Eccentricity of an ellipse

Percentage Accurate: 76.2% → 100.0%
Time: 5.3s
Alternatives: 5
Speedup: 211.0×

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 5 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: 76.2% 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, 0.7× speedup?

\[\begin{array}{l} \\ e^{\mathsf{log1p}\left(-{\left(\frac{b}{a}\right)}^{2}\right) \cdot 0.5} \end{array} \]
(FPCore (a b) :precision binary64 (exp (* (log1p (- (pow (/ b a) 2.0))) 0.5)))
double code(double a, double b) {
	return exp((log1p(-pow((b / a), 2.0)) * 0.5));
}
public static double code(double a, double b) {
	return Math.exp((Math.log1p(-Math.pow((b / a), 2.0)) * 0.5));
}
def code(a, b):
	return math.exp((math.log1p(-math.pow((b / a), 2.0)) * 0.5))
function code(a, b)
	return exp(Float64(log1p(Float64(-(Float64(b / a) ^ 2.0))) * 0.5))
end
code[a_, b_] := N[Exp[N[(N[Log[1 + (-N[Power[N[(b / a), $MachinePrecision], 2.0], $MachinePrecision])], $MachinePrecision] * 0.5), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
e^{\mathsf{log1p}\left(-{\left(\frac{b}{a}\right)}^{2}\right) \cdot 0.5}
\end{array}
Derivation
  1. Initial program 78.5%

    \[\sqrt{\left|\frac{a \cdot a - b \cdot b}{a \cdot a}\right|} \]
  2. Step-by-step derivation
    1. sqr-neg78.5%

      \[\leadsto \sqrt{\left|\frac{a \cdot a - \color{blue}{\left(-b\right) \cdot \left(-b\right)}}{a \cdot a}\right|} \]
    2. associate-/r*78.4%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{\frac{a \cdot a - \left(-b\right) \cdot \left(-b\right)}{a}}{a}}\right|} \]
    3. sqr-neg78.4%

      \[\leadsto \sqrt{\left|\frac{\frac{a \cdot a - \color{blue}{b \cdot b}}{a}}{a}\right|} \]
    4. associate-/r*78.5%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{a \cdot a - b \cdot b}{a \cdot a}}\right|} \]
    5. div-sub78.5%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{a \cdot a}{a \cdot a} - \frac{b \cdot b}{a \cdot a}}\right|} \]
    6. fabs-sub78.5%

      \[\leadsto \sqrt{\color{blue}{\left|\frac{b \cdot b}{a \cdot a} - \frac{a \cdot a}{a \cdot a}\right|}} \]
    7. times-frac78.5%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{b}{a} \cdot \frac{b}{a}} - \frac{a \cdot a}{a \cdot a}\right|} \]
    8. *-inverses100.0%

      \[\leadsto \sqrt{\left|\frac{b}{a} \cdot \frac{b}{a} - \color{blue}{1}\right|} \]
  3. Simplified100.0%

    \[\leadsto \color{blue}{\sqrt{\left|\frac{b}{a} \cdot \frac{b}{a} - 1\right|}} \]
  4. Step-by-step derivation
    1. pow1/2100.0%

      \[\leadsto \color{blue}{{\left(\left|\frac{b}{a} \cdot \frac{b}{a} - 1\right|\right)}^{0.5}} \]
    2. fabs-sub100.0%

      \[\leadsto {\color{blue}{\left(\left|1 - \frac{b}{a} \cdot \frac{b}{a}\right|\right)}}^{0.5} \]
    3. *-inverses78.5%

      \[\leadsto {\left(\left|\color{blue}{\frac{a \cdot a}{a \cdot a}} - \frac{b}{a} \cdot \frac{b}{a}\right|\right)}^{0.5} \]
    4. frac-times78.5%

      \[\leadsto {\left(\left|\frac{a \cdot a}{a \cdot a} - \color{blue}{\frac{b \cdot b}{a \cdot a}}\right|\right)}^{0.5} \]
    5. div-sub78.5%

      \[\leadsto {\left(\left|\color{blue}{\frac{a \cdot a - b \cdot b}{a \cdot a}}\right|\right)}^{0.5} \]
    6. pow-to-exp78.5%

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

    \[\leadsto \color{blue}{e^{\mathsf{log1p}\left(-{\left(\frac{b}{a}\right)}^{2}\right) \cdot 0.5}} \]
  6. Final simplification100.0%

    \[\leadsto e^{\mathsf{log1p}\left(-{\left(\frac{b}{a}\right)}^{2}\right) \cdot 0.5} \]

Alternative 2: 100.0% accurate, 1.9× speedup?

