Eccentricity of an ellipse

Percentage Accurate: 77.4% → 100.0%
Time: 4.2s
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: 77.4% 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?

\[\begin{array}{l} \\ {\left({\left(\frac{\frac{b}{a}}{\frac{a}{b}} + -1\right)}^{2}\right)}^{0.25} \end{array} \]
(FPCore (a b)
 :precision binary64
 (pow (pow (+ (/ (/ b a) (/ a b)) -1.0) 2.0) 0.25))
double code(double a, double b) {
	return pow(pow((((b / a) / (a / b)) + -1.0), 2.0), 0.25);
}
real(8) function code(a, b)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    code = ((((b / a) / (a / b)) + (-1.0d0)) ** 2.0d0) ** 0.25d0
end function
public static double code(double a, double b) {
	return Math.pow(Math.pow((((b / a) / (a / b)) + -1.0), 2.0), 0.25);
}
def code(a, b):
	return math.pow(math.pow((((b / a) / (a / b)) + -1.0), 2.0), 0.25)
function code(a, b)
	return (Float64(Float64(Float64(b / a) / Float64(a / b)) + -1.0) ^ 2.0) ^ 0.25
end
function tmp = code(a, b)
	tmp = ((((b / a) / (a / b)) + -1.0) ^ 2.0) ^ 0.25;
end
code[a_, b_] := N[Power[N[Power[N[(N[(N[(b / a), $MachinePrecision] / N[(a / b), $MachinePrecision]), $MachinePrecision] + -1.0), $MachinePrecision], 2.0], $MachinePrecision], 0.25], $MachinePrecision]
\begin{array}{l}

\\
{\left({\left(\frac{\frac{b}{a}}{\frac{a}{b}} + -1\right)}^{2}\right)}^{0.25}
\end{array}
Derivation
  1. Initial program 75.0%

    \[\sqrt{\left|\frac{a \cdot a - b \cdot b}{a \cdot a}\right|} \]
  2. Step-by-step derivation
    1. sqr-neg75.0%

      \[\leadsto \sqrt{\left|\frac{a \cdot a - \color{blue}{\left(-b\right) \cdot \left(-b\right)}}{a \cdot a}\right|} \]
    2. associate-/r*75.5%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{\frac{a \cdot a - \left(-b\right) \cdot \left(-b\right)}{a}}{a}}\right|} \]
    3. sqr-neg75.5%

      \[\leadsto \sqrt{\left|\frac{\frac{a \cdot a - \color{blue}{b \cdot b}}{a}}{a}\right|} \]
    4. associate-/r*75.0%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{a \cdot a - b \cdot b}{a \cdot a}}\right|} \]
    5. div-sub75.0%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{a \cdot a}{a \cdot a} - \frac{b \cdot b}{a \cdot a}}\right|} \]
    6. fabs-sub75.0%

      \[\leadsto \sqrt{\color{blue}{\left|\frac{b \cdot b}{a \cdot a} - \frac{a \cdot a}{a \cdot a}\right|}} \]
    7. times-frac75.0%

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

      \[\leadsto {\color{blue}{\left(\sqrt{\left|\frac{b}{a} \cdot \frac{b}{a} - 1\right|} \cdot \sqrt{\left|\frac{b}{a} \cdot \frac{b}{a} - 1\right|}\right)}}^{0.5} \]
    3. sqrt-unprod100.0%

      \[\leadsto {\color{blue}{\left(\sqrt{\left|\frac{b}{a} \cdot \frac{b}{a} - 1\right| \cdot \left|\frac{b}{a} \cdot \frac{b}{a} - 1\right|}\right)}}^{0.5} \]
    4. pow1/2100.0%

      \[\leadsto {\color{blue}{\left({\left(\left|\frac{b}{a} \cdot \frac{b}{a} - 1\right| \cdot \left|\frac{b}{a} \cdot \frac{b}{a} - 1\right|\right)}^{0.5}\right)}}^{0.5} \]
    5. pow-pow100.0%

      \[\leadsto \color{blue}{{\left(\left|\frac{b}{a} \cdot \frac{b}{a} - 1\right| \cdot \left|\frac{b}{a} \cdot \frac{b}{a} - 1\right|\right)}^{\left(0.5 \cdot 0.5\right)}} \]
  5. Applied egg-rr100.0%

