Average Error: 1.7 → 1.7
Time: 21.2s
Precision: 64
\[\frac{\left(\left(-b_2\right) - \left(\sqrt{\left(\left(b_2 \cdot b_2\right) - \left(a \cdot c\right)\right)}\right)\right)}{a}\]
↓
\[\frac{\left(-b_2\right) - \sqrt{\left(\mathsf{qms}\left(\left(\left(b_2 \cdot b_2\right)\right), a, c\right)\right)}}{a}\]
\frac{\left(\left(-b_2\right) - \left(\sqrt{\left(\left(b_2 \cdot b_2\right) - \left(a \cdot c\right)\right)}\right)\right)}{a}
↓
\frac{\left(-b_2\right) - \sqrt{\left(\mathsf{qms}\left(\left(\left(b_2 \cdot b_2\right)\right), a, c\right)\right)}}{a}
double f(double a, double b_2, double c) {
        double r1134709 = b_2;
        double r1134710 = -r1134709;
        double r1134711 = r1134709 * r1134709;
        double r1134712 = a;
        double r1134713 = c;
        double r1134714 = r1134712 * r1134713;
        double r1134715 = r1134711 - r1134714;
        double r1134716 = sqrt(r1134715);
        double r1134717 = r1134710 - r1134716;
        double r1134718 = r1134717 / r1134712;
        return r1134718;
}
↓
double f(double a, double b_2, double c) {
        double r1134719 = b_2;
        double r1134720 = -r1134719;
        double r1134721 = r1134719 * r1134719;
        double r1134722 = /*Error: no posit support in C */;
        double r1134723 = a;
        double r1134724 = c;
        double r1134725 = /*Error: no posit support in C */;
        double r1134726 = /*Error: no posit support in C */;
        double r1134727 = sqrt(r1134726);
        double r1134728 = r1134720 - r1134727;
        double r1134729 = r1134728 / r1134723;
        return r1134729;
}

Error

Bits error versus a

Bits error versus b_2

Bits error versus c

Derivation

  1. Initial program 1.7

    \[\frac{\left(\left(-b_2\right) - \left(\sqrt{\left(\left(b_2 \cdot b_2\right) - \left(a \cdot c\right)\right)}\right)\right)}{a}\]
  2. Using strategy rm

  3. Applied introduce-quire1.7

    \[\leadsto \frac{\left(\left(-b_2\right) - \left(\sqrt{\left(\color{blue}{\left(\left(\left(b_2 \cdot b_2\right)\right)\right)} - \left(a \cdot c\right)\right)}\right)\right)}{a}\]

  4. Applied insert-quire-fdp-sub1.7

    \[\leadsto \frac{\left(\left(-b_2\right) - \left(\sqrt{\color{blue}{\left(\left(\mathsf{qms}\left(\left(\left(b_2 \cdot b_2\right)\right), a, c\right)\right)\right)}}\right)\right)}{a}\]

  5. Final simplification1.7

    \[\leadsto \frac{\left(-b_2\right) - \sqrt{\left(\mathsf{qms}\left(\left(\left(b_2 \cdot b_2\right)\right), a, c\right)\right)}}{a}\]

Reproduce

herbie shell --seed 2019163 
(FPCore (a b_2 c)
  :name "quad2m (problem 3.2.1, negative)"
  (/.p16 (-.p16 (neg.p16 b_2) (sqrt.p16 (-.p16 (*.p16 b_2 b_2) (*.p16 a c)))) a))