2log (problem 3.3.6)

Percentage Accurate: 23.9% → 96.9%
Time: 7.9s
Alternatives: 6
Speedup: 17.3×

Specification

?
\[N > 1 \land N < 10^{+40}\]
\[\begin{array}{l} \\ \log \left(N + 1\right) - \log N \end{array} \]
(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 6 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: 23.9% 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: 96.9% accurate, 3.2× speedup?

\[\begin{array}{l} \\ \frac{1}{\mathsf{fma}\left(-N, -1, \frac{\frac{\frac{0.041666666666666664}{N} - 0.08333333333333333}{N} - -0.5}{N} \cdot N\right)} \end{array} \]
(FPCore (N)
 :precision binary64
 (/
  1.0
  (fma
   (- N)
   -1.0
   (*
    (/ (- (/ (- (/ 0.041666666666666664 N) 0.08333333333333333) N) -0.5) N)
    N))))
double code(double N) {
	return 1.0 / fma(-N, -1.0, ((((((0.041666666666666664 / N) - 0.08333333333333333) / N) - -0.5) / N) * N));
}
function code(N)
	return Float64(1.0 / fma(Float64(-N), -1.0, Float64(Float64(Float64(Float64(Float64(Float64(0.041666666666666664 / N) - 0.08333333333333333) / N) - -0.5) / N) * N)))
end
code[N_] := N[(1.0 / N[((-N) * -1.0 + N[(N[(N[(N[(N[(N[(0.041666666666666664 / N), $MachinePrecision] - 0.08333333333333333), $MachinePrecision] / N), $MachinePrecision] - -0.5), $MachinePrecision] / N), $MachinePrecision] * N), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{1}{\mathsf{fma}\left(-N, -1, \frac{\frac{\frac{0.041666666666666664}{N} - 0.08333333333333333}{N} - -0.5}{N} \cdot N\right)}
\end{array}
Derivation
  1. Initial program 21.8%

    \[\log \left(N + 1\right) - \log N \]
  2. Add Preprocessing
  3. Taylor expanded in N around inf

    \[\leadsto \color{blue}{\frac{\left(1 + \frac{\frac{1}{3}}{{N}^{2}}\right) - \left(\frac{1}{2} \cdot \frac{1}{N} + \frac{1}{4} \cdot \frac{1}{{N}^{3}}\right)}{N}} \]
  4. Applied rewrites97.9%

    \[\leadsto \color{blue}{\frac{\frac{-0.5 - \frac{\frac{0.25}{N} - 0.3333333333333333}{N}}{N} - -1}{N}} \]
  5. Step-by-step derivation
    1. Applied rewrites98.0%

      \[\leadsto \frac{1}{\color{blue}{\frac{N}{\frac{-0.5 - \frac{\frac{0.25}{N} - 0.3333333333333333}{N}}{N} - -1}}} \]
    2. Taylor expanded in N around -inf

      \[\leadsto \frac{1}{-1 \cdot \color{blue}{\left(N \cdot \left(-1 \cdot \frac{\frac{1}{2} + -1 \cdot \frac{\frac{1}{12} - \frac{1}{24} \cdot \frac{1}{N}}{N}}{N} - 1\right)\right)}} \]
    3. Step-by-step derivation
      1. Applied rewrites98.2%

        \[\leadsto \frac{1}{\left(-N\right) \cdot \color{blue}{\left(-1 - \frac{0.5 - \frac{0.08333333333333333 - \frac{0.041666666666666664}{N}}{N}}{N}\right)}} \]
      2. Step-by-step derivation
        1. Applied rewrites98.3%

          \[\leadsto \frac{1}{\mathsf{fma}\left(-N, -1, \left(-N\right) \cdot \frac{-0.5 + \frac{0.08333333333333333 - \frac{0.041666666666666664}{N}}{N}}{N}\right)} \]
        2. Final simplification98.3%

          \[\leadsto \frac{1}{\mathsf{fma}\left(-N, -1, \frac{\frac{\frac{0.041666666666666664}{N} - 0.08333333333333333}{N} - -0.5}{N} \cdot N\right)} \]
        3. Add Preprocessing

        Alternative 2: 96.8% accurate, 3.7× speedup?

