Average Error: 14.3 → 0.0
Time: 1.3s
Precision: binary64
\[0 \leq b \land b \leq a \land a \leq 1\]
\[\sqrt{\left|\frac{a \cdot a - b \cdot b}{a \cdot a}\right|}\]
↓
\[\sqrt{\left|1 - {\left(\frac{b}{a}\right)}^{2}\right|}\]
\sqrt{\left|\frac{a \cdot a - b \cdot b}{a \cdot a}\right|}
↓
\sqrt{\left|1 - {\left(\frac{b}{a}\right)}^{2}\right|}
(FPCore (a b)
 :precision binary64
 (sqrt (fabs (/ (- (* a a) (* b b)) (* a a)))))
↓
(FPCore (a b) :precision binary64 (sqrt (fabs (- 1.0 (pow (/ b a) 2.0)))))
double code(double a, double b) {
	return sqrt(fabs(((a * a) - (b * b)) / (a * a)));
}
↓
double code(double a, double b) {
	return sqrt(fabs(1.0 - pow((b / a), 2.0)));
}

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 14.3

    \[\sqrt{\left|\frac{a \cdot a - b \cdot b}{a \cdot a}\right|}\]

  2. Simplified14.3

    \[\leadsto \color{blue}{\sqrt{\left|1 - \frac{b \cdot b}{a \cdot a}\right|}}\]

  3. Taylor expanded around 0 14.3

    \[\leadsto \sqrt{\left|1 - \color{blue}{\frac{{b}^{2}}{{a}^{2}}}\right|}\]

  4. Simplified0.0

    \[\leadsto \sqrt{\left|1 - \color{blue}{{\left(\frac{b}{a}\right)}^{2}}\right|}\]

  5. Final simplification0.0

    \[\leadsto \sqrt{\left|1 - {\left(\frac{b}{a}\right)}^{2}\right|}\]

Reproduce

herbie shell --seed 2020232 
(FPCore (a b)
  :name "Eccentricity of an ellipse"
  :precision binary64
  :pre (<= 0.0 b a 1.0)
  (sqrt (fabs (/ (- (* a a) (* b b)) (* a a)))))