n)) * -0.5));
	elseif (t_1 <= Inf)
		tmp = Float64(exp(Float64(x / n)) - t_0);
	else
		tmp = Float64(t_0 / Float64(x * n));
	end
	return tmp
end
code[x_, n_] := N[(N[Power[N[(x + 1.0), $MachinePrecision], N[(1.0 / n), $MachinePrecision]], $MachinePrecision] - N[Power[x, N[(1.0 / n), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
code[x_, n_] := Block[{t$95$0 = N[Power[x, N[(1.0 / n), $MachinePrecision]], $MachinePrecision]}, Block[{t$95$1 = N[(N[Power[N[(x + 1.0), $MachinePrecision], N[(1.0 / n), $MachinePrecision]], $MachinePrecision] - t$95$0), $MachinePrecision]}, If[LessEqual[t$95$1, (-Infinity)], N[(1.0 - t$95$0), $MachinePrecision], If[LessEqual[t$95$1, 0.0], N[(N[(0.5 * N[(N[Power[N[Log[1 + x], $MachinePrecision], 2.0], $MachinePrecision] / N[(n * n), $MachinePrecision]), $MachinePrecision] + N[(N[(N[Log[1 + x], $MachinePrecision] - N[Log[x], $MachinePrecision]), $MachinePrecision] / n), $MachinePrecision]), $MachinePrecision] + N[(N[(N[Power[N[Log[x], $MachinePrecision], 2.0], $MachinePrecision] / N[(n * n), $MachinePrecision]), $MachinePrecision] * -0.5), $MachinePrecision]), $MachinePrecision], If[LessEqual[t$95$1, Infinity], N[(N[Exp[N[(x / n), $MachinePrecision]], $MachinePrecision] - t$95$0), $MachinePrecision], N[(t$95$0 / N[(x * n), $MachinePrecision]), $MachinePrecision]]]]]]
{\left(x + 1\right)}^{\left(\frac{1}{n}\right)} - {x}^{\left(\frac{1}{n}\right)}
\begin{array}{l}
t_0 := {x}^{\left(\frac{1}{n}\right)}\\
t_1 := {\left(x + 1\right)}^{\left(\frac{1}{n}\right)} - t_0\\
\mathbf{if}\;t_1 \leq -\infty:\\
\;\;\;\;1 - t_0\\

\mathbf{elif}\;t_1 \leq 0:\\
\;\;\;\;\mathsf{fma}\left(0.5, \frac{{\left(\mathsf{log1p}\left(x\right)\right)}^{2}}{n \cdot n}, \frac{\mathsf{log1p}\left(x\right) - \log x}{n}\right) + \frac{{\log x}^{2}}{n \cdot n} \cdot -0.5\\

\mathbf{elif}\;t_1 \leq \infty:\\
\;\;\;\;e^{\frac{x}{n}} - t_0\\

\mathbf{else}:\\
\;\;\;\;\frac{t_0}{x \cdot n}\\


\end{array}

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.

Herbie found 16 alternatives:

AlternativeAccuracySpeedup

Accuracy vs Speed

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.

Bogosity?

Bogosity

Derivation?

  1. Split input into 4 regimes
  2. if (-.f64 (pow.f64 (+.f64 x 1) (/.f64 1 n)) (pow.f64 x (/.f64 1 n))) < -inf.0

    1. Initial program 100.0%

      \[{\left(x + 1\right)}^{\left(\frac{1}{n}\right)} - {x}^{\left(\frac{1}{n}\right)} \]
    2. Taylor expanded in x around 0 100.0%

      \[\leadsto \color{blue}{1 - e^{\frac{\log x}{n}}} \]
    3. Simplified100.0%

      \[\leadsto \color{blue}{1 - {x}^{\left(\frac{1}{n}\right)}} \]
      Step-by-step derivation

      [Start]100.0%

      \[ 1 - e^{\frac{\log x}{n}} \]

      *-rgt-identity [<=]100.0%

      \[ 1 - e^{\frac{\color{blue}{\log x \cdot 1}}{n}} \]

      associate-*r/ [<=]100.0%

      \[ 1 - e^{\color{blue}{\log x \cdot \frac{1}{n}}} \]

      unpow-1 [<=]100.0%

      \[ 1 - e^{\log x \cdot \color{blue}{{n}^{-1}}} \]

      exp-to-pow [=>]100.0%

      \[ 1 - \color{blue}{{x}^{\left({n}^{-1}\right)}} \]

      unpow-1 [=>]100.0%

      \[ 1 - {x}^{\color{blue}{\left(\frac{1}{n}\right)}} \]

    if -inf.0 < (-.f64 (pow.f64 (+.f64 x 1) (/.f64 1 n)) (pow.f64 x (/.f64 1 n))) < 0.0

