Average Error: 29.3 → 0.1
Time: 6.5s
Precision: binary64
Cost: 19908
\[\log \left(N + 1\right) - \log N \]
\[\begin{array}{l} \mathbf{if}\;\log \left(N + 1\right) - \log N \leq 5 \cdot 10^{-5}:\\ \;\;\;\;\frac{1}{N} + \left(\frac{-0.5}{N \cdot N} + \frac{\frac{\frac{-0.25}{N} + 0.3333333333333333}{N \cdot N}}{N}\right)\\ \mathbf{else}:\\ \;\;\;\;\log \left(\frac{N + 1}{N}\right)\\ \end{array} \]
(FPCore (N) :precision binary64 (- (log (+ N 1.0)) (log N)))
(FPCore (N)
 :precision binary64
 (if (<= (- (log (+ N 1.0)) (log N)) 5e-5)
   (+
    (/ 1.0 N)
    (+ (/ -0.5 (* N N)) (/ (/ (+ (/ -0.25 N) 0.3333333333333333) (* N N)) N)))
   (log (/ (+ N 1.0) N))))
double code(double N) {
	return log((N + 1.0)) - log(N);
}
double code(double N) {
	double tmp;
	if ((log((N + 1.0)) - log(N)) <= 5e-5) {
		tmp = (1.0 / N) + ((-0.5 / (N * N)) + ((((-0.25 / N) + 0.3333333333333333) / (N * N)) / N));
	} else {
		tmp = log(((N + 1.0) / N));
	}
	return tmp;
}
real(8) function code(n)
    real(8), intent (in) :: n
    code = log((n + 1.0d0)) - log(n)
end function
real(8) function code(n)
    real(8), intent (in) :: n
    real(8) :: tmp
    if ((log((n + 1.0d0)) - log(n)) <= 5d-5) then
        tmp = (1.0d0 / n) + (((-0.5d0) / (n * n)) + (((((-0.25d0) / n) + 0.3333333333333333d0) / (n * n)) / n))
    else
        tmp = log(((n + 1.0d0) / n))
    end if
    code = tmp
end function
public static double code(double N) {
	return Math.log((N + 1.0)) - Math.log(N);
}
public static double code(double N) {
	double tmp;
	if ((Math.log((N + 1.0)) - Math.log(N)) <= 5e-5) {
		tmp = (1.0 / N) + ((-0.5 / (N * N)) + ((((-0.25 / N) + 0.3333333333333333) / (N * N)) / N));
	} else {
		tmp = Math.log(((N + 1.0) / N));
	}
	return tmp;
}
def code(N):
	return math.log((N + 1.0)) - math.log(N)
def code(N):
	tmp = 0
	if (math.log((N + 1.0)) - math.log(N)) <= 5e-5:
		tmp = (1.0 / N) + ((-0.5 / (N * N)) + ((((-0.25 / N) + 0.3333333333333333) / (N * N)) / N))
	else:
		tmp = math.log(((N + 1.0) / N))
	return tmp
function code(N)
	return Float64(log(Float64(N + 1.0)) - log(N))
end
function code(N)
	tmp = 0.0
	if (Float64(log(Float64(N + 1.0)) - log(N)) <= 5e-5)
		tmp = Float64(Float64(1.0 / N) + Float64(Float64(-0.5 / Float64(N * N)) + Float64(Float64(Float64(Float64(-0.25 / N) + 0.3333333333333333) / Float64(N * N)) / N)));
	else
		tmp = log(Float64(Float64(N + 1.0) / N));
	end
	return tmp
end
function tmp = code(N)
	tmp = log((N + 1.0)) - log(N);
end
function tmp_2 = code(N)
	tmp = 0.0;
	if ((log((N + 1.0)) - log(N)) <= 5e-5)
		tmp = (1.0 / N) + ((-0.5 / (N * N)) + ((((-0.25 / N) + 0.3333333333333333) / (N * N)) / N));
	else
		tmp = log(((N + 1.0) / N));
	end
	tmp_2 = tmp;
end
code[N_] := N[(N[Log[N[(N + 1.0), $MachinePrecision]], $MachinePrecision] - N[Log[N], $MachinePrecision]), $MachinePrecision]
code[N_] := If[LessEqual[N[(N[Log[N[(N + 1.0), $MachinePrecision]], $MachinePrecision] - N[Log[N], $MachinePrecision]), $MachinePrecision], 5e-5], N[(N[(1.0 / N), $MachinePrecision] + N[(N[(-0.5 / N[(N * N), $MachinePrecision]), $MachinePrecision] + N[(N[(N[(N[(-0.25 / N), $MachinePrecision] + 0.3333333333333333), $MachinePrecision] / N[(N * N), $MachinePrecision]), $MachinePrecision] / N), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[Log[N[(N[(N + 1.0), $MachinePrecision] / N), $MachinePrecision]], $MachinePrecision]]
\log \left(N + 1\right) - \log N
\begin{array}{l}
\mathbf{if}\;\log \left(N + 1\right) - \log N \leq 5 \cdot 10^{-5}:\\
\;\;\;\;\frac{1}{N} + \left(\frac{-0.5}{N \cdot N} + \frac{\frac{\frac{-0.25}{N} + 0.3333333333333333}{N \cdot N}}{N}\right)\\