    \[\leadsto \color{blue}{{\left({\left({\left(\frac{a}{b}\right)}^{-2} + -1\right)}^{2}\right)}^{0.25}} \]
  6. Step-by-step derivation
    1. metadata-eval100.0%

      \[\leadsto {\left({\left({\left(\frac{a}{b}\right)}^{\color{blue}{\left(2 \cdot -1\right)}} + -1\right)}^{2}\right)}^{0.25} \]
    2. pow-sqr100.0%

      \[\leadsto {\left({\left(\color{blue}{{\left(\frac{a}{b}\right)}^{-1} \cdot {\left(\frac{a}{b}\right)}^{-1}} + -1\right)}^{2}\right)}^{0.25} \]
    3. inv-pow100.0%

      \[\leadsto {\left({\left(\color{blue}{\frac{1}{\frac{a}{b}}} \cdot {\left(\frac{a}{b}\right)}^{-1} + -1\right)}^{2}\right)}^{0.25} \]
    4. clear-num100.0%

      \[\leadsto {\left({\left(\color{blue}{\frac{b}{a}} \cdot {\left(\frac{a}{b}\right)}^{-1} + -1\right)}^{2}\right)}^{0.25} \]
    5. inv-pow100.0%

      \[\leadsto {\left({\left(\frac{b}{a} \cdot \color{blue}{\frac{1}{\frac{a}{b}}} + -1\right)}^{2}\right)}^{0.25} \]
    6. un-div-inv100.0%

      \[\leadsto {\left({\left(\color{blue}{\frac{\frac{b}{a}}{\frac{a}{b}}} + -1\right)}^{2}\right)}^{0.25} \]
  7. Applied egg-rr100.0%

    \[\leadsto {\left({\left(\color{blue}{\frac{\frac{b}{a}}{\frac{a}{b}}} + -1\right)}^{2}\right)}^{0.25} \]
  8. Final simplification100.0%

    \[\leadsto {\left({\left(\frac{\frac{b}{a}}{\frac{a}{b}} + -1\right)}^{2}\right)}^{0.25} \]

Alternative 2: 100.0% accurate, 1.0× speedup?

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

\\
\sqrt{\left|-1 + \frac{b}{a} \cdot \frac{b}{a}\right|}
\end{array}
Derivation
  1. Initial program 75.0%

    \[\sqrt{\left|\frac{a \cdot a - b \cdot b}{a \cdot a}\right|} \]
  2. Step-by-step derivation
    1. sqr-neg75.0%

      \[\leadsto \sqrt{\left|\frac{a \cdot a - \color{blue}{\left(-b\right) \cdot \left(-b\right)}}{a \cdot a}\right|} \]
    2. associate-/r*75.5%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{\frac{a \cdot a - \left(-b\right) \cdot \left(-b\right)}{a}}{a}}\right|} \]
    3. sqr-neg75.5%

      \[\leadsto \sqrt{\left|\frac{\frac{a \cdot a - \color{blue}{b \cdot b}}{a}}{a}\right|} \]
    4. associate-/r*75.0%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{a \cdot a - b \cdot b}{a \cdot a}}\right|} \]
    5. div-sub75.0%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{a \cdot a}{a \cdot a} - \frac{b \cdot b}{a \cdot a}}\right|} \]
    6. fabs-sub75.0%

      \[\leadsto \sqrt{\color{blue}{\left|\frac{b \cdot b}{a \cdot a} - \frac{a \cdot a}{a \cdot a}\right|}} \]
    7. times-frac75.0%

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

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

Alternative 3: 99.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \mathsf{fma}\left(-0.5, {\left(\frac{b}{a}\right)}^{2}, 1\right) \end{array} \]
(FPCore (a b) :precision binary64 (fma -0.5 (pow (/ b a) 2.0) 1.0))
double code(double a, double b) {
	return fma(-0.5, pow((b / a), 2.0), 1.0);
}
function code(a, b)
	return fma(-0.5, (Float64(b / a) ^ 2.0), 1.0)
end
code[a_, b_] := N[(-0.5 * N[Power[N[(b / a), $MachinePrecision], 2.0], $MachinePrecision] + 1.0), $MachinePrecision]
\begin{array}{l}