    1. Initial program 28.3%

      \[{\left(x + 1\right)}^{\left(\frac{1}{n}\right)} - {x}^{\left(\frac{1}{n}\right)} \]
    2. Taylor expanded in n around inf 82.4%

      \[\leadsto \color{blue}{\left(0.5 \cdot \frac{{\log \left(1 + x\right)}^{2}}{{n}^{2}} + \frac{\log \left(1 + x\right)}{n}\right) - \left(\frac{\log x}{n} + 0.5 \cdot \frac{{\log x}^{2}}{{n}^{2}}\right)} \]
    3. Simplified82.4%

      \[\leadsto \color{blue}{\mathsf{fma}\left(0.5, \frac{{\left(\mathsf{log1p}\left(x\right)\right)}^{2}}{n \cdot n}, \frac{\mathsf{log1p}\left(x\right) - \log x}{n}\right) + \frac{{\log x}^{2}}{n \cdot n} \cdot -0.5} \]
      Step-by-step derivation

      [Start]82.4%

      \[ \left(0.5 \cdot \frac{{\log \left(1 + x\right)}^{2}}{{n}^{2}} + \frac{\log \left(1 + x\right)}{n}\right) - \left(\frac{\log x}{n} + 0.5 \cdot \frac{{\log x}^{2}}{{n}^{2}}\right) \]

      associate--r+ [=>]74.5%

      \[ \color{blue}{\left(\left(0.5 \cdot \frac{{\log \left(1 + x\right)}^{2}}{{n}^{2}} + \frac{\log \left(1 + x\right)}{n}\right) - \frac{\log x}{n}\right) - 0.5 \cdot \frac{{\log x}^{2}}{{n}^{2}}} \]

      sub-neg [=>]74.5%

      \[ \color{blue}{\left(\left(0.5 \cdot \frac{{\log \left(1 + x\right)}^{2}}{{n}^{2}} + \frac{\log \left(1 + x\right)}{n}\right) - \frac{\log x}{n}\right) + \left(-0.5 \cdot \frac{{\log x}^{2}}{{n}^{2}}\right)} \]

    if 0.0 < (-.f64 (pow.f64 (+.f64 x 1) (/.f64 1 n)) (pow.f64 x (/.f64 1 n))) < +inf.0

    1. Initial program 56.1%

      \[{\left(x + 1\right)}^{\left(\frac{1}{n}\right)} - {x}^{\left(\frac{1}{n}\right)} \]
    2. Taylor expanded in n around 0 56.1%

      \[\leadsto \color{blue}{e^{\frac{\log \left(1 + x\right)}{n}} - e^{\frac{\log x}{n}}} \]
    3. Simplified99.9%

      \[\leadsto \color{blue}{e^{\frac{\mathsf{log1p}\left(x\right)}{n}} - {x}^{\left(\frac{1}{n}\right)}} \]
      Step-by-step derivation

      [Start]56.1%

      \[ e^{\frac{\log \left(1 + x\right)}{n}} - e^{\frac{\log x}{n}} \]

      log1p-def [=>]99.9%

      \[ e^{\frac{\color{blue}{\mathsf{log1p}\left(x\right)}}{n}} - e^{\frac{\log x}{n}} \]

      *-rgt-identity [<=]99.9%

      \[ e^{\frac{\mathsf{log1p}\left(x\right)}{n}} - e^{\frac{\color{blue}{\log x \cdot 1}}{n}} \]

      associate-*r/ [<=]99.9%

      \[ e^{\frac{\mathsf{log1p}\left(x\right)}{n}} - e^{\color{blue}{\log x \cdot \frac{1}{n}}} \]

      unpow-1 [<=]99.9%

      \[ e^{\frac{\mathsf{log1p}\left(x\right)}{n}} - e^{\log x \cdot \color{blue}{{n}^{-1}}} \]

      exp-to-pow [=>]99.9%

      \[ e^{\frac{\mathsf{log1p}\left(x\right)}{n}} - \color{blue}{{x}^{\left({n}^{-1}\right)}} \]

