Average Error: 33.5 → 10.6
Time: 27.9s
Precision: 64
Internal Precision: 128
\[\frac{\left(-b_2\right) - \sqrt{b_2 \cdot b_2 - a \cdot c}}{a}\]
\[\begin{array}{l} \mathbf{if}\;b_2 \le -2.8328889513248502 \cdot 10^{-121}:\\ \;\;\;\;\frac{-1}{2} \cdot \frac{c}{b_2}\\ \mathbf{elif}\;b_2 \le 3.0964691378674393 \cdot 10^{+108}:\\ \;\;\;\;\frac{1}{\frac{a}{\left(-b_2\right) - \sqrt{{b_2}^{2} - c \cdot a}}}\\ \mathbf{else}:\\ \;\;\;\;\frac{c}{b_2} \cdot \frac{1}{2} - 2 \cdot \frac{b_2}{a}\\ \end{array}\]

Error

Bits error versus a

Bits error versus b_2

Bits error versus c

Try it out

Your Program's Arguments

Results

Enter valid numbers for all inputs

Derivation

  1. Split input into 3 regimes
  2. if b_2 < -2.8328889513248502e-121

    1. Initial program 50.8

      \[\frac{\left(-b_2\right) - \sqrt{b_2 \cdot b_2 - a \cdot c}}{a}\]
    2. Initial simplification50.8

      \[\leadsto \frac{\left(-b_2\right) - \sqrt{b_2 \cdot b_2 - a \cdot c}}{a}\]
    3. Taylor expanded around -inf 11.6

      \[\leadsto \color{blue}{\frac{-1}{2} \cdot \frac{c}{b_2}}\]

    if -2.8328889513248502e-121 < b_2 < 3.0964691378674393e+108

    1. Initial program 11.9

      \[\frac{\left(-b_2\right) - \sqrt{b_2 \cdot b_2 - a \cdot c}}{a}\]
    2. Initial simplification11.9

      \[\leadsto \frac{\left(-b_2\right) - \sqrt{b_2 \cdot b_2 - a \cdot c}}{a}\]
    3. Taylor expanded around 0 11.9

      \[\leadsto \frac{\left(-b_2\right) - \sqrt{\color{blue}{{b_2}^{2} - a \cdot c}}}{a}\]
    4. Using strategy rm
    5. Applied *-un-lft-identity11.9

      \[\leadsto \frac{\left(-b_2\right) - \color{blue}{1 \cdot \sqrt{{b_2}^{2} - a \cdot c}}}{a}\]
    6. Applied *-un-lft-identity11.9

      \[\leadsto \frac{\color{blue}{1 \cdot \left(-b_2\right)} - 1 \cdot \sqrt{{b_2}^{2} - a \cdot c}}{a}\]
    7. Applied distribute-lft-out--11.9

      \[\leadsto \frac{\color{blue}{1 \cdot \left(\left(-b_2\right) - \sqrt{{b_2}^{2} - a \cdot c}\right)}}{a}\]
    8. Applied associate-/l*12.0

      \[\leadsto \color{blue}{\frac{1}{\frac{a}{\left(-b_2\right) - \sqrt{{b_2}^{2} - a \cdot c}}}}\]

    if 3.0964691378674393e+108 < b_2

    1. Initial program 46.3

      \[\frac{\left(-b_2\right) - \sqrt{b_2 \cdot b_2 - a \cdot c}}{a}\]
    2. Initial simplification46.3

      \[\leadsto \frac{\left(-b_2\right) - \sqrt{b_2 \cdot b_2 - a \cdot c}}{a}\]
    3. Taylor expanded around inf 3.5

      \[\leadsto \color{blue}{\frac{1}{2} \cdot \frac{c}{b_2} - 2 \cdot \frac{b_2}{a}}\]
  3. Recombined 3 regimes into one program.
  4. Final simplification10.6

    \[\leadsto \begin{array}{l} \mathbf{if}\;b_2 \le -2.8328889513248502 \cdot 10^{-121}:\\ \;\;\;\;\frac{-1}{2} \cdot \frac{c}{b_2}\\ \mathbf{elif}\;b_2 \le 3.0964691378674393 \cdot 10^{+108}:\\ \;\;\;\;\frac{1}{\frac{a}{\left(-b_2\right) - \sqrt{{b_2}^{2} - c \cdot a}}}\\ \mathbf{else}:\\ \;\;\;\;\frac{c}{b_2} \cdot \frac{1}{2} - 2 \cdot \frac{b_2}{a}\\ \end{array}\]