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


\end{array}

Error

Try it out

Your Program's Arguments

Results

Enter valid numbers for all inputs

Derivation

  1. Split input into 2 regimes
  2. if (-.f64 (log.f64 (+.f64 N 1)) (log.f64 N)) < 5.00000000000000024e-5

    1. Initial program 59.5

      \[\log \left(N + 1\right) - \log N \]
    2. Simplified59.5

      \[\leadsto \color{blue}{\mathsf{log1p}\left(N\right) - \log N} \]
      Proof
      (-.f64 (log1p.f64 N) (log.f64 N)): 0 points increase in error, 0 points decrease in error
      (-.f64 (Rewrite<= log1p-def_binary64 (log.f64 (+.f64 1 N))) (log.f64 N)): 0 points increase in error, 0 points decrease in error
      (-.f64 (log.f64 (Rewrite<= +-commutative_binary64 (+.f64 N 1))) (log.f64 N)): 0 points increase in error, 0 points decrease in error
    3. Taylor expanded in N around inf 0.0

      \[\leadsto \color{blue}{\left(\frac{1}{N} + 0.3333333333333333 \cdot \frac{1}{{N}^{3}}\right) - \left(0.25 \cdot \frac{1}{{N}^{4}} + 0.5 \cdot \frac{1}{{N}^{2}}\right)} \]
    4. Simplified0.0

