Eccentricity of an ellipse

Percentage Accurate: 78.0% → 100.0%
Time: 8.6s
Alternatives: 4
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 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: 78.0% 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?

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

\\
\sqrt{\left|\frac{b \cdot \frac{b}{a}}{a} + -1\right|}
\end{array}
Derivation
  1. Initial program 73.7%

    \[\sqrt{\left|\frac{a \cdot a - b \cdot b}{a \cdot a}\right|} \]
  2. Step-by-step derivation
    1. sqrt-lowering-sqrt.f64N/A

      \[\leadsto \mathsf{sqrt.f64}\left(\left(\left|\frac{a \cdot a - b \cdot b}{a \cdot a}\right|\right)\right) \]
    2. div-subN/A

      \[\leadsto \mathsf{sqrt.f64}\left(\left(\left|\frac{a \cdot a}{a \cdot a} - \frac{b \cdot b}{a \cdot a}\right|\right)\right) \]
    3. fabs-subN/A

      \[\leadsto \mathsf{sqrt.f64}\left(\left(\left|\frac{b \cdot b}{a \cdot a} - \frac{a \cdot a}{a \cdot a}\right|\right)\right) \]
    4. fabs-lowering-fabs.f64N/A

      \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\left(\frac{b \cdot b}{a \cdot a} - \frac{a \cdot a}{a \cdot a}\right)\right)\right) \]
    5. sub-negN/A

      \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\left(\frac{b \cdot b}{a \cdot a} + \left(\mathsf{neg}\left(\frac{a \cdot a}{a \cdot a}\right)\right)\right)\right)\right) \]
    6. *-inversesN/A

      \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\left(\frac{b \cdot b}{a \cdot a} + \left(\mathsf{neg}\left(1\right)\right)\right)\right)\right) \]
    7. metadata-evalN/A

      \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\left(\frac{b \cdot b}{a \cdot a} + -1\right)\right)\right) \]
    8. +-lowering-+.f64N/A

      \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\mathsf{+.f64}\left(\left(\frac{b \cdot b}{a \cdot a}\right), -1\right)\right)\right) \]
    9. associate-/r*N/A

      \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\mathsf{+.f64}\left(\left(\frac{\frac{b \cdot b}{a}}{a}\right), -1\right)\right)\right) \]
    10. /-lowering-/.f64N/A

      \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\mathsf{+.f64}\left(\mathsf{/.f64}\left(\left(\frac{b \cdot b}{a}\right), a\right), -1\right)\right)\right) \]
    11. associate-/l*N/A

      \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\mathsf{+.f64}\left(\mathsf{/.f64}\left(\left(b \cdot \frac{b}{a}\right), a\right), -1\right)\right)\right) \]
    12. *-lowering-*.f64N/A

      \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\mathsf{+.f64}\left(\mathsf{/.f64}\left(\mathsf{*.f64}\left(b, \left(\frac{b}{a}\right)\right), a\right), -1\right)\right)\right) \]
    13. /-lowering-/.f64100.0%

      \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\mathsf{+.f64}\left(\mathsf{/.f64}\left(\mathsf{*.f64}\left(b, \mathsf{/.f64}\left(b, a\right)\right), a\right), -1\right)\right)\right) \]
  3. Simplified100.0%

    \[\leadsto \color{blue}{\sqrt{\left|\frac{b \cdot \frac{b}{a}}{a} + -1\right|}} \]
  4. Add Preprocessing
  5. Add Preprocessing

Alternative 2: 98.9% accurate, 1.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := 1 + \frac{b}{\frac{a}{\frac{b}{a}}}\\ {\left(t\_0 \cdot t\_0\right)}^{-0.25} \end{array} \end{array} \]
(FPCore (a b)
 :precision binary64
 (let* ((t_0 (+ 1.0 (/ b (/ a (/ b a)))))) (pow (* t_0 t_0) -0.25)))
double code(double a, double b) {
	double t_0 = 1.0 + (b / (a / (b / a)));
	return pow((t_0 * t_0), -0.25);
}
real(8) function code(a, b)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    real(8) :: t_0
    t_0 = 1.0d0 + (b / (a / (b / a)))
    code = (t_0 * t_0) ** (-0.25d0)
end function
public static double code(double a, double b) {
	double t_0 = 1.0 + (b / (a / (b / a)));
	return Math.pow((t_0 * t_0), -0.25);
}
def code(a, b):
	t_0 = 1.0 + (b / (a / (b / a)))
	return math.pow((t_0 * t_0), -0.25)
function code(a, b)
	t_0 = Float64(1.0 + Float64(b / Float64(a / Float64(b / a))))
	return Float64(t_0 * t_0) ^ -0.25
end
function tmp = code(a, b)
	t_0 = 1.0 + (b / (a / (b / a)));
	tmp = (t_0 * t_0) ^ -0.25;
end
code[a_, b_] := Block[{t$95$0 = N[(1.0 + N[(b / N[(a / N[(b / a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, N[Power[N[(t$95$0 * t$95$0), $MachinePrecision], -0.25], $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := 1 + \frac{b}{\frac{a}{\frac{b}{a}}}\\
{\left(t\_0 \cdot t\_0\right)}^{-0.25}
\end{array}
\end{array}
Derivation
  1. Initial program 73.7%