      /-rgt-identity [<=]99.9%

      \[ e^{\frac{\mathsf{log1p}\left(x\right)}{n}} - {x}^{\color{blue}{\left(\frac{{n}^{-1}}{1}\right)}} \]

      metadata-eval [<=]99.9%

      \[ e^{\frac{\mathsf{log1p}\left(x\right)}{n}} - {x}^{\left(\frac{{n}^{-1}}{\color{blue}{\frac{2}{2}}}\right)} \]

      associate-/l* [<=]99.9%

      \[ e^{\frac{\mathsf{log1p}\left(x\right)}{n}} - {x}^{\color{blue}{\left(\frac{{n}^{-1} \cdot 2}{2}\right)}} \]

      *-commutative [<=]99.9%

      \[ e^{\frac{\mathsf{log1p}\left(x\right)}{n}} - {x}^{\left(\frac{\color{blue}{2 \cdot {n}^{-1}}}{2}\right)} \]

      *-commutative [=>]99.9%

      \[ e^{\frac{\mathsf{log1p}\left(x\right)}{n}} - {x}^{\left(\frac{\color{blue}{{n}^{-1} \cdot 2}}{2}\right)} \]

      associate-/l* [=>]99.9%

      \[ e^{\frac{\mathsf{log1p}\left(x\right)}{n}} - {x}^{\color{blue}{\left(\frac{{n}^{-1}}{\frac{2}{2}}\right)}} \]

      metadata-eval [=>]99.9%

      \[ e^{\frac{\mathsf{log1p}\left(x\right)}{n}} - {x}^{\left(\frac{{n}^{-1}}{\color{blue}{1}}\right)} \]

      /-rgt-identity [=>]99.9%

      \[ e^{\frac{\mathsf{log1p}\left(x\right)}{n}} - {x}^{\color{blue}{\left({n}^{-1}\right)}} \]

      unpow-1 [=>]99.9%

      \[ e^{\frac{\mathsf{log1p}\left(x\right)}{n}} - {x}^{\color{blue}{\left(\frac{1}{n}\right)}} \]
    4. Taylor expanded in x around 0 99.9%

      \[\leadsto e^{\color{blue}{\frac{x}{n}}} - {x}^{\left(\frac{1}{n}\right)} \]

    if +inf.0 < (-.f64 (pow.f64 (+.f64 x 1) (/.f64 1 n)) (pow.f64 x (/.f64 1 n)))

    1. Initial program 0.0%

      \[{\left(x + 1\right)}^{\left(\frac{1}{n}\right)} - {x}^{\left(\frac{1}{n}\right)} \]
    2. Taylor expanded in x around inf 100.0%

      \[\leadsto \color{blue}{\frac{e^{-1 \cdot \frac{\log \left(\frac{1}{x}\right)}{n}}}{n \cdot x}} \]
    3. Simplified100.0%

      \[\leadsto \color{blue}{\frac{{x}^{\left(\frac{1}{n}\right)}}{x \cdot n}} \]
      Step-by-step derivation

      [Start]100.0%

      \[ \frac{e^{-1 \cdot \frac{\log \left(\frac{1}{x}\right)}{n}}}{n \cdot x} \]

      log-rec [=>]100.0%

      \[ \frac{e^{-1 \cdot \frac{\color{blue}{-\log x}}{n}}}{n \cdot x} \]

      mul-1-neg [<=]100.0%

      \[ \frac{e^{-1 \cdot \frac{\color{blue}{-1 \cdot \log x}}{n}}}{n \cdot x} \]

      mul-1-neg [=>]100.0%

      \[ \frac{e^{-1 \cdot \frac{\color{blue}{-\log x}}{n}}}{n \cdot x} \]

      distribute-frac-neg [=>]100.0%

      \[ \frac{e^{-1 \cdot \color{blue}{\left(-\frac{\log x}{n}\right)}}}{n \cdot x} \]

      neg-mul-1 [<=]100.0%

      \[ \frac{e^{\color{blue}{-\left(-\frac{\log x}{n}\right)}}}{n \cdot x} \]

      remove-double-neg [=>]100.0%

      \[ \frac{e^{\color{blue}{\frac{\log x}{n}}}}{n \cdot x} \]

