Average Error: 14.1 → 0.3
Time: 48.6s
Precision: 64
Internal Precision: 128
\[\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right)\]
\[\frac{1}{a + b} \cdot \frac{\frac{\pi}{2 \cdot a} - \frac{\pi}{2 \cdot b}}{b - a}\]

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 14.1

    \[\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right)\]
  2. Simplified9.2

    \[\leadsto \color{blue}{\frac{(\left(\frac{\pi}{2}\right) \cdot \left(\frac{-1}{b}\right) + \left(\frac{\frac{\pi}{2}}{a}\right))_*}{\left(a + b\right) \cdot \left(b - a\right)}}\]
  3. Using strategy rm
  4. Applied *-un-lft-identity9.2

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

    \[\leadsto \color{blue}{\frac{1}{a + b} \cdot \frac{(\left(\frac{\pi}{2}\right) \cdot \left(\frac{-1}{b}\right) + \left(\frac{\frac{\pi}{2}}{a}\right))_*}{b - a}}\]
  6. Simplified0.3

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

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

Reproduce

herbie shell --seed 2019002 +o rules:numerics
(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: 47.8s)Debug log

sample52.0ms

Algorithm
intervals

simplify349.0ms

Counts
1 → 1
Calls

1 calls. Slowest were:

348.0ms
(* (* (/ 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: 11.1b

localize44.0ms

Local error

Found 3 expressions with local error:

11.1b
(/ (fma (/ PI 2) (/ -1 b) (/ (/ PI 2) a)) (* (+ a b) (- b a)))
0.2b
(/ (/ PI 2) a)
0.1b
(fma (/ PI 2) (/ -1 b) (/ (/ PI 2) a))

rewrite9.0ms

Algorithm
rewrite-expression-head
Counts
3 → 58
Calls

3 calls. Slowest were:

6.0ms
(/ (fma (/ PI 2) (/ -1 b) (/ (/ PI 2) a)) (* (+ a b) (- b a)))
2.0ms
(/ (/ PI 2) a)
0.0ms
(fma (/ PI 2) (/ -1 b) (/ (/ PI 2) a))

series257.0ms

Counts
3 → 9
Calls

3 calls. Slowest were:

131.0ms
(/ (fma (/ PI 2) (/ -1 b) (/ (/ PI 2) a)) (* (+ a b) (- b a)))
71.0ms
(/ (/ PI 2) a)
55.0ms
(fma (/ PI 2) (/ -1 b) (/ (/ PI 2) a))

simplify2.3s

Counts
32 → 67
Calls

32 calls. Slowest were:

378.0ms
(* (- a b) (+ b a))
279.0ms
(* (+ (* a a) (- (* b b) (* a b))) (+ (* b b) (+ (* a a) (* b a))))
237.0ms
(- (log (fma (/ PI 2) (/ -1 b) (/ (/ PI 2) a))) (log (* (+ a b) (- b a))))

prune732.0ms

Pruning

9 alts after pruning (9 fresh and 0 done)

Merged error: 0.0b

localize12.0ms

Local error

Found 4 expressions with local error:

0.3b
(/ (fma (/ PI 2) (/ -1 b) (/ (/ PI 2) a)) (+ a b))
0.2b
(/ (/ PI 2) a)
0.2b
(/ (/ (fma (/ PI 2) (/ -1 b) (/ (/ PI 2) a)) (+ a b)) (- b a))
0.1b
(fma (/ PI 2) (/ -1 b) (/ (/ PI 2) a))

rewrite19.0ms

Algorithm
rewrite-expression-head
Counts
4 → 140
Calls

4 calls. Slowest were:

7.0ms
(/ (fma (/ PI 2) (/ -1 b) (/ (/ PI 2) a)) (+ a b))
6.0ms
(/ (/ (fma (/ PI 2) (/ -1 b) (/ (/ PI 2) a)) (+ a b)) (- b a))
4.0ms
(/ (/ PI 2) a)

series319.0ms

Counts
4 → 12
Calls

4 calls. Slowest were:

111.0ms
(/ (/ (fma (/ PI 2) (/ -1 b) (/ (/ PI 2) a)) (+ a b)) (- b a))
86.0ms
(/ (fma (/ PI 2) (/ -1 b) (/ (/ PI 2) a)) (+ a b))
75.0ms
(/ (/ PI 2) a)
47.0ms
(fma (/ PI 2) (/ -1 b) (/ (/ PI 2) a))

simplify10.1s

Counts
155 → 152
Calls

155 calls. Slowest were:

