2log (problem 3.3.6)

Percentage Accurate: 53.5% → 99.8%
Time: 7.8s
Alternatives: 8
Speedup: 2.0×

Specification

?
\[\begin{array}{l} \\ \log \left(N + 1\right) - \log N \end{array} \]
(FPCore (N) :precision binary64 (- (log (+ N 1.0)) (log N)))
double code(double N) {
	return log((N + 1.0)) - log(N);
}
real(8) function code(n)
    real(8), intent (in) :: n
    code = log((n + 1.0d0)) - log(n)
end function
public static double code(double N) {
	return Math.log((N + 1.0)) - Math.log(N);
}
def code(N):
	return math.log((N + 1.0)) - math.log(N)
function code(N)
	return Float64(log(Float64(N + 1.0)) - log(N))
end
function tmp = code(N)
	tmp = log((N + 1.0)) - log(N);
end
code[N_] := N[(N[Log[N[(N + 1.0), $MachinePrecision]], $MachinePrecision] - N[Log[N], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\log \left(N + 1\right) - \log N
\end{array}

Sampling outcomes in binary64 precision:

Local Percentage Accuracy vs ?

The average percentage accuracy by input value. Horizontal axis shows value of an input variable; the variable is choosen in the title. Vertical axis is accuracy; higher is better. Red represent the original program, while blue represents Herbie's suggestion. These can be toggled with buttons below the plot. The line is an average while dots represent individual samples.

Accuracy vs Speed?

Herbie found 8 alternatives:

AlternativeAccuracySpeedup
The accuracy (vertical axis) and speed (horizontal axis) of each alternatives. Up and to the right is better. The red square shows the initial program, and each blue circle shows an alternative.The line shows the best available speed-accuracy tradeoffs.

Initial Program: 53.5% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \log \left(N + 1\right) - \log N \end{array} \]
(FPCore (N) :precision binary64 (- (log (+ N 1.0)) (log N)))
double code(double N) {
	return log((N + 1.0)) - log(N);
}
real(8) function code(n)
    real(8), intent (in) :: n
    code = log((n + 1.0d0)) - log(n)
end function
public static double code(double N) {
	return Math.log((N + 1.0)) - Math.log(N);
}
def code(N):
	return math.log((N + 1.0)) - math.log(N)
function code(N)
	return Float64(log(Float64(N + 1.0)) - log(N))
end
function tmp = code(N)
	tmp = log((N + 1.0)) - log(N);
end
code[N_] := N[(N[Log[N[(N + 1.0), $MachinePrecision]], $MachinePrecision] - N[Log[N], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\log \left(N + 1\right) - \log N
\end{array}

Alternative 1: 99.8% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\log \left(N + 1\right) - \log N \leq 2 \cdot 10^{-7}:\\ \;\;\;\;\frac{1}{N} + \left(\frac{0.3333333333333333}{{N}^{3}} - \frac{0.5}{N \cdot N}\right)\\ \mathbf{else}:\\ \;\;\;\;2 \cdot \left(-\log \left(\sqrt{\frac{N}{N + 1}}\right)\right)\\ \end{array} \end{array} \]
(FPCore (N)
 :precision binary64
 (if (<= (- (log (+ N 1.0)) (log N)) 2e-7)
   (+ (/ 1.0 N) (- (/ 0.3333333333333333 (pow N 3.0)) (/ 0.5 (* N N))))
   (* 2.0 (- (log (sqrt (/ N (+ N 1.0))))))))
double code(double N) {
	double tmp;
	if ((log((N + 1.0)) - log(N)) <= 2e-7) {
		tmp = (1.0 / N) + ((0.3333333333333333 / pow(N, 3.0)) - (0.5 / (N * N)));
	} else {
		tmp = 2.0 * -log(sqrt((N / (N + 1.0))));
	}
	return tmp;
}
real(8) function code(n)
    real(8), intent (in) :: n
    real(8) :: tmp
    if ((log((n + 1.0d0)) - log(n)) <= 2d-7) then
        tmp = (1.0d0 / n) + ((0.3333333333333333d0 / (n ** 3.0d0)) - (0.5d0 / (n * n)))
    else
        tmp = 2.0d0 * -log(sqrt((n / (n + 1.0d0))))
    end if
    code = tmp
end function
public static double code(double N) {
	double tmp;
	if ((Math.log((N + 1.0)) - Math.log(N)) <= 2e-7) {
		tmp = (1.0 / N) + ((0.3333333333333333 / Math.pow(N, 3.0)) - (0.5 / (N * N)));
	} else {
		tmp = 2.0 * -Math.log(Math.sqrt((N / (N + 1.0))));
	}
	return tmp;
}
def code(N):
	tmp = 0
	if (math.log((N + 1.0)) - math.log(N)) <= 2e-7:
		tmp = (1.0 / N) + ((0.3333333333333333 / math.pow(N, 3.0)) - (0.5 / (N * N)))
	else:
		tmp = 2.0 * -math.log(math.sqrt((N / (N + 1.0))))
	return tmp
function code(N)
	tmp = 0.0
	if (Float64(log(Float64(N + 1.0)) - log(N)) <= 2e-7)
		tmp = Float64(Float64(1.0 / N) + Float64(Float64(0.3333333333333333 / (N ^ 3.0)) - Float64(0.5 / Float64(N * N))));
	else
		tmp = Float64(2.0 * Float64(-log(sqrt(Float64(N / Float64(N + 1.0))))));
	end
	return tmp
end
function tmp_2 = code(N)
	tmp = 0.0;
	if ((log((N + 1.0)) - log(N)) <= 2e-7)
		tmp = (1.0 / N) + ((0.3333333333333333 / (N ^ 3.0)) - (0.5 / (N * N)));
	else
		tmp = 2.0 * -log(sqrt((N / (N + 1.0))));
	end
	tmp_2 = tmp;
end
code[N_] := If[LessEqual[N[(N[Log[N[(N + 1.0), $MachinePrecision]], $MachinePrecision] - N[Log[N], $MachinePrecision]), $MachinePrecision], 2e-7], N[(N[(1.0 / N), $MachinePrecision] + N[(N[(0.3333333333333333 / N[Power[N, 3.0], $MachinePrecision]), $MachinePrecision] - N[(0.5 / N[(N * N), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(2.0 * (-N[Log[N[Sqrt[N[(N / N[(N + 1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]], $MachinePrecision])), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\log \left(N + 1\right) - \log N \leq 2 \cdot 10^{-7}:\\
\;\;\;\;\frac{1}{N} + \left(\frac{0.3333333333333333}{{N}^{3}} - \frac{0.5}{N \cdot N}\right)\\