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

\\
\sqrt{1 - \frac{b}{a \cdot \frac{a}{b}}}
\end{array}
Derivation
  1. Initial program 78.5%

    \[\sqrt{\left|\frac{a \cdot a - b \cdot b}{a \cdot a}\right|} \]
  2. Step-by-step derivation
    1. sqr-neg78.5%

      \[\leadsto \sqrt{\left|\frac{a \cdot a - \color{blue}{\left(-b\right) \cdot \left(-b\right)}}{a \cdot a}\right|} \]
    2. associate-/r*78.4%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{\frac{a \cdot a - \left(-b\right) \cdot \left(-b\right)}{a}}{a}}\right|} \]
    3. sqr-neg78.4%

      \[\leadsto \sqrt{\left|\frac{\frac{a \cdot a - \color{blue}{b \cdot b}}{a}}{a}\right|} \]
    4. associate-/r*78.5%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{a \cdot a - b \cdot b}{a \cdot a}}\right|} \]
    5. div-sub78.5%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{a \cdot a}{a \cdot a} - \frac{b \cdot b}{a \cdot a}}\right|} \]
    6. fabs-sub78.5%

      \[\leadsto \sqrt{\color{blue}{\left|\frac{b \cdot b}{a \cdot a} - \frac{a \cdot a}{a \cdot a}\right|}} \]
    7. times-frac78.5%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{b}{a} \cdot \frac{b}{a}} - \frac{a \cdot a}{a \cdot a}\right|} \]
    8. *-inverses100.0%

      \[\leadsto \sqrt{\left|\frac{b}{a} \cdot \frac{b}{a} - \color{blue}{1}\right|} \]
  3. Simplified100.0%

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

      \[\leadsto \sqrt{\color{blue}{\left|1 - \frac{b}{a} \cdot \frac{b}{a}\right|}} \]
    2. *-inverses78.5%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{a \cdot a}{a \cdot a}} - \frac{b}{a} \cdot \frac{b}{a}\right|} \]
    3. frac-times78.5%

      \[\leadsto \sqrt{\left|\frac{a \cdot a}{a \cdot a} - \color{blue}{\frac{b \cdot b}{a \cdot a}}\right|} \]
    4. div-sub78.5%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{a \cdot a - b \cdot b}{a \cdot a}}\right|} \]
    5. add-sqr-sqrt78.5%

      \[\leadsto \sqrt{\left|\color{blue}{\sqrt{\frac{a \cdot a - b \cdot b}{a \cdot a}} \cdot \sqrt{\frac{a \cdot a - b \cdot b}{a \cdot a}}}\right|} \]
    6. fabs-sqr78.5%

      \[\leadsto \sqrt{\color{blue}{\sqrt{\frac{a \cdot a - b \cdot b}{a \cdot a}} \cdot \sqrt{\frac{a \cdot a - b \cdot b}{a \cdot a}}}} \]
    7. add-sqr-sqrt78.5%

      \[\leadsto \sqrt{\color{blue}{\frac{a \cdot a - b \cdot b}{a \cdot a}}} \]
    8. associate-/r*78.4%

      \[\leadsto \sqrt{\color{blue}{\frac{\frac{a \cdot a - b \cdot b}{a}}{a}}} \]
    9. sqrt-div78.4%

      \[\leadsto \color{blue}{\frac{\sqrt{\frac{a \cdot a - b \cdot b}{a}}}{\sqrt{a}}} \]
  5. Applied egg-rr78.4%

    \[\leadsto \color{blue}{\frac{\sqrt{\frac{a \cdot a - b \cdot b}{a}}}{\sqrt{a}}} \]
  6. Step-by-step derivation
    1. div-sub78.4%

      \[\leadsto \frac{\sqrt{\color{blue}{\frac{a \cdot a}{a} - \frac{b \cdot b}{a}}}}{\sqrt{a}} \]
    2. associate-/l*98.7%

      \[\leadsto \frac{\sqrt{\color{blue}{\frac{a}{\frac{a}{a}}} - \frac{b \cdot b}{a}}}{\sqrt{a}} \]
    3. *-inverses98.7%

