Error: 34.6 → 6.4
Time: 32.5s
Precision: 64
Ground Truth: 128
\[\frac{\left(-b/2\right) + \sqrt{{b/2}^2 - a \cdot c}}{a}\]
\[\begin{cases} \frac{\frac{1}{2}}{b/2} \cdot c - 2 \cdot \frac{b/2}{a} & \text{when } b/2 \le -3.2138303248745144 \cdot 10^{+50} \\ \frac{\left(-b/2\right) + \sqrt{{b/2}^2 - a \cdot c}}{a} & \text{when } b/2 \le -3.147839144939969 \cdot 10^{-238} \\ \frac{\frac{a}{1} \cdot \frac{c}{\left(-b/2\right) - \sqrt{{b/2}^2 - a \cdot c}}}{a} & \text{when } b/2 \le 1.5588782102575123 \cdot 10^{+76} \\ \frac{c}{\left(\left(-b/2\right) - b/2\right) + \frac{c \cdot \frac{1}{2}}{\frac{b/2}{a}}} & \text{otherwise} \end{cases}\]

Error

Bits error versus a

Bits error versus b/2

Bits error versus c

Derivation

    if b/2 < -3.2138303248745144e+50

    1. Initial program 40.1

      \[\frac{\left(-b/2\right) + \sqrt{{b/2}^2 - a \cdot c}}{a}\]
    2. Applied taylor 11.0

      \[\leadsto \frac{\frac{1}{2} \cdot \frac{a \cdot c}{b/2} - 2 \cdot b/2}{a}\]
    3. Taylor expanded around -inf 11.0

      \[\leadsto \frac{\color{blue}{\frac{1}{2} \cdot \frac{a \cdot c}{b/2} - 2 \cdot b/2}}{a}\]
    4. Applied simplify 0.1

      \[\leadsto \color{blue}{\frac{\frac{1}{2}}{b/2} \cdot c - 2 \cdot \frac{b/2}{a}}\]

    if -3.2138303248745144e+50 < b/2 < -3.147839144939969e-238

    1. Initial program 8.5

      \[\frac{\left(-b/2\right) + \sqrt{{b/2}^2 - a \cdot c}}{a}\]

    if -3.147839144939969e-238 < b/2 < 1.5588782102575123e+76

    1. Initial program 27.6

      \[\frac{\left(-b/2\right) + \sqrt{{b/2}^2 - a \cdot c}}{a}\]
    2. Using strategy rm
    3. Applied flip-+ 27.7

      \[\leadsto \frac{\color{blue}{\frac{{\left(-b/2\right)}^2 - {\left(\sqrt{{b/2}^2 - a \cdot c}\right)}^2}{\left(-b/2\right) - \sqrt{{b/2}^2 - a \cdot c}}}}{a}\]
    4. Applied simplify 15.7

      \[\leadsto \frac{\frac{\color{blue}{a \cdot c}}{\left(-b/2\right) - \sqrt{{b/2}^2 - a \cdot c}}}{a}\]
    5. Using strategy rm
    6. Applied *-un-lft-identity 15.7

      \[\leadsto \frac{\frac{a \cdot c}{\color{blue}{1 \cdot \left(\left(-b/2\right) - \sqrt{{b/2}^2 - a \cdot c}\right)}}}{a}\]
    7. Applied times-frac 13.5

      \[\leadsto \frac{\color{blue}{\frac{a}{1} \cdot \frac{c}{\left(-b/2\right) - \sqrt{{b/2}^2 - a \cdot c}}}}{a}\]

    if 1.5588782102575123e+76 < b/2

    1. Initial program 58.2

      \[\frac{\left(-b/2\right) + \sqrt{{b/2}^2 - a \cdot c}}{a}\]
    2. Using strategy rm
    3. Applied flip-+ 58.2

      \[\leadsto \frac{\color{blue}{\frac{{\left(-b/2\right)}^2 - {\left(\sqrt{{b/2}^2 - a \cdot c}\right)}^2}{\left(-b/2\right) - \sqrt{{b/2}^2 - a \cdot c}}}}{a}\]
    4. Applied simplify 32.4

      \[\leadsto \frac{\frac{\color{blue}{a \cdot c}}{\left(-b/2\right) - \sqrt{{b/2}^2 - a \cdot c}}}{a}\]
    5. Applied taylor 16.0

      \[\leadsto \frac{\frac{a \cdot c}{\left(-b/2\right) - \left(b/2 - \frac{1}{2} \cdot \frac{a \cdot c}{b/2}\right)}}{a}\]
    6. Taylor expanded around inf 16.0

      \[\leadsto \frac{\frac{a \cdot c}{\left(-b/2\right) - \color{blue}{\left(b/2 - \frac{1}{2} \cdot \frac{a \cdot c}{b/2}\right)}}}{a}\]
    7. Applied simplify 1.5

      \[\leadsto \color{blue}{\frac{c}{\left(\left(-b/2\right) - b/2\right) + \frac{c \cdot \frac{1}{2}}{\frac{b/2}{a}}}}\]
  1. Removed slow pow expressions

Runtime

Total time: 32.5s Debug log

Please report a bug with the following info:

herbie --seed '#(3998637471 2327741461 3535618413 852106778 676758467 1297175556)'
(FPCore (a b/2 c)
  :name "NMSE problem 3.2.1, positive"
  (/ (+ (- b/2) (sqrt (- (sqr b/2) (* a c)))) a))