\\
\mathsf{fma}\left(-0.5, {\left(\frac{b}{a}\right)}^{2}, 1\right)
\end{array}
Derivation
  1. Initial program 75.0%

    \[\sqrt{\left|\frac{a \cdot a - b \cdot b}{a \cdot a}\right|} \]
  2. Step-by-step derivation
    1. sqr-neg75.0%

      \[\leadsto \sqrt{\left|\frac{a \cdot a - \color{blue}{\left(-b\right) \cdot \left(-b\right)}}{a \cdot a}\right|} \]
    2. associate-/r*75.5%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{\frac{a \cdot a - \left(-b\right) \cdot \left(-b\right)}{a}}{a}}\right|} \]
    3. sqr-neg75.5%

      \[\leadsto \sqrt{\left|\frac{\frac{a \cdot a - \color{blue}{b \cdot b}}{a}}{a}\right|} \]
    4. associate-/r*75.0%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{a \cdot a - b \cdot b}{a \cdot a}}\right|} \]
    5. div-sub75.0%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{a \cdot a}{a \cdot a} - \frac{b \cdot b}{a \cdot a}}\right|} \]
    6. fabs-sub75.0%

      \[\leadsto \sqrt{\color{blue}{\left|\frac{b \cdot b}{a \cdot a} - \frac{a \cdot a}{a \cdot a}\right|}} \]
    7. times-frac75.0%

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

      \[\leadsto {\color{blue}{\left(\sqrt{\left|\frac{b}{a} \cdot \frac{b}{a} - 1\right|} \cdot \sqrt{\left|\frac{b}{a} \cdot \frac{b}{a} - 1\right|}\right)}}^{0.5} \]
    3. sqrt-unprod100.0%

      \[\leadsto {\color{blue}{\left(\sqrt{\left|\frac{b}{a} \cdot \frac{b}{a} - 1\right| \cdot \left|\frac{b}{a} \cdot \frac{b}{a} - 1\right|}\right)}}^{0.5} \]
    4. pow1/2100.0%

      \[\leadsto {\color{blue}{\left({\left(\left|\frac{b}{a} \cdot \frac{b}{a} - 1\right| \cdot \left|\frac{b}{a} \cdot \frac{b}{a} - 1\right|\right)}^{0.5}\right)}}^{0.5} \]
    5. pow-pow100.0%

      \[\leadsto \color{blue}{{\left(\left|\frac{b}{a} \cdot \frac{b}{a} - 1\right| \cdot \left|\frac{b}{a} \cdot \frac{b}{a} - 1\right|\right)}^{\left(0.5 \cdot 0.5\right)}} \]
  5. Applied egg-rr100.0%

    \[\leadsto \color{blue}{{\left({\left({\left(\frac{a}{b}\right)}^{-2} + -1\right)}^{2}\right)}^{0.25}} \]
  6. Step-by-step derivation
    1. metadata-eval100.0%

      \[\leadsto {\left({\left({\left(\frac{a}{b}\right)}^{\color{blue}{\left(2 \cdot -1\right)}} + -1\right)}^{2}\right)}^{0.25} \]
    2. pow-sqr100.0%

      \[\leadsto {\left({\left(\color{blue}{{\left(\frac{a}{b}\right)}^{-1} \cdot {\left(\frac{a}{b}\right)}^{-1}} + -1\right)}^{2}\right)}^{0.25} \]
    3. inv-pow100.0%

      \[\leadsto {\left({\left(\color{blue}{\frac{1}{\frac{a}{b}}} \cdot {\left(\frac{a}{b}\right)}^{-1} + -1\right)}^{2}\right)}^{0.25} \]
    4. clear-num100.0%

      \[\leadsto {\left({\left(\color{blue}{\frac{b}{a}} \cdot {\left(\frac{a}{b}\right)}^{-1} + -1\right)}^{2}\right)}^{0.25} \]
    5. inv-pow100.0%

      \[\leadsto {\left({\left(\frac{b}{a} \cdot \color{blue}{\frac{1}{\frac{a}{b}}} + -1\right)}^{2}\right)}^{0.25} \]
    6. un-div-inv100.0%