\mathbf{else}:\\
\;\;\;\;2 \cdot \left(-\log \left(\sqrt{\frac{N}{N + 1}}\right)\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (-.f64 (log.f64 (+.f64 N 1)) (log.f64 N)) < 1.9999999999999999e-7

    1. Initial program 6.9%

      \[\log \left(N + 1\right) - \log N \]
    2. Step-by-step derivation
      1. +-commutative6.9%

        \[\leadsto \log \color{blue}{\left(1 + N\right)} - \log N \]
      2. log1p-def6.9%

        \[\leadsto \color{blue}{\mathsf{log1p}\left(N\right)} - \log N \]
    3. Simplified6.9%

      \[\leadsto \color{blue}{\mathsf{log1p}\left(N\right) - \log N} \]
    4. Taylor expanded in N around inf 100.0%

      \[\leadsto \color{blue}{\left(\frac{1}{N} + 0.3333333333333333 \cdot \frac{1}{{N}^{3}}\right) - 0.5 \cdot \frac{1}{{N}^{2}}} \]
    5. Step-by-step derivation
      1. associate--l+100.0%

        \[\leadsto \color{blue}{\frac{1}{N} + \left(0.3333333333333333 \cdot \frac{1}{{N}^{3}} - 0.5 \cdot \frac{1}{{N}^{2}}\right)} \]
      2. associate-*r/100.0%

        \[\leadsto \frac{1}{N} + \left(\color{blue}{\frac{0.3333333333333333 \cdot 1}{{N}^{3}}} - 0.5 \cdot \frac{1}{{N}^{2}}\right) \]
      3. metadata-eval100.0%

        \[\leadsto \frac{1}{N} + \left(\frac{\color{blue}{0.3333333333333333}}{{N}^{3}} - 0.5 \cdot \frac{1}{{N}^{2}}\right) \]
      4. associate-*r/100.0%

        \[\leadsto \frac{1}{N} + \left(\frac{0.3333333333333333}{{N}^{3}} - \color{blue}{\frac{0.5 \cdot 1}{{N}^{2}}}\right) \]
      5. metadata-eval100.0%

        \[\leadsto \frac{1}{N} + \left(\frac{0.3333333333333333}{{N}^{3}} - \frac{\color{blue}{0.5}}{{N}^{2}}\right) \]
      6. unpow2100.0%

        \[\leadsto \frac{1}{N} + \left(\frac{0.3333333333333333}{{N}^{3}} - \frac{0.5}{\color{blue}{N \cdot N}}\right) \]
    6. Simplified100.0%

      \[\leadsto \color{blue}{\frac{1}{N} + \left(\frac{0.3333333333333333}{{N}^{3}} - \frac{0.5}{N \cdot N}\right)} \]

    if 1.9999999999999999e-7 < (-.f64 (log.f64 (+.f64 N 1)) (log.f64 N))

    1. Initial program 99.9%

      \[\log \left(N + 1\right) - \log N \]
    2. Step-by-step derivation
      1. +-commutative99.9%

        \[\leadsto \log \color{blue}{\left(1 + N\right)} - \log N \]
      2. log1p-def99.9%

        \[\leadsto \color{blue}{\mathsf{log1p}\left(N\right)} - \log N \]
    3. Simplified99.9%

      \[\leadsto \color{blue}{\mathsf{log1p}\left(N\right) - \log N} \]
    4. Step-by-step derivation
      1. log1p-udef99.9%

        \[\leadsto \color{blue}{\log \left(1 + N\right)} - \log N \]
      2. diff-log99.9%

        \[\leadsto \color{blue}{\log \left(\frac{1 + N}{N}\right)} \]
      3. +-commutative99.9%

        \[\leadsto \log \left(\frac{\color{blue}{N + 1}}{N}\right) \]
    5. Applied egg-rr99.9%

      \[\leadsto \color{blue}{\log \left(\frac{N + 1}{N}\right)} \]
    6. Step-by-step derivation
      1. clear-num99.9%

        \[\leadsto \log \color{blue}{\left(\frac{1}{\frac{N}{N + 1}}\right)} \]
      2. log-div99.9%

        \[\leadsto \color{blue}{\log 1 - \log \left(\frac{N}{N + 1}\right)} \]
      3. metadata-eval99.9%

        \[\leadsto \color{blue}{0} - \log \left(\frac{N}{N + 1}\right) \]
    7. Applied egg-rr99.9%

      \[\leadsto \color{blue}{0 - \log \left(\frac{N}{N + 1}\right)} \]
    8. Step-by-step derivation
      1. neg-sub099.9%

        \[\leadsto \color{blue}{-\log \left(\frac{N}{N + 1}\right)} \]
    9. Simplified99.9%

      \[\leadsto \color{blue}{-\log \left(\frac{N}{N + 1}\right)} \]
    10. Step-by-step derivation
      1. add-sqr-sqrt99.9%

        \[\leadsto -\log \color{blue}{\left(\sqrt{\frac{N}{N + 1}} \cdot \sqrt{\frac{N}{N + 1}}\right)} \]
      2. log-prod100.0%

        \[\leadsto -\color{blue}{\left(\log \left(\sqrt{\frac{N}{N + 1}}\right) + \log \left(\sqrt{\frac{N}{N + 1}}\right)\right)} \]
    11. Applied egg-rr100.0%

      \[\leadsto -\color{blue}{\left(\log \left(\sqrt{\frac{N}{N + 1}}\right) + \log \left(\sqrt{\frac{N}{N + 1}}\right)\right)} \]
    12. Step-by-step derivation
      1. count-2100.0%

        \[\leadsto -\color{blue}{2 \cdot \log \left(\sqrt{\frac{N}{N + 1}}\right)} \]
    13. Simplified100.0%

      \[\leadsto -\color{blue}{2 \cdot \log \left(\sqrt{\frac{N}{N + 1}}\right)} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification100.0%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\log \left(N + 1\right) - \log N \leq 2 \cdot 10^{-7}:\\ \;\;\;\;\frac{1}{N} + \left(\frac{0.3333333333333333}{{N}^{3}} - \frac{0.5}{N \cdot N}\right)\\ \mathbf{else}:\\ \;\;\;\;2 \cdot \left(-\log \left(\sqrt{\frac{N}{N + 1}}\right)\right)\\ \end{array} \]