      \[\leadsto \frac{\sqrt{\frac{a}{\color{blue}{1}} - \frac{b \cdot b}{a}}}{\sqrt{a}} \]
    4. /-rgt-identity98.7%

      \[\leadsto \frac{\sqrt{\color{blue}{a} - \frac{b \cdot b}{a}}}{\sqrt{a}} \]
    5. associate-*r/99.9%

      \[\leadsto \frac{\sqrt{a - \color{blue}{b \cdot \frac{b}{a}}}}{\sqrt{a}} \]
  7. Simplified99.9%

    \[\leadsto \color{blue}{\frac{\sqrt{a - b \cdot \frac{b}{a}}}{\sqrt{a}}} \]
  8. Step-by-step derivation
    1. add-log-exp99.9%

      \[\leadsto \color{blue}{\log \left(e^{\frac{\sqrt{a - b \cdot \frac{b}{a}}}{\sqrt{a}}}\right)} \]
    2. *-un-lft-identity99.9%

      \[\leadsto \log \color{blue}{\left(1 \cdot e^{\frac{\sqrt{a - b \cdot \frac{b}{a}}}{\sqrt{a}}}\right)} \]
    3. log-prod99.9%

      \[\leadsto \color{blue}{\log 1 + \log \left(e^{\frac{\sqrt{a - b \cdot \frac{b}{a}}}{\sqrt{a}}}\right)} \]
    4. metadata-eval99.9%

      \[\leadsto \color{blue}{0} + \log \left(e^{\frac{\sqrt{a - b \cdot \frac{b}{a}}}{\sqrt{a}}}\right) \]
    5. add-log-exp99.9%

      \[\leadsto 0 + \color{blue}{\frac{\sqrt{a - b \cdot \frac{b}{a}}}{\sqrt{a}}} \]
    6. sqrt-undiv100.0%

      \[\leadsto 0 + \color{blue}{\sqrt{\frac{a - b \cdot \frac{b}{a}}{a}}} \]
    7. div-sub100.0%

      \[\leadsto 0 + \sqrt{\color{blue}{\frac{a}{a} - \frac{b \cdot \frac{b}{a}}{a}}} \]
    8. associate-*l/100.0%

      \[\leadsto 0 + \sqrt{\frac{a}{a} - \color{blue}{\frac{b}{a} \cdot \frac{b}{a}}} \]
    9. unpow2100.0%

      \[\leadsto 0 + \sqrt{\frac{a}{a} - \color{blue}{{\left(\frac{b}{a}\right)}^{2}}} \]
  9. Applied egg-rr100.0%

    \[\leadsto \color{blue}{0 + \sqrt{\frac{a}{a} - {\left(\frac{b}{a}\right)}^{2}}} \]
  10. Step-by-step derivation
    1. +-lft-identity100.0%

      \[\leadsto \color{blue}{\sqrt{\frac{a}{a} - {\left(\frac{b}{a}\right)}^{2}}} \]
    2. *-inverses100.0%

      \[\leadsto \sqrt{\color{blue}{1} - {\left(\frac{b}{a}\right)}^{2}} \]
  11. Simplified100.0%

    \[\leadsto \color{blue}{\sqrt{1 - {\left(\frac{b}{a}\right)}^{2}}} \]
  12. Step-by-step derivation
    1. unpow2100.0%

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

      \[\leadsto \sqrt{1 - \color{blue}{\frac{1}{\frac{a}{b}}} \cdot \frac{b}{a}} \]
    3. frac-times100.0%

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

      \[\leadsto \sqrt{1 - \frac{\color{blue}{b}}{\frac{a}{b} \cdot a}} \]
  13. Applied egg-rr100.0%

    \[\leadsto \sqrt{1 - \color{blue}{\frac{b}{\frac{a}{b} \cdot a}}} \]
  14. Final simplification100.0%

    \[\leadsto \sqrt{1 - \frac{b}{a \cdot \frac{a}{b}}} \]

Alternative 3: 99.0% accurate, 16.2× speedup?