      \[\leadsto {\left({\left(\color{blue}{\frac{\frac{b}{a}}{\frac{a}{b}}} + -1\right)}^{2}\right)}^{0.25} \]
  7. Applied egg-rr100.0%

    \[\leadsto {\left({\left(\color{blue}{\frac{\frac{b}{a}}{\frac{a}{b}}} + -1\right)}^{2}\right)}^{0.25} \]
  8. Taylor expanded in b around 0 74.6%

    \[\leadsto {\color{blue}{\left(1 + -2 \cdot \frac{{b}^{2}}{{a}^{2}}\right)}}^{0.25} \]
  9. Step-by-step derivation
    1. *-commutative74.6%

      \[\leadsto {\left(1 + \color{blue}{\frac{{b}^{2}}{{a}^{2}} \cdot -2}\right)}^{0.25} \]
    2. unpow274.6%

      \[\leadsto {\left(1 + \frac{\color{blue}{b \cdot b}}{{a}^{2}} \cdot -2\right)}^{0.25} \]
    3. unpow274.6%

      \[\leadsto {\left(1 + \frac{b \cdot b}{\color{blue}{a \cdot a}} \cdot -2\right)}^{0.25} \]
  10. Simplified74.6%

    \[\leadsto {\color{blue}{\left(1 + \frac{b \cdot b}{a \cdot a} \cdot -2\right)}}^{0.25} \]
  11. Taylor expanded in b around 0 74.7%

    \[\leadsto \color{blue}{1 + -0.5 \cdot \frac{{b}^{2}}{{a}^{2}}} \]
  12. Step-by-step derivation
    1. +-commutative74.7%

      \[\leadsto \color{blue}{-0.5 \cdot \frac{{b}^{2}}{{a}^{2}} + 1} \]
    2. fma-def74.7%

      \[\leadsto \color{blue}{\mathsf{fma}\left(-0.5, \frac{{b}^{2}}{{a}^{2}}, 1\right)} \]
    3. unpow274.7%

      \[\leadsto \mathsf{fma}\left(-0.5, \frac{\color{blue}{b \cdot b}}{{a}^{2}}, 1\right) \]
    4. unpow274.7%

      \[\leadsto \mathsf{fma}\left(-0.5, \frac{b \cdot b}{\color{blue}{a \cdot a}}, 1\right) \]
    5. times-frac99.1%

      \[\leadsto \mathsf{fma}\left(-0.5, \color{blue}{\frac{b}{a} \cdot \frac{b}{a}}, 1\right) \]
    6. unpow299.1%

      \[\leadsto \mathsf{fma}\left(-0.5, \color{blue}{{\left(\frac{b}{a}\right)}^{2}}, 1\right) \]
  13. Simplified99.1%

    \[\leadsto \color{blue}{\mathsf{fma}\left(-0.5, {\left(\frac{b}{a}\right)}^{2}, 1\right)} \]
  14. Final simplification99.1%

    \[\leadsto \mathsf{fma}\left(-0.5, {\left(\frac{b}{a}\right)}^{2}, 1\right) \]

Alternative 4: 99.0% accurate, 1.9× speedup?

\[\begin{array}{l} \\ {\left(1 + \frac{b \cdot -2}{\frac{a}{\frac{b}{a}}}\right)}^{0.25} \end{array} \]
(FPCore (a b)
 :precision binary64
 (pow (+ 1.0 (/ (* b -2.0) (/ a (/ b a)))) 0.25))
double code(double a, double b) {
	return pow((1.0 + ((b * -2.0) / (a / (b / a)))), 0.25);
}
real(8) function code(a, b)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    code = (1.0d0 + ((b * (-2.0d0)) / (a / (b / a)))) ** 0.25d0
end function
public static double code(double a, double b) {
	return Math.pow((1.0 + ((b * -2.0) / (a / (b / a)))), 0.25);
}
def code(a, b):
	return math.pow((1.0 + ((b * -2.0) / (a / (b / a)))), 0.25)
function code(a, b)
	return Float64(1.0 + Float64(Float64(b * -2.0) / Float64(a / Float64(b / a)))) ^ 0.25
end
function tmp = code(a, b)
	tmp = (1.0 + ((b * -2.0) / (a / (b / a)))) ^ 0.25;
end
code[a_, b_] := N[Power[N[(1.0 + N[(N[(b * -2.0), $MachinePrecision] / N[(a / N[(b / a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], 0.25], $MachinePrecision]
\begin{array}{l}