Alternative 2: 99.8% accurate, 0.6× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\log \left(N + 1\right) - \log N \leq 2 \cdot 10^{-7}:\\ \;\;\;\;\frac{1}{N} + \left(\frac{0.3333333333333333}{{N}^{3}} - \frac{0.5}{N \cdot N}\right)\\ \mathbf{else}:\\ \;\;\;\;-\log \left(\frac{N}{N + 1}\right)\\ \end{array} \end{array} \]
(FPCore (N)
 :precision binary64
 (if (<= (- (log (+ N 1.0)) (log N)) 2e-7)
   (+ (/ 1.0 N) (- (/ 0.3333333333333333 (pow N 3.0)) (/ 0.5 (* N N))))
   (- (log (/ N (+ N 1.0))))))
double code(double N) {
	double tmp;
	if ((log((N + 1.0)) - log(N)) <= 2e-7) {
		tmp = (1.0 / N) + ((0.3333333333333333 / pow(N, 3.0)) - (0.5 / (N * N)));
	} else {
		tmp = -log((N / (N + 1.0)));
	}
	return tmp;
}
real(8) function code(n)
    real(8), intent (in) :: n
    real(8) :: tmp
    if ((log((n + 1.0d0)) - log(n)) <= 2d-7) then
        tmp = (1.0d0 / n) + ((0.3333333333333333d0 / (n ** 3.0d0)) - (0.5d0 / (n * n)))
    else
        tmp = -log((n / (n + 1.0d0)))
    end if
    code = tmp
end function
public static double code(double N) {
	double tmp;
	if ((Math.log((N + 1.0)) - Math.log(N)) <= 2e-7) {
		tmp = (1.0 / N) + ((0.3333333333333333 / Math.pow(N, 3.0)) - (0.5 / (N * N)));
	} else {
		tmp = -Math.log((N / (N + 1.0)));
	}
	return tmp;
}
def code(N):
	tmp = 0
	if (math.log((N + 1.0)) - math.log(N)) <= 2e-7:
		tmp = (1.0 / N) + ((0.3333333333333333 / math.pow(N, 3.0)) - (0.5 / (N * N)))
	else:
		tmp = -math.log((N / (N + 1.0)))
	return tmp
function code(N)
	tmp = 0.0
	if (Float64(log(Float64(N + 1.0)) - log(N)) <= 2e-7)
		tmp = Float64(Float64(1.0 / N) + Float64(Float64(0.3333333333333333 / (N ^ 3.0)) - Float64(0.5 / Float64(N * N))));
	else
		tmp = Float64(-log(Float64(N / Float64(N + 1.0))));
	end
	return tmp
end
function tmp_2 = code(N)
	tmp = 0.0;
	if ((log((N + 1.0)) - log(N)) <= 2e-7)
		tmp = (1.0 / N) + ((0.3333333333333333 / (N ^ 3.0)) - (0.5 / (N * N)));
	else
		tmp = -log((N / (N + 1.0)));
	end
	tmp_2 = tmp;
end
code[N_] := If[LessEqual[N[(N[Log[N[(N + 1.0), $MachinePrecision]], $MachinePrecision] - N[Log[N], $MachinePrecision]), $MachinePrecision], 2e-7], N[(N[(1.0 / N), $MachinePrecision] + N[(N[(0.3333333333333333 / N[Power[N, 3.0], $MachinePrecision]), $MachinePrecision] - N[(0.5 / N[(N * N), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], (-N[Log[N[(N / N[(N + 1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision])]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\log \left(N + 1\right) - \log N \leq 2 \cdot 10^{-7}:\\
\;\;\;\;\frac{1}{N} + \left(\frac{0.3333333333333333}{{N}^{3}} - \frac{0.5}{N \cdot N}\right)\\

\mathbf{else}:\\
\;\;\;\;-\log \left(\frac{N}{N + 1}\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (-.f64 (log.f64 (+.f64 N 1)) (log.f64 N)) < 1.9999999999999999e-7

    1. Initial program 6.9%

      \[\log \left(N + 1\right) - \log N \]
    2. Step-by-step derivation
      1. +-commutative6.9%

        \[\leadsto \log \color{blue}{\left(1 + N\right)} - \log N \]
      2. log1p-def6.9%

        \[\leadsto \color{blue}{\mathsf{log1p}\left(N\right)} - \log N \]
    3. Simplified6.9%

      \[\leadsto \color{blue}{\mathsf{log1p}\left(N\right) - \log N} \]
    4. Taylor expanded in N around inf 100.0%

      \[\leadsto \color{blue}{\left(\frac{1}{N} + 0.3333333333333333 \cdot \frac{1}{{N}^{3}}\right) - 0.5 \cdot \frac{1}{{N}^{2}}} \]
    5. Step-by-step derivation
      1. associate--l+100.0%

        \[\leadsto \color{blue}{\frac{1}{N} + \left(0.3333333333333333 \cdot \frac{1}{{N}^{3}} - 0.5 \cdot \frac{1}{{N}^{2}}\right)} \]
      2. associate-*r/100.0%

        \[\leadsto \frac{1}{N} + \left(\color{blue}{\frac{0.3333333333333333 \cdot 1}{{N}^{3}}} - 0.5 \cdot \frac{1}{{N}^{2}}\right) \]
      3. metadata-eval100.0%

        \[\leadsto \frac{1}{N} + \left(\frac{\color{blue}{0.3333333333333333}}{{N}^{3}} - 0.5 \cdot \frac{1}{{N}^{2}}\right) \]
      4. associate-*r/100.0%

        \[\leadsto \frac{1}{N} + \left(\frac{0.3333333333333333}{{N}^{3}} - \color{blue}{\frac{0.5 \cdot 1}{{N}^{2}}}\right) \]
      5. metadata-eval100.0%

        \[\leadsto \frac{1}{N} + \left(\frac{0.3333333333333333}{{N}^{3}} - \frac{\color{blue}{0.5}}{{N}^{2}}\right) \]
      6. unpow2100.0%

        \[\leadsto \frac{1}{N} + \left(\frac{0.3333333333333333}{{N}^{3}} - \frac{0.5}{\color{blue}{N \cdot N}}\right) \]
    6. Simplified100.0%

      \[\leadsto \color{blue}{\frac{1}{N} + \left(\frac{0.3333333333333333}{{N}^{3}} - \frac{0.5}{N \cdot N}\right)} \]

    if 1.9999999999999999e-7 < (-.f64 (log.f64 (+.f64 N 1)) (log.f64 N))