        \[\begin{array}{l} \\ \frac{1}{\left(1 - \frac{\frac{\mathsf{fma}\left(0.08333333333333333, N, -0.041666666666666664\right)}{N \cdot N} - 0.5}{N}\right) \cdot N} \end{array} \]
        (FPCore (N)
         :precision binary64
         (/
          1.0
          (*
           (-
            1.0
            (/
             (- (/ (fma 0.08333333333333333 N -0.041666666666666664) (* N N)) 0.5)
             N))
           N)))
        double code(double N) {
        	return 1.0 / ((1.0 - (((fma(0.08333333333333333, N, -0.041666666666666664) / (N * N)) - 0.5) / N)) * N);
        }
        
        function code(N)
        	return Float64(1.0 / Float64(Float64(1.0 - Float64(Float64(Float64(fma(0.08333333333333333, N, -0.041666666666666664) / Float64(N * N)) - 0.5) / N)) * N))
        end
        
        code[N_] := N[(1.0 / N[(N[(1.0 - N[(N[(N[(N[(0.08333333333333333 * N + -0.041666666666666664), $MachinePrecision] / N[(N * N), $MachinePrecision]), $MachinePrecision] - 0.5), $MachinePrecision] / N), $MachinePrecision]), $MachinePrecision] * N), $MachinePrecision]), $MachinePrecision]
        
        \begin{array}{l}
        
        \\
        \frac{1}{\left(1 - \frac{\frac{\mathsf{fma}\left(0.08333333333333333, N, -0.041666666666666664\right)}{N \cdot N} - 0.5}{N}\right) \cdot N}
        \end{array}
        
        Derivation
        1. Initial program 21.8%

          \[\log \left(N + 1\right) - \log N \]
        2. Add Preprocessing
        3. Taylor expanded in N around inf

          \[\leadsto \color{blue}{\frac{\left(1 + \frac{\frac{1}{3}}{{N}^{2}}\right) - \left(\frac{1}{2} \cdot \frac{1}{N} + \frac{1}{4} \cdot \frac{1}{{N}^{3}}\right)}{N}} \]
        4. Applied rewrites97.9%

          \[\leadsto \color{blue}{\frac{\frac{-0.5 - \frac{\frac{0.25}{N} - 0.3333333333333333}{N}}{N} - -1}{N}} \]
        5. Step-by-step derivation
          1. Applied rewrites98.0%

            \[\leadsto \frac{1}{\color{blue}{\frac{N}{\frac{-0.5 - \frac{\frac{0.25}{N} - 0.3333333333333333}{N}}{N} - -1}}} \]
          2. Taylor expanded in N around -inf

            \[\leadsto \frac{1}{-1 \cdot \color{blue}{\left(N \cdot \left(-1 \cdot \frac{\frac{1}{2} + -1 \cdot \frac{\frac{1}{12} - \frac{1}{24} \cdot \frac{1}{N}}{N}}{N} - 1\right)\right)}} \]
          3. Step-by-step derivation
            1. Applied rewrites98.2%

              \[\leadsto \frac{1}{\left(-N\right) \cdot \color{blue}{\left(-1 - \frac{0.5 - \frac{0.08333333333333333 - \frac{0.041666666666666664}{N}}{N}}{N}\right)}} \]
            2. Taylor expanded in N around 0

              \[\leadsto \frac{1}{\left(-N\right) \cdot \left(-1 - \frac{\frac{1}{2} - \frac{\frac{1}{12} \cdot N - \frac{1}{24}}{{N}^{2}}}{N}\right)} \]
            3. Step-by-step derivation
              1. Applied rewrites98.2%

                \[\leadsto \frac{1}{\left(-N\right) \cdot \left(-1 - \frac{0.5 - \frac{\mathsf{fma}\left(0.08333333333333333, N, -0.041666666666666664\right)}{N \cdot N}}{N}\right)} \]
              2. Final simplification98.2%

                \[\leadsto \frac{1}{\left(1 - \frac{\frac{\mathsf{fma}\left(0.08333333333333333, N, -0.041666666666666664\right)}{N \cdot N} - 0.5}{N}\right) \cdot N} \]
              3. Add Preprocessing

              Alternative 3: 96.7% accurate, 4.8× speedup?

