Eccentricity of an ellipse

Percentage Accurate: 77.9% → 100.0%
Time: 6.3s
Alternatives: 4
Speedup: 2.0×

Specification

?
\[\left(0 \leq b \land b \leq a\right) \land a \leq 1\]
\[\begin{array}{l} \\ \sqrt{\left|\frac{a \cdot a - b \cdot b}{a \cdot a}\right|} \end{array} \]
(FPCore (a b)
 :precision binary64
 (sqrt (fabs (/ (- (* a a) (* b b)) (* a a)))))
double code(double a, double b) {
	return sqrt(fabs((((a * a) - (b * b)) / (a * a))));
}
real(8) function code(a, b)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    code = sqrt(abs((((a * a) - (b * b)) / (a * a))))
end function
public static double code(double a, double b) {
	return Math.sqrt(Math.abs((((a * a) - (b * b)) / (a * a))));
}
def code(a, b):
	return math.sqrt(math.fabs((((a * a) - (b * b)) / (a * a))))
function code(a, b)
	return sqrt(abs(Float64(Float64(Float64(a * a) - Float64(b * b)) / Float64(a * a))))
end
function tmp = code(a, b)
	tmp = sqrt(abs((((a * a) - (b * b)) / (a * a))));
end
code[a_, b_] := N[Sqrt[N[Abs[N[(N[(N[(a * a), $MachinePrecision] - N[(b * b), $MachinePrecision]), $MachinePrecision] / N[(a * a), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
\sqrt{\left|\frac{a \cdot a - b \cdot b}{a \cdot a}\right|}
\end{array}

Sampling outcomes in binary64 precision:

Local Percentage Accuracy vs ?

The average percentage accuracy by input value. Horizontal axis shows value of an input variable; the variable is choosen in the title. Vertical axis is accuracy; higher is better. Red represent the original program, while blue represents Herbie's suggestion. These can be toggled with buttons below the plot. The line is an average while dots represent individual samples.

Accuracy vs Speed?

Herbie found 4 alternatives:

AlternativeAccuracySpeedup
The accuracy (vertical axis) and speed (horizontal axis) of each alternatives. Up and to the right is better. The red square shows the initial program, and each blue circle shows an alternative.The line shows the best available speed-accuracy tradeoffs.

Initial Program: 77.9% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \sqrt{\left|\frac{a \cdot a - b \cdot b}{a \cdot a}\right|} \end{array} \]
(FPCore (a b)
 :precision binary64
 (sqrt (fabs (/ (- (* a a) (* b b)) (* a a)))))
double code(double a, double b) {
	return sqrt(fabs((((a * a) - (b * b)) / (a * a))));
}
real(8) function code(a, b)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    code = sqrt(abs((((a * a) - (b * b)) / (a * a))))
end function
public static double code(double a, double b) {
	return Math.sqrt(Math.abs((((a * a) - (b * b)) / (a * a))));
}
def code(a, b):
	return math.sqrt(math.fabs((((a * a) - (b * b)) / (a * a))))
function code(a, b)
	return sqrt(abs(Float64(Float64(Float64(a * a) - Float64(b * b)) / Float64(a * a))))
end
function tmp = code(a, b)
	tmp = sqrt(abs((((a * a) - (b * b)) / (a * a))));
end
code[a_, b_] := N[Sqrt[N[Abs[N[(N[(N[(a * a), $MachinePrecision] - N[(b * b), $MachinePrecision]), $MachinePrecision] / N[(a * a), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
\sqrt{\left|\frac{a \cdot a - b \cdot b}{a \cdot a}\right|}
\end{array}

Alternative 1: 100.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ e^{\mathsf{log1p}\left(\frac{\frac{b}{a}}{\frac{a}{-b}}\right) \cdot 0.5} \end{array} \]
(FPCore (a b)
 :precision binary64
 (exp (* (log1p (/ (/ b a) (/ a (- b)))) 0.5)))
double code(double a, double b) {
	return exp((log1p(((b / a) / (a / -b))) * 0.5));
}
public static double code(double a, double b) {
	return Math.exp((Math.log1p(((b / a) / (a / -b))) * 0.5));
}
def code(a, b):
	return math.exp((math.log1p(((b / a) / (a / -b))) * 0.5))
function code(a, b)
	return exp(Float64(log1p(Float64(Float64(b / a) / Float64(a / Float64(-b)))) * 0.5))
end
code[a_, b_] := N[Exp[N[(N[Log[1 + N[(N[(b / a), $MachinePrecision] / N[(a / (-b)), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * 0.5), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
e^{\mathsf{log1p}\left(\frac{\frac{b}{a}}{\frac{a}{-b}}\right) \cdot 0.5}
\end{array}
Derivation
  1. Initial program 77.3%