    1. Initial program 99.9%

      \[\log \left(N + 1\right) - \log N \]
    2. Step-by-step derivation
      1. +-commutative99.9%

        \[\leadsto \log \color{blue}{\left(1 + N\right)} - \log N \]
      2. log1p-def99.9%

        \[\leadsto \color{blue}{\mathsf{log1p}\left(N\right)} - \log N \]
    3. Simplified99.9%

      \[\leadsto \color{blue}{\mathsf{log1p}\left(N\right) - \log N} \]
    4. Step-by-step derivation
      1. log1p-udef99.9%

        \[\leadsto \color{blue}{\log \left(1 + N\right)} - \log N \]
      2. diff-log99.9%

        \[\leadsto \color{blue}{\log \left(\frac{1 + N}{N}\right)} \]
      3. +-commutative99.9%

        \[\leadsto \log \left(\frac{\color{blue}{N + 1}}{N}\right) \]
    5. Applied egg-rr99.9%

      \[\leadsto \color{blue}{\log \left(\frac{N + 1}{N}\right)} \]
    6. Step-by-step derivation
      1. clear-num99.9%

        \[\leadsto \log \color{blue}{\left(\frac{1}{\frac{N}{N + 1}}\right)} \]
      2. log-div99.9%

        \[\leadsto \color{blue}{\log 1 - \log \left(\frac{N}{N + 1}\right)} \]
      3. metadata-eval99.9%

        \[\leadsto \color{blue}{0} - \log \left(\frac{N}{N + 1}\right) \]
    7. Applied egg-rr99.9%

      \[\leadsto \color{blue}{0 - \log \left(\frac{N}{N + 1}\right)} \]
    8. Step-by-step derivation
      1. neg-sub099.9%

        \[\leadsto \color{blue}{-\log \left(\frac{N}{N + 1}\right)} \]
    9. Simplified99.9%

      \[\leadsto \color{blue}{-\log \left(\frac{N}{N + 1}\right)} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification100.0%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\log \left(N + 1\right) - \log N \leq 2 \cdot 10^{-7}:\\ \;\;\;\;\frac{1}{N} + \left(\frac{0.3333333333333333}{{N}^{3}} - \frac{0.5}{N \cdot N}\right)\\ \mathbf{else}:\\ \;\;\;\;-\log \left(\frac{N}{N + 1}\right)\\ \end{array} \]

Alternative 3: 99.8% accurate, 1.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;N \leq 240000:\\ \;\;\;\;-\log \left(\frac{N}{N + 1}\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{1}{N} - \frac{\frac{0.5}{N}}{N}\\ \end{array} \end{array} \]
(FPCore (N)
 :precision binary64
 (if (<= N 240000.0) (- (log (/ N (+ N 1.0)))) (- (/ 1.0 N) (/ (/ 0.5 N) N))))
double code(double N) {
	double tmp;
	if (N <= 240000.0) {
		tmp = -log((N / (N + 1.0)));
	} else {
		tmp = (1.0 / N) - ((0.5 / N) / N);
	}
	return tmp;
}
real(8) function code(n)
    real(8), intent (in) :: n
    real(8) :: tmp
    if (n <= 240000.0d0) then
        tmp = -log((n / (n + 1.0d0)))
    else
        tmp = (1.0d0 / n) - ((0.5d0 / n) / n)
    end if
    code = tmp
end function
public static double code(double N) {
	double tmp;
	if (N <= 240000.0) {
		tmp = -Math.log((N / (N + 1.0)));
	} else {
		tmp = (1.0 / N) - ((0.5 / N) / N);
	}
	return tmp;
}
def code(N):
	tmp = 0
	if N <= 240000.0:
		tmp = -math.log((N / (N + 1.0)))
	else:
		tmp = (1.0 / N) - ((0.5 / N) / N)
	return tmp
function code(N)
	tmp = 0.0
	if (N <= 240000.0)
		tmp = Float64(-log(Float64(N / Float64(N + 1.0))));
	else
		tmp = Float64(Float64(1.0 / N) - Float64(Float64(0.5 / N) / N));
	end
	return tmp
end
function tmp_2 = code(N)
	tmp = 0.0;
	if (N <= 240000.0)
		tmp = -log((N / (N + 1.0)));
	else
		tmp = (1.0 / N) - ((0.5 / N) / N);
	end
	tmp_2 = tmp;
end
code[N_] := If[LessEqual[N, 240000.0], (-N[Log[N[(N / N[(N + 1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), N[(N[(1.0 / N), $MachinePrecision] - N[(N[(0.5 / N), $MachinePrecision] / N), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;N \leq 240000:\\
\;\;\;\;-\log \left(\frac{N}{N + 1}\right)\\

\mathbf{else}:\\
\;\;\;\;\frac{1}{N} - \frac{\frac{0.5}{N}}{N}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if N < 2.4e5