\[\begin{array}{l} \\ 1 + -0.5 \cdot \frac{1}{\frac{a}{b} \cdot \frac{a}{b}} \end{array} \]
(FPCore (a b) :precision binary64 (+ 1.0 (* -0.5 (/ 1.0 (* (/ a b) (/ a b))))))
double code(double a, double b) {
	return 1.0 + (-0.5 * (1.0 / ((a / b) * (a / b))));
}
real(8) function code(a, b)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    code = 1.0d0 + ((-0.5d0) * (1.0d0 / ((a / b) * (a / b))))
end function
public static double code(double a, double b) {
	return 1.0 + (-0.5 * (1.0 / ((a / b) * (a / b))));
}
def code(a, b):
	return 1.0 + (-0.5 * (1.0 / ((a / b) * (a / b))))
function code(a, b)
	return Float64(1.0 + Float64(-0.5 * Float64(1.0 / Float64(Float64(a / b) * Float64(a / b)))))
end
function tmp = code(a, b)
	tmp = 1.0 + (-0.5 * (1.0 / ((a / b) * (a / b))));
end
code[a_, b_] := N[(1.0 + N[(-0.5 * N[(1.0 / N[(N[(a / b), $MachinePrecision] * N[(a / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
1 + -0.5 \cdot \frac{1}{\frac{a}{b} \cdot \frac{a}{b}}
\end{array}
Derivation
  1. Initial program 78.5%

    \[\sqrt{\left|\frac{a \cdot a - b \cdot b}{a \cdot a}\right|} \]
  2. Step-by-step derivation
    1. sqr-neg78.5%

      \[\leadsto \sqrt{\left|\frac{a \cdot a - \color{blue}{\left(-b\right) \cdot \left(-b\right)}}{a \cdot a}\right|} \]
    2. associate-/r*78.4%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{\frac{a \cdot a - \left(-b\right) \cdot \left(-b\right)}{a}}{a}}\right|} \]
    3. sqr-neg78.4%

      \[\leadsto \sqrt{\left|\frac{\frac{a \cdot a - \color{blue}{b \cdot b}}{a}}{a}\right|} \]
    4. associate-/r*78.5%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{a \cdot a - b \cdot b}{a \cdot a}}\right|} \]
    5. div-sub78.5%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{a \cdot a}{a \cdot a} - \frac{b \cdot b}{a \cdot a}}\right|} \]
    6. fabs-sub78.5%

      \[\leadsto \sqrt{\color{blue}{\left|\frac{b \cdot b}{a \cdot a} - \frac{a \cdot a}{a \cdot a}\right|}} \]
    7. times-frac78.5%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{b}{a} \cdot \frac{b}{a}} - \frac{a \cdot a}{a \cdot a}\right|} \]
    8. *-inverses100.0%

      \[\leadsto \sqrt{\left|\frac{b}{a} \cdot \frac{b}{a} - \color{blue}{1}\right|} \]
  3. Simplified100.0%

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

      \[\leadsto \sqrt{\color{blue}{\left|1 - \frac{b}{a} \cdot \frac{b}{a}\right|}} \]
    2. *-inverses78.5%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{a \cdot a}{a \cdot a}} - \frac{b}{a} \cdot \frac{b}{a}\right|} \]
    3. frac-times78.5%

      \[\leadsto \sqrt{\left|\frac{a \cdot a}{a \cdot a} - \color{blue}{\frac{b \cdot b}{a \cdot a}}\right|} \]
    4. div-sub78.5%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{a \cdot a - b \cdot b}{a \cdot a}}\right|} \]
    5. add-sqr-sqrt78.5%

      \[\leadsto \sqrt{\left|\color{blue}{\sqrt{\frac{a \cdot a - b \cdot b}{a \cdot a}} \cdot \sqrt{\frac{a \cdot a - b \cdot b}{a \cdot a}}}\right|} \]
    6. fabs-sqr78.5%

      \[\leadsto \sqrt{\color{blue}{\sqrt{\frac{a \cdot a - b \cdot b}{a \cdot a}} \cdot \sqrt{\frac{a \cdot a - b \cdot b}{a \cdot a}}}} \]
    7. add-sqr-sqrt78.5%

      \[\leadsto \sqrt{\color{blue}{\frac{a \cdot a - b \cdot b}{a \cdot a}}} \]
    8. associate-/r*78.4%

      \[\leadsto \sqrt{\color{blue}{\frac{\frac{a \cdot a - b \cdot b}{a}}{a}}} \]
    9. sqrt-div78.4%

      \[\leadsto \color{blue}{\frac{\sqrt{\frac{a \cdot a - b \cdot b}{a}}}{\sqrt{a}}} \]
  5. Applied egg-rr78.4%