    \[\sqrt{\left|\frac{a \cdot a - b \cdot b}{a \cdot a}\right|} \]
  2. Step-by-step derivation
    1. sqr-neg77.3%

      \[\leadsto \sqrt{\left|\frac{a \cdot a - \color{blue}{\left(-b\right) \cdot \left(-b\right)}}{a \cdot a}\right|} \]
    2. fabs-div77.3%

      \[\leadsto \sqrt{\color{blue}{\frac{\left|a \cdot a - \left(-b\right) \cdot \left(-b\right)\right|}{\left|a \cdot a\right|}}} \]
    3. sqr-neg77.3%

      \[\leadsto \sqrt{\frac{\left|a \cdot a - \color{blue}{b \cdot b}\right|}{\left|a \cdot a\right|}} \]
    4. fabs-sub77.3%

      \[\leadsto \sqrt{\frac{\color{blue}{\left|b \cdot b - a \cdot a\right|}}{\left|a \cdot a\right|}} \]
    5. sqr-neg77.3%

      \[\leadsto \sqrt{\frac{\left|b \cdot b - a \cdot a\right|}{\left|\color{blue}{\left(-a\right) \cdot \left(-a\right)}\right|}} \]
    6. distribute-rgt-neg-out77.3%

      \[\leadsto \sqrt{\frac{\left|b \cdot b - a \cdot a\right|}{\left|\color{blue}{-\left(-a\right) \cdot a}\right|}} \]
    7. fabs-neg77.3%

      \[\leadsto \sqrt{\frac{\left|b \cdot b - a \cdot a\right|}{\color{blue}{\left|\left(-a\right) \cdot a\right|}}} \]
    8. fabs-div77.3%

      \[\leadsto \sqrt{\color{blue}{\left|\frac{b \cdot b - a \cdot a}{\left(-a\right) \cdot a}\right|}} \]
    9. cancel-sign-sub-inv77.3%

      \[\leadsto \sqrt{\left|\frac{\color{blue}{b \cdot b + \left(-a\right) \cdot a}}{\left(-a\right) \cdot a}\right|} \]
    10. +-commutative77.3%

      \[\leadsto \sqrt{\left|\frac{\color{blue}{\left(-a\right) \cdot a + b \cdot b}}{\left(-a\right) \cdot a}\right|} \]
    11. sqr-neg77.3%

      \[\leadsto \sqrt{\left|\frac{\left(-a\right) \cdot a + \color{blue}{\left(-b\right) \cdot \left(-b\right)}}{\left(-a\right) \cdot a}\right|} \]
    12. cancel-sign-sub-inv77.3%

      \[\leadsto \sqrt{\left|\frac{\color{blue}{\left(-a\right) \cdot a - b \cdot \left(-b\right)}}{\left(-a\right) \cdot a}\right|} \]
  3. Simplified78.0%

    \[\leadsto \color{blue}{\sqrt{\left|1 - b \cdot \frac{b}{a \cdot a}\right|}} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. pow1/278.0%

      \[\leadsto \color{blue}{{\left(\left|1 - b \cdot \frac{b}{a \cdot a}\right|\right)}^{0.5}} \]
    2. pow-to-exp78.0%

      \[\leadsto \color{blue}{e^{\log \left(\left|1 - b \cdot \frac{b}{a \cdot a}\right|\right) \cdot 0.5}} \]
    3. add-sqr-sqrt77.3%

      \[\leadsto e^{\log \left(\left|\color{blue}{\sqrt{1 - b \cdot \frac{b}{a \cdot a}} \cdot \sqrt{1 - b \cdot \frac{b}{a \cdot a}}}\right|\right) \cdot 0.5} \]
    4. fabs-sqr77.3%

      \[\leadsto e^{\log \color{blue}{\left(\sqrt{1 - b \cdot \frac{b}{a \cdot a}} \cdot \sqrt{1 - b \cdot \frac{b}{a \cdot a}}\right)} \cdot 0.5} \]
    5. add-sqr-sqrt77.3%

      \[\leadsto e^{\log \color{blue}{\left(1 - b \cdot \frac{b}{a \cdot a}\right)} \cdot 0.5} \]
    6. sub-neg77.3%

      \[\leadsto e^{\log \color{blue}{\left(1 + \left(-b \cdot \frac{b}{a \cdot a}\right)\right)} \cdot 0.5} \]
    7. log1p-define77.3%

      \[\leadsto e^{\color{blue}{\mathsf{log1p}\left(-b \cdot \frac{b}{a \cdot a}\right)} \cdot 0.5} \]
    8. associate-*r/77.3%

      \[\leadsto e^{\mathsf{log1p}\left(-\color{blue}{\frac{b \cdot b}{a \cdot a}}\right) \cdot 0.5} \]
    9. frac-times100.0%