    \[\sqrt{\left|\frac{a \cdot a - b \cdot b}{a \cdot a}\right|} \]
  2. Step-by-step derivation
    1. sqrt-lowering-sqrt.f64N/A

      \[\leadsto \mathsf{sqrt.f64}\left(\left(\left|\frac{a \cdot a - b \cdot b}{a \cdot a}\right|\right)\right) \]
    2. div-subN/A

      \[\leadsto \mathsf{sqrt.f64}\left(\left(\left|\frac{a \cdot a}{a \cdot a} - \frac{b \cdot b}{a \cdot a}\right|\right)\right) \]
    3. fabs-subN/A

      \[\leadsto \mathsf{sqrt.f64}\left(\left(\left|\frac{b \cdot b}{a \cdot a} - \frac{a \cdot a}{a \cdot a}\right|\right)\right) \]
    4. fabs-lowering-fabs.f64N/A

      \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\left(\frac{b \cdot b}{a \cdot a} - \frac{a \cdot a}{a \cdot a}\right)\right)\right) \]
    5. sub-negN/A

      \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\left(\frac{b \cdot b}{a \cdot a} + \left(\mathsf{neg}\left(\frac{a \cdot a}{a \cdot a}\right)\right)\right)\right)\right) \]
    6. *-inversesN/A

      \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\left(\frac{b \cdot b}{a \cdot a} + \left(\mathsf{neg}\left(1\right)\right)\right)\right)\right) \]
    7. metadata-evalN/A

      \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\left(\frac{b \cdot b}{a \cdot a} + -1\right)\right)\right) \]
    8. +-lowering-+.f64N/A

      \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\mathsf{+.f64}\left(\left(\frac{b \cdot b}{a \cdot a}\right), -1\right)\right)\right) \]
    9. associate-/r*N/A

      \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\mathsf{+.f64}\left(\left(\frac{\frac{b \cdot b}{a}}{a}\right), -1\right)\right)\right) \]
    10. /-lowering-/.f64N/A

      \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\mathsf{+.f64}\left(\mathsf{/.f64}\left(\left(\frac{b \cdot b}{a}\right), a\right), -1\right)\right)\right) \]
    11. associate-/l*N/A

      \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\mathsf{+.f64}\left(\mathsf{/.f64}\left(\left(b \cdot \frac{b}{a}\right), a\right), -1\right)\right)\right) \]
    12. *-lowering-*.f64N/A

      \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\mathsf{+.f64}\left(\mathsf{/.f64}\left(\mathsf{*.f64}\left(b, \left(\frac{b}{a}\right)\right), a\right), -1\right)\right)\right) \]
    13. /-lowering-/.f64100.0%

      \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\mathsf{+.f64}\left(\mathsf{/.f64}\left(\mathsf{*.f64}\left(b, \mathsf{/.f64}\left(b, a\right)\right), a\right), -1\right)\right)\right) \]
  3. Simplified100.0%

    \[\leadsto \color{blue}{\sqrt{\left|\frac{b \cdot \frac{b}{a}}{a} + -1\right|}} \]
  4. Add Preprocessing
  5. Applied egg-rr72.9%

    \[\leadsto \sqrt{\left|\color{blue}{\frac{\frac{\frac{\frac{b}{\frac{a}{b}}}{\frac{a}{b \cdot b}}}{a \cdot a} + 1}{-1 - \frac{b}{\frac{a \cdot a}{b}}}}\right|} \]
  6. Taylor expanded in b around 0