    \[\leadsto \color{blue}{\frac{\sqrt{\frac{a \cdot a - b \cdot b}{a}}}{\sqrt{a}}} \]
  6. Step-by-step derivation
    1. div-sub78.4%

      \[\leadsto \frac{\sqrt{\color{blue}{\frac{a \cdot a}{a} - \frac{b \cdot b}{a}}}}{\sqrt{a}} \]
    2. associate-/l*98.7%

      \[\leadsto \frac{\sqrt{\color{blue}{\frac{a}{\frac{a}{a}}} - \frac{b \cdot b}{a}}}{\sqrt{a}} \]
    3. *-inverses98.7%

      \[\leadsto \frac{\sqrt{\frac{a}{\color{blue}{1}} - \frac{b \cdot b}{a}}}{\sqrt{a}} \]
    4. /-rgt-identity98.7%

      \[\leadsto \frac{\sqrt{\color{blue}{a} - \frac{b \cdot b}{a}}}{\sqrt{a}} \]
    5. associate-*r/99.9%

      \[\leadsto \frac{\sqrt{a - \color{blue}{b \cdot \frac{b}{a}}}}{\sqrt{a}} \]
  7. Simplified99.9%

    \[\leadsto \color{blue}{\frac{\sqrt{a - b \cdot \frac{b}{a}}}{\sqrt{a}}} \]
  8. Taylor expanded in a around inf 78.0%

    \[\leadsto \color{blue}{1 + -0.5 \cdot \frac{{b}^{2}}{{a}^{2}}} \]
  9. Step-by-step derivation
    1. unpow278.0%

      \[\leadsto 1 + -0.5 \cdot \frac{\color{blue}{b \cdot b}}{{a}^{2}} \]
    2. unpow278.0%

      \[\leadsto 1 + -0.5 \cdot \frac{b \cdot b}{\color{blue}{a \cdot a}} \]
    3. times-frac99.0%

      \[\leadsto 1 + -0.5 \cdot \color{blue}{\left(\frac{b}{a} \cdot \frac{b}{a}\right)} \]
    4. unpow299.0%

      \[\leadsto 1 + -0.5 \cdot \color{blue}{{\left(\frac{b}{a}\right)}^{2}} \]
  10. Simplified99.0%

    \[\leadsto \color{blue}{1 + -0.5 \cdot {\left(\frac{b}{a}\right)}^{2}} \]
  11. Step-by-step derivation
    1. unpow299.0%

      \[\leadsto 1 + -0.5 \cdot \color{blue}{\left(\frac{b}{a} \cdot \frac{b}{a}\right)} \]
    2. clear-num99.0%

      \[\leadsto 1 + -0.5 \cdot \left(\color{blue}{\frac{1}{\frac{a}{b}}} \cdot \frac{b}{a}\right) \]
    3. clear-num99.0%

      \[\leadsto 1 + -0.5 \cdot \left(\frac{1}{\frac{a}{b}} \cdot \color{blue}{\frac{1}{\frac{a}{b}}}\right) \]
    4. frac-times99.0%

      \[\leadsto 1 + -0.5 \cdot \color{blue}{\frac{1 \cdot 1}{\frac{a}{b} \cdot \frac{a}{b}}} \]
    5. metadata-eval99.0%

      \[\leadsto 1 + -0.5 \cdot \frac{\color{blue}{1}}{\frac{a}{b} \cdot \frac{a}{b}} \]
  12. Applied egg-rr99.0%

    \[\leadsto 1 + -0.5 \cdot \color{blue}{\frac{1}{\frac{a}{b} \cdot \frac{a}{b}}} \]
  13. Final simplification99.0%

    \[\leadsto 1 + -0.5 \cdot \frac{1}{\frac{a}{b} \cdot \frac{a}{b}} \]

Alternative 4: 99.0% accurate, 19.2× speedup?