    1. Initial program 99.9%

      \[\log \left(N + 1\right) - \log N \]
    2. Step-by-step derivation
      1. +-commutative99.9%

        \[\leadsto \log \color{blue}{\left(1 + N\right)} - \log N \]
      2. log1p-def99.9%

        \[\leadsto \color{blue}{\mathsf{log1p}\left(N\right)} - \log N \]
    3. Simplified99.9%

      \[\leadsto \color{blue}{\mathsf{log1p}\left(N\right) - \log N} \]
    4. Step-by-step derivation
      1. log1p-udef99.9%

        \[\leadsto \color{blue}{\log \left(1 + N\right)} - \log N \]
      2. diff-log99.9%

        \[\leadsto \color{blue}{\log \left(\frac{1 + N}{N}\right)} \]
      3. +-commutative99.9%

        \[\leadsto \log \left(\frac{\color{blue}{N + 1}}{N}\right) \]
    5. Applied egg-rr99.9%

      \[\leadsto \color{blue}{\log \left(\frac{N + 1}{N}\right)} \]
    6. Step-by-step derivation
      1. clear-num99.9%

        \[\leadsto \log \color{blue}{\left(\frac{1}{\frac{N}{N + 1}}\right)} \]
      2. log-div99.9%

        \[\leadsto \color{blue}{\log 1 - \log \left(\frac{N}{N + 1}\right)} \]
      3. metadata-eval99.9%

        \[\leadsto \color{blue}{0} - \log \left(\frac{N}{N + 1}\right) \]
    7. Applied egg-rr99.9%

      \[\leadsto \color{blue}{0 - \log \left(\frac{N}{N + 1}\right)} \]
    8. Step-by-step derivation
      1. neg-sub099.9%

        \[\leadsto \color{blue}{-\log \left(\frac{N}{N + 1}\right)} \]
    9. Simplified99.9%

      \[\leadsto \color{blue}{-\log \left(\frac{N}{N + 1}\right)} \]

    if 2.4e5 < N

    1. Initial program 6.9%

      \[\log \left(N + 1\right) - \log N \]
    2. Step-by-step derivation
      1. +-commutative6.9%

        \[\leadsto \log \color{blue}{\left(1 + N\right)} - \log N \]
      2. log1p-def6.9%

        \[\leadsto \color{blue}{\mathsf{log1p}\left(N\right)} - \log N \]
    3. Simplified6.9%

      \[\leadsto \color{blue}{\mathsf{log1p}\left(N\right) - \log N} \]
    4. Taylor expanded in N around inf 99.8%

      \[\leadsto \color{blue}{\frac{1}{N} - 0.5 \cdot \frac{1}{{N}^{2}}} \]
    5. Step-by-step derivation
      1. associate-*r/99.8%

        \[\leadsto \frac{1}{N} - \color{blue}{\frac{0.5 \cdot 1}{{N}^{2}}} \]
      2. metadata-eval99.8%

        \[\leadsto \frac{1}{N} - \frac{\color{blue}{0.5}}{{N}^{2}} \]
      3. unpow299.8%

        \[\leadsto \frac{1}{N} - \frac{0.5}{\color{blue}{N \cdot N}} \]
      4. associate-/r*99.8%

        \[\leadsto \frac{1}{N} - \color{blue}{\frac{\frac{0.5}{N}}{N}} \]
    6. Simplified99.8%

      \[\leadsto \color{blue}{\frac{1}{N} - \frac{\frac{0.5}{N}}{N}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification99.9%

    \[\leadsto \begin{array}{l} \mathbf{if}\;N \leq 240000:\\ \;\;\;\;-\log \left(\frac{N}{N + 1}\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{1}{N} - \frac{\frac{0.5}{N}}{N}\\ \end{array} \]

Alternative 4: 99.8% accurate, 1.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;N \leq 205000:\\ \;\;\;\;\log \left(\frac{N + 1}{N}\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{1}{N} - \frac{\frac{0.5}{N}}{N}\\ \end{array} \end{array} \]
(FPCore (N)
 :precision binary64
 (if (<= N 205000.0) (log (/ (+ N 1.0) N)) (- (/ 1.0 N) (/ (/ 0.5 N) N))))
double code(double N) {
	double tmp;
	if (N <= 205000.0) {
		tmp = log(((N + 1.0) / N));
	} else {
		tmp = (1.0 / N) - ((0.5 / N) / N);
	}
	return tmp;
}
real(8) function code(n)
    real(8), intent (in) :: n
    real(8) :: tmp
    if (n <= 205000.0d0) then
        tmp = log(((n + 1.0d0) / n))
    else
        tmp = (1.0d0 / n) - ((0.5d0 / n) / n)
    end if
    code = tmp
end function
public static double code(double N) {
	double tmp;
	if (N <= 205000.0) {
		tmp = Math.log(((N + 1.0) / N));
	} else {
		tmp = (1.0 / N) - ((0.5 / N) / N);
	}
	return tmp;
}
def code(N):
	tmp = 0
	if N <= 205000.0:
		tmp = math.log(((N + 1.0) / N))
	else:
		tmp = (1.0 / N) - ((0.5 / N) / N)
	return tmp
function code(N)
	tmp = 0.0
	if (N <= 205000.0)
		tmp = log(Float64(Float64(N + 1.0) / N));
	else
		tmp = Float64(Float64(1.0 / N) - Float64(Float64(0.5 / N) / N));
	end
	return tmp
end
function tmp_2 = code(N)
	tmp = 0.0;
	if (N <= 205000.0)
		tmp = log(((N + 1.0) / N));
	else
		tmp = (1.0 / N) - ((0.5 / N) / N);
	end
	tmp_2 = tmp;
end
code[N_] := If[LessEqual[N, 205000.0], N[Log[N[(N[(N + 1.0), $MachinePrecision] / N), $MachinePrecision]], $MachinePrecision], N[(N[(1.0 / N), $MachinePrecision] - N[(N[(0.5 / N), $MachinePrecision] / N), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;N \leq 205000:\\
\;\;\;\;\log \left(\frac{N + 1}{N}\right)\\

\mathbf{else}:\\
\;\;\;\;\frac{1}{N} - \frac{\frac{0.5}{N}}{N}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if N < 205000

