Average Error: 14.5 → 0.3
Time: 8.8s
Precision: 64
\[\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right)\]
↓
\[\frac{\frac{\pi}{2}}{\frac{b - a}{1 \cdot b - a \cdot 1}} \cdot \frac{\frac{1}{b + a}}{a \cdot b}\]
\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}}{\frac{b - a}{1 \cdot b - a \cdot 1}} \cdot \frac{\frac{1}{b + a}}{a \cdot b}
double code(double a, double b) {
	return (((((double) M_PI) / 2.0) * (1.0 / ((b * b) - (a * a)))) * ((1.0 / a) - (1.0 / b)));
}
↓
double code(double a, double b) {
	return (((((double) M_PI) / 2.0) / ((b - a) / ((1.0 * b) - (a * 1.0)))) * ((1.0 / (b + a)) / (a * b)));
}

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 14.5

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

  3. Applied difference-of-squares9.7

    \[\leadsto \left(\frac{\pi}{2} \cdot \frac{1}{\color{blue}{\left(b + a\right) \cdot \left(b - a\right)}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right)\]

  4. Applied associate-/r*9.2

    \[\leadsto \left(\frac{\pi}{2} \cdot \color{blue}{\frac{\frac{1}{b + a}}{b - a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right)\]
  5. Using strategy rm

  6. Applied associate-*r/9.2

    \[\leadsto \color{blue}{\frac{\frac{\pi}{2} \cdot \frac{1}{b + a}}{b - a}} \cdot \left(\frac{1}{a} - \frac{1}{b}\right)\]

  7. Applied associate-*l/0.3

    \[\leadsto \color{blue}{\frac{\left(\frac{\pi}{2} \cdot \frac{1}{b + a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right)}{b - a}}\]
  8. Using strategy rm

  9. Applied associate-/l*0.3

    \[\leadsto \color{blue}{\frac{\frac{\pi}{2} \cdot \frac{1}{b + a}}{\frac{b - a}{\frac{1}{a} - \frac{1}{b}}}}\]
  10. Using strategy rm

  11. Applied frac-sub0.3

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

  12. Applied associate-/r/0.3

    \[\leadsto \frac{\frac{\pi}{2} \cdot \frac{1}{b + a}}{\color{blue}{\frac{b - a}{1 \cdot b - a \cdot 1} \cdot \left(a \cdot b\right)}}\]

  13. Applied times-frac0.3

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

  14. Final simplification0.3

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

Reproduce

herbie shell --seed 2020057 +o rules:numerics
(FPCore (a b)
  :name "NMSE Section 6.1 mentioned, B"
  :precision binary64
  (* (* (/ PI 2) (/ 1 (- (* b b) (* a a)))) (- (/ 1 a) (/ 1 b))))