\[\begin{array}{l} \\ 1 + -0.5 \cdot \frac{\frac{b}{\frac{a}{b}}}{a} \end{array} \]
(FPCore (a b) :precision binary64 (+ 1.0 (* -0.5 (/ (/ b (/ a b)) a))))
double code(double a, double b) {
	return 1.0 + (-0.5 * ((b / (a / b)) / a));
}
real(8) function code(a, b)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    code = 1.0d0 + ((-0.5d0) * ((b / (a / b)) / a))
end function
public static double code(double a, double b) {
	return 1.0 + (-0.5 * ((b / (a / b)) / a));
}
def code(a, b):
	return 1.0 + (-0.5 * ((b / (a / b)) / a))
function code(a, b)
	return Float64(1.0 + Float64(-0.5 * Float64(Float64(b / Float64(a / b)) / a)))
end
function tmp = code(a, b)
	tmp = 1.0 + (-0.5 * ((b / (a / b)) / a));
end
code[a_, b_] := N[(1.0 + N[(-0.5 * N[(N[(b / N[(a / b), $MachinePrecision]), $MachinePrecision] / a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
1 + -0.5 \cdot \frac{\frac{b}{\frac{a}{b}}}{a}
\end{array}
Derivation
  1. Initial program 78.5%

    \[\sqrt{\left|\frac{a \cdot a - b \cdot b}{a \cdot a}\right|} \]
  2. Step-by-step derivation
    1. sqr-neg78.5%

      \[\leadsto \sqrt{\left|\frac{a \cdot a - \color{blue}{\left(-b\right) \cdot \left(-b\right)}}{a \cdot a}\right|} \]
    2. associate-/r*78.4%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{\frac{a \cdot a - \left(-b\right) \cdot \left(-b\right)}{a}}{a}}\right|} \]
    3. sqr-neg78.4%

      \[\leadsto \sqrt{\left|\frac{\frac{a \cdot a - \color{blue}{b \cdot b}}{a}}{a}\right|} \]
    4. associate-/r*78.5%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{a \cdot a - b \cdot b}{a \cdot a}}\right|} \]
    5. div-sub78.5%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{a \cdot a}{a \cdot a} - \frac{b \cdot b}{a \cdot a}}\right|} \]
    6. fabs-sub78.5%

      \[\leadsto \sqrt{\color{blue}{\left|\frac{b \cdot b}{a \cdot a} - \frac{a \cdot a}{a \cdot a}\right|}} \]
    7. times-frac78.5%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{b}{a} \cdot \frac{b}{a}} - \frac{a \cdot a}{a \cdot a}\right|} \]
    8. *-inverses100.0%

      \[\leadsto \sqrt{\left|\frac{b}{a} \cdot \frac{b}{a} - \color{blue}{1}\right|} \]
  3. Simplified100.0%

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

      \[\leadsto \sqrt{\color{blue}{\left|1 - \frac{b}{a} \cdot \frac{b}{a}\right|}} \]
    2. *-inverses78.5%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{a \cdot a}{a \cdot a}} - \frac{b}{a} \cdot \frac{b}{a}\right|} \]
    3. frac-times78.5%

      \[\leadsto \sqrt{\left|\frac{a \cdot a}{a \cdot a} - \color{blue}{\frac{b \cdot b}{a \cdot a}}\right|} \]
    4. div-sub78.5%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{a \cdot a - b \cdot b}{a \cdot a}}\right|} \]
    5. add-sqr-sqrt78.5%

      \[\leadsto \sqrt{\left|\color{blue}{\sqrt{\frac{a \cdot a - b \cdot b}{a \cdot a}} \cdot \sqrt{\frac{a \cdot a - b \cdot b}{a \cdot a}}}\right|} \]
    6. fabs-sqr78.5%

      \[\leadsto \sqrt{\color{blue}{\sqrt{\frac{a \cdot a - b \cdot b}{a \cdot a}} \cdot \sqrt{\frac{a \cdot a - b \cdot b}{a \cdot a}}}} \]
    7. add-sqr-sqrt78.5%

      \[\leadsto \sqrt{\color{blue}{\frac{a \cdot a - b \cdot b}{a \cdot a}}} \]
    8. associate-/r*78.4%

      \[\leadsto \sqrt{\color{blue}{\frac{\frac{a \cdot a - b \cdot b}{a}}{a}}} \]
    9. sqrt-div78.4%

      \[\leadsto \color{blue}{\frac{\sqrt{\frac{a \cdot a - b \cdot b}{a}}}{\sqrt{a}}} \]
  5. Applied egg-rr78.4%

    \[\leadsto \color{blue}{\frac{\sqrt{\frac{a \cdot a - b \cdot b}{a}}}{\sqrt{a}}} \]
  6. Step-by-step derivation
    1. div-sub78.4%

