Average Error: 1.0 → 0.0
Time: 1.2m
Precision: 64
Internal Precision: 128
\[\frac{4}{\left(\left(3 \cdot \pi\right) \cdot \left(1 - v \cdot v\right)\right) \cdot \sqrt{2 - 6 \cdot \left(v \cdot v\right)}}\]
\[\frac{\frac{\frac{1}{\pi}}{1 - v \cdot v}}{\sqrt{(-6 \cdot \left(v \cdot v\right) + 2)_*}} \cdot \frac{4}{3}\]

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. Simplified0.0

    \[\leadsto \color{blue}{\frac{\frac{\frac{\frac{4}{3}}{\pi}}{1 - v \cdot v}}{\sqrt{(-6 \cdot \left(v \cdot v\right) + 2)_*}}}\]
  3. Using strategy rm
  4. Applied *-un-lft-identity0.0

    \[\leadsto \frac{\frac{\frac{\frac{4}{3}}{\pi}}{1 - v \cdot v}}{\sqrt{\color{blue}{1 \cdot (-6 \cdot \left(v \cdot v\right) + 2)_*}}}\]
  5. Applied sqrt-prod0.0

    \[\leadsto \frac{\frac{\frac{\frac{4}{3}}{\pi}}{1 - v \cdot v}}{\color{blue}{\sqrt{1} \cdot \sqrt{(-6 \cdot \left(v \cdot v\right) + 2)_*}}}\]
  6. Applied *-un-lft-identity0.0

    \[\leadsto \frac{\frac{\frac{\frac{4}{3}}{\pi}}{\color{blue}{1 \cdot \left(1 - v \cdot v\right)}}}{\sqrt{1} \cdot \sqrt{(-6 \cdot \left(v \cdot v\right) + 2)_*}}\]
  7. Applied div-inv0.0

    \[\leadsto \frac{\frac{\color{blue}{\frac{4}{3} \cdot \frac{1}{\pi}}}{1 \cdot \left(1 - v \cdot v\right)}}{\sqrt{1} \cdot \sqrt{(-6 \cdot \left(v \cdot v\right) + 2)_*}}\]
  8. Applied times-frac0.0

    \[\leadsto \frac{\color{blue}{\frac{\frac{4}{3}}{1} \cdot \frac{\frac{1}{\pi}}{1 - v \cdot v}}}{\sqrt{1} \cdot \sqrt{(-6 \cdot \left(v \cdot v\right) + 2)_*}}\]
  9. Applied times-frac0.0

    \[\leadsto \color{blue}{\frac{\frac{\frac{4}{3}}{1}}{\sqrt{1}} \cdot \frac{\frac{\frac{1}{\pi}}{1 - v \cdot v}}{\sqrt{(-6 \cdot \left(v \cdot v\right) + 2)_*}}}\]
  10. Simplified0.0

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

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

Reproduce

herbie shell --seed 2019004 +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: 1.2m)Debug log

sample175.0ms

Algorithm
intervals

simplify122.0ms

Counts
1 → 1
Calls

1 calls. Slowest were:

122.0ms
(/ 4 (* (* (* 3 PI) (- 1 (* v v))) (sqrt (- 2 (* 6 (* v v))))))

prune22.0ms

Pruning

2 alts after pruning (2 fresh and 0 done)

Merged error: 0b

localize28.0ms

Local error

Found 3 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)))

rewrite24.0ms

Algorithm
rewrite-expression-head
Counts
3 → 197
Calls

3 calls. Slowest were:

15.0ms
(/ (/ (/ 4/3 PI) (- 1 (* v v))) (sqrt (fma -6 (* v v) 2)))
6.0ms
(/ (/ 4/3 PI) (- 1 (* v v)))
0.0ms
(/ 4/3 PI)

series282.0ms

Counts
3 → 7
Calls

3 calls. Slowest were:

197.0ms
(/ (/ (/ 4/3 PI) (- 1 (* v v))) (sqrt (fma -6 (* v v) 2)))
85.0ms
(/ (/ 4/3 PI) (- 1 (* v v)))
0.0ms
(/ 4/3 PI)

simplify24.1s

Counts
284 → 204
Calls

284 calls. Slowest were:

826.0ms
(- (+ (* 4/3 (/ 1 (* (pow v 2) PI))) (+ (* 4/3 (/ 1 (* (pow v 4) PI))) (* 4/3 (/ 1 (* (pow v 6) PI))))))
636.0ms
(- (+ (* 4/3 (/ 1 (* (pow v 2) PI))) (+ (* 4/3 (/ 1 (* (pow v 4) PI))) (* 4/3 (/ 1 (* (pow v 6) PI))))))
449.0ms
(/ (/ (/ 4/3 PI) (- (pow 1 3) (pow (* v v) 3))) (sqrt (sqrt (fma -6 (* v v) 2))))

prune2.5s

Pruning

1 alts after pruning (1 fresh and 0 done)

Merged error: 0b

localize20.0ms

Local error

Found 3 expressions with local error:

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

rewrite25.0ms

Algorithm
rewrite-expression-head
Counts
3 → 308
Calls

3 calls. Slowest were:

7.0ms
(/ (/ (/ 1 PI) (- 1 (* v v))) (sqrt (fma -6 (* v v) 2)))
4.0ms
(* 4/3 (/ (/ (/ 1 PI) (- 1 (* v v))) (sqrt (fma -6 (* v v) 2))))
3.0ms
(/ (/ 1 PI) (- 1 (* v v)))

series432.0ms

Counts
3 → 9
Calls

3 calls. Slowest were:

200.0ms
(* 4/3 (/ (/ (/ 1 PI) (- 1 (* v v))) (sqrt (fma -6 (* v v) 2))))
169.0ms
(/ (/ (/ 1 PI) (- 1 (* v v))) (sqrt (fma -6 (* v v) 2)))
63.0ms
(/ (/ 1 PI) (- 1 (* v v)))

simplify36.0s

Counts
399 → 317
Calls

399 calls. Slowest were:

686.0ms
(/ (/ (/ 1 PI) (- 1 (* v v))) (cbrt (sqrt (fma -6 (* v v) 2))))
653.0ms
(/ (* (* (/ (/ 1 PI) (- 1 (* v v))) (/ (/ 1 PI) (- 1 (* v v)))) (/ (/ 1 PI) (- 1 (* v v)))) (* (* (sqrt (fma -6 (* v v) 2)) (sqrt (fma -6 (* v v) 2))) (sqrt (fma -6 (* v v) 2))))
473.0ms
(/ (/ (/ 1 PI) (- (* 1 1) (* (* v v) (* v v)))) (sqrt 1))

prune3.7s

Pruning

1 alts after pruning (0 fresh and 1 done)

Merged error: 0b

end0.0ms

sample3.4s

Algorithm
intervals