Average Error: 0.4 → 0.4
Time: 37.5s
Precision: 64
Internal Precision: 128
\[\frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \pi\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)}\]
\[\frac{1}{\frac{\sqrt{k}}{{2}^{\left(\frac{1}{2} - \frac{k}{2}\right)} \cdot {n}^{\left(\frac{1}{2} - \frac{k}{2}\right)}}} \cdot {\pi}^{\left(\frac{1}{2} - \frac{k}{2}\right)}\]

Error

Bits error versus k

Bits error versus n

Try it out

Your Program's Arguments

Results

Enter valid numbers for all inputs

Derivation

  1. Initial program 0.4

    \[\frac{1}{\sqrt{k}} \cdot {\left(\left(2 \cdot \pi\right) \cdot n\right)}^{\left(\frac{1 - k}{2}\right)}\]
  2. Initial simplification0.3

    \[\leadsto \frac{{\left(\pi \cdot \left(n \cdot 2\right)\right)}^{\left(\frac{1}{2} - \frac{k}{2}\right)}}{\sqrt{k}}\]
  3. Using strategy rm
  4. Applied *-un-lft-identity0.3

    \[\leadsto \frac{\color{blue}{1 \cdot {\left(\pi \cdot \left(n \cdot 2\right)\right)}^{\left(\frac{1}{2} - \frac{k}{2}\right)}}}{\sqrt{k}}\]
  5. Applied associate-/l*0.4

    \[\leadsto \color{blue}{\frac{1}{\frac{\sqrt{k}}{{\left(\pi \cdot \left(n \cdot 2\right)\right)}^{\left(\frac{1}{2} - \frac{k}{2}\right)}}}}\]
  6. Using strategy rm
  7. Applied unpow-prod-down0.5

    \[\leadsto \frac{1}{\frac{\sqrt{k}}{\color{blue}{{\pi}^{\left(\frac{1}{2} - \frac{k}{2}\right)} \cdot {\left(n \cdot 2\right)}^{\left(\frac{1}{2} - \frac{k}{2}\right)}}}}\]
  8. Applied *-un-lft-identity0.5

    \[\leadsto \frac{1}{\frac{\color{blue}{1 \cdot \sqrt{k}}}{{\pi}^{\left(\frac{1}{2} - \frac{k}{2}\right)} \cdot {\left(n \cdot 2\right)}^{\left(\frac{1}{2} - \frac{k}{2}\right)}}}\]
  9. Applied times-frac0.4

    \[\leadsto \frac{1}{\color{blue}{\frac{1}{{\pi}^{\left(\frac{1}{2} - \frac{k}{2}\right)}} \cdot \frac{\sqrt{k}}{{\left(n \cdot 2\right)}^{\left(\frac{1}{2} - \frac{k}{2}\right)}}}}\]
  10. Using strategy rm
  11. Applied associate-*l/0.5

    \[\leadsto \frac{1}{\color{blue}{\frac{1 \cdot \frac{\sqrt{k}}{{\left(n \cdot 2\right)}^{\left(\frac{1}{2} - \frac{k}{2}\right)}}}{{\pi}^{\left(\frac{1}{2} - \frac{k}{2}\right)}}}}\]
  12. Applied associate-/r/0.5

    \[\leadsto \color{blue}{\frac{1}{1 \cdot \frac{\sqrt{k}}{{\left(n \cdot 2\right)}^{\left(\frac{1}{2} - \frac{k}{2}\right)}}} \cdot {\pi}^{\left(\frac{1}{2} - \frac{k}{2}\right)}}\]
  13. Using strategy rm
  14. Applied unpow-prod-down0.4

    \[\leadsto \frac{1}{1 \cdot \frac{\sqrt{k}}{\color{blue}{{n}^{\left(\frac{1}{2} - \frac{k}{2}\right)} \cdot {2}^{\left(\frac{1}{2} - \frac{k}{2}\right)}}}} \cdot {\pi}^{\left(\frac{1}{2} - \frac{k}{2}\right)}\]
  15. Final simplification0.4

    \[\leadsto \frac{1}{\frac{\sqrt{k}}{{2}^{\left(\frac{1}{2} - \frac{k}{2}\right)} \cdot {n}^{\left(\frac{1}{2} - \frac{k}{2}\right)}}} \cdot {\pi}^{\left(\frac{1}{2} - \frac{k}{2}\right)}\]

Reproduce

herbie shell --seed 2018360 +o rules:numerics
(FPCore (k n)
  :name "Migdal et al, Equation (51)"
  (* (/ 1 (sqrt k)) (pow (* (* 2 PI) n) (/ (- 1 k) 2))))