      \[\leadsto \frac{\sqrt{\color{blue}{\frac{a \cdot a}{a} - \frac{b \cdot b}{a}}}}{\sqrt{a}} \]
    2. associate-/l*98.7%

      \[\leadsto \frac{\sqrt{\color{blue}{\frac{a}{\frac{a}{a}}} - \frac{b \cdot b}{a}}}{\sqrt{a}} \]
    3. *-inverses98.7%

      \[\leadsto \frac{\sqrt{\frac{a}{\color{blue}{1}} - \frac{b \cdot b}{a}}}{\sqrt{a}} \]
    4. /-rgt-identity98.7%

      \[\leadsto \frac{\sqrt{\color{blue}{a} - \frac{b \cdot b}{a}}}{\sqrt{a}} \]
    5. associate-*r/99.9%

      \[\leadsto \frac{\sqrt{a - \color{blue}{b \cdot \frac{b}{a}}}}{\sqrt{a}} \]
  7. Simplified99.9%

    \[\leadsto \color{blue}{\frac{\sqrt{a - b \cdot \frac{b}{a}}}{\sqrt{a}}} \]
  8. Taylor expanded in a around inf 78.0%

    \[\leadsto \color{blue}{1 + -0.5 \cdot \frac{{b}^{2}}{{a}^{2}}} \]
  9. Step-by-step derivation
    1. unpow278.0%

      \[\leadsto 1 + -0.5 \cdot \frac{\color{blue}{b \cdot b}}{{a}^{2}} \]
    2. unpow278.0%

      \[\leadsto 1 + -0.5 \cdot \frac{b \cdot b}{\color{blue}{a \cdot a}} \]
    3. times-frac99.0%

      \[\leadsto 1 + -0.5 \cdot \color{blue}{\left(\frac{b}{a} \cdot \frac{b}{a}\right)} \]
    4. unpow299.0%

      \[\leadsto 1 + -0.5 \cdot \color{blue}{{\left(\frac{b}{a}\right)}^{2}} \]
  10. Simplified99.0%

    \[\leadsto \color{blue}{1 + -0.5 \cdot {\left(\frac{b}{a}\right)}^{2}} \]
  11. Step-by-step derivation
    1. unpow299.0%

      \[\leadsto 1 + -0.5 \cdot \color{blue}{\left(\frac{b}{a} \cdot \frac{b}{a}\right)} \]
    2. associate-*l/99.0%

      \[\leadsto 1 + -0.5 \cdot \color{blue}{\frac{b \cdot \frac{b}{a}}{a}} \]
    3. clear-num99.0%

      \[\leadsto 1 + -0.5 \cdot \frac{b \cdot \color{blue}{\frac{1}{\frac{a}{b}}}}{a} \]
    4. un-div-inv99.0%

      \[\leadsto 1 + -0.5 \cdot \frac{\color{blue}{\frac{b}{\frac{a}{b}}}}{a} \]
  12. Applied egg-rr99.0%

    \[\leadsto 1 + -0.5 \cdot \color{blue}{\frac{\frac{b}{\frac{a}{b}}}{a}} \]
  13. Final simplification99.0%

    \[\leadsto 1 + -0.5 \cdot \frac{\frac{b}{\frac{a}{b}}}{a} \]

Alternative 5: 97.9% accurate, 211.0× speedup?

\[\begin{array}{l} \\ 1 \end{array} \]
(FPCore (a b) :precision binary64 1.0)
double code(double a, double b) {
	return 1.0;
}
real(8) function code(a, b)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    code = 1.0d0
end function
public static double code(double a, double b) {
	return 1.0;
}
def code(a, b):
	return 1.0
function code(a, b)
	return 1.0
end
function tmp = code(a, b)
	tmp = 1.0;
end
code[a_, b_] := 1.0
\begin{array}{l}