      *-rgt-identity [<=]100.0%

      \[ \frac{e^{\frac{\color{blue}{\log x \cdot 1}}{n}}}{n \cdot x} \]

      associate-*r/ [<=]100.0%

      \[ \frac{e^{\color{blue}{\log x \cdot \frac{1}{n}}}}{n \cdot x} \]

      unpow-1 [<=]100.0%

      \[ \frac{e^{\log x \cdot \color{blue}{{n}^{-1}}}}{n \cdot x} \]

      exp-to-pow [=>]100.0%

      \[ \frac{\color{blue}{{x}^{\left({n}^{-1}\right)}}}{n \cdot x} \]

      unpow-1 [=>]100.0%

      \[ \frac{{x}^{\color{blue}{\left(\frac{1}{n}\right)}}}{n \cdot x} \]

      *-commutative [=>]100.0%

      \[ \frac{{x}^{\left(\frac{1}{n}\right)}}{\color{blue}{x \cdot n}} \]
  3. Recombined 4 regimes into one program.
  4. Final simplification90.7%

    \[\leadsto \begin{array}{l} \mathbf{if}\;{\left(x + 1\right)}^{\left(\frac{1}{n}\right)} - {x}^{\left(\frac{1}{n}\right)} \leq -\infty:\\ \;\;\;\;1 - {x}^{\left(\frac{1}{n}\right)}\\ \mathbf{elif}\;{\left(x + 1\right)}^{\left(\frac{1}{n}\right)} - {x}^{\left(\frac{1}{n}\right)} \leq 0:\\ \;\;\;\;\mathsf{fma}\left(0.5, \frac{{\left(\mathsf{log1p}\left(x\right)\right)}^{2}}{n \cdot n}, \frac{\mathsf{log1p}\left(x\right) - \log x}{n}\right) + \frac{{\log x}^{2}}{n \cdot n} \cdot -0.5\\ \mathbf{elif}\;{\left(x + 1\right)}^{\left(\frac{1}{n}\right)} - {x}^{\left(\frac{1}{n}\right)} \leq \infty:\\ \;\;\;\;e^{\frac{x}{n}} - {x}^{\left(\frac{1}{n}\right)}\\ \mathbf{else}:\\ \;\;\;\;\frac{{x}^{\left(\frac{1}{n}\right)}}{x \cdot n}\\ \end{array} \]