\\
{\left(1 + \frac{b \cdot -2}{\frac{a}{\frac{b}{a}}}\right)}^{0.25}
\end{array}
Derivation
  1. Initial program 75.0%

    \[\sqrt{\left|\frac{a \cdot a - b \cdot b}{a \cdot a}\right|} \]
  2. Step-by-step derivation
    1. sqr-neg75.0%

      \[\leadsto \sqrt{\left|\frac{a \cdot a - \color{blue}{\left(-b\right) \cdot \left(-b\right)}}{a \cdot a}\right|} \]
    2. associate-/r*75.5%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{\frac{a \cdot a - \left(-b\right) \cdot \left(-b\right)}{a}}{a}}\right|} \]
    3. sqr-neg75.5%

      \[\leadsto \sqrt{\left|\frac{\frac{a \cdot a - \color{blue}{b \cdot b}}{a}}{a}\right|} \]
    4. associate-/r*75.0%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{a \cdot a - b \cdot b}{a \cdot a}}\right|} \]
    5. div-sub75.0%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{a \cdot a}{a \cdot a} - \frac{b \cdot b}{a \cdot a}}\right|} \]
    6. fabs-sub75.0%

      \[\leadsto \sqrt{\color{blue}{\left|\frac{b \cdot b}{a \cdot a} - \frac{a \cdot a}{a \cdot a}\right|}} \]
    7. times-frac75.0%

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

      \[\leadsto {\color{blue}{\left(\sqrt{\left|\frac{b}{a} \cdot \frac{b}{a} - 1\right|} \cdot \sqrt{\left|\frac{b}{a} \cdot \frac{b}{a} - 1\right|}\right)}}^{0.5} \]
    3. sqrt-unprod100.0%

      \[\leadsto {\color{blue}{\left(\sqrt{\left|\frac{b}{a} \cdot \frac{b}{a} - 1\right| \cdot \left|\frac{b}{a} \cdot \frac{b}{a} - 1\right|}\right)}}^{0.5} \]
    4. pow1/2100.0%

      \[\leadsto {\color{blue}{\left({\left(\left|\frac{b}{a} \cdot \frac{b}{a} - 1\right| \cdot \left|\frac{b}{a} \cdot \frac{b}{a} - 1\right|\right)}^{0.5}\right)}}^{0.5} \]
    5. pow-pow100.0%

      \[\leadsto \color{blue}{{\left(\left|\frac{b}{a} \cdot \frac{b}{a} - 1\right| \cdot \left|\frac{b}{a} \cdot \frac{b}{a} - 1\right|\right)}^{\left(0.5 \cdot 0.5\right)}} \]
  5. Applied egg-rr100.0%

    \[\leadsto \color{blue}{{\left({\left({\left(\frac{a}{b}\right)}^{-2} + -1\right)}^{2}\right)}^{0.25}} \]
  6. Step-by-step derivation
    1. metadata-eval100.0%

      \[\leadsto {\left({\left({\left(\frac{a}{b}\right)}^{\color{blue}{\left(2 \cdot -1\right)}} + -1\right)}^{2}\right)}^{0.25} \]
    2. pow-sqr100.0%

      \[\leadsto {\left({\left(\color{blue}{{\left(\frac{a}{b}\right)}^{-1} \cdot {\left(\frac{a}{b}\right)}^{-1}} + -1\right)}^{2}\right)}^{0.25} \]
    3. inv-pow100.0%

      \[\leadsto {\left({\left(\color{blue}{\frac{1}{\frac{a}{b}}} \cdot {\left(\frac{a}{b}\right)}^{-1} + -1\right)}^{2}\right)}^{0.25} \]
    4. clear-num100.0%

      \[\leadsto {\left({\left(\color{blue}{\frac{b}{a}} \cdot {\left(\frac{a}{b}\right)}^{-1} + -1\right)}^{2}\right)}^{0.25} \]
    5. inv-pow100.0%