    1. Initial program 99.9%

      \[\log \left(N + 1\right) - \log N \]
    2. Step-by-step derivation
      1. +-commutative99.9%

        \[\leadsto \log \color{blue}{\left(1 + N\right)} - \log N \]
      2. log1p-def99.9%

        \[\leadsto \color{blue}{\mathsf{log1p}\left(N\right)} - \log N \]
    3. Simplified99.9%

      \[\leadsto \color{blue}{\mathsf{log1p}\left(N\right) - \log N} \]
    4. Step-by-step derivation
      1. log1p-udef99.9%

        \[\leadsto \color{blue}{\log \left(1 + N\right)} - \log N \]
      2. diff-log99.9%

        \[\leadsto \color{blue}{\log \left(\frac{1 + N}{N}\right)} \]
      3. +-commutative99.9%

        \[\leadsto \log \left(\frac{\color{blue}{N + 1}}{N}\right) \]
    5. Applied egg-rr99.9%

      \[\leadsto \color{blue}{\log \left(\frac{N + 1}{N}\right)} \]

    if 205000 < N

    1. Initial program 6.9%

      \[\log \left(N + 1\right) - \log N \]
    2. Step-by-step derivation
      1. +-commutative6.9%

        \[\leadsto \log \color{blue}{\left(1 + N\right)} - \log N \]
      2. log1p-def6.9%

        \[\leadsto \color{blue}{\mathsf{log1p}\left(N\right)} - \log N \]
    3. Simplified6.9%

      \[\leadsto \color{blue}{\mathsf{log1p}\left(N\right) - \log N} \]
    4. Taylor expanded in N around inf 99.8%

      \[\leadsto \color{blue}{\frac{1}{N} - 0.5 \cdot \frac{1}{{N}^{2}}} \]
    5. Step-by-step derivation
      1. associate-*r/99.8%

        \[\leadsto \frac{1}{N} - \color{blue}{\frac{0.5 \cdot 1}{{N}^{2}}} \]
      2. metadata-eval99.8%

        \[\leadsto \frac{1}{N} - \frac{\color{blue}{0.5}}{{N}^{2}} \]
      3. unpow299.8%

        \[\leadsto \frac{1}{N} - \frac{0.5}{\color{blue}{N \cdot N}} \]
      4. associate-/r*99.8%

        \[\leadsto \frac{1}{N} - \color{blue}{\frac{\frac{0.5}{N}}{N}} \]
    6. Simplified99.8%

      \[\leadsto \color{blue}{\frac{1}{N} - \frac{\frac{0.5}{N}}{N}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification99.9%

    \[\leadsto \begin{array}{l} \mathbf{if}\;N \leq 205000:\\ \;\;\;\;\log \left(\frac{N + 1}{N}\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{1}{N} - \frac{\frac{0.5}{N}}{N}\\ \end{array} \]

Alternative 5: 99.0% accurate, 2.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;N \leq 0.9:\\ \;\;\;\;N - \log N\\ \mathbf{else}:\\ \;\;\;\;\frac{1}{N} - \frac{\frac{0.5}{N}}{N}\\ \end{array} \end{array} \]
(FPCore (N)
 :precision binary64
 (if (<= N 0.9) (- N (log N)) (- (/ 1.0 N) (/ (/ 0.5 N) N))))
double code(double N) {
	double tmp;
	if (N <= 0.9) {
		tmp = N - log(N);
	} else {
		tmp = (1.0 / N) - ((0.5 / N) / N);
	}
	return tmp;
}
real(8) function code(n)
    real(8), intent (in) :: n
    real(8) :: tmp
    if (n <= 0.9d0) then
        tmp = n - log(n)
    else
        tmp = (1.0d0 / n) - ((0.5d0 / n) / n)
    end if
    code = tmp
end function
public static double code(double N) {
	double tmp;
	if (N <= 0.9) {
		tmp = N - Math.log(N);
	} else {
		tmp = (1.0 / N) - ((0.5 / N) / N);
	}
	return tmp;
}
def code(N):
	tmp = 0
	if N <= 0.9:
		tmp = N - math.log(N)
	else:
		tmp = (1.0 / N) - ((0.5 / N) / N)
	return tmp
function code(N)
	tmp = 0.0
	if (N <= 0.9)
		tmp = Float64(N - log(N));
	else
		tmp = Float64(Float64(1.0 / N) - Float64(Float64(0.5 / N) / N));
	end
	return tmp
end
function tmp_2 = code(N)
	tmp = 0.0;
	if (N <= 0.9)
		tmp = N - log(N);
	else
		tmp = (1.0 / N) - ((0.5 / N) / N);
	end
	tmp_2 = tmp;
end
code[N_] := If[LessEqual[N, 0.9], N[(N - N[Log[N], $MachinePrecision]), $MachinePrecision], N[(N[(1.0 / N), $MachinePrecision] - N[(N[(0.5 / N), $MachinePrecision] / N), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;N \leq 0.9:\\
\;\;\;\;N - \log N\\

\mathbf{else}:\\
\;\;\;\;\frac{1}{N} - \frac{\frac{0.5}{N}}{N}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if N < 0.900000000000000022

    1. Initial program 100.0%

      \[\log \left(N + 1\right) - \log N \]
    2. Step-by-step derivation
      1. +-commutative100.0%

        \[\leadsto \log \color{blue}{\left(1 + N\right)} - \log N \]
      2. log1p-def100.0%

        \[\leadsto \color{blue}{\mathsf{log1p}\left(N\right)} - \log N \]
    3. Simplified100.0%

      \[\leadsto \color{blue}{\mathsf{log1p}\left(N\right) - \log N} \]
    4. Taylor expanded in N around 0 99.5%

      \[\leadsto \color{blue}{N + -1 \cdot \log N} \]
    5. Step-by-step derivation
      1. neg-mul-199.5%

        \[\leadsto N + \color{blue}{\left(-\log N\right)} \]
      2. unsub-neg99.5%

        \[\leadsto \color{blue}{N - \log N} \]
    6. Simplified99.5%

      \[\leadsto \color{blue}{N - \log N} \]

    if 0.900000000000000022 < N

    1. Initial program 7.6%

      \[\log \left(N + 1\right) - \log N \]
    2. Step-by-step derivation
      1. +-commutative7.6%

        \[\leadsto \log \color{blue}{\left(1 + N\right)} - \log N \]
      2. log1p-def7.6%

        \[\leadsto \color{blue}{\mathsf{log1p}\left(N\right)} - \log N \]
    3. Simplified7.6%

      \[\leadsto \color{blue}{\mathsf{log1p}\left(N\right) - \log N} \]
    4. Taylor expanded in N around inf 99.3%

      \[\leadsto \color{blue}{\frac{1}{N} - 0.5 \cdot \frac{1}{{N}^{2}}} \]
    5. Step-by-step derivation
      1. associate-*r/99.3%

        \[\leadsto \frac{1}{N} - \color{blue}{\frac{0.5 \cdot 1}{{N}^{2}}} \]
      2. metadata-eval99.3%

        \[\leadsto \frac{1}{N} - \frac{\color{blue}{0.5}}{{N}^{2}} \]
      3. unpow299.3%

        \[\leadsto \frac{1}{N} - \frac{0.5}{\color{blue}{N \cdot N}} \]
      4. associate-/r*99.3%

        \[\leadsto \frac{1}{N} - \color{blue}{\frac{\frac{0.5}{N}}{N}} \]
    6. Simplified99.3%

      \[\leadsto \color{blue}{\frac{1}{N} - \frac{\frac{0.5}{N}}{N}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification99.4%

    \[\leadsto \begin{array}{l} \mathbf{if}\;N \leq 0.9:\\ \;\;\;\;N - \log N\\ \mathbf{else}:\\ \;\;\;\;\frac{1}{N} - \frac{\frac{0.5}{N}}{N}\\ \end{array} \]