Alternatives

Alternative 1
Accuracy90.4%
Cost73288
\[\begin{array}{l} t_0 := {x}^{\left(\frac{1}{n}\right)}\\ t_1 := {\left(x + 1\right)}^{\left(\frac{1}{n}\right)} - t_0\\ \mathbf{if}\;t_1 \leq -\infty:\\ \;\;\;\;1 - t_0\\ \mathbf{elif}\;t_1 \leq 0:\\ \;\;\;\;\mathsf{fma}\left(0.5, \frac{{\left(\mathsf{log1p}\left(x\right)\right)}^{2}}{n \cdot n}, \frac{\mathsf{log1p}\left(x\right) - \log x}{n}\right) + \frac{{\log x}^{2}}{n \cdot n} \cdot -0.5\\ \mathbf{elif}\;t_1 \leq \infty:\\ \;\;\;\;e^{\frac{x}{n}} - t_0\\ \mathbf{else}:\\ \;\;\;\;\frac{t_0}{x \cdot n}\\ \end{array} \]
Alternative 2
Accuracy90.3%
Cost54028
\[\begin{array}{l} t_0 := {x}^{\left(\frac{1}{n}\right)}\\ t_1 := {\left(x + 1\right)}^{\left(\frac{1}{n}\right)} - t_0\\ \mathbf{if}\;t_1 \leq -\infty:\\ \;\;\;\;1 - t_0\\ \mathbf{elif}\;t_1 \leq 0:\\ \;\;\;\;\frac{\log \left(\frac{x + 1}{x}\right)}{n}\\ \mathbf{elif}\;t_1 \leq \infty:\\ \;\;\;\;e^{\frac{x}{n}} - t_0\\ \mathbf{else}:\\ \;\;\;\;\frac{t_0}{x \cdot n}\\ \end{array} \]
Alternative 3
Accuracy77.5%
Cost8528
\[\begin{array}{l} t_0 := {x}^{\left(\frac{1}{n}\right)}\\ t_1 := \frac{1}{x \cdot n}\\ \mathbf{if}\;\frac{1}{n} \leq -10:\\ \;\;\;\;\frac{t_0}{x \cdot n}\\ \mathbf{elif}\;\frac{1}{n} \leq 10^{-19}:\\ \;\;\;\;\frac{\log \left(\frac{x + 1}{x}\right)}{n}\\ \mathbf{elif}\;\frac{1}{n} \leq 5 \cdot 10^{+101}:\\ \;\;\;\;\frac{1}{n} \cdot \frac{t_0}{x}\\ \mathbf{elif}\;\frac{1}{n} \leq 2 \cdot 10^{+148}:\\ \;\;\;\;\sqrt[3]{t_1 \cdot \left(t_1 \cdot t_1\right)}\\ \mathbf{else}:\\ \;\;\;\;0.5 \cdot \frac{x \cdot x}{n \cdot n}\\ \end{array} \]
Alternative 4
Accuracy78.4%
Cost7820
\[\begin{array}{l} t_0 := {x}^{\left(\frac{1}{n}\right)}\\ \mathbf{if}\;\frac{1}{n} \leq -10:\\ \;\;\;\;\frac{t_0}{x \cdot n}\\ \mathbf{elif}\;\frac{1}{n} \leq 10^{-19}:\\ \;\;\;\;\frac{\log \left(\frac{x + 1}{x}\right)}{n}\\ \mathbf{elif}\;\frac{1}{n} \leq 5 \cdot 10^{+65}:\\ \;\;\;\;\frac{1}{n} \cdot \frac{t_0}{x}\\ \mathbf{else}:\\ \;\;\;\;\frac{x}{n} + \left(x \cdot x\right) \cdot \left(\frac{0.5}{n \cdot n} - \frac{0.5}{n}\right)\\ \end{array} \]
Alternative 5
Accuracy78.4%
Cost7820
\[\begin{array}{l} t_0 := {x}^{\left(\frac{1}{n}\right)}\\ \mathbf{if}\;\frac{1}{n} \leq -10:\\ \;\;\;\;\frac{t_0}{x \cdot n}\\ \mathbf{elif}\;\frac{1}{n} \leq 10^{-19}:\\ \;\;\;\;\frac{\log \left(\frac{x + 1}{x}\right)}{n}\\ \mathbf{elif}\;\frac{1}{n} \leq 5 \cdot 10^{+65}:\\ \;\;\;\;\frac{1}{\frac{x \cdot n}{t_0}}\\ \mathbf{else}:\\ \;\;\;\;\frac{x}{n} + \left(x \cdot x\right) \cdot \left(\frac{0.5}{n \cdot n} - \frac{0.5}{n}\right)\\ \end{array} \]
Alternative 6
Accuracy58.8%
Cost7696
\[\begin{array}{l} t_0 := \frac{1}{x \cdot n}\\ t_1 := -\frac{\log x}{n}\\ \mathbf{if}\;\frac{1}{n} \leq -10:\\ \;\;\;\;t_0\\ \mathbf{elif}\;\frac{1}{n} \leq 10^{-298}:\\ \;\;\;\;t_1\\ \mathbf{elif}\;\frac{1}{n} \leq 10^{-80}:\\ \;\;\;\;t_0\\ \mathbf{elif}\;\frac{1}{n} \leq 2 \cdot 10^{-48}:\\ \;\;\;\;t_1\\ \mathbf{elif}\;\frac{1}{n} \leq 0.05:\\ \;\;\;\;\frac{\frac{1}{x} - \frac{0.5}{x \cdot x}}{n}\\ \mathbf{else}:\\ \;\;\;\;\frac{x}{n} + \left(x \cdot x\right) \cdot \left(\frac{0.5}{n \cdot n} - \frac{0.5}{n}\right)\\ \end{array} \]