      \[\leadsto {\left({\left(\frac{b}{a} \cdot \color{blue}{\frac{1}{\frac{a}{b}}} + -1\right)}^{2}\right)}^{0.25} \]
    6. un-div-inv100.0%

      \[\leadsto {\left({\left(\color{blue}{\frac{\frac{b}{a}}{\frac{a}{b}}} + -1\right)}^{2}\right)}^{0.25} \]
  7. Applied egg-rr100.0%

    \[\leadsto {\left({\left(\color{blue}{\frac{\frac{b}{a}}{\frac{a}{b}}} + -1\right)}^{2}\right)}^{0.25} \]
  8. Taylor expanded in b around 0 74.6%

    \[\leadsto {\color{blue}{\left(1 + -2 \cdot \frac{{b}^{2}}{{a}^{2}}\right)}}^{0.25} \]
  9. Step-by-step derivation
    1. *-commutative74.6%

      \[\leadsto {\left(1 + \color{blue}{\frac{{b}^{2}}{{a}^{2}} \cdot -2}\right)}^{0.25} \]
    2. unpow274.6%

      \[\leadsto {\left(1 + \frac{\color{blue}{b \cdot b}}{{a}^{2}} \cdot -2\right)}^{0.25} \]
    3. unpow274.6%

      \[\leadsto {\left(1 + \frac{b \cdot b}{\color{blue}{a \cdot a}} \cdot -2\right)}^{0.25} \]
  10. Simplified74.6%

    \[\leadsto {\color{blue}{\left(1 + \frac{b \cdot b}{a \cdot a} \cdot -2\right)}}^{0.25} \]
  11. Step-by-step derivation
    1. associate-/l*75.4%

      \[\leadsto {\left(1 + \color{blue}{\frac{b}{\frac{a \cdot a}{b}}} \cdot -2\right)}^{0.25} \]
    2. associate-*l/75.4%

      \[\leadsto {\left(1 + \color{blue}{\frac{b \cdot -2}{\frac{a \cdot a}{b}}}\right)}^{0.25} \]
    3. associate-/l*99.1%

      \[\leadsto {\left(1 + \frac{b \cdot -2}{\color{blue}{\frac{a}{\frac{b}{a}}}}\right)}^{0.25} \]
  12. Applied egg-rr99.1%

    \[\leadsto {\left(1 + \color{blue}{\frac{b \cdot -2}{\frac{a}{\frac{b}{a}}}}\right)}^{0.25} \]
  13. Final simplification99.1%

    \[\leadsto {\left(1 + \frac{b \cdot -2}{\frac{a}{\frac{b}{a}}}\right)}^{0.25} \]

Alternative 5: 98.0% 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 75.0%

    \[\sqrt{\left|\frac{a \cdot a - b \cdot b}{a \cdot a}\right|} \]
  2. Step-by-step derivation
    1. sqr-neg75.0%

      \[\leadsto \sqrt{\left|\frac{a \cdot a - \color{blue}{\left(-b\right) \cdot \left(-b\right)}}{a \cdot a}\right|} \]
    2. associate-/r*75.5%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{\frac{a \cdot a - \left(-b\right) \cdot \left(-b\right)}{a}}{a}}\right|} \]
    3. sqr-neg75.5%

      \[\leadsto \sqrt{\left|\frac{\frac{a \cdot a - \color{blue}{b \cdot b}}{a}}{a}\right|} \]
    4. associate-/r*75.0%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{a \cdot a - b \cdot b}{a \cdot a}}\right|} \]
    5. div-sub75.0%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{a \cdot a}{a \cdot a} - \frac{b \cdot b}{a \cdot a}}\right|} \]
    6. fabs-sub75.0%

      \[\leadsto \sqrt{\color{blue}{\left|\frac{b \cdot b}{a \cdot a} - \frac{a \cdot a}{a \cdot a}\right|}} \]
    7. times-frac75.0%