      \[\leadsto \color{blue}{\frac{1}{N} + \left(\frac{-0.5}{N \cdot N} + \frac{1}{{N}^{3}} \cdot \left(\frac{-0.25}{N} + 0.3333333333333333\right)\right)} \]
      Proof
      (+.f64 (/.f64 1 N) (+.f64 (/.f64 -1/2 (*.f64 N N)) (*.f64 (/.f64 1 (pow.f64 N 3)) (+.f64 (/.f64 -1/4 N) 1/3)))): 0 points increase in error, 0 points decrease in error
      (+.f64 (/.f64 1 N) (+.f64 (/.f64 (Rewrite<= metadata-eval (neg.f64 1/2)) (*.f64 N N)) (*.f64 (/.f64 1 (pow.f64 N 3)) (+.f64 (/.f64 -1/4 N) 1/3)))): 0 points increase in error, 0 points decrease in error
      (+.f64 (/.f64 1 N) (+.f64 (/.f64 (neg.f64 1/2) (Rewrite<= unpow2_binary64 (pow.f64 N 2))) (*.f64 (/.f64 1 (pow.f64 N 3)) (+.f64 (/.f64 -1/4 N) 1/3)))): 0 points increase in error, 0 points decrease in error
      (+.f64 (/.f64 1 N) (+.f64 (Rewrite<= distribute-neg-frac_binary64 (neg.f64 (/.f64 1/2 (pow.f64 N 2)))) (*.f64 (/.f64 1 (pow.f64 N 3)) (+.f64 (/.f64 -1/4 N) 1/3)))): 0 points increase in error, 0 points decrease in error
      (+.f64 (/.f64 1 N) (+.f64 (neg.f64 (/.f64 (Rewrite<= metadata-eval (*.f64 1/2 1)) (pow.f64 N 2))) (*.f64 (/.f64 1 (pow.f64 N 3)) (+.f64 (/.f64 -1/4 N) 1/3)))): 0 points increase in error, 0 points decrease in error
      (+.f64 (/.f64 1 N) (+.f64 (neg.f64 (Rewrite<= associate-*r/_binary64 (*.f64 1/2 (/.f64 1 (pow.f64 N 2))))) (*.f64 (/.f64 1 (pow.f64 N 3)) (+.f64 (/.f64 -1/4 N) 1/3)))): 0 points increase in error, 0 points decrease in error
      (+.f64 (/.f64 1 N) (+.f64 (neg.f64 (*.f64 1/2 (/.f64 1 (pow.f64 N 2)))) (*.f64 (/.f64 1 (pow.f64 N 3)) (+.f64 (/.f64 (Rewrite<= metadata-eval (neg.f64 1/4)) N) 1/3)))): 0 points increase in error, 0 points decrease in error
      (+.f64 (/.f64 1 N) (+.f64 (neg.f64 (*.f64 1/2 (/.f64 1 (pow.f64 N 2)))) (Rewrite<= distribute-rgt-out_binary64 (+.f64 (*.f64 (/.f64 (neg.f64 1/4) N) (/.f64 1 (pow.f64 N 3))) (*.f64 1/3 (/.f64 1 (pow.f64 N 3))))))): 1 points increase in error, 3 points decrease in error
      (+.f64 (/.f64 1 N) (+.f64 (neg.f64 (*.f64 1/2 (/.f64 1 (pow.f64 N 2)))) (+.f64 (*.f64 (/.f64 (neg.f64 1/4) N) (/.f64 1 (Rewrite=> unpow3_binary64 (*.f64 (*.f64 N N) N)))) (*.f64 1/3 (/.f64 1 (pow.f64 N 3)))))): 2 points increase in error, 2 points decrease in error
      (+.f64 (/.f64 1 N) (+.f64 (neg.f64 (*.f64 1/2 (/.f64 1 (pow.f64 N 2)))) (+.f64 (*.f64 (/.f64 (neg.f64 1/4) N) (/.f64 1 (*.f64 (Rewrite<= unpow2_binary64 (pow.f64 N 2)) N))) (*.f64 1/3 (/.f64 1 (pow.f64 N 3)))))): 0 points increase in error, 0 points decrease in error
      (+.f64 (/.f64 1 N) (+.f64 (neg.f64 (*.f64 1/2 (/.f64 1 (pow.f64 N 2)))) (+.f64 (*.f64 (/.f64 (neg.f64 1/4) N) (Rewrite=> associate-/r*_binary64 (/.f64 (/.f64 1 (pow.f64 N 2)) N))) (*.f64 1/3 (/.f64 1 (pow.f64 N 3)))))): 6 points increase in error, 4 points decrease in error
      (+.f64 (/.f64 1 N) (+.f64 (neg.f64 (*.f64 1/2 (/.f64 1 (pow.f64 N 2)))) (+.f64 (Rewrite<= times-frac_binary64 (/.f64 (*.f64 (neg.f64 1/4) (/.f64 1 (pow.f64 N 2))) (*.f64 N N))) (*.f64 1/3 (/.f64 1 (pow.f64 N 3)))))): 8 points increase in error, 7 points decrease in error
      (+.f64 (/.f64 1 N) (+.f64 (neg.f64 (*.f64 1/2 (/.f64 1 (pow.f64 N 2)))) (+.f64 (/.f64 (*.f64 (neg.f64 1/4) (/.f64 1 (pow.f64 N 2))) (Rewrite<= unpow2_binary64 (pow.f64 N 2))) (*.f64 1/3 (/.f64 1 (pow.f64 N 3)))))): 0 points increase in error, 0 points decrease in error
      (+.f64 (/.f64 1 N) (+.f64 (neg.f64 (*.f64 1/2 (/.f64 1 (pow.f64 N 2)))) (+.f64 (Rewrite<= associate-*r/_binary64 (*.f64 (neg.f64 1/4) (/.f64 (/.f64 1 (pow.f64 N 2)) (pow.f64 N 2)))) (*.f64 1/3 (/.f64 1 (pow.f64 N 3)))))): 0 points increase in error, 0 points decrease in error
