Average Error: 6.1 → 1.3
Time: 2.3s
Precision: 64
\[x + \frac{\left(y - x\right) \cdot z}{t}\]
\[\begin{array}{l} \mathbf{if}\;x + \frac{\left(y - x\right) \cdot z}{t} = -\infty \lor \neg \left(x + \frac{\left(y - x\right) \cdot z}{t} \le -2.12540069280457327 \cdot 10^{-224}\right):\\ \;\;\;\;\mathsf{fma}\left(y - x, \frac{z}{t}, x\right)\\ \mathbf{else}:\\ \;\;\;\;x + \frac{\left(y - x\right) \cdot z}{t}\\ \end{array}\]
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 -2.12540069280457327 \cdot 10^{-224}\right):\\
\;\;\;\;\mathsf{fma}\left(y - x, \frac{z}{t}, 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 r444638 = x;
        double r444639 = y;
        double r444640 = r444639 - r444638;
        double r444641 = z;
        double r444642 = r444640 * r444641;
        double r444643 = t;
        double r444644 = r444642 / r444643;
        double r444645 = r444638 + r444644;
        return r444645;
}

double f(double x, double y, double z, double t) {
        double r444646 = x;
        double r444647 = y;
        double r444648 = r444647 - r444646;
        double r444649 = z;
        double r444650 = r444648 * r444649;
        double r444651 = t;
        double r444652 = r444650 / r444651;
        double r444653 = r444646 + r444652;
        double r444654 = -inf.0;
        bool r444655 = r444653 <= r444654;
        double r444656 = -2.1254006928045733e-224;
        bool r444657 = r444653 <= r444656;
        double r444658 = !r444657;
        bool r444659 = r444655 || r444658;
        double r444660 = r444649 / r444651;
        double r444661 = fma(r444648, r444660, r444646);
        double r444662 = r444659 ? r444661 : r444653;
        return r444662;
}

Error

Bits error versus x

Bits error versus y

Bits error versus z

Bits error versus t

Target

Original6.1
Target2.0
Herbie1.3
\[\begin{array}{l} \mathbf{if}\;x \lt -9.0255111955330046 \cdot 10^{-135}:\\ \;\;\;\;x - \frac{z}{t} \cdot \left(x - y\right)\\ \mathbf{elif}\;x \lt 4.2750321637007147 \cdot 10^{-250}:\\ \;\;\;\;x + \frac{y - x}{t} \cdot z\\ \mathbf{else}:\\ \;\;\;\;x + \frac{y - x}{\frac{t}{z}}\\ \end{array}\]

Derivation

  1. Split input into 2 regimes
  2. if (+ x (/ (* (- y x) z) t)) < -inf.0 or -2.1254006928045733e-224 < (+ x (/ (* (- y x) z) t))

    1. Initial program 10.4

      \[x + \frac{\left(y - x\right) \cdot z}{t}\]
    2. Simplified5.6

      \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{y - x}{t}, z, x\right)}\]
    3. Using strategy rm
    4. Applied fma-udef5.6

      \[\leadsto \color{blue}{\frac{y - x}{t} \cdot z + x}\]
    5. Using strategy rm
    6. Applied div-inv5.6

      \[\leadsto \color{blue}{\left(\left(y - x\right) \cdot \frac{1}{t}\right)} \cdot z + x\]
    7. Applied associate-*l*2.0

      \[\leadsto \color{blue}{\left(y - x\right) \cdot \left(\frac{1}{t} \cdot z\right)} + x\]
    8. Simplified2.0

      \[\leadsto \left(y - x\right) \cdot \color{blue}{\frac{z}{t}} + x\]
    9. Using strategy rm
    10. Applied fma-def2.0

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

    if -inf.0 < (+ x (/ (* (- y x) z) t)) < -2.1254006928045733e-224

    1. Initial program 0.4

      \[x + \frac{\left(y - x\right) \cdot z}{t}\]
  3. Recombined 2 regimes into one program.
  4. Final simplification1.3

    \[\leadsto \begin{array}{l} \mathbf{if}\;x + \frac{\left(y - x\right) \cdot z}{t} = -\infty \lor \neg \left(x + \frac{\left(y - x\right) \cdot z}{t} \le -2.12540069280457327 \cdot 10^{-224}\right):\\ \;\;\;\;\mathsf{fma}\left(y - x, \frac{z}{t}, x\right)\\ \mathbf{else}:\\ \;\;\;\;x + \frac{\left(y - x\right) \cdot z}{t}\\ \end{array}\]

Reproduce

herbie shell --seed 2020089 +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)))