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

      \[\leadsto {\color{blue}{\left(\sqrt{\left|\frac{b}{a} \cdot \frac{b}{a} - 1\right|} \cdot \sqrt{\left|\frac{b}{a} \cdot \frac{b}{a} - 1\right|}\right)}}^{0.5} \]
    3. sqrt-unprod100.0%

      \[\leadsto {\color{blue}{\left(\sqrt{\left|\frac{b}{a} \cdot \frac{b}{a} - 1\right| \cdot \left|\frac{b}{a} \cdot \frac{b}{a} - 1\right|}\right)}}^{0.5} \]
    4. pow1/2100.0%

      \[\leadsto {\color{blue}{\left({\left(\left|\frac{b}{a} \cdot \frac{b}{a} - 1\right| \cdot \left|\frac{b}{a} \cdot \frac{b}{a} - 1\right|\right)}^{0.5}\right)}}^{0.5} \]
    5. pow-pow100.0%

      \[\leadsto \color{blue}{{\left(\left|\frac{b}{a} \cdot \frac{b}{a} - 1\right| \cdot \left|\frac{b}{a} \cdot \frac{b}{a} - 1\right|\right)}^{\left(0.5 \cdot 0.5\right)}} \]
  5. Applied egg-rr100.0%

    \[\leadsto \color{blue}{{\left({\left({\left(\frac{a}{b}\right)}^{-2} + -1\right)}^{2}\right)}^{0.25}} \]
  6. Step-by-step derivation
    1. metadata-eval100.0%

      \[\leadsto {\left({\left({\left(\frac{a}{b}\right)}^{\color{blue}{\left(2 \cdot -1\right)}} + -1\right)}^{2}\right)}^{0.25} \]
    2. pow-sqr100.0%

      \[\leadsto {\left({\left(\color{blue}{{\left(\frac{a}{b}\right)}^{-1} \cdot {\left(\frac{a}{b}\right)}^{-1}} + -1\right)}^{2}\right)}^{0.25} \]
    3. inv-pow100.0%

      \[\leadsto {\left({\left(\color{blue}{\frac{1}{\frac{a}{b}}} \cdot {\left(\frac{a}{b}\right)}^{-1} + -1\right)}^{2}\right)}^{0.25} \]
    4. clear-num100.0%

      \[\leadsto {\left({\left(\color{blue}{\frac{b}{a}} \cdot {\left(\frac{a}{b}\right)}^{-1} + -1\right)}^{2}\right)}^{0.25} \]
    5. inv-pow100.0%

      \[\leadsto {\left({\left(\frac{b}{a} \cdot \color{blue}{\frac{1}{\frac{a}{b}}} + -1\right)}^{2}\right)}^{0.25} \]
    6. un-div-inv100.0%

      \[\leadsto {\left({\left(\color{blue}{\frac{\frac{b}{a}}{\frac{a}{b}}} + -1\right)}^{2}\right)}^{0.25} \]
  7. Applied egg-rr100.0%

    \[\leadsto {\left({\left(\color{blue}{\frac{\frac{b}{a}}{\frac{a}{b}}} + -1\right)}^{2}\right)}^{0.25} \]
  8. Taylor expanded in b around 0 74.6%

    \[\leadsto {\color{blue}{\left(1 + -2 \cdot \frac{{b}^{2}}{{a}^{2}}\right)}}^{0.25} \]
  9. Step-by-step derivation
    1. *-commutative74.6%

      \[\leadsto {\left(1 + \color{blue}{\frac{{b}^{2}}{{a}^{2}} \cdot -2}\right)}^{0.25} \]
    2. unpow274.6%

      \[\leadsto {\left(1 + \frac{\color{blue}{b \cdot b}}{{a}^{2}} \cdot -2\right)}^{0.25} \]
    3. unpow274.6%

      \[\leadsto {\left(1 + \frac{b \cdot b}{\color{blue}{a \cdot a}} \cdot -2\right)}^{0.25} \]
  10. Simplified74.6%

    \[\leadsto {\color{blue}{\left(1 + \frac{b \cdot b}{a \cdot a} \cdot -2\right)}}^{0.25} \]
  11. Taylor expanded in b around 0 98.2%

    \[\leadsto \color{blue}{1} \]
  12. Final simplification98.2%

    \[\leadsto 1 \]

Reproduce

?
herbie shell --seed 2023292 
(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)))))