Average Error: 1.0 → 0.0
Time: 35.9s
Precision: 64
Internal Precision: 128
\[\frac{4}{\left(\left(3 \cdot \pi\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}}\]
\[\frac{e^{\log \left(\frac{\frac{4}{3}}{\pi}\right) - \log \left(1 - v \cdot v\right)}}{\sqrt{(-6 \cdot \left(v \cdot v\right) + 2)_*}}\]

Error

Bits error versus v

Derivation

  1. Initial program 1.0

    \[\frac{4}{\left(\left(3 \cdot \pi\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}}\]
  2. Initial simplification0.0

    \[\leadsto \frac{\frac{\frac{\frac{4}{3}}{\pi}}{1 - v \cdot v}}{\sqrt{(-6 \cdot \left(v \cdot v\right) + 2)_*}}\]
  3. Using strategy rm
  4. Applied add-exp-log0.0

    \[\leadsto \frac{\frac{\frac{\frac{4}{3}}{\pi}}{\color{blue}{e^{\log \left(1 - v \cdot v\right)}}}}{\sqrt{(-6 \cdot \left(v \cdot v\right) + 2)_*}}\]
  5. Applied add-exp-log0.0

    \[\leadsto \frac{\frac{\color{blue}{e^{\log \left(\frac{\frac{4}{3}}{\pi}\right)}}}{e^{\log \left(1 - v \cdot v\right)}}}{\sqrt{(-6 \cdot \left(v \cdot v\right) + 2)_*}}\]
  6. Applied div-exp0.0

    \[\leadsto \frac{\color{blue}{e^{\log \left(\frac{\frac{4}{3}}{\pi}\right) - \log \left(1 - v \cdot v\right)}}}{\sqrt{(-6 \cdot \left(v \cdot v\right) + 2)_*}}\]
  7. Final simplification0.0

    \[\leadsto \frac{e^{\log \left(\frac{\frac{4}{3}}{\pi}\right) - \log \left(1 - v \cdot v\right)}}{\sqrt{(-6 \cdot \left(v \cdot v\right) + 2)_*}}\]

Reproduce

herbie shell --seed 2018360 +o rules:numerics
(FPCore (v)
  :name "Falkner and Boettcher, Equation (22+)"
  (/ 4 (* (* (* 3 PI) (- 1 (* v v))) (sqrt (- 2 (* 6 (* v v)))))))

Details

Time bar (total: 30.6s)Debug log

start112.0ms

Algorithm
intervals

setup549.0ms

Pruning

1 alts after pruning (1 fresh and 0 done)

Merged error: 0.0b

localize47.0ms

Local error

Found 4 expressions with local error:

1.0b
(/ 4/3 PI)
0.0b
(/ (/ 4/3 PI) (- 1 (* v v)))
0.0b
(/ (/ (/ 4/3 PI) (- 1 (* v v))) (sqrt (fma -6 (* v v) 2)))
0.0b
(- 1 (* v v))

rewrite28.0ms

Algorithm
rewrite-expression-head
Counts
4 → 210
Calls

4 calls. Slowest were:

13.0ms
(/ (/ (/ 4/3 PI) (- 1 (* v v))) (sqrt (fma -6 (* v v) 2)))
6.0ms
(/ (/ 4/3 PI) (- 1 (* v v)))
1.0ms
(- 1 (* v v))

series328.0ms

Counts
4 → 10
Calls

4 calls. Slowest were:

232.0ms
(/ (/ (/ 4/3 PI) (- 1 (* v v))) (sqrt (fma -6 (* v v) 2)))
68.0ms
(/ (/ 4/3 PI) (- 1 (* v v)))
28.0ms
(- 1 (* v v))
0.0ms
(/ 4/3 PI)

simplify19.9s

Counts
287 → 220
Calls

287 calls. Slowest were:

510.0ms
(/ (/ (/ 4/3 PI) (- (pow 1 3) (pow (* v v) 3))) (sqrt 1))
474.0ms
(/ (/ (/ 4/3 PI) (- (pow 1 3) (pow (* v v) 3))) (* (cbrt (sqrt (fma -6 (* v v) 2))) (cbrt (sqrt (fma -6 (* v v) 2)))))
468.0ms
(/ (/ (/ 4/3 PI) (- (* 1 1) (* (* v v) (* v v)))) (sqrt (sqrt (fma -6 (* v v) 2))))

prune3.4s

Pruning

2 alts after pruning (1 fresh and 1 done)

Merged error: 0b

localize15.0ms

Local error

Found 4 expressions with local error:

5.3b
(log (- 1 (* v v)))
1.0b
(/ 4/3 PI)
1.0b
(log (/ 4/3 PI))
1.0b
(exp (- (log (/ 4/3 PI)) (log (- 1 (* v v)))))

rewrite27.0ms

Algorithm
rewrite-expression-head
Counts
4 → 90
Calls

4 calls. Slowest were:

23.0ms
(exp (- (log (/ 4/3 PI)) (log (- 1 (* v v)))))
1.0ms
(log (- 1 (* v v)))
1.0ms
(log (/ 4/3 PI))

series391.0ms

Counts
4 → 8
Calls

4 calls. Slowest were:

239.0ms
(exp (- (log (/ 4/3 PI)) (log (- 1 (* v v)))))
151.0ms
(log (- 1 (* v v)))
0.0ms
(/ 4/3 PI)
0.0ms
(log (/ 4/3 PI))

simplify3.6s

Counts
57 → 98
Calls

57 calls. Slowest were:

376.0ms
(- (log -1) (+ (* 2 (log (/ 1 v))) (+ (* 1/2 (/ 1 (pow v 4))) (/ 1 (pow v 2)))))
208.0ms
(exp (fma 1 (log (/ 4/3 PI)) (- (* (log (- 1 (* v v))) 1))))
195.0ms
(- (log -1) (+ (* 2 (log (/ -1 v))) (+ (* 1/2 (/ 1 (pow v 4))) (/ 1 (pow v 2)))))

prune2.1s

Pruning

2 alts after pruning (0 fresh and 2 done)

Merged error: 0b

regimes80.0ms

Accuracy

0% (0.0b remaining)

Error of 0.0b against oracle of 0.0b and baseline of 0.0b

bsearch3.0ms