      (+.f64 (/.f64 1 N) (+.f64 (neg.f64 (*.f64 1/2 (/.f64 1 (pow.f64 N 2)))) (+.f64 (*.f64 (neg.f64 1/4) (Rewrite<= associate-/r*_binary64 (/.f64 1 (*.f64 (pow.f64 N 2) (pow.f64 N 2))))) (*.f64 1/3 (/.f64 1 (pow.f64 N 3)))))): 8 points increase in error, 4 points decrease in error
      (+.f64 (/.f64 1 N) (+.f64 (neg.f64 (*.f64 1/2 (/.f64 1 (pow.f64 N 2)))) (+.f64 (*.f64 (neg.f64 1/4) (/.f64 1 (Rewrite=> pow-sqr_binary64 (pow.f64 N (*.f64 2 2))))) (*.f64 1/3 (/.f64 1 (pow.f64 N 3)))))): 9 points increase in error, 4 points decrease in error
      (+.f64 (/.f64 1 N) (+.f64 (neg.f64 (*.f64 1/2 (/.f64 1 (pow.f64 N 2)))) (+.f64 (*.f64 (neg.f64 1/4) (/.f64 1 (pow.f64 N (Rewrite=> metadata-eval 4)))) (*.f64 1/3 (/.f64 1 (pow.f64 N 3)))))): 0 points increase in error, 0 points decrease in error
      (+.f64 (/.f64 1 N) (+.f64 (neg.f64 (*.f64 1/2 (/.f64 1 (pow.f64 N 2)))) (+.f64 (Rewrite<= distribute-lft-neg-in_binary64 (neg.f64 (*.f64 1/4 (/.f64 1 (pow.f64 N 4))))) (*.f64 1/3 (/.f64 1 (pow.f64 N 3)))))): 0 points increase in error, 0 points decrease in error
      (+.f64 (/.f64 1 N) (Rewrite<= associate-+l+_binary64 (+.f64 (+.f64 (neg.f64 (*.f64 1/2 (/.f64 1 (pow.f64 N 2)))) (neg.f64 (*.f64 1/4 (/.f64 1 (pow.f64 N 4))))) (*.f64 1/3 (/.f64 1 (pow.f64 N 3)))))): 0 points increase in error, 0 points decrease in error
      (+.f64 (/.f64 1 N) (+.f64 (Rewrite=> unsub-neg_binary64 (-.f64 (neg.f64 (*.f64 1/2 (/.f64 1 (pow.f64 N 2)))) (*.f64 1/4 (/.f64 1 (pow.f64 N 4))))) (*.f64 1/3 (/.f64 1 (pow.f64 N 3))))): 0 points increase in error, 0 points decrease in error
      (+.f64 (/.f64 1 N) (Rewrite=> associate-+l-_binary64 (-.f64 (neg.f64 (*.f64 1/2 (/.f64 1 (pow.f64 N 2)))) (-.f64 (*.f64 1/4 (/.f64 1 (pow.f64 N 4))) (*.f64 1/3 (/.f64 1 (pow.f64 N 3))))))): 0 points increase in error, 0 points decrease in error
      (+.f64 (/.f64 1 N) (Rewrite<= associate-+l-_binary64 (+.f64 (-.f64 (neg.f64 (*.f64 1/2 (/.f64 1 (pow.f64 N 2)))) (*.f64 1/4 (/.f64 1 (pow.f64 N 4)))) (*.f64 1/3 (/.f64 1 (pow.f64 N 3)))))): 0 points increase in error, 0 points decrease in error
      (+.f64 (/.f64 1 N) (+.f64 (Rewrite<= unsub-neg_binary64 (+.f64 (neg.f64 (*.f64 1/2 (/.f64 1 (pow.f64 N 2)))) (neg.f64 (*.f64 1/4 (/.f64 1 (pow.f64 N 4)))))) (*.f64 1/3 (/.f64 1 (pow.f64 N 3))))): 0 points increase in error, 0 points decrease in error
      (+.f64 (/.f64 1 N) (+.f64 (Rewrite<= distribute-neg-in_binary64 (neg.f64 (+.f64 (*.f64 1/2 (/.f64 1 (pow.f64 N 2))) (*.f64 1/4 (/.f64 1 (pow.f64 N 4)))))) (*.f64 1/3 (/.f64 1 (pow.f64 N 3))))): 0 points increase in error, 0 points decrease in error
      (+.f64 (/.f64 1 N) (+.f64 (neg.f64 (Rewrite<= +-commutative_binary64 (+.f64 (*.f64 1/4 (/.f64 1 (pow.f64 N 4))) (*.f64 1/2 (/.f64 1 (pow.f64 N 2)))))) (*.f64 1/3 (/.f64 1 (pow.f64 N 3))))): 0 points increase in error, 0 points decrease in error
      (+.f64 (/.f64 1 N) (Rewrite<= +-commutative_binary64 (+.f64 (*.f64 1/3 (/.f64 1 (pow.f64 N 3))) (neg.f64 (+.f64 (*.f64 1/4 (/.f64 1 (pow.f64 N 4))) (*.f64 1/2 (/.f64 1 (pow.f64 N 2)))))))): 0 points increase in error, 0 points decrease in error
      (+.f64 (/.f64 1 N) (Rewrite<= sub-neg_binary64 (-.f64 (*.f64 1/3 (/.f64 1 (pow.f64 N 3))) (+.f64 (*.f64 1/4 (/.f64 1 (pow.f64 N 4))) (*.f64 1/2 (/.f64 1 (pow.f64 N 2))))))): 0 points increase in error, 0 points decrease in error
      (Rewrite<= associate--l+_binary64 (-.f64 (+.f64 (/.f64 1 N) (*.f64 1/3 (/.f64 1 (pow.f64 N 3)))) (+.f64 (*.f64 1/4 (/.f64 1 (pow.f64 N 4))) (*.f64 1/2 (/.f64 1 (pow.f64 N 2)))))): 3 points increase in error, 1 points decrease in error
    5. Applied egg-rr0.0