      \[\leadsto e^{\mathsf{log1p}\left(-\color{blue}{\frac{b}{a} \cdot \frac{b}{a}}\right) \cdot 0.5} \]
    10. pow2100.0%

      \[\leadsto e^{\mathsf{log1p}\left(-\color{blue}{{\left(\frac{b}{a}\right)}^{2}}\right) \cdot 0.5} \]
  6. Applied egg-rr100.0%

    \[\leadsto \color{blue}{e^{\mathsf{log1p}\left(-{\left(\frac{b}{a}\right)}^{2}\right) \cdot 0.5}} \]
  7. Step-by-step derivation
    1. unpow2100.0%

      \[\leadsto e^{\mathsf{log1p}\left(-\color{blue}{\frac{b}{a} \cdot \frac{b}{a}}\right) \cdot 0.5} \]
    2. clear-num100.0%

      \[\leadsto e^{\mathsf{log1p}\left(-\frac{b}{a} \cdot \color{blue}{\frac{1}{\frac{a}{b}}}\right) \cdot 0.5} \]
    3. div-inv100.0%

      \[\leadsto e^{\mathsf{log1p}\left(-\color{blue}{\frac{\frac{b}{a}}{\frac{a}{b}}}\right) \cdot 0.5} \]
  8. Applied egg-rr100.0%

    \[\leadsto e^{\mathsf{log1p}\left(-\color{blue}{\frac{\frac{b}{a}}{\frac{a}{b}}}\right) \cdot 0.5} \]
  9. Final simplification100.0%

    \[\leadsto e^{\mathsf{log1p}\left(\frac{\frac{b}{a}}{\frac{a}{-b}}\right) \cdot 0.5} \]
  10. Add Preprocessing

Alternative 2: 100.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \sqrt{\left|1 - \frac{\frac{b}{a}}{\frac{a}{b}}\right|} \end{array} \]
(FPCore (a b) :precision binary64 (sqrt (fabs (- 1.0 (/ (/ b a) (/ a b))))))
double code(double a, double b) {
	return sqrt(fabs((1.0 - ((b / a) / (a / b)))));
}
real(8) function code(a, b)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    code = sqrt(abs((1.0d0 - ((b / a) / (a / b)))))
end function
public static double code(double a, double b) {
	return Math.sqrt(Math.abs((1.0 - ((b / a) / (a / b)))));
}
def code(a, b):
	return math.sqrt(math.fabs((1.0 - ((b / a) / (a / b)))))
function code(a, b)
	return sqrt(abs(Float64(1.0 - Float64(Float64(b / a) / Float64(a / b)))))
end
function tmp = code(a, b)
	tmp = sqrt(abs((1.0 - ((b / a) / (a / b)))));
end
code[a_, b_] := N[Sqrt[N[Abs[N[(1.0 - N[(N[(b / a), $MachinePrecision] / N[(a / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
\sqrt{\left|1 - \frac{\frac{b}{a}}{\frac{a}{b}}\right|}
\end{array}
Derivation
  1. Initial program 77.3%

    \[\sqrt{\left|\frac{a \cdot a - b \cdot b}{a \cdot a}\right|} \]
  2. Step-by-step derivation
    1. sqr-neg77.3%

      \[\leadsto \sqrt{\left|\frac{a \cdot a - \color{blue}{\left(-b\right) \cdot \left(-b\right)}}{a \cdot a}\right|} \]
    2. fabs-div77.3%

      \[\leadsto \sqrt{\color{blue}{\frac{\left|a \cdot a - \left(-b\right) \cdot \left(-b\right)\right|}{\left|a \cdot a\right|}}} \]
    3. sqr-neg77.3%

      \[\leadsto \sqrt{\frac{\left|a \cdot a - \color{blue}{b \cdot b}\right|}{\left|a \cdot a\right|}} \]
    4. fabs-sub77.3%

      \[\leadsto \sqrt{\frac{\color{blue}{\left|b \cdot b - a \cdot a\right|}}{\left|a \cdot a\right|}} \]
    5. sqr-neg77.3%

      \[\leadsto \sqrt{\frac{\left|b \cdot b - a \cdot a\right|}{\left|\color{blue}{\left(-a\right) \cdot \left(-a\right)}\right|}} \]
    6. distribute-rgt-neg-out77.3%

      \[\leadsto \sqrt{\frac{\left|b \cdot b - a \cdot a\right|}{\left|\color{blue}{-\left(-a\right) \cdot a}\right|}} \]
    7. fabs-neg77.3%

      \[\leadsto \sqrt{\frac{\left|b \cdot b - a \cdot a\right|}{\color{blue}{\left|\left(-a\right) \cdot a\right|}}} \]
    8. fabs-div77.3%