Details

Time bar (total: 23.3s)Debug log

start405.0ms

Algorithm
intervals

setup94.0ms

Pruning

2 alts after pruning (2 fresh and 0 done)

Merged error: 0.3b

localize30.0ms

Local error

Found 3 expressions with local error:

0.7b
(pow (* PI (* n 2)) (- 1/2 (/ k 2)))
0.3b
(* PI (* n 2))
0.2b
(/ (pow (* PI (* n 2)) (- 1/2 (/ k 2))) (sqrt k))

rewrite14.0ms

Algorithm
rewrite-expression-head
Counts
3 → 74
Calls

3 calls. Slowest were:

7.0ms
(pow (* PI (* n 2)) (- 1/2 (/ k 2)))
5.0ms
(/ (pow (* PI (* n 2)) (- 1/2 (/ k 2))) (sqrt k))
1.0ms
(* PI (* n 2))

series446.0ms

Counts
3 → 9
Calls

3 calls. Slowest were:

237.0ms
(/ (pow (* PI (* n 2)) (- 1/2 (/ k 2))) (sqrt k))
155.0ms
(pow (* PI (* n 2)) (- 1/2 (/ k 2)))
54.0ms
(* PI (* n 2))

simplify4.0s

Counts
67 → 83
Calls

67 calls. Slowest were:

654.0ms
(- (* (log (* PI (* n 2))) (- 1/2 (/ k 2))) (log (sqrt k)))
584.0ms
(- (* (log (* PI (* n 2))) (- 1/2 (/ k 2))) (log (sqrt k)))
584.0ms
(exp (* (- 1/2 (* 1/2 k)) (- (log (* 2 PI)) (log (/ 1 n)))))

prune1.2s

Pruning

10 alts after pruning (10 fresh and 0 done)

Merged error: 0.0b

localize12.0ms

Local error

Found 4 expressions with local error:

0.7b
(pow (* PI (* n 2)) (- 1/2 (/ k 2)))
0.3b
(* PI (* n 2))
0.2b
(/ (sqrt k) (pow (* PI (* n 2)) (- 1/2 (/ k 2))))
0.1b
(/ 1 (/ (sqrt k) (pow (* PI (* n 2)) (- 1/2 (/ k 2)))))

rewrite24.0ms

Algorithm
rewrite-expression-head
Counts
4 → 116
Calls

4 calls. Slowest were:

8.0ms
(/ (sqrt k) (pow (* PI (* n 2)) (- 1/2 (/ k 2))))
6.0ms
(pow (* PI (* n 2)) (- 1/2 (/ k 2)))
5.0ms
(/ 1 (/ (sqrt k) (pow (* PI (* n 2)) (- 1/2 (/ k 2)))))

series495.0ms

Counts
4 → 12
Calls

4 calls. Slowest were:

185.0ms
(/ 1 (/ (sqrt k) (pow (* PI (* n 2)) (- 1/2 (/ k 2)))))
139.0ms
(/ (sqrt k) (pow (* PI (* n 2)) (- 1/2 (/ k 2))))
113.0ms
(pow (* PI (* n 2)) (- 1/2 (/ k 2)))
57.0ms
(* PI (* n 2))

simplify2.8s

Counts
95 → 128
Calls

95 calls. Slowest were:

337.0ms
(* (log (* PI (* n 2))) (- 1/2 (/ k 2)))
321.0ms
(- (log (sqrt k)) (log (pow (* PI (* n 2)) (- 1/2 (/ k 2)))))
284.0ms
(- (+ (* 1/4 (* (log (* 2 PI)) (* (exp (* 1/2 (+ (log n) (log (* 2 PI))))) (* (log n) (pow k 2))))) (+ (* 1/8 (* (exp (* 1/2 (+ (log n) (log (* 2 PI))))) (* (pow (log n) 2) (pow k 2)))) (+ (exp (* 1/2 (+ (log n) (log (* 2 PI))))) (* 1/8 (* (pow (log (* 2 PI)) 2) (* (exp (* 1/2 (+ (log n) (log (* 2 PI))))) (pow k 2))))))) (+ (* 1/2 (* (exp (* 1/2 (+ (log n) (log (* 2 PI))))) (* (log n) k))) (* 1/2 (* (log (* 2 PI)) (* (exp (* 1/2 (+ (log n) (log (* 2 PI))))) k)))))

prune1.8s

Pruning

9 alts after pruning (9 fresh and 0 done)

Merged error: 0.0b

localize42.0ms

Local error

Found 4 expressions with local error:

0.6b
(pow (* n 2) (- 1/2 (/ k 2)))
0.5b
(pow PI (- 1/2 (/ k 2)))
0.2b
(/ (sqrt k) (pow (* n 2) (- 1/2 (/ k 2))))
0.1b
(/ 1 (* (/ 1 (pow PI (- 1/2 (/ k 2)))) (/ (sqrt k) (pow (* n 2) (- 1/2 (/ k 2))))))

rewrite21.0ms

Algorithm
rewrite-expression-head
Counts
4 → 111
Calls

4 calls. Slowest were:

9.0ms
(/ (sqrt k) (pow (* n 2) (- 1/2 (/ k 2))))
6.0ms
(/ 1 (* (/ 1 (pow PI (- 1/2 (/ k 2)))) (/ (sqrt k) (pow (* n 2) (- 1/2 (/ k 2))))))
3.0ms
(pow (* n 2) (- 1/2 (/ k 2)))

series487.0ms

Counts
4 → 12
Calls

4 calls. Slowest were:

233.0ms
(/ 1 (* (/ 1 (pow PI (- 1/2 (/ k 2)))) (/ (sqrt k) (pow (* n 2) (- 1/2 (/ k 2))))))
140.0ms
(/ (sqrt k) (pow (* n 2) (- 1/2 (/ k 2))))
73.0ms
(pow (* n 2) (- 1/2 (/ k 2)))
41.0ms
(pow PI (- 1/2 (/ k 2)))

simplify2.5s

Counts
82 → 123
Calls

82 calls. Slowest were:

596.0ms
(exp (* (- (log 2) (log (/ 1 n))) (- 1/2 (* 1/2 k))))
305.0ms
(- (+ (exp (* 1/2 (+ (log 2) (log n)))) (+ (* 1/8 (* (pow (log 2) 2) (* (exp (* 1/2 (+ (log 2) (log n)))) (pow k 2)))) (+ (* 1/4 (* (log 2) (* (exp (* 1/2 (+ (log 2) (log n)))) (* (log n) (pow k 2))))) (* 1/8 (* (exp (* 1/2 (+ (log 2) (log n)))) (* (pow (log n) 2) (pow k 2))))))) (+ (* 1/2 (* (exp (* 1/2 (+ (log 2) (log n)))) (* (log n) k))) (* 1/2 (* (log 2) (* (exp (* 1/2 (+ (log 2) (log n)))) k)))))
293.0ms
(* (log (* n 2)) (- 1/2 (/ k 2)))

prune1.9s

Pruning

8 alts after pruning (8 fresh and 0 done)

Merged error: 0b

localize8.0ms

Local error

Found 4 expressions with local error:

0.6b
(pow (* n 2) (- 1/2 (/ k 2)))
0.5b
(pow PI (- 1/2 (/ k 2)))
0.2b
(/ (sqrt k) (pow (* n 2) (- 1/2 (/ k 2))))
0.2b
(* (/ 1 (* 1 (/ (sqrt k) (pow (* n 2) (- 1/2 (/ k 2)))))) (pow PI (- 1/2 (/ k 2))))

rewrite16.0ms

Algorithm
rewrite-expression-head
Counts
4 → 107
Calls

4 calls. Slowest were:

9.0ms
(* (/ 1 (* 1 (/ (sqrt k) (pow (* n 2) (- 1/2 (/ k 2)))))) (pow PI (- 1/2 (/ k 2))))
4.0ms
(/ (sqrt k) (pow (* n 2) (- 1/2 (/ k 2))))
1.0ms
(pow (* n 2) (- 1/2 (/ k 2)))

series514.0ms

Counts
4 → 12
Calls

4 calls. Slowest were:

296.0ms
(* (/ 1 (* 1 (/ (sqrt k) (pow (* n 2) (- 1/2 (/ k 2)))))) (pow PI (- 1/2 (/ k 2))))
110.0ms
(/ (sqrt k) (pow (* n 2) (- 1/2 (/ k 2))))
84.0ms
(pow (* n 2) (- 1/2 (/ k 2)))
23.0ms
(pow PI (- 1/2 (/ k 2)))

simplify4.6s

Counts
93 → 119
Calls

93 calls. Slowest were:

601.0ms
(exp (* (- (log 2) (log (/ 1 n))) (- 1/2 (* 1/2 k))))
550.0ms
(+ (log (/ 1 (* 1 (/ (sqrt k) (pow (* n 2) (- 1/2 (/ k 2))))))) (log (pow PI (- 1/2 (/ k 2)))))
360.0ms
(+ (- (log (* 1 (/ (sqrt k) (pow (* n 2) (- 1/2 (/ k 2))))))) (* (log PI) (- 1/2 (/ k 2))))

prune1.9s

Pruning

6 alts after pruning (6 fresh and 0 done)

Merged error: 0b

regimes118.0ms

Accuracy

0% (0.4b remaining)

Error of 0.4b against oracle of 0.0b and baseline of 0.4b

bsearch2.0ms