      \[\leadsto \frac{1}{N} + \left(\frac{-0.5}{N \cdot N} + \color{blue}{\frac{\frac{\frac{-0.25}{N} + 0.3333333333333333}{N \cdot N}}{N}}\right) \]

    if 5.00000000000000024e-5 < (-.f64 (log.f64 (+.f64 N 1)) (log.f64 N))

    1. Initial program 0.1

      \[\log \left(N + 1\right) - \log N \]
    2. Simplified0.1

      \[\leadsto \color{blue}{\mathsf{log1p}\left(N\right) - \log N} \]
      Proof
      (-.f64 (log1p.f64 N) (log.f64 N)): 0 points increase in error, 0 points decrease in error
      (-.f64 (Rewrite<= log1p-def_binary64 (log.f64 (+.f64 1 N))) (log.f64 N)): 0 points increase in error, 0 points decrease in error
      (-.f64 (log.f64 (Rewrite<= +-commutative_binary64 (+.f64 N 1))) (log.f64 N)): 0 points increase in error, 0 points decrease in error
    3. Applied egg-rr0.1

      \[\leadsto \color{blue}{\log \left(\frac{N + 1}{N}\right)} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification0.1

    \[\leadsto \begin{array}{l} \mathbf{if}\;\log \left(N + 1\right) - \log N \leq 5 \cdot 10^{-5}:\\ \;\;\;\;\frac{1}{N} + \left(\frac{-0.5}{N \cdot N} + \frac{\frac{\frac{-0.25}{N} + 0.3333333333333333}{N \cdot N}}{N}\right)\\ \mathbf{else}:\\ \;\;\;\;\log \left(\frac{N + 1}{N}\right)\\ \end{array} \]

Alternatives

Alternative 1
Error0.5
Cost6724
\[\begin{array}{l} \mathbf{if}\;N \leq 0.13137983386600421:\\ \;\;\;\;N - \log N\\ \mathbf{else}:\\ \;\;\;\;\frac{1}{N} + \left(\frac{-0.5}{N \cdot N} + \frac{\frac{\frac{-0.25}{N} + 0.3333333333333333}{N \cdot N}}{N}\right)\\ \end{array} \]
Alternative 2
Error0.7
Cost6660
\[\begin{array}{l} \mathbf{if}\;N \leq 0.13137983386600421:\\ \;\;\;\;-\log N\\ \mathbf{else}:\\ \;\;\;\;\frac{1}{N} + \left(\frac{-0.5}{N \cdot N} + \frac{\frac{\frac{-0.25}{N} + 0.3333333333333333}{N \cdot N}}{N}\right)\\ \end{array} \]
Alternative 3
Error31.0
Cost192
\[\frac{1}{N} \]
Alternative 4
Error61.1
Cost64
\[N \]

Error

Reproduce

herbie shell --seed 2022318 
(FPCore (N)
  :name "2log (problem 3.3.6)"
  :precision binary64
  (- (log (+ N 1.0)) (log N)))