      \[\leadsto \sqrt{\color{blue}{\left|\frac{b \cdot b - a \cdot a}{\left(-a\right) \cdot a}\right|}} \]
    9. cancel-sign-sub-inv77.3%

      \[\leadsto \sqrt{\left|\frac{\color{blue}{b \cdot b + \left(-a\right) \cdot a}}{\left(-a\right) \cdot a}\right|} \]
    10. +-commutative77.3%

      \[\leadsto \sqrt{\left|\frac{\color{blue}{\left(-a\right) \cdot a + b \cdot b}}{\left(-a\right) \cdot a}\right|} \]
    11. sqr-neg77.3%

      \[\leadsto \sqrt{\left|\frac{\left(-a\right) \cdot a + \color{blue}{\left(-b\right) \cdot \left(-b\right)}}{\left(-a\right) \cdot a}\right|} \]
    12. cancel-sign-sub-inv77.3%

      \[\leadsto \sqrt{\left|\frac{\color{blue}{\left(-a\right) \cdot a - b \cdot \left(-b\right)}}{\left(-a\right) \cdot a}\right|} \]
  3. Simplified78.0%

    \[\leadsto \color{blue}{\sqrt{\left|1 - b \cdot \frac{b}{a \cdot a}\right|}} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. associate-*r/77.3%

      \[\leadsto \sqrt{\left|1 - \color{blue}{\frac{b \cdot b}{a \cdot a}}\right|} \]
    2. frac-times100.0%

      \[\leadsto \sqrt{\left|1 - \color{blue}{\frac{b}{a} \cdot \frac{b}{a}}\right|} \]
    3. clear-num100.0%

      \[\leadsto \sqrt{\left|1 - \frac{b}{a} \cdot \color{blue}{\frac{1}{\frac{a}{b}}}\right|} \]
    4. un-div-inv100.0%

      \[\leadsto \sqrt{\left|1 - \color{blue}{\frac{\frac{b}{a}}{\frac{a}{b}}}\right|} \]
  6. Applied egg-rr100.0%

    \[\leadsto \sqrt{\left|1 - \color{blue}{\frac{\frac{b}{a}}{\frac{a}{b}}}\right|} \]
  7. Final simplification100.0%

    \[\leadsto \sqrt{\left|1 - \frac{\frac{b}{a}}{\frac{a}{b}}\right|} \]
  8. Add Preprocessing

Alternative 3: 99.0% accurate, 1.9× speedup?

\[\begin{array}{l} \\ e^{0.5 \cdot \frac{\frac{b}{\frac{a}{b}}}{-a}} \end{array} \]
(FPCore (a b) :precision binary64 (exp (* 0.5 (/ (/ b (/ a b)) (- a)))))
double code(double a, double b) {
	return exp((0.5 * ((b / (a / b)) / -a)));
}
real(8) function code(a, b)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    code = exp((0.5d0 * ((b / (a / b)) / -a)))
end function
public static double code(double a, double b) {
	return Math.exp((0.5 * ((b / (a / b)) / -a)));
}
def code(a, b):
	return math.exp((0.5 * ((b / (a / b)) / -a)))
function code(a, b)
	return exp(Float64(0.5 * Float64(Float64(b / Float64(a / b)) / Float64(-a))))
end
function tmp = code(a, b)
	tmp = exp((0.5 * ((b / (a / b)) / -a)));
end
code[a_, b_] := N[Exp[N[(0.5 * N[(N[(b / N[(a / b), $MachinePrecision]), $MachinePrecision] / (-a)), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
e^{0.5 \cdot \frac{\frac{b}{\frac{a}{b}}}{-a}}
\end{array}
Derivation
  1. Initial program 77.3%

    \[\sqrt{\left|\frac{a \cdot a - b \cdot b}{a \cdot a}\right|} \]
  2. Step-by-step derivation
    1. sqr-neg77.3%

      \[\leadsto \sqrt{\left|\frac{a \cdot a - \color{blue}{\left(-b\right) \cdot \left(-b\right)}}{a \cdot a}\right|} \]
    2. fabs-div77.3%

      \[\leadsto \sqrt{\color{blue}{\frac{\left|a \cdot a - \left(-b\right) \cdot \left(-b\right)\right|}{\left|a \cdot a\right|}}} \]
    3. sqr-neg77.3%

      \[\leadsto \sqrt{\frac{\left|a \cdot a - \color{blue}{b \cdot b}\right|}{\left|a \cdot a\right|}} \]
    4. fabs-sub77.3%

      \[\leadsto \sqrt{\frac{\color{blue}{\left|b \cdot b - a \cdot a\right|}}{\left|a \cdot a\right|}} \]
    5. sqr-neg77.3%

      \[\leadsto \sqrt{\frac{\left|b \cdot b - a \cdot a\right|}{\left|\color{blue}{\left(-a\right) \cdot \left(-a\right)}\right|}} \]
    6. distribute-rgt-neg-out77.3%