    \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\mathsf{/.f64}\left(\color{blue}{1}, \mathsf{\_.f64}\left(-1, \mathsf{/.f64}\left(b, \mathsf{/.f64}\left(\mathsf{*.f64}\left(a, a\right), b\right)\right)\right)\right)\right)\right) \]
  7. Step-by-step derivation
    1. Simplified73.8%

      \[\leadsto \sqrt{\left|\frac{\color{blue}{1}}{-1 - \frac{b}{\frac{a \cdot a}{b}}}\right|} \]
    2. Step-by-step derivation
      1. pow1/2N/A

        \[\leadsto {\left(\left|\frac{1}{-1 - \frac{b}{\frac{a \cdot a}{b}}}\right|\right)}^{\color{blue}{\frac{1}{2}}} \]
      2. sqr-powN/A

        \[\leadsto {\left(\left|\frac{1}{-1 - \frac{b}{\frac{a \cdot a}{b}}}\right|\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \color{blue}{{\left(\left|\frac{1}{-1 - \frac{b}{\frac{a \cdot a}{b}}}\right|\right)}^{\left(\frac{\frac{1}{2}}{2}\right)}} \]
      3. pow-prod-downN/A

        \[\leadsto {\left(\left|\frac{1}{-1 - \frac{b}{\frac{a \cdot a}{b}}}\right| \cdot \left|\frac{1}{-1 - \frac{b}{\frac{a \cdot a}{b}}}\right|\right)}^{\color{blue}{\left(\frac{\frac{1}{2}}{2}\right)}} \]
    3. Applied egg-rr73.8%

      \[\leadsto \color{blue}{{\left(\frac{1}{-1 - \frac{b}{\frac{a \cdot a}{b}}} \cdot \frac{1}{-1 - \frac{b}{\frac{a \cdot a}{b}}}\right)}^{0.25}} \]
    4. Step-by-step derivation
      1. frac-timesN/A

        \[\leadsto {\left(\frac{1 \cdot 1}{\left(-1 - \frac{b}{\frac{a \cdot a}{b}}\right) \cdot \left(-1 - \frac{b}{\frac{a \cdot a}{b}}\right)}\right)}^{\frac{1}{4}} \]
      2. metadata-evalN/A

        \[\leadsto {\left(\frac{1}{\left(-1 - \frac{b}{\frac{a \cdot a}{b}}\right) \cdot \left(-1 - \frac{b}{\frac{a \cdot a}{b}}\right)}\right)}^{\frac{1}{4}} \]
      3. inv-powN/A

        \[\leadsto {\left({\left(\left(-1 - \frac{b}{\frac{a \cdot a}{b}}\right) \cdot \left(-1 - \frac{b}{\frac{a \cdot a}{b}}\right)\right)}^{-1}\right)}^{\frac{1}{4}} \]
      4. pow-powN/A

        \[\leadsto {\left(\left(-1 - \frac{b}{\frac{a \cdot a}{b}}\right) \cdot \left(-1 - \frac{b}{\frac{a \cdot a}{b}}\right)\right)}^{\color{blue}{\left(-1 \cdot \frac{1}{4}\right)}} \]
      5. pow-lowering-pow.f64N/A

        \[\leadsto \mathsf{pow.f64}\left(\left(\left(-1 - \frac{b}{\frac{a \cdot a}{b}}\right) \cdot \left(-1 - \frac{b}{\frac{a \cdot a}{b}}\right)\right), \color{blue}{\left(-1 \cdot \frac{1}{4}\right)}\right) \]
    5. Applied egg-rr98.2%

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

    Alternative 3: 98.5% accurate, 19.2× speedup?

    \[\begin{array}{l} \\ 1 + \frac{-0.5 \cdot \frac{b \cdot b}{a}}{a} \end{array} \]
    (FPCore (a b) :precision binary64 (+ 1.0 (/ (* -0.5 (/ (* b b) a)) a)))
    double code(double a, double b) {
    	return 1.0 + ((-0.5 * ((b * b) / a)) / a);
    }
    
    real(8) function code(a, b)
        real(8), intent (in) :: a
        real(8), intent (in) :: b
        code = 1.0d0 + (((-0.5d0) * ((b * b) / a)) / a)
    end function
    
    public static double code(double a, double b) {
    	return 1.0 + ((-0.5 * ((b * b) / a)) / a);
    }
    
    def code(a, b):
    	return 1.0 + ((-0.5 * ((b * b) / a)) / a)
    
    function code(a, b)
    	return Float64(1.0 + Float64(Float64(-0.5 * Float64(Float64(b * b) / a)) / a))
    end
    
    function tmp = code(a, b)
    	tmp = 1.0 + ((-0.5 * ((b * b) / a)) / a);
    end
    
    code[a_, b_] := N[(1.0 + N[(N[(-0.5 * N[(N[(b * b), $MachinePrecision] / a), $MachinePrecision]), $MachinePrecision] / a), $MachinePrecision]), $MachinePrecision]
    