Average Error: 14.6 → 0.3
Time: 28.9s
Precision: 64
Internal Precision: 128
\[\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right)\]
\[\frac{\frac{\pi}{2}}{a + b} \cdot \frac{\frac{1}{a} - \frac{1}{b}}{b - a}\]

Error

Bits error versus a

Bits error versus b

Try it out

Your Program's Arguments

Results

Enter valid numbers for all inputs

Derivation

  1. Initial program 14.6

    \[\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right)\]
  2. Simplified0.3

    \[\leadsto \color{blue}{\frac{\frac{1}{a} - \frac{1}{b}}{b - a} \cdot \frac{\frac{\pi}{2}}{a + b}}\]
  3. Using strategy rm
  4. Applied associate-*r/0.3

    \[\leadsto \color{blue}{\frac{\frac{\frac{1}{a} - \frac{1}{b}}{b - a} \cdot \frac{\pi}{2}}{a + b}}\]
  5. Using strategy rm
  6. Applied *-un-lft-identity0.3

    \[\leadsto \frac{\frac{\frac{1}{a} - \frac{1}{b}}{b - a} \cdot \frac{\pi}{2}}{\color{blue}{1 \cdot \left(a + b\right)}}\]
  7. Applied times-frac0.3

    \[\leadsto \color{blue}{\frac{\frac{\frac{1}{a} - \frac{1}{b}}{b - a}}{1} \cdot \frac{\frac{\pi}{2}}{a + b}}\]
  8. Simplified0.3

    \[\leadsto \color{blue}{\frac{\frac{1}{a} - \frac{1}{b}}{b - a}} \cdot \frac{\frac{\pi}{2}}{a + b}\]
  9. Final simplification0.3

    \[\leadsto \frac{\frac{\pi}{2}}{a + b} \cdot \frac{\frac{1}{a} - \frac{1}{b}}{b - a}\]

Reproduce

herbie shell --seed 2019008 
(FPCore (a b)
  :name "NMSE Section 6.1 mentioned, B"
  (* (* (/ PI 2) (/ 1 (- (* b b) (* a a)))) (- (/ 1 a) (/ 1 b))))

Details

Time bar (total: 28.4s)Debug log

sample90.0ms

Algorithm
intervals

simplify360.0ms

Counts
1 → 1
Calls

1 calls. Slowest were:

360.0ms
(* (* (/ PI 2) (/ 1 (- (* b b) (* a a)))) (- (/ 1 a) (/ 1 b)))

prune22.0ms

Pruning

2 alts after pruning (2 fresh and 0 done)

Merged error: 0.1b

localize44.0ms

Local error

Found 4 expressions with local error:

0.3b
(/ (- (/ 1 a) (/ 1 b)) (- b a))
0.2b
(* (/ (- (/ 1 a) (/ 1 b)) (- b a)) (/ (/ PI 2) (+ a b)))
0.2b
(/ (/ PI 2) (+ a b))
0.0b
(- (/ 1 a) (/ 1 b))

rewrite29.0ms

Algorithm
rewrite-expression-head
Counts
4 → 173
Calls

4 calls. Slowest were:

11.0ms
(* (/ (- (/ 1 a) (/ 1 b)) (- b a)) (/ (/ PI 2) (+ a b)))
9.0ms
(/ (- (/ 1 a) (/ 1 b)) (- b a))
3.0ms
(- (/ 1 a) (/ 1 b))

series185.0ms

Counts
4 → 12
Calls

4 calls. Slowest were:

79.0ms
(/ (/ PI 2) (+ a b))
74.0ms
(* (/ (- (/ 1 a) (/ 1 b)) (- b a)) (/ (/ PI 2) (+ a b)))
17.0ms
(/ (- (/ 1 a) (/ 1 b)) (- b a))
13.0ms
(- (/ 1 a) (/ 1 b))

simplify5.4s

Counts
176 → 185
Calls

176 calls. Slowest were:

537.0ms
(+ (log (/ (- (/ 1 a) (/ 1 b)) (- b a))) (log (/ (/ PI 2) (+ a b))))
418.0ms
(+ (- (log (- (/ 1 a) (/ 1 b))) (log (- b a))) (- (log (/ PI 2)) (log (+ a b))))
343.0ms
(/ (* (* (/ PI 2) (/ PI 2)) (/ PI 2)) (* (* (+ a b) (+ a b)) (+ a b)))

prune1.9s

Pruning

9 alts after pruning (9 fresh and 0 done)

Merged error: 0b

localize12.0ms

Local error

Found 4 expressions with local error:

0.3b
(* (/ (- (/ 1 a) (/ 1 b)) (- b a)) (/ PI 2))
0.3b
(/ (- (/ 1 a) (/ 1 b)) (- b a))
0.2b
(/ (* (/ (- (/ 1 a) (/ 1 b)) (- b a)) (/ PI 2)) (+ a b))
0.0b
(- (/ 1 a) (/ 1 b))

rewrite39.0ms

Algorithm
rewrite-expression-head
Counts
4 → 149
Calls

4 calls. Slowest were:

14.0ms
(* (/ (- (/ 1 a) (/ 1 b)) (- b a)) (/ PI 2))
10.0ms
(/ (* (/ (- (/ 1 a) (/ 1 b)) (- b a)) (/ PI 2)) (+ a b))
9.0ms
(/ (- (/ 1 a) (/ 1 b)) (- b a))

series165.0ms

Counts
4 → 12
Calls

4 calls. Slowest were:

83.0ms
(/ (* (/ (- (/ 1 a) (/ 1 b)) (- b a)) (/ PI 2)) (+ a b))
40.0ms
(* (/ (- (/ 1 a) (/ 1 b)) (- b a)) (/ PI 2))
29.0ms
(/ (- (/ 1 a) (/ 1 b)) (- b a))
13.0ms
(- (/ 1 a) (/ 1 b))

simplify5.3s

Counts
145 → 161
Calls

145 calls. Slowest were:

311.0ms
(+ (- (log (- (/ 1 a) (/ 1 b))) (log (- b a))) (log (/ PI 2)))
284.0ms
(- (+ (log (/ (- (/ 1 a) (/ 1 b)) (- b a))) (log (/ PI 2))) (log (+ a b)))
279.0ms
(- (log (* (/ (- (/ 1 a) (/ 1 b)) (- b a)) (/ PI 2))) (log (+ a b)))

prune1.6s

Pruning

7 alts after pruning (7 fresh and 0 done)

Merged error: 0b

localize1.0ms

Local error

Found 4 expressions with local error:

0.3b
(/ (- (/ 1 a) (/ 1 b)) (- b a))
0.2b
(* (/ (- (/ 1 a) (/ 1 b)) (- b a)) (/ (/ PI 2) (+ a b)))
0.2b
(/ (/ PI 2) (+ a b))
0.0b
(- (/ 1 a) (/ 1 b))

rewrite47.0ms

Algorithm
rewrite-expression-head
Counts
4 → 173
Calls

4 calls. Slowest were:

21.0ms
(* (/ (- (/ 1 a) (/ 1 b)) (- b a)) (/ (/ PI 2) (+ a b)))
9.0ms
(/ (- (/ 1 a) (/ 1 b)) (- b a))
6.0ms
(/ (/ PI 2) (+ a b))

series175.0ms

Counts
4 → 12
Calls

4 calls. Slowest were:

80.0ms
(* (/ (- (/ 1 a) (/ 1 b)) (- b a)) (/ (/ PI 2) (+ a b)))
69.0ms
(/ (/ PI 2) (+ a b))
17.0ms
(/ (- (/ 1 a) (/ 1 b)) (- b a))
8.0ms
(- (/ 1 a) (/ 1 b))

simplify5.1s

Counts
176 → 185
Calls

176 calls. Slowest were:

371.0ms
(+ (- (log (- (/ 1 a) (/ 1 b))) (log (- b a))) (- (log (/ PI 2)) (log (+ a b))))
339.0ms
(+ (log (/ (- (/ 1 a) (/ 1 b)) (- b a))) (- (log (/ PI 2)) (log (+ a b))))
336.0ms
(/ (* (* (/ PI 2) (/ PI 2)) (/ PI 2)) (* (* (+ a b) (+ a b)) (+ a b)))

prune1.8s

Pruning

7 alts after pruning (6 fresh and 1 done)

Merged error: 0b

localize8.0ms

Local error

Found 3 expressions with local error:

1.0b
(/ 1 (* a b))
0.2b
(* (/ 1 (* a b)) (/ (/ PI 2) (+ a b)))
0.2b
(/ (/ PI 2) (+ a b))

rewrite22.0ms

Algorithm
rewrite-expression-head
Counts
3 → 88
Calls

3 calls. Slowest were:

12.0ms
(* (/ 1 (* a b)) (/ (/ PI 2) (+ a b)))
6.0ms
(/ (/ PI 2) (+ a b))
1.0ms
(/ 1 (* a b))

series149.0ms

Counts
3 → 9
Calls

3 calls. Slowest were:

72.0ms
(/ (/ PI 2) (+ a b))
64.0ms
(* (/ 1 (* a b)) (/ (/ PI 2) (+ a b)))
14.0ms
(/ 1 (* a b))

simplify2.4s

Counts
74 → 97
Calls

74 calls. Slowest were:

421.0ms
(+ (log (/ 1 (* a b))) (- (log (/ PI 2)) (log (+ a b))))
381.0ms
(/ (* (* (/ PI 2) (/ PI 2)) (/ PI 2)) (* (* (+ a b) (+ a b)) (+ a b)))
262.0ms
(+ (- (log (* a b))) (- (log (/ PI 2)) (log (+ a b))))

prune782.0ms

Pruning

7 alts after pruning (5 fresh and 2 done)

Merged error: 0b

regimes128.0ms

Accuracy

0% (0.3b remaining)

Error of 0.3b against oracle of 0.0b and baseline of 0.3b

bsearch3.0ms

end0.0ms

sample2.6s

Algorithm
intervals