      \[\leadsto \sqrt{\frac{\left|b \cdot b - a \cdot a\right|}{\left|\color{blue}{-\left(-a\right) \cdot a}\right|}} \]
    7. fabs-neg77.3%

      \[\leadsto \sqrt{\frac{\left|b \cdot b - a \cdot a\right|}{\color{blue}{\left|\left(-a\right) \cdot a\right|}}} \]
    8. fabs-div77.3%

      \[\leadsto \sqrt{\color{blue}{\left|\frac{b \cdot b - a \cdot a}{\left(-a\right) \cdot a}\right|}} \]
    9. cancel-sign-sub-inv77.3%

      \[\leadsto \sqrt{\left|\frac{\color{blue}{b \cdot b + \left(-a\right) \cdot a}}{\left(-a\right) \cdot a}\right|} \]
    10. +-commutative77.3%

      \[\leadsto \sqrt{\left|\frac{\color{blue}{\left(-a\right) \cdot a + b \cdot b}}{\left(-a\right) \cdot a}\right|} \]
    11. sqr-neg77.3%

      \[\leadsto \sqrt{\left|\frac{\left(-a\right) \cdot a + \color{blue}{\left(-b\right) \cdot \left(-b\right)}}{\left(-a\right) \cdot a}\right|} \]
    12. cancel-sign-sub-inv77.3%

      \[\leadsto \sqrt{\left|\frac{\color{blue}{\left(-a\right) \cdot a - b \cdot \left(-b\right)}}{\left(-a\right) \cdot a}\right|} \]
  3. Simplified78.0%

    \[\leadsto \color{blue}{\sqrt{\left|1 - b \cdot \frac{b}{a \cdot a}\right|}} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. pow1/278.0%

      \[\leadsto \color{blue}{{\left(\left|1 - b \cdot \frac{b}{a \cdot a}\right|\right)}^{0.5}} \]
    2. pow-to-exp78.0%

      \[\leadsto \color{blue}{e^{\log \left(\left|1 - b \cdot \frac{b}{a \cdot a}\right|\right) \cdot 0.5}} \]
    3. add-sqr-sqrt77.3%

      \[\leadsto e^{\log \left(\left|\color{blue}{\sqrt{1 - b \cdot \frac{b}{a \cdot a}} \cdot \sqrt{1 - b \cdot \frac{b}{a \cdot a}}}\right|\right) \cdot 0.5} \]
    4. fabs-sqr77.3%

      \[\leadsto e^{\log \color{blue}{\left(\sqrt{1 - b \cdot \frac{b}{a \cdot a}} \cdot \sqrt{1 - b \cdot \frac{b}{a \cdot a}}\right)} \cdot 0.5} \]
    5. add-sqr-sqrt77.3%

      \[\leadsto e^{\log \color{blue}{\left(1 - b \cdot \frac{b}{a \cdot a}\right)} \cdot 0.5} \]
    6. sub-neg77.3%

      \[\leadsto e^{\log \color{blue}{\left(1 + \left(-b \cdot \frac{b}{a \cdot a}\right)\right)} \cdot 0.5} \]
    7. log1p-define77.3%

      \[\leadsto e^{\color{blue}{\mathsf{log1p}\left(-b \cdot \frac{b}{a \cdot a}\right)} \cdot 0.5} \]
    8. associate-*r/77.3%

      \[\leadsto e^{\mathsf{log1p}\left(-\color{blue}{\frac{b \cdot b}{a \cdot a}}\right) \cdot 0.5} \]
    9. frac-times100.0%

      \[\leadsto e^{\mathsf{log1p}\left(-\color{blue}{\frac{b}{a} \cdot \frac{b}{a}}\right) \cdot 0.5} \]
    10. pow2100.0%

      \[\leadsto e^{\mathsf{log1p}\left(-\color{blue}{{\left(\frac{b}{a}\right)}^{2}}\right) \cdot 0.5} \]
  6. Applied egg-rr100.0%

    \[\leadsto \color{blue}{e^{\mathsf{log1p}\left(-{\left(\frac{b}{a}\right)}^{2}\right) \cdot 0.5}} \]
  7. Taylor expanded in b around 0 76.9%

    \[\leadsto e^{\color{blue}{\left(-1 \cdot \frac{{b}^{2}}{{a}^{2}}\right)} \cdot 0.5} \]
  8. Step-by-step derivation
    1. associate-*r/76.9%

      \[\leadsto e^{\color{blue}{\frac{-1 \cdot {b}^{2}}{{a}^{2}}} \cdot 0.5} \]
    2. neg-mul-176.9%

      \[\leadsto e^{\frac{\color{blue}{-{b}^{2}}}{{a}^{2}} \cdot 0.5} \]
    3. unpow276.9%