              \[\begin{array}{l} \\ \frac{1}{\frac{\mathsf{fma}\left(\mathsf{fma}\left(0.5 + N, N, -0.08333333333333333\right), N, 0.041666666666666664\right)}{N \cdot N}} \end{array} \]
              (FPCore (N)
               :precision binary64
               (/
                1.0
                (/
                 (fma (fma (+ 0.5 N) N -0.08333333333333333) N 0.041666666666666664)
                 (* N N))))
              double code(double N) {
              	return 1.0 / (fma(fma((0.5 + N), N, -0.08333333333333333), N, 0.041666666666666664) / (N * N));
              }
              
              function code(N)
              	return Float64(1.0 / Float64(fma(fma(Float64(0.5 + N), N, -0.08333333333333333), N, 0.041666666666666664) / Float64(N * N)))
              end
              
              code[N_] := N[(1.0 / N[(N[(N[(N[(0.5 + N), $MachinePrecision] * N + -0.08333333333333333), $MachinePrecision] * N + 0.041666666666666664), $MachinePrecision] / N[(N * N), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
              
              \begin{array}{l}
              
              \\
              \frac{1}{\frac{\mathsf{fma}\left(\mathsf{fma}\left(0.5 + N, N, -0.08333333333333333\right), N, 0.041666666666666664\right)}{N \cdot N}}
              \end{array}
              
              Derivation
              1. Initial program 21.8%

                \[\log \left(N + 1\right) - \log N \]
              2. Add Preprocessing
              3. Taylor expanded in N around inf

                \[\leadsto \color{blue}{\frac{\left(1 + \frac{\frac{1}{3}}{{N}^{2}}\right) - \left(\frac{1}{2} \cdot \frac{1}{N} + \frac{1}{4} \cdot \frac{1}{{N}^{3}}\right)}{N}} \]
              4. Applied rewrites97.9%

                \[\leadsto \color{blue}{\frac{\frac{-0.5 - \frac{\frac{0.25}{N} - 0.3333333333333333}{N}}{N} - -1}{N}} \]
              5. Step-by-step derivation
                1. Applied rewrites98.0%

                  \[\leadsto \frac{1}{\color{blue}{\frac{N}{\frac{-0.5 - \frac{\frac{0.25}{N} - 0.3333333333333333}{N}}{N} - -1}}} \]
                2. Taylor expanded in N around -inf

                  \[\leadsto \frac{1}{-1 \cdot \color{blue}{\left(N \cdot \left(-1 \cdot \frac{\frac{1}{2} + -1 \cdot \frac{\frac{1}{12} - \frac{1}{24} \cdot \frac{1}{N}}{N}}{N} - 1\right)\right)}} \]
                3. Step-by-step derivation
                  1. Applied rewrites98.2%

                    \[\leadsto \frac{1}{\left(-N\right) \cdot \color{blue}{\left(-1 - \frac{0.5 - \frac{0.08333333333333333 - \frac{0.041666666666666664}{N}}{N}}{N}\right)}} \]
                  2. Taylor expanded in N around 0

                    \[\leadsto \frac{1}{\frac{\frac{1}{24} + N \cdot \left(N \cdot \left(\frac{1}{2} + N\right) - \frac{1}{12}\right)}{{N}^{\color{blue}{2}}}} \]
                  3. Step-by-step derivation
                    1. Applied rewrites98.0%

                      \[\leadsto \frac{1}{\frac{\mathsf{fma}\left(\mathsf{fma}\left(0.5 + N, N, -0.08333333333333333\right), N, 0.041666666666666664\right)}{N \cdot \color{blue}{N}}} \]
                    2. Add Preprocessing

                    Alternative 4: 95.1% accurate, 5.2× speedup?

