Average Error: 6.7 → 0.8
Time: 2.5s
Precision: 64
\[x + \frac{\left(y - x\right) \cdot z}{t}\]
\[\begin{array}{l} \mathbf{if}\;x + \frac{\left(y - x\right) \cdot z}{t} = -\infty \lor \neg \left(x + \frac{\left(y - x\right) \cdot z}{t} \le 9.7386606994553072 \cdot 10^{291}\right):\\ \;\;\;\;\mathsf{fma}\left(\frac{z}{t}, y, x - \frac{1}{\frac{\frac{t}{z}}{x}}\right)\\ \mathbf{else}:\\ \;\;\;\;x + \frac{\left(y - x\right) \cdot z}{t}\\ \end{array}\]
x + \frac{\left(y - x\right) \cdot z}{t}
\begin{array}{l}
\mathbf{if}\;x + \frac{\left(y - x\right) \cdot z}{t} = -\infty \lor \neg \left(x + \frac{\left(y - x\right) \cdot z}{t} \le 9.7386606994553072 \cdot 10^{291}\right):\\
\;\;\;\;\mathsf{fma}\left(\frac{z}{t}, y, x - \frac{1}{\frac{\frac{t}{z}}{x}}\right)\\

\mathbf{else}:\\
\;\;\;\;x + \frac{\left(y - x\right) \cdot z}{t}\\

\end{array}
double f(double x, double y, double z, double t) {
        double r449648 = x;
        double r449649 = y;
        double r449650 = r449649 - r449648;
        double r449651 = z;
        double r449652 = r449650 * r449651;
        double r449653 = t;
        double r449654 = r449652 / r449653;
        double r449655 = r449648 + r449654;
        return r449655;
}

double f(double x, double y, double z, double t) {
        double r449656 = x;
        double r449657 = y;
        double r449658 = r449657 - r449656;
        double r449659 = z;
        double r449660 = r449658 * r449659;
        double r449661 = t;
        double r449662 = r449660 / r449661;
        double r449663 = r449656 + r449662;
        double r449664 = -inf.0;
        bool r449665 = r449663 <= r449664;
        double r449666 = 9.738660699455307e+291;
        bool r449667 = r449663 <= r449666;
        double r449668 = !r449667;
        bool r449669 = r449665 || r449668;
        double r449670 = r449659 / r449661;
        double r449671 = 1.0;
        double r449672 = r449661 / r449659;
        double r449673 = r449672 / r449656;
        double r449674 = r449671 / r449673;
        double r449675 = r449656 - r449674;
        double r449676 = fma(r449670, r449657, r449675);
        double r449677 = r449669 ? r449676 : r449663;
        return r449677;
}

Error

Bits error versus x

Bits error versus y

Bits error versus z

Bits error versus t

Target

Original6.7
Target2.0
Herbie0.8
\[\begin{array}{l} \mathbf{if}\;x \lt -9.0255111955330046 \cdot 10^{-135}:\\ \;\;\;\;x - \frac{z}{t} \cdot \left(x - y\right)\\ \mathbf{elif}\;x \lt 4.2750321637007147 \cdot 10^{-250}:\\ \;\;\;\;x + \frac{y - x}{t} \cdot z\\ \mathbf{else}:\\ \;\;\;\;x + \frac{y - x}{\frac{t}{z}}\\ \end{array}\]

Derivation

  1. Split input into 2 regimes
  2. if (+ x (/ (* (- y x) z) t)) < -inf.0 or 9.738660699455307e+291 < (+ x (/ (* (- y x) z) t))

    1. Initial program 54.8

      \[x + \frac{\left(y - x\right) \cdot z}{t}\]
    2. Simplified3.4

      \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{y - x}{t}, z, x\right)}\]
    3. Using strategy rm
    4. Applied div-sub3.4

      \[\leadsto \mathsf{fma}\left(\color{blue}{\frac{y}{t} - \frac{x}{t}}, z, x\right)\]
    5. Taylor expanded around inf 54.8

      \[\leadsto \color{blue}{\left(\frac{z \cdot y}{t} + x\right) - \frac{x \cdot z}{t}}\]
    6. Simplified33.1

      \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{z}{t}, y, x - \frac{x \cdot z}{t}\right)}\]
    7. Using strategy rm
    8. Applied associate-/l*0.7

      \[\leadsto \mathsf{fma}\left(\frac{z}{t}, y, x - \color{blue}{\frac{x}{\frac{t}{z}}}\right)\]
    9. Using strategy rm
    10. Applied clear-num0.8

      \[\leadsto \mathsf{fma}\left(\frac{z}{t}, y, x - \color{blue}{\frac{1}{\frac{\frac{t}{z}}{x}}}\right)\]

    if -inf.0 < (+ x (/ (* (- y x) z) t)) < 9.738660699455307e+291

    1. Initial program 0.8

      \[x + \frac{\left(y - x\right) \cdot z}{t}\]
  3. Recombined 2 regimes into one program.
  4. Final simplification0.8

    \[\leadsto \begin{array}{l} \mathbf{if}\;x + \frac{\left(y - x\right) \cdot z}{t} = -\infty \lor \neg \left(x + \frac{\left(y - x\right) \cdot z}{t} \le 9.7386606994553072 \cdot 10^{291}\right):\\ \;\;\;\;\mathsf{fma}\left(\frac{z}{t}, y, x - \frac{1}{\frac{\frac{t}{z}}{x}}\right)\\ \mathbf{else}:\\ \;\;\;\;x + \frac{\left(y - x\right) \cdot z}{t}\\ \end{array}\]

Reproduce

herbie shell --seed 2020039 +o rules:numerics
(FPCore (x y z t)
  :name "Numeric.Histogram:binBounds from Chart-1.5.3"
  :precision binary64

  :herbie-target
  (if (< x -9.025511195533005e-135) (- x (* (/ z t) (- x y))) (if (< x 4.275032163700715e-250) (+ x (* (/ (- y x) t) z)) (+ x (/ (- y x) (/ t z)))))

  (+ x (/ (* (- y x) z) t)))