\\
1
\end{array}
Derivation
  1. Initial program 78.5%

    \[\sqrt{\left|\frac{a \cdot a - b \cdot b}{a \cdot a}\right|} \]
  2. Step-by-step derivation
    1. sqr-neg78.5%

      \[\leadsto \sqrt{\left|\frac{a \cdot a - \color{blue}{\left(-b\right) \cdot \left(-b\right)}}{a \cdot a}\right|} \]
    2. associate-/r*78.4%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{\frac{a \cdot a - \left(-b\right) \cdot \left(-b\right)}{a}}{a}}\right|} \]
    3. sqr-neg78.4%

      \[\leadsto \sqrt{\left|\frac{\frac{a \cdot a - \color{blue}{b \cdot b}}{a}}{a}\right|} \]
    4. associate-/r*78.5%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{a \cdot a - b \cdot b}{a \cdot a}}\right|} \]
    5. div-sub78.5%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{a \cdot a}{a \cdot a} - \frac{b \cdot b}{a \cdot a}}\right|} \]
    6. fabs-sub78.5%

      \[\leadsto \sqrt{\color{blue}{\left|\frac{b \cdot b}{a \cdot a} - \frac{a \cdot a}{a \cdot a}\right|}} \]
    7. times-frac78.5%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{b}{a} \cdot \frac{b}{a}} - \frac{a \cdot a}{a \cdot a}\right|} \]
    8. *-inverses100.0%

      \[\leadsto \sqrt{\left|\frac{b}{a} \cdot \frac{b}{a} - \color{blue}{1}\right|} \]
  3. Simplified100.0%

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

      \[\leadsto \sqrt{\color{blue}{\left|1 - \frac{b}{a} \cdot \frac{b}{a}\right|}} \]
    2. *-inverses78.5%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{a \cdot a}{a \cdot a}} - \frac{b}{a} \cdot \frac{b}{a}\right|} \]
    3. frac-times78.5%

      \[\leadsto \sqrt{\left|\frac{a \cdot a}{a \cdot a} - \color{blue}{\frac{b \cdot b}{a \cdot a}}\right|} \]
    4. div-sub78.5%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{a \cdot a - b \cdot b}{a \cdot a}}\right|} \]
    5. add-sqr-sqrt78.5%

      \[\leadsto \sqrt{\left|\color{blue}{\sqrt{\frac{a \cdot a - b \cdot b}{a \cdot a}} \cdot \sqrt{\frac{a \cdot a - b \cdot b}{a \cdot a}}}\right|} \]
    6. fabs-sqr78.5%

      \[\leadsto \sqrt{\color{blue}{\sqrt{\frac{a \cdot a - b \cdot b}{a \cdot a}} \cdot \sqrt{\frac{a \cdot a - b \cdot b}{a \cdot a}}}} \]
    7. add-sqr-sqrt78.5%

      \[\leadsto \sqrt{\color{blue}{\frac{a \cdot a - b \cdot b}{a \cdot a}}} \]
    8. associate-/r*78.4%

      \[\leadsto \sqrt{\color{blue}{\frac{\frac{a \cdot a - b \cdot b}{a}}{a}}} \]
    9. sqrt-div78.4%

      \[\leadsto \color{blue}{\frac{\sqrt{\frac{a \cdot a - b \cdot b}{a}}}{\sqrt{a}}} \]
  5. Applied egg-rr78.4%

    \[\leadsto \color{blue}{\frac{\sqrt{\frac{a \cdot a - b \cdot b}{a}}}{\sqrt{a}}} \]
  6. Step-by-step derivation
    1. div-sub78.4%

      \[\leadsto \frac{\sqrt{\color{blue}{\frac{a \cdot a}{a} - \frac{b \cdot b}{a}}}}{\sqrt{a}} \]
    2. associate-/l*98.7%

      \[\leadsto \frac{\sqrt{\color{blue}{\frac{a}{\frac{a}{a}}} - \frac{b \cdot b}{a}}}{\sqrt{a}} \]
    3. *-inverses98.7%

      \[\leadsto \frac{\sqrt{\frac{a}{\color{blue}{1}} - \frac{b \cdot b}{a}}}{\sqrt{a}} \]
    4. /-rgt-identity98.7%

      \[\leadsto \frac{\sqrt{\color{blue}{a} - \frac{b \cdot b}{a}}}{\sqrt{a}} \]
    5. associate-*r/99.9%

      \[\leadsto \frac{\sqrt{a - \color{blue}{b \cdot \frac{b}{a}}}}{\sqrt{a}} \]
  7. Simplified99.9%

    \[\leadsto \color{blue}{\frac{\sqrt{a - b \cdot \frac{b}{a}}}{\sqrt{a}}} \]
  8. Taylor expanded in a around inf 97.4%

    \[\leadsto \color{blue}{1} \]
  9. Final simplification97.4%

    \[\leadsto 1 \]

Reproduce

?
herbie shell --seed 2023264 
(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)))))