                    \[\begin{array}{l} \\ \frac{\frac{\frac{0.3333333333333333}{N} - 0.5}{N} - -1}{N} \end{array} \]
                    (FPCore (N)
                     :precision binary64
                     (/ (- (/ (- (/ 0.3333333333333333 N) 0.5) N) -1.0) N))
                    double code(double N) {
                    	return ((((0.3333333333333333 / N) - 0.5) / N) - -1.0) / N;
                    }
                    
                    real(8) function code(n)
                        real(8), intent (in) :: n
                        code = ((((0.3333333333333333d0 / n) - 0.5d0) / n) - (-1.0d0)) / n
                    end function
                    
                    public static double code(double N) {
                    	return ((((0.3333333333333333 / N) - 0.5) / N) - -1.0) / N;
                    }
                    
                    def code(N):
                    	return ((((0.3333333333333333 / N) - 0.5) / N) - -1.0) / N
                    
                    function code(N)
                    	return Float64(Float64(Float64(Float64(Float64(0.3333333333333333 / N) - 0.5) / N) - -1.0) / N)
                    end
                    
                    function tmp = code(N)
                    	tmp = ((((0.3333333333333333 / N) - 0.5) / N) - -1.0) / N;
                    end
                    
                    code[N_] := N[(N[(N[(N[(N[(0.3333333333333333 / N), $MachinePrecision] - 0.5), $MachinePrecision] / N), $MachinePrecision] - -1.0), $MachinePrecision] / N), $MachinePrecision]
                    
                    \begin{array}{l}
                    
                    \\
                    \frac{\frac{\frac{0.3333333333333333}{N} - 0.5}{N} - -1}{N}
                    \end{array}
                    
                    Derivation
                    1. Initial program 21.8%

                      \[\log \left(N + 1\right) - \log N \]
                    2. Add Preprocessing
                    3. Taylor expanded in N around inf

                      \[\leadsto \color{blue}{\frac{\left(1 + \frac{\frac{1}{3}}{{N}^{2}}\right) - \frac{1}{2} \cdot \frac{1}{N}}{N}} \]
                    4. Step-by-step derivation
                      1. lower-/.f64N/A

                        \[\leadsto \color{blue}{\frac{\left(1 + \frac{\frac{1}{3}}{{N}^{2}}\right) - \frac{1}{2} \cdot \frac{1}{N}}{N}} \]
                      2. associate--l+N/A

                        \[\leadsto \frac{\color{blue}{1 + \left(\frac{\frac{1}{3}}{{N}^{2}} - \frac{1}{2} \cdot \frac{1}{N}\right)}}{N} \]
                      3. +-commutativeN/A

                        \[\leadsto \frac{\color{blue}{\left(\frac{\frac{1}{3}}{{N}^{2}} - \frac{1}{2} \cdot \frac{1}{N}\right) + 1}}{N} \]
                      4. unpow2N/A

                        \[\leadsto \frac{\left(\frac{\frac{1}{3}}{\color{blue}{N \cdot N}} - \frac{1}{2} \cdot \frac{1}{N}\right) + 1}{N} \]
                      5. associate-/r*N/A

                        \[\leadsto \frac{\left(\color{blue}{\frac{\frac{\frac{1}{3}}{N}}{N}} - \frac{1}{2} \cdot \frac{1}{N}\right) + 1}{N} \]
                      6. metadata-evalN/A

                        \[\leadsto \frac{\left(\frac{\frac{\color{blue}{\frac{1}{3} \cdot 1}}{N}}{N} - \frac{1}{2} \cdot \frac{1}{N}\right) + 1}{N} \]
                      7. associate-*r/N/A

                        \[\leadsto \frac{\left(\frac{\color{blue}{\frac{1}{3} \cdot \frac{1}{N}}}{N} - \frac{1}{2} \cdot \frac{1}{N}\right) + 1}{N} \]
                      8. associate-*r/N/A

                        \[\leadsto \frac{\left(\frac{\frac{1}{3} \cdot \frac{1}{N}}{N} - \color{blue}{\frac{\frac{1}{2} \cdot 1}{N}}\right) + 1}{N} \]
                      9. metadata-evalN/A

                        \[\leadsto \frac{\left(\frac{\frac{1}{3} \cdot \frac{1}{N}}{N} - \frac{\color{blue}{\frac{1}{2}}}{N}\right) + 1}{N} \]
                      10. div-subN/A

                        \[\leadsto \frac{\color{blue}{\frac{\frac{1}{3} \cdot \frac{1}{N} - \frac{1}{2}}{N}} + 1}{N} \]
                      11. metadata-evalN/A

                        \[\leadsto \frac{\frac{\frac{1}{3} \cdot \frac{1}{N} - \frac{1}{2}}{N} + \color{blue}{\left(\mathsf{neg}\left(-1\right)\right)}}{N} \]
                      12. sub-negN/A