Reproduce

herbie shell --seed 2018365 
(FPCore (a b_2 c)
  :name "NMSE problem 3.2.1"
  (/ (- (- b_2) (sqrt (- (* b_2 b_2) (* a c)))) a))

Details

Time bar (total: 21.0s)Debug log

start167.0ms

Algorithm
intervals

setup49.0ms

Pruning

1 alts after pruning (1 fresh and 0 done)

Merged error: 34.5b

localize32.0ms

Local error

Found 4 expressions with local error:

24.1b
(sqrt (- (* b_2 b_2) (* a c)))
1.3b
(- (- b_2) (sqrt (- (* b_2 b_2) (* a c))))
0.8b
(- (* b_2 b_2) (* a c))
0.1b
(/ (- (- b_2) (sqrt (- (* b_2 b_2) (* a c)))) a)

rewrite25.0ms

Algorithm
rewrite-expression-head
Counts
4 → 61
Calls

4 calls. Slowest were:

15.0ms
(/ (- (- b_2) (sqrt (- (* b_2 b_2) (* a c)))) a)
6.0ms
(- (- b_2) (sqrt (- (* b_2 b_2) (* a c))))
2.0ms
(sqrt (- (* b_2 b_2) (* a c)))

series185.0ms

Counts
4 → 12
Calls

4 calls. Slowest were:

80.0ms
(/ (- (- b_2) (sqrt (- (* b_2 b_2) (* a c)))) a)
43.0ms
(- (- b_2) (sqrt (- (* b_2 b_2) (* a c))))
37.0ms
(sqrt (- (* b_2 b_2) (* a c)))
24.0ms
(- (* b_2 b_2) (* a c))

simplify1.7s

Counts
32 → 73
Calls

32 calls. Slowest were:

319.0ms
(- (pow (- b_2) 3) (pow (sqrt (- (* b_2 b_2) (* a c))) 3))
297.0ms
(sqrt (- (* (* b_2 b_2) (* b_2 b_2)) (* (* a c) (* a c))))
288.0ms
(sqrt (- (pow (* b_2 b_2) 3) (pow (* a c) 3)))

prune798.0ms

Pruning

9 alts after pruning (9 fresh and 0 done)

Merged error: 5.9b

localize29.0ms

Local error

Found 4 expressions with local error:

24.1b
(sqrt (- (pow b_2 2) (* a c)))
1.3b
(- (- b_2) (sqrt (- (pow b_2 2) (* a c))))
0.8b
(- (pow b_2 2) (* a c))
0.1b
(/ (- (- b_2) (sqrt (- (pow b_2 2) (* a c)))) a)

rewrite52.0ms

Algorithm
rewrite-expression-head
Counts
4 → 61
Calls

4 calls. Slowest were:

27.0ms
(/ (- (- b_2) (sqrt (- (pow b_2 2) (* a c)))) a)
13.0ms
(- (- b_2) (sqrt (- (pow b_2 2) (* a c))))
6.0ms
(- (pow b_2 2) (* a c))

series178.0ms

Counts
4 → 12
Calls

4 calls. Slowest were:

59.0ms
(/ (- (- b_2) (sqrt (- (pow b_2 2) (* a c)))) a)
51.0ms
(- (- b_2) (sqrt (- (pow b_2 2) (* a c))))
38.0ms
(sqrt (- (pow b_2 2) (* a c)))
30.0ms
(- (pow b_2 2) (* a c))

simplify2.6s

Counts
32 → 73
Calls

32 calls. Slowest were:

737.0ms
(- (* (- b_2) (- b_2)) (* (sqrt (- (pow b_2 2) (* a c))) (sqrt (- (pow b_2 2) (* a c)))))
729.0ms
(sqrt (- (pow (pow b_2 2) 3) (pow (* a c) 3)))
345.0ms
(- (pow (- b_2) 3) (pow (sqrt (- (pow b_2 2) (* a c))) 3))

prune891.0ms

Pruning

9 alts after pruning (8 fresh and 1 done)

Merged error: 5.9b

localize6.0ms

Local error

Found 4 expressions with local error:

24.1b
(sqrt (- (pow b_2 2) (* a c)))
1.3b
(- (- b_2) (sqrt (- (pow b_2 2) (* a c))))
0.8b
(- (pow b_2 2) (* a c))
0.2b
(/ 1 (/ a (- (- b_2) (sqrt (- (pow b_2 2) (* a c))))))

rewrite14.0ms

Algorithm
rewrite-expression-head
Counts
4 → 62
Calls

4 calls. Slowest were:

7.0ms
(- (- b_2) (sqrt (- (pow b_2 2) (* a c))))
3.0ms
(- (pow b_2 2) (* a c))
3.0ms
(sqrt (- (pow b_2 2) (* a c)))

series216.0ms

Counts
4 → 12
Calls

4 calls. Slowest were:

85.0ms
(/ 1 (/ a (- (- b_2) (sqrt (- (pow b_2 2) (* a c))))))
53.0ms
(sqrt (- (pow b_2 2) (* a c)))
45.0ms
(- (- b_2) (sqrt (- (pow b_2 2) (* a c))))
33.0ms
(- (pow b_2 2) (* a c))

simplify1.6s

Counts
33 → 74
Calls

33 calls. Slowest were:

393.0ms
(sqrt (- (pow (pow b_2 2) 3) (pow (* a c) 3)))
328.0ms
(+ (* (- b_2) (- b_2)) (+ (* (sqrt (- (pow b_2 2) (* a c))) (sqrt (- (pow b_2 2) (* a c)))) (* (- b_2) (sqrt (- (pow b_2 2) (* a c))))))
233.0ms
(sqrt (- (* (pow b_2 2) (pow b_2 2)) (* (* a c) (* a c))))

prune907.0ms

Pruning

8 alts after pruning (7 fresh and 1 done)

Merged error: 5.9b

localize18.0ms

Local error

Found 4 expressions with local error:

24.1b
(sqrt (- (pow b_2 2) (* a c)))
1.3b
(- (- b_2) (sqrt (- (pow b_2 2) (* a c))))
0.8b
(- (pow b_2 2) (* a c))
0.3b
(/ (/ 1 a) (/ 1 (- (- b_2) (sqrt (- (pow b_2 2) (* a c))))))

rewrite37.0ms

Algorithm
rewrite-expression-head
Counts
4 → 91
Calls

4 calls. Slowest were:

14.0ms
(- (- b_2) (sqrt (- (pow b_2 2) (* a c))))
9.0ms
(sqrt (- (pow b_2 2) (* a c)))
7.0ms
(/ (/ 1 a) (/ 1 (- (- b_2) (sqrt (- (pow b_2 2) (* a c))))))

series206.0ms

Counts
4 → 12
Calls

4 calls. Slowest were:

86.0ms
(/ (/ 1 a) (/ 1 (- (- b_2) (sqrt (- (pow b_2 2) (* a c))))))
52.0ms
(- (- b_2) (sqrt (- (pow b_2 2) (* a c))))
35.0ms
(sqrt (- (pow b_2 2) (* a c)))
32.0ms
(- (pow b_2 2) (* a c))

simplify9.4s

Counts
85 → 103
Calls

85 calls. Slowest were:

1.7s
(/ (* (* (/ 1 a) (/ 1 a)) (/ 1 a)) (* (* (/ 1 (- (- b_2) (sqrt (- (pow b_2 2) (* a c))))) (/ 1 (- (- b_2) (sqrt (- (pow b_2 2) (* a c)))))) (/ 1 (- (- b_2) (sqrt (- (pow b_2 2) (* a c)))))))
466.0ms
(/ (sqrt (/ 1 a)) (/ 1 (- (* (- b_2) (- b_2)) (* (sqrt (- (pow b_2 2) (* a c))) (sqrt (- (pow b_2 2) (* a c)))))))
428.0ms
(/ (sqrt (/ 1 a)) (+ (* (- b_2) (- b_2)) (+ (* (sqrt (- (pow b_2 2) (* a c))) (sqrt (- (pow b_2 2) (* a c)))) (* (- b_2) (sqrt (- (pow b_2 2) (* a c)))))))

prune1.3s

Pruning

8 alts after pruning (6 fresh and 2 done)

Merged error: 5.9b

regimes336.0ms

Accuracy

82.3% (5.0b remaining)

Error of 10.6b against oracle of 5.6b and baseline of 33.6b

bsearch266.0ms