Alternative 6: 98.6% accurate, 2.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;N \leq 0.65:\\ \;\;\;\;-\log N\\ \mathbf{else}:\\ \;\;\;\;\frac{1}{N} - \frac{\frac{0.5}{N}}{N}\\ \end{array} \end{array} \]
(FPCore (N)
 :precision binary64
 (if (<= N 0.65) (- (log N)) (- (/ 1.0 N) (/ (/ 0.5 N) N))))
double code(double N) {
	double tmp;
	if (N <= 0.65) {
		tmp = -log(N);
	} else {
		tmp = (1.0 / N) - ((0.5 / N) / N);
	}
	return tmp;
}
real(8) function code(n)
    real(8), intent (in) :: n
    real(8) :: tmp
    if (n <= 0.65d0) then
        tmp = -log(n)
    else
        tmp = (1.0d0 / n) - ((0.5d0 / n) / n)
    end if
    code = tmp
end function
public static double code(double N) {
	double tmp;
	if (N <= 0.65) {
		tmp = -Math.log(N);
	} else {
		tmp = (1.0 / N) - ((0.5 / N) / N);
	}
	return tmp;
}
def code(N):
	tmp = 0
	if N <= 0.65:
		tmp = -math.log(N)
	else:
		tmp = (1.0 / N) - ((0.5 / N) / N)
	return tmp
function code(N)
	tmp = 0.0
	if (N <= 0.65)
		tmp = Float64(-log(N));
	else
		tmp = Float64(Float64(1.0 / N) - Float64(Float64(0.5 / N) / N));
	end
	return tmp
end
function tmp_2 = code(N)
	tmp = 0.0;
	if (N <= 0.65)
		tmp = -log(N);
	else
		tmp = (1.0 / N) - ((0.5 / N) / N);
	end
	tmp_2 = tmp;
end
code[N_] := If[LessEqual[N, 0.65], (-N[Log[N], $MachinePrecision]), N[(N[(1.0 / N), $MachinePrecision] - N[(N[(0.5 / N), $MachinePrecision] / N), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;N \leq 0.65:\\
\;\;\;\;-\log N\\

\mathbf{else}:\\
\;\;\;\;\frac{1}{N} - \frac{\frac{0.5}{N}}{N}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if N < 0.650000000000000022

    1. Initial program 100.0%

      \[\log \left(N + 1\right) - \log N \]
    2. Step-by-step derivation
      1. +-commutative100.0%

        \[\leadsto \log \color{blue}{\left(1 + N\right)} - \log N \]
      2. log1p-def100.0%

        \[\leadsto \color{blue}{\mathsf{log1p}\left(N\right)} - \log N \]
    3. Simplified100.0%

      \[\leadsto \color{blue}{\mathsf{log1p}\left(N\right) - \log N} \]
    4. Taylor expanded in N around 0 98.1%

      \[\leadsto \color{blue}{-1 \cdot \log N} \]
    5. Step-by-step derivation
      1. neg-mul-198.1%

        \[\leadsto \color{blue}{-\log N} \]
    6. Simplified98.1%

      \[\leadsto \color{blue}{-\log N} \]

    if 0.650000000000000022 < N

    1. Initial program 7.6%

      \[\log \left(N + 1\right) - \log N \]
    2. Step-by-step derivation
      1. +-commutative7.6%

        \[\leadsto \log \color{blue}{\left(1 + N\right)} - \log N \]
      2. log1p-def7.6%

        \[\leadsto \color{blue}{\mathsf{log1p}\left(N\right)} - \log N \]
    3. Simplified7.6%

      \[\leadsto \color{blue}{\mathsf{log1p}\left(N\right) - \log N} \]
    4. Taylor expanded in N around inf 99.3%

      \[\leadsto \color{blue}{\frac{1}{N} - 0.5 \cdot \frac{1}{{N}^{2}}} \]
    5. Step-by-step derivation
      1. associate-*r/99.3%

        \[\leadsto \frac{1}{N} - \color{blue}{\frac{0.5 \cdot 1}{{N}^{2}}} \]
      2. metadata-eval99.3%

        \[\leadsto \frac{1}{N} - \frac{\color{blue}{0.5}}{{N}^{2}} \]
      3. unpow299.3%

        \[\leadsto \frac{1}{N} - \frac{0.5}{\color{blue}{N \cdot N}} \]
      4. associate-/r*99.3%

        \[\leadsto \frac{1}{N} - \color{blue}{\frac{\frac{0.5}{N}}{N}} \]
    6. Simplified99.3%

      \[\leadsto \color{blue}{\frac{1}{N} - \frac{\frac{0.5}{N}}{N}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification98.6%

    \[\leadsto \begin{array}{l} \mathbf{if}\;N \leq 0.65:\\ \;\;\;\;-\log N\\ \mathbf{else}:\\ \;\;\;\;\frac{1}{N} - \frac{\frac{0.5}{N}}{N}\\ \end{array} \]

Alternative 7: 52.3% accurate, 68.3× speedup?

\[\begin{array}{l} \\ \frac{1}{N} \end{array} \]
(FPCore (N) :precision binary64 (/ 1.0 N))
double code(double N) {
	return 1.0 / N;
}
real(8) function code(n)
    real(8), intent (in) :: n
    code = 1.0d0 / n
end function
public static double code(double N) {
	return 1.0 / N;
}
def code(N):
	return 1.0 / N
function code(N)
	return Float64(1.0 / N)
end
function tmp = code(N)
	tmp = 1.0 / N;
end
code[N_] := N[(1.0 / N), $MachinePrecision]
\begin{array}{l}