                        \[\leadsto \frac{\color{blue}{\frac{\frac{1}{3} \cdot \frac{1}{N} - \frac{1}{2}}{N} - -1}}{N} \]
                      13. lower--.f64N/A

                        \[\leadsto \frac{\color{blue}{\frac{\frac{1}{3} \cdot \frac{1}{N} - \frac{1}{2}}{N} - -1}}{N} \]
                      14. lower-/.f64N/A

                        \[\leadsto \frac{\color{blue}{\frac{\frac{1}{3} \cdot \frac{1}{N} - \frac{1}{2}}{N}} - -1}{N} \]
                      15. lower--.f64N/A

                        \[\leadsto \frac{\frac{\color{blue}{\frac{1}{3} \cdot \frac{1}{N} - \frac{1}{2}}}{N} - -1}{N} \]
                      16. associate-*r/N/A

                        \[\leadsto \frac{\frac{\color{blue}{\frac{\frac{1}{3} \cdot 1}{N}} - \frac{1}{2}}{N} - -1}{N} \]
                      17. metadata-evalN/A

                        \[\leadsto \frac{\frac{\frac{\color{blue}{\frac{1}{3}}}{N} - \frac{1}{2}}{N} - -1}{N} \]
                      18. lower-/.f6496.8

                        \[\leadsto \frac{\frac{\color{blue}{\frac{0.3333333333333333}{N}} - 0.5}{N} - -1}{N} \]
                    5. Applied rewrites96.8%

                      \[\leadsto \color{blue}{\frac{\frac{\frac{0.3333333333333333}{N} - 0.5}{N} - -1}{N}} \]
                    6. Add Preprocessing

                    Alternative 5: 93.0% accurate, 13.8× speedup?

                    \[\begin{array}{l} \\ \frac{1}{0.5 + N} \end{array} \]
                    (FPCore (N) :precision binary64 (/ 1.0 (+ 0.5 N)))
                    double code(double N) {
                    	return 1.0 / (0.5 + N);
                    }
                    
                    real(8) function code(n)
                        real(8), intent (in) :: n
                        code = 1.0d0 / (0.5d0 + n)
                    end function
                    
                    public static double code(double N) {
                    	return 1.0 / (0.5 + N);
                    }
                    
                    def code(N):
                    	return 1.0 / (0.5 + N)
                    
                    function code(N)
                    	return Float64(1.0 / Float64(0.5 + N))
                    end
                    
                    function tmp = code(N)
                    	tmp = 1.0 / (0.5 + N);
                    end
                    
                    code[N_] := N[(1.0 / N[(0.5 + N), $MachinePrecision]), $MachinePrecision]
                    
                    \begin{array}{l}
                    
                    \\
                    \frac{1}{0.5 + N}
                    \end{array}
                    
                    Derivation
                    1. Initial program 21.8%

                      \[\log \left(N + 1\right) - \log N \]
                    2. Add Preprocessing
                    3. Taylor expanded in N around inf

                      \[\leadsto \color{blue}{\frac{\left(1 + \frac{\frac{1}{3}}{{N}^{2}}\right) - \left(\frac{1}{2} \cdot \frac{1}{N} + \frac{1}{4} \cdot \frac{1}{{N}^{3}}\right)}{N}} \]
                    4. Applied rewrites97.9%

                      \[\leadsto \color{blue}{\frac{\frac{-0.5 - \frac{\frac{0.25}{N} - 0.3333333333333333}{N}}{N} - -1}{N}} \]
                    5. Step-by-step derivation
                      1. Applied rewrites98.0%

                        \[\leadsto \frac{1}{\color{blue}{\frac{N}{\frac{-0.5 - \frac{\frac{0.25}{N} - 0.3333333333333333}{N}}{N} - -1}}} \]
                      2. Taylor expanded in N around inf

                        \[\leadsto \frac{1}{N \cdot \color{blue}{\left(1 + \frac{1}{2} \cdot \frac{1}{N}\right)}} \]
                      3. Step-by-step derivation
                        1. Applied rewrites94.9%

                          \[\leadsto \frac{1}{0.5 + \color{blue}{N}} \]
                        2. Add Preprocessing

                        Alternative 6: 84.3% accurate, 17.3× 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 21.8%

                          \[\log \left(N + 1\right) - \log N \]
                        2. Add Preprocessing
                        3. Taylor expanded in N around inf

                          \[\leadsto \color{blue}{\frac{1}{N}} \]
                        4. Step-by-step derivation
                          1. lower-/.f6486.2

                            \[\leadsto \color{blue}{\frac{1}{N}} \]
                        5. Applied rewrites86.2%

                          \[\leadsto \color{blue}{\frac{1}{N}} \]
                        6. Add Preprocessing

                        Developer Target 1: 96.4% accurate, 0.6× speedup?

                        \[\begin{array}{l} \\ \left(\left(\frac{1}{N} + \frac{-1}{2 \cdot {N}^{2}}\right) + \frac{1}{3 \cdot {N}^{3}}\right) + \frac{-1}{4 \cdot {N}^{4}} \end{array} \]
                        (FPCore (N)
                         :precision binary64
                         (+
                          (+ (+ (/ 1.0 N) (/ -1.0 (* 2.0 (pow N 2.0)))) (/ 1.0 (* 3.0 (pow N 3.0))))
                          (/ -1.0 (* 4.0 (pow N 4.0)))))
                        double code(double N) {
                        	return (((1.0 / N) + (-1.0 / (2.0 * pow(N, 2.0)))) + (1.0 / (3.0 * pow(N, 3.0)))) + (-1.0 / (4.0 * pow(N, 4.0)));
                        }
                        
                        real(8) function code(n)
                            real(8), intent (in) :: n
                            code = (((1.0d0 / n) + ((-1.0d0) / (2.0d0 * (n ** 2.0d0)))) + (1.0d0 / (3.0d0 * (n ** 3.0d0)))) + ((-1.0d0) / (4.0d0 * (n ** 4.0d0)))
                        end function
                        
                        public static double code(double N) {
                        	return (((1.0 / N) + (-1.0 / (2.0 * Math.pow(N, 2.0)))) + (1.0 / (3.0 * Math.pow(N, 3.0)))) + (-1.0 / (4.0 * Math.pow(N, 4.0)));
                        }
                        
                        def code(N):
                        	return (((1.0 / N) + (-1.0 / (2.0 * math.pow(N, 2.0)))) + (1.0 / (3.0 * math.pow(N, 3.0)))) + (-1.0 / (4.0 * math.pow(N, 4.0)))
                        
                        function code(N)
                        	return Float64(Float64(Float64(Float64(1.0 / N) + Float64(-1.0 / Float64(2.0 * (N ^ 2.0)))) + Float64(1.0 / Float64(3.0 * (N ^ 3.0)))) + Float64(-1.0 / Float64(4.0 * (N ^ 4.0))))
                        end
                        
                        function tmp = code(N)
                        	tmp = (((1.0 / N) + (-1.0 / (2.0 * (N ^ 2.0)))) + (1.0 / (3.0 * (N ^ 3.0)))) + (-1.0 / (4.0 * (N ^ 4.0)));
                        end
                        
                        code[N_] := N[(N[(N[(N[(1.0 / N), $MachinePrecision] + N[(-1.0 / N[(2.0 * N[Power[N, 2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(1.0 / N[(3.0 * N[Power[N, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(-1.0 / N[(4.0 * N[Power[N, 4.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
                        
                        \begin{array}{l}
                        
                        \\
                        \left(\left(\frac{1}{N} + \frac{-1}{2 \cdot {N}^{2}}\right) + \frac{1}{3 \cdot {N}^{3}}\right) + \frac{-1}{4 \cdot {N}^{4}}
                        \end{array}
                        

                        Reproduce

                        ?
                        herbie shell --seed 2024255 
                        (FPCore (N)
                          :name "2log (problem 3.3.6)"
                          :precision binary64
                          :pre (and (> N 1.0) (< N 1e+40))
                        
                          :alt
                          (! :herbie-platform default (+ (/ 1 N) (/ -1 (* 2 (pow N 2))) (/ 1 (* 3 (pow N 3))) (/ -1 (* 4 (pow N 4)))))
                        
                          (- (log (+ N 1.0)) (log N)))