Alternative 7
Accuracy78.4%
Cost7692
\[\begin{array}{l} t_0 := \frac{{x}^{\left(\frac{1}{n}\right)}}{x \cdot n}\\ \mathbf{if}\;\frac{1}{n} \leq -10:\\ \;\;\;\;t_0\\ \mathbf{elif}\;\frac{1}{n} \leq 10^{-19}:\\ \;\;\;\;\frac{\log \left(\frac{x + 1}{x}\right)}{n}\\ \mathbf{elif}\;\frac{1}{n} \leq 5 \cdot 10^{+65}:\\ \;\;\;\;t_0\\ \mathbf{else}:\\ \;\;\;\;\frac{x}{n} + \left(x \cdot x\right) \cdot \left(\frac{0.5}{n \cdot n} - \frac{0.5}{n}\right)\\ \end{array} \]
Alternative 8
Accuracy75.9%
Cost7368
\[\begin{array}{l} \mathbf{if}\;\frac{1}{n} \leq -10:\\ \;\;\;\;1 - {x}^{\left(\frac{1}{n}\right)}\\ \mathbf{elif}\;\frac{1}{n} \leq 20000000:\\ \;\;\;\;\frac{\log \left(\frac{x + 1}{x}\right)}{n}\\ \mathbf{else}:\\ \;\;\;\;\frac{x}{n} + \left(x \cdot x\right) \cdot \left(\frac{0.5}{n \cdot n} - \frac{0.5}{n}\right)\\ \end{array} \]
Alternative 9
Accuracy67.3%
Cost7048
\[\begin{array}{l} \mathbf{if}\;n \leq -24000000000:\\ \;\;\;\;\frac{x - \log x}{n}\\ \mathbf{elif}\;n \leq 2 \cdot 10^{-309}:\\ \;\;\;\;1 - {x}^{\left(\frac{1}{n}\right)}\\ \mathbf{elif}\;n \leq 0.73:\\ \;\;\;\;\frac{x}{n} + \left(x \cdot x\right) \cdot \left(\frac{0.5}{n \cdot n} - \frac{0.5}{n}\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{1}{x \cdot n}\\ \end{array} \]
Alternative 10
Accuracy67.3%
Cost7048
\[\begin{array}{l} \mathbf{if}\;n \leq -21000000000:\\ \;\;\;\;\frac{1}{n} \cdot \left(x - \log x\right)\\ \mathbf{elif}\;n \leq 2 \cdot 10^{-309}:\\ \;\;\;\;1 - {x}^{\left(\frac{1}{n}\right)}\\ \mathbf{elif}\;n \leq 0.73:\\ \;\;\;\;\frac{x}{n} + \left(x \cdot x\right) \cdot \left(\frac{0.5}{n \cdot n} - \frac{0.5}{n}\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{1}{x \cdot n}\\ \end{array} \]
Alternative 11
Accuracy59.3%
Cost6852
\[\begin{array}{l} \mathbf{if}\;n \leq -2:\\ \;\;\;\;\frac{x - \log x}{n}\\ \mathbf{elif}\;n \leq 2 \cdot 10^{-309} \lor \neg \left(n \leq 0.8\right):\\ \;\;\;\;\frac{1}{x \cdot n}\\ \mathbf{else}:\\ \;\;\;\;\frac{x}{n} + \left(x \cdot x\right) \cdot \left(\frac{0.5}{n \cdot n} - \frac{0.5}{n}\right)\\ \end{array} \]
Alternative 12
Accuracy45.2%
Cost1348
\[\begin{array}{l} \mathbf{if}\;\frac{1}{n} \leq 0.05:\\ \;\;\;\;\frac{1}{x \cdot n}\\ \mathbf{else}:\\ \;\;\;\;\frac{x}{n} + \left(x \cdot x\right) \cdot \left(\frac{0.5}{n \cdot n} - \frac{0.5}{n}\right)\\ \end{array} \]
Alternative 13
Accuracy44.8%
Cost836
\[\begin{array}{l} \mathbf{if}\;\frac{1}{n} \leq 20000000:\\ \;\;\;\;\frac{1}{x \cdot n}\\ \mathbf{else}:\\ \;\;\;\;0.5 \cdot \frac{x \cdot x}{n \cdot n}\\ \end{array} \]
Alternative 14
Accuracy35.4%
Cost585
\[\begin{array}{l} \mathbf{if}\;n \leq 2.5 \cdot 10^{-281} \lor \neg \left(n \leq 1\right):\\ \;\;\;\;\frac{1}{x \cdot n}\\ \mathbf{else}:\\ \;\;\;\;\frac{x}{n}\\ \end{array} \]
Alternative 15
Accuracy20.1%
Cost324
\[\begin{array}{l} \mathbf{if}\;n \leq 7.2 \cdot 10^{+34}:\\ \;\;\;\;\frac{x}{n}\\ \mathbf{else}:\\ \;\;\;\;0\\ \end{array} \]
Alternative 16
Accuracy11.4%
Cost64
\[0 \]

Reproduce?

herbie shell --seed 2023272 
(FPCore (x n)
  :name "2nthrt (problem 3.4.6)"
  :precision binary64
  (- (pow (+ x 1.0) (/ 1.0 n)) (pow x (/ 1.0 n))))