512.0ms
(/ (/ (fma (/ PI 2) (/ -1 b) (/ (/ PI 2) a)) (- (* a a) (* b b))) (* (cbrt (- b a)) (cbrt (- b a))))
388.0ms
(/ (/ (fma (/ PI 2) (/ -1 b) (/ (/ PI 2) a)) (- (* a a) (* b b))) 1)
291.0ms
(/ (/ (* (cbrt (fma (/ PI 2) (/ -1 b) (/ (/ PI 2) a))) (cbrt (fma (/ PI 2) (/ -1 b) (/ (/ PI 2) a)))) (* (cbrt (+ a b)) (cbrt (+ a b)))) (* (cbrt (- b a)) (cbrt (- b a))))

prune1.6s

Pruning

11 alts after pruning (11 fresh and 0 done)

Merged error: 0b

localize32.0ms

Local error

Found 4 expressions with local error:

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

rewrite28.0ms

Algorithm
rewrite-expression-head
Counts
4 → 123
Calls

4 calls. Slowest were:

14.0ms
(/ (- (/ PI (* a 2)) (/ PI (* 2 b))) (- b a))
12.0ms
(* (/ 1 (+ a b)) (/ (- (/ PI (* a 2)) (/ PI (* 2 b))) (- b a)))
0.0ms
(/ PI (* 2 b))

series383.0ms

Counts
4 → 12
Calls

4 calls. Slowest were:

125.0ms
(* (/ 1 (+ a b)) (/ (- (/ PI (* a 2)) (/ PI (* 2 b))) (- b a)))
90.0ms
(/ PI (* a 2))
89.0ms
(/ (- (/ PI (* a 2)) (/ PI (* 2 b))) (- b a))
79.0ms
(/ PI (* 2 b))

simplify5.3s

Counts
101 → 135
Calls

101 calls. Slowest were:

352.0ms
(- (pow (/ PI (* a 2)) 3) (pow (/ PI (* 2 b)) 3))
268.0ms
(/ (* (* (- (/ PI (* a 2)) (/ PI (* 2 b))) (- (/ PI (* a 2)) (/ PI (* 2 b)))) (- (/ PI (* a 2)) (/ PI (* 2 b)))) (* (* (- b a) (- b a)) (- b a)))
226.0ms
(* 1 (/ (- (/ PI (* a 2)) (/ PI (* 2 b))) (- b a)))

prune1.5s

Pruning

9 alts after pruning (8 fresh and 1 done)

Merged error: 0b

localize13.0ms

Local error

Found 4 expressions with local error:

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

rewrite36.0ms

Algorithm
rewrite-expression-head
Counts
4 → 128
Calls

4 calls. Slowest were:

18.0ms
(* (/ 1 (+ a b)) (- (/ PI (* a 2)) (/ PI (* 2 b))))
15.0ms
(/ (* (/ 1 (+ a b)) (- (/ PI (* a 2)) (/ PI (* 2 b)))) (- b a))
0.0ms
(/ PI (* 2 b))

series382.0ms

Counts
4 → 12
Calls

4 calls. Slowest were:

122.0ms
(/ (* (/ 1 (+ a b)) (- (/ PI (* a 2)) (/ PI (* 2 b)))) (- b a))
104.0ms
(* (/ 1 (+ a b)) (- (/ PI (* a 2)) (/ PI (* 2 b))))
88.0ms
(/ PI (* 2 b))
68.0ms
(/ PI (* a 2))

simplify20.2s

Counts
96 → 140
Calls

96 calls. Slowest were:

961.0ms
(* (* (* (/ 1 (+ a b)) (/ 1 (+ a b))) (/ 1 (+ a b))) (* (* (- (/ PI (* a 2)) (/ PI (* 2 b))) (- (/ PI (* a 2)) (/ PI (* 2 b)))) (- (/ PI (* a 2)) (/ PI (* 2 b)))))
913.0ms
(* (fma (- (/ 1 (* 2 b))) PI (* (/ 1 (* 2 b)) PI)) (/ 1 (+ a b)))
580.0ms
(* (- (/ PI (* 2 b))) (/ 1 (+ a b)))

prune1.6s

Pruning

7 alts after pruning (5 fresh and 2 done)

Merged error: 0b

regimes94.0ms

Accuracy

0% (0.3b remaining)

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

bsearch4.0ms

end0.0ms

sample2.4s

Algorithm
intervals