\[\frac{e^{x} - 1}{x}\]
Test:
Kahan's exp quotient
Bits:
128 bits
Bits error versus x
Time: 5.9 s
Input Error: 42.9
Output Error: 3.1
Log: ⚲
Profile: 🕒
\(\begin{cases} \frac{\frac{{\left(e^{x}\right)}^2 - {1}^2}{e^{x} + 1}}{x} & \text{when } x \le -6.025113626725801 \cdot 10^{-15} \\ \frac{\left(\frac{1}{2} + \frac{1}{6} \cdot x\right) \cdot {x}^2 + x}{x} & \text{otherwise} \end{cases}\)

    if x < -6.025113626725801e-15

    1. Started with
      \[\frac{e^{x} - 1}{x}\]
      0.9
    2. Using strategy rm
      0.9
    3. Applied flip-- to get
      \[\frac{\color{red}{e^{x} - 1}}{x} \leadsto \frac{\color{blue}{\frac{{\left(e^{x}\right)}^2 - {1}^2}{e^{x} + 1}}}{x}\]
      0.9

    if -6.025113626725801e-15 < x

    1. Started with
      \[\frac{e^{x} - 1}{x}\]
      61.0
    2. Applied taylor to get
      \[\frac{e^{x} - 1}{x} \leadsto \frac{\frac{1}{2} \cdot {x}^2 + \left(\frac{1}{6} \cdot {x}^{3} + x\right)}{x}\]
      4.0
    3. Taylor expanded around 0 to get
      \[\frac{\color{red}{\frac{1}{2} \cdot {x}^2 + \left(\frac{1}{6} \cdot {x}^{3} + x\right)}}{x} \leadsto \frac{\color{blue}{\frac{1}{2} \cdot {x}^2 + \left(\frac{1}{6} \cdot {x}^{3} + x\right)}}{x}\]
      4.0
    4. Applied simplify to get
      \[\color{red}{\frac{\frac{1}{2} \cdot {x}^2 + \left(\frac{1}{6} \cdot {x}^{3} + x\right)}{x}} \leadsto \color{blue}{\frac{\left(x \cdot x\right) \cdot \left(x \cdot \frac{1}{6} + \frac{1}{2}\right) + x}{x}}\]
      4.0
    5. Applied simplify to get
      \[\frac{\color{red}{\left(x \cdot x\right) \cdot \left(x \cdot \frac{1}{6} + \frac{1}{2}\right) + x}}{x} \leadsto \frac{\color{blue}{\left(\frac{1}{2} + \frac{1}{6} \cdot x\right) \cdot {x}^2 + x}}{x}\]
      4.0
  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)))