\\
\frac{1}{N}
\end{array}
Derivation
  1. Initial program 59.2%

    \[\log \left(N + 1\right) - \log N \]
  2. Step-by-step derivation
    1. +-commutative59.2%

      \[\leadsto \log \color{blue}{\left(1 + N\right)} - \log N \]
    2. log1p-def59.2%

      \[\leadsto \color{blue}{\mathsf{log1p}\left(N\right)} - \log N \]
  3. Simplified59.2%

    \[\leadsto \color{blue}{\mathsf{log1p}\left(N\right) - \log N} \]
  4. Taylor expanded in N around inf 46.4%

    \[\leadsto \color{blue}{\frac{1}{N}} \]
  5. Final simplification46.4%

    \[\leadsto \frac{1}{N} \]

Alternative 8: 1.9% accurate, 205.0× speedup?

\[\begin{array}{l} \\ -0.5 \end{array} \]
(FPCore (N) :precision binary64 -0.5)
double code(double N) {
	return -0.5;
}
real(8) function code(n)
    real(8), intent (in) :: n
    code = -0.5d0
end function
public static double code(double N) {
	return -0.5;
}
def code(N):
	return -0.5
function code(N)
	return -0.5
end
function tmp = code(N)
	tmp = -0.5;
end
code[N_] := -0.5
\begin{array}{l}

\\
-0.5
\end{array}
Derivation
  1. Initial program 59.2%

    \[\log \left(N + 1\right) - \log N \]
  2. Step-by-step derivation
    1. +-commutative59.2%

      \[\leadsto \log \color{blue}{\left(1 + N\right)} - \log N \]
    2. log1p-def59.2%

      \[\leadsto \color{blue}{\mathsf{log1p}\left(N\right)} - \log N \]
  3. Simplified59.2%

    \[\leadsto \color{blue}{\mathsf{log1p}\left(N\right) - \log N} \]
  4. Taylor expanded in N around inf 44.3%

    \[\leadsto \color{blue}{\frac{1}{N} - 0.5 \cdot \frac{1}{{N}^{2}}} \]
  5. Step-by-step derivation
    1. associate-*r/44.3%

      \[\leadsto \frac{1}{N} - \color{blue}{\frac{0.5 \cdot 1}{{N}^{2}}} \]
    2. metadata-eval44.3%

      \[\leadsto \frac{1}{N} - \frac{\color{blue}{0.5}}{{N}^{2}} \]
    3. unpow244.3%

      \[\leadsto \frac{1}{N} - \frac{0.5}{\color{blue}{N \cdot N}} \]
    4. associate-/r*44.3%

      \[\leadsto \frac{1}{N} - \color{blue}{\frac{\frac{0.5}{N}}{N}} \]
  6. Simplified44.3%

    \[\leadsto \color{blue}{\frac{1}{N} - \frac{\frac{0.5}{N}}{N}} \]
  7. Step-by-step derivation
    1. sub-div44.3%

      \[\leadsto \color{blue}{\frac{1 - \frac{0.5}{N}}{N}} \]
    2. div-inv44.3%

      \[\leadsto \frac{1 - \color{blue}{0.5 \cdot \frac{1}{N}}}{N} \]
    3. cancel-sign-sub-inv44.3%

      \[\leadsto \frac{\color{blue}{1 + \left(-0.5\right) \cdot \frac{1}{N}}}{N} \]
    4. metadata-eval44.3%

      \[\leadsto \frac{1 + \color{blue}{-0.5} \cdot \frac{1}{N}}{N} \]
    5. add-exp-log44.3%

      \[\leadsto \frac{1 + -0.5 \cdot \color{blue}{e^{\log \left(\frac{1}{N}\right)}}}{N} \]
    6. neg-log44.3%

      \[\leadsto \frac{1 + -0.5 \cdot e^{\color{blue}{-\log N}}}{N} \]
    7. add-sqr-sqrt0.5%

      \[\leadsto \frac{1 + -0.5 \cdot e^{\color{blue}{\sqrt{-\log N} \cdot \sqrt{-\log N}}}}{N} \]
    8. sqrt-unprod1.5%

      \[\leadsto \frac{1 + -0.5 \cdot e^{\color{blue}{\sqrt{\left(-\log N\right) \cdot \left(-\log N\right)}}}}{N} \]
    9. sqr-neg1.5%

      \[\leadsto \frac{1 + -0.5 \cdot e^{\sqrt{\color{blue}{\log N \cdot \log N}}}}{N} \]
    10. unpow21.5%

      \[\leadsto \frac{1 + -0.5 \cdot e^{\sqrt{\color{blue}{{\log N}^{2}}}}}{N} \]
    11. unpow21.5%

      \[\leadsto \frac{1 + -0.5 \cdot e^{\sqrt{\color{blue}{\log N \cdot \log N}}}}{N} \]
    12. sqrt-prod1.0%

      \[\leadsto \frac{1 + -0.5 \cdot e^{\color{blue}{\sqrt{\log N} \cdot \sqrt{\log N}}}}{N} \]
    13. add-sqr-sqrt4.1%

      \[\leadsto \frac{1 + -0.5 \cdot e^{\color{blue}{\log N}}}{N} \]
    14. add-exp-log4.1%

      \[\leadsto \frac{1 + -0.5 \cdot \color{blue}{N}}{N} \]
  8. Applied egg-rr4.1%

    \[\leadsto \color{blue}{\frac{1 + -0.5 \cdot N}{N}} \]
  9. Step-by-step derivation
    1. *-commutative4.1%

      \[\leadsto \frac{1 + \color{blue}{N \cdot -0.5}}{N} \]
  10. Simplified4.1%

    \[\leadsto \color{blue}{\frac{1 + N \cdot -0.5}{N}} \]
  11. Taylor expanded in N around inf 1.9%

    \[\leadsto \color{blue}{-0.5} \]
  12. Final simplification1.9%

    \[\leadsto -0.5 \]

Reproduce

?
herbie shell --seed 2023273 
(FPCore (N)
  :name "2log (problem 3.3.6)"
  :precision binary64
  (- (log (+ N 1.0)) (log N)))