      \[\leadsto e^{\frac{-\color{blue}{b \cdot b}}{{a}^{2}} \cdot 0.5} \]
    4. distribute-lft-neg-out76.9%

      \[\leadsto e^{\frac{\color{blue}{\left(-b\right) \cdot b}}{{a}^{2}} \cdot 0.5} \]
    5. unpow276.9%

      \[\leadsto e^{\frac{\left(-b\right) \cdot b}{\color{blue}{a \cdot a}} \cdot 0.5} \]
    6. times-frac98.8%

      \[\leadsto e^{\color{blue}{\left(\frac{-b}{a} \cdot \frac{b}{a}\right)} \cdot 0.5} \]
    7. neg-mul-198.8%

      \[\leadsto e^{\left(\frac{\color{blue}{-1 \cdot b}}{a} \cdot \frac{b}{a}\right) \cdot 0.5} \]
    8. associate-*r/98.8%

      \[\leadsto e^{\left(\color{blue}{\left(-1 \cdot \frac{b}{a}\right)} \cdot \frac{b}{a}\right) \cdot 0.5} \]
    9. associate-*r*98.8%

      \[\leadsto e^{\color{blue}{\left(-1 \cdot \left(\frac{b}{a} \cdot \frac{b}{a}\right)\right)} \cdot 0.5} \]
    10. unpow298.8%

      \[\leadsto e^{\left(-1 \cdot \color{blue}{{\left(\frac{b}{a}\right)}^{2}}\right) \cdot 0.5} \]
    11. neg-mul-198.8%

      \[\leadsto e^{\color{blue}{\left(-{\left(\frac{b}{a}\right)}^{2}\right)} \cdot 0.5} \]
  9. Simplified98.8%

    \[\leadsto e^{\color{blue}{\left(-{\left(\frac{b}{a}\right)}^{2}\right)} \cdot 0.5} \]
  10. Step-by-step derivation
    1. unpow298.8%

      \[\leadsto e^{\left(-\color{blue}{\frac{b}{a} \cdot \frac{b}{a}}\right) \cdot 0.5} \]
    2. clear-num98.8%

      \[\leadsto e^{\left(-\frac{b}{a} \cdot \color{blue}{\frac{1}{\frac{a}{b}}}\right) \cdot 0.5} \]
    3. div-inv98.8%

      \[\leadsto e^{\left(-\color{blue}{\frac{\frac{b}{a}}{\frac{a}{b}}}\right) \cdot 0.5} \]
    4. associate-/l/98.8%

      \[\leadsto e^{\left(-\color{blue}{\frac{b}{\frac{a}{b} \cdot a}}\right) \cdot 0.5} \]
    5. associate-/r*98.8%

      \[\leadsto e^{\left(-\color{blue}{\frac{\frac{b}{\frac{a}{b}}}{a}}\right) \cdot 0.5} \]
  11. Applied egg-rr98.8%

    \[\leadsto e^{\left(-\color{blue}{\frac{\frac{b}{\frac{a}{b}}}{a}}\right) \cdot 0.5} \]
  12. Final simplification98.8%

    \[\leadsto e^{0.5 \cdot \frac{\frac{b}{\frac{a}{b}}}{-a}} \]
  13. Add Preprocessing

Alternative 4: 98.0% accurate, 2.0× speedup?

\[\begin{array}{l} \\ \mathsf{hypot}\left(1, \frac{b}{a}\right) \end{array} \]
(FPCore (a b) :precision binary64 (hypot 1.0 (/ b a)))
double code(double a, double b) {
	return hypot(1.0, (b / a));
}
public static double code(double a, double b) {
	return Math.hypot(1.0, (b / a));
}
def code(a, b):
	return math.hypot(1.0, (b / a))
function code(a, b)
	return hypot(1.0, Float64(b / a))
end
function tmp = code(a, b)
	tmp = hypot(1.0, (b / a));
end
code[a_, b_] := N[Sqrt[1.0 ^ 2 + N[(b / a), $MachinePrecision] ^ 2], $MachinePrecision]
\begin{array}{l}

\\
\mathsf{hypot}\left(1, \frac{b}{a}\right)
\end{array}
Derivation
  1. Initial program 77.3%

    \[\sqrt{\left|\frac{a \cdot a - b \cdot b}{a \cdot a}\right|} \]
  2. Step-by-step derivation
    1. sqr-neg77.3%

      \[\leadsto \sqrt{\left|\frac{a \cdot a - \color{blue}{\left(-b\right) \cdot \left(-b\right)}}{a \cdot a}\right|} \]
    2. fabs-div77.3%

      \[\leadsto \sqrt{\color{blue}{\frac{\left|a \cdot a - \left(-b\right) \cdot \left(-b\right)\right|}{\left|a \cdot a\right|}}} \]
    3. sqr-neg77.3%

      \[\leadsto \sqrt{\frac{\left|a \cdot a - \color{blue}{b \cdot b}\right|}{\left|a \cdot a\right|}} \]
    4. fabs-sub77.3%

      \[\leadsto \sqrt{\frac{\color{blue}{\left|b \cdot b - a \cdot a\right|}}{\left|a \cdot a\right|}} \]
    5. sqr-neg77.3%

      \[\leadsto \sqrt{\frac{\left|b \cdot b - a \cdot a\right|}{\left|\color{blue}{\left(-a\right) \cdot \left(-a\right)}\right|}} \]
    6. distribute-rgt-neg-out77.3%

      \[\leadsto \sqrt{\frac{\left|b \cdot b - a \cdot a\right|}{\left|\color{blue}{-\left(-a\right) \cdot a}\right|}} \]
    7. fabs-neg77.3%

      \[\leadsto \sqrt{\frac{\left|b \cdot b - a \cdot a\right|}{\color{blue}{\left|\left(-a\right) \cdot a\right|}}} \]
    8. fabs-div77.3%

      \[\leadsto \sqrt{\color{blue}{\left|\frac{b \cdot b - a \cdot a}{\left(-a\right) \cdot a}\right|}} \]
    9. cancel-sign-sub-inv77.3%

      \[\leadsto \sqrt{\left|\frac{\color{blue}{b \cdot b + \left(-a\right) \cdot a}}{\left(-a\right) \cdot a}\right|} \]
    10. +-commutative77.3%

      \[\leadsto \sqrt{\left|\frac{\color{blue}{\left(-a\right) \cdot a + b \cdot b}}{\left(-a\right) \cdot a}\right|} \]
    11. sqr-neg77.3%

      \[\leadsto \sqrt{\left|\frac{\left(-a\right) \cdot a + \color{blue}{\left(-b\right) \cdot \left(-b\right)}}{\left(-a\right) \cdot a}\right|} \]
    12. cancel-sign-sub-inv77.3%

      \[\leadsto \sqrt{\left|\frac{\color{blue}{\left(-a\right) \cdot a - b \cdot \left(-b\right)}}{\left(-a\right) \cdot a}\right|} \]
  3. Simplified78.0%

    \[\leadsto \color{blue}{\sqrt{\left|1 - b \cdot \frac{b}{a \cdot a}\right|}} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. add-sqr-sqrt77.3%

      \[\leadsto \sqrt{\left|\color{blue}{\sqrt{1 - b \cdot \frac{b}{a \cdot a}} \cdot \sqrt{1 - b \cdot \frac{b}{a \cdot a}}}\right|} \]
    2. fabs-sqr77.3%

      \[\leadsto \sqrt{\left|\color{blue}{\left|\sqrt{1 - b \cdot \frac{b}{a \cdot a}} \cdot \sqrt{1 - b \cdot \frac{b}{a \cdot a}}\right|}\right|} \]
    3. add-sqr-sqrt78.0%

      \[\leadsto \sqrt{\left|\left|\color{blue}{1 - b \cdot \frac{b}{a \cdot a}}\right|\right|} \]
    4. fabs-sub78.0%

      \[\leadsto \sqrt{\left|\color{blue}{\left|b \cdot \frac{b}{a \cdot a} - 1\right|}\right|} \]
    5. sub-neg78.0%

      \[\leadsto \sqrt{\left|\left|\color{blue}{b \cdot \frac{b}{a \cdot a} + \left(-1\right)}\right|\right|} \]
    6. metadata-eval78.0%

      \[\leadsto \sqrt{\left|\left|b \cdot \frac{b}{a \cdot a} + \color{blue}{-1}\right|\right|} \]
    7. associate-*r/77.3%

      \[\leadsto \sqrt{\left|\left|\color{blue}{\frac{b \cdot b}{a \cdot a}} + -1\right|\right|} \]
    8. frac-times100.0%

      \[\leadsto \sqrt{\left|\left|\color{blue}{\frac{b}{a} \cdot \frac{b}{a}} + -1\right|\right|} \]
    9. fma-undefine100.0%

      \[\leadsto \sqrt{\left|\left|\color{blue}{\mathsf{fma}\left(\frac{b}{a}, \frac{b}{a}, -1\right)}\right|\right|} \]
    10. add-sqr-sqrt0.0%

      \[\leadsto \sqrt{\left|\left|\color{blue}{\sqrt{\mathsf{fma}\left(\frac{b}{a}, \frac{b}{a}, -1\right)} \cdot \sqrt{\mathsf{fma}\left(\frac{b}{a}, \frac{b}{a}, -1\right)}}\right|\right|} \]
    11. fabs-sqr0.0%

      \[\leadsto \sqrt{\left|\color{blue}{\sqrt{\mathsf{fma}\left(\frac{b}{a}, \frac{b}{a}, -1\right)} \cdot \sqrt{\mathsf{fma}\left(\frac{b}{a}, \frac{b}{a}, -1\right)}}\right|} \]
    12. add-sqr-sqrt100.0%

      \[\leadsto \sqrt{\left|\color{blue}{\mathsf{fma}\left(\frac{b}{a}, \frac{b}{a}, -1\right)}\right|} \]
    13. fma-undefine100.0%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{b}{a} \cdot \frac{b}{a} + -1}\right|} \]
    14. difference-of-sqr--199.9%

      \[\leadsto \sqrt{\left|\color{blue}{\left(\frac{b}{a} + 1\right) \cdot \left(\frac{b}{a} - 1\right)}\right|} \]
  6. Applied egg-rr99.9%

    \[\leadsto \sqrt{\left|\color{blue}{\left(\frac{b}{a} + 1\right) \cdot \left(\frac{b}{a} - 1\right)}\right|} \]
  7. Step-by-step derivation
    1. difference-of-sqr-1100.0%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{b}{a} \cdot \frac{b}{a} - 1}\right|} \]
    2. clear-num100.0%

      \[\leadsto \sqrt{\left|\frac{b}{a} \cdot \color{blue}{\frac{1}{\frac{a}{b}}} - 1\right|} \]
    3. div-inv100.0%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{\frac{b}{a}}{\frac{a}{b}}} - 1\right|} \]
    4. fabs-sub100.0%

      \[\leadsto \sqrt{\color{blue}{\left|1 - \frac{\frac{b}{a}}{\frac{a}{b}}\right|}} \]
    5. add-sqr-sqrt100.0%

      \[\leadsto \sqrt{\left|\color{blue}{\sqrt{1 - \frac{\frac{b}{a}}{\frac{a}{b}}} \cdot \sqrt{1 - \frac{\frac{b}{a}}{\frac{a}{b}}}}\right|} \]
    6. fabs-sqr100.0%

      \[\leadsto \sqrt{\color{blue}{\sqrt{1 - \frac{\frac{b}{a}}{\frac{a}{b}}} \cdot \sqrt{1 - \frac{\frac{b}{a}}{\frac{a}{b}}}}} \]
    7. add-sqr-sqrt100.0%

      \[\leadsto \sqrt{\color{blue}{1 - \frac{\frac{b}{a}}{\frac{a}{b}}}} \]
    8. *-un-lft-identity100.0%

      \[\leadsto \color{blue}{1 \cdot \sqrt{1 - \frac{\frac{b}{a}}{\frac{a}{b}}}} \]
    9. sub-neg100.0%

      \[\leadsto 1 \cdot \sqrt{\color{blue}{1 + \left(-\frac{\frac{b}{a}}{\frac{a}{b}}\right)}} \]
    10. div-inv100.0%

      \[\leadsto 1 \cdot \sqrt{1 + \left(-\color{blue}{\frac{b}{a} \cdot \frac{1}{\frac{a}{b}}}\right)} \]
    11. clear-num100.0%

      \[\leadsto 1 \cdot \sqrt{1 + \left(-\frac{b}{a} \cdot \color{blue}{\frac{b}{a}}\right)} \]
    12. unpow2100.0%

      \[\leadsto 1 \cdot \sqrt{1 + \left(-\color{blue}{{\left(\frac{b}{a}\right)}^{2}}\right)} \]
    13. add-sqr-sqrt22.7%

      \[\leadsto 1 \cdot \sqrt{1 + \color{blue}{\sqrt{-{\left(\frac{b}{a}\right)}^{2}} \cdot \sqrt{-{\left(\frac{b}{a}\right)}^{2}}}} \]
  8. Applied egg-rr97.7%

    \[\leadsto \color{blue}{1 \cdot \mathsf{hypot}\left(1, \frac{b}{a}\right)} \]
  9. Step-by-step derivation
    1. *-lft-identity97.7%

      \[\leadsto \color{blue}{\mathsf{hypot}\left(1, \frac{b}{a}\right)} \]
  10. Simplified97.7%

    \[\leadsto \color{blue}{\mathsf{hypot}\left(1, \frac{b}{a}\right)} \]
  11. Final simplification97.7%

    \[\leadsto \mathsf{hypot}\left(1, \frac{b}{a}\right) \]
  12. Add Preprocessing

Reproduce

?
herbie shell --seed 2024039 
(FPCore (a b)
  :name "Eccentricity of an ellipse"
  :precision binary64
  :pre (and (and (<= 0.0 b) (<= b a)) (<= a 1.0))
  (sqrt (fabs (/ (- (* a a) (* b b)) (* a a)))))