\[\frac{e^{x} - 1}{x}\]
Test:
Kahan's exp quotient
Bits:
128 bits
Bits error versus x
Time: 7.5 s
Input Error: 19.3
Output Error: 0.2
Log:
Profile: 🕒
\(\begin{cases} \frac{{\left(e^{x}\right)}^{3} - {1}^{3}}{\left(\left(e^{x} + 1\right) + e^{x + x}\right) \cdot x} & \text{when } x \le -0.0012153552f0 \\ \frac{1}{6} \cdot {x}^2 + \left(1 + \frac{1}{2} \cdot x\right) & \text{otherwise} \end{cases}\)

    if x < -0.0012153552f0

    1. Started with
      \[\frac{e^{x} - 1}{x}\]
      0.2
    2. Using strategy rm
      0.2
    3. Applied flip3-- to get
      \[\frac{\color{red}{e^{x} - 1}}{x} \leadsto \frac{\color{blue}{\frac{{\left(e^{x}\right)}^{3} - {1}^{3}}{{\left(e^{x}\right)}^2 + \left({1}^2 + e^{x} \cdot 1\right)}}}{x}\]
      0.3
    4. Applied associate-/l/ to get
      \[\color{red}{\frac{\frac{{\left(e^{x}\right)}^{3} - {1}^{3}}{{\left(e^{x}\right)}^2 + \left({1}^2 + e^{x} \cdot 1\right)}}{x}} \leadsto \color{blue}{\frac{{\left(e^{x}\right)}^{3} - {1}^{3}}{x \cdot \left({\left(e^{x}\right)}^2 + \left({1}^2 + e^{x} \cdot 1\right)\right)}}\]
      0.3
    5. Applied simplify to get
      \[\frac{{\left(e^{x}\right)}^{3} - {1}^{3}}{\color{red}{x \cdot \left({\left(e^{x}\right)}^2 + \left({1}^2 + e^{x} \cdot 1\right)\right)}} \leadsto \frac{{\left(e^{x}\right)}^{3} - {1}^{3}}{\color{blue}{\left(\left(e^{x} + 1\right) + e^{x + x}\right) \cdot x}}\]
      0.3

    if -0.0012153552f0 < x

    1. Started with
      \[\frac{e^{x} - 1}{x}\]
      27.5
    2. Applied taylor to get
      \[\frac{e^{x} - 1}{x} \leadsto \frac{1}{6} \cdot {x}^2 + \left(1 + \frac{1}{2} \cdot x\right)\]
      0.2
    3. Taylor expanded around 0 to get
      \[\color{red}{\frac{1}{6} \cdot {x}^2 + \left(1 + \frac{1}{2} \cdot x\right)} \leadsto \color{blue}{\frac{1}{6} \cdot {x}^2 + \left(1 + \frac{1}{2} \cdot x\right)}\]
      0.2

  1. Removed slow pow expressions

Original test:


(lambda ((x default))
  #:name "Kahan's exp quotient"
  (/ (- (exp x) 1) x)
  #:target
  (if (and (< x 1) (> x -1)) (/ (- (exp x) 1) (log (exp x))) (/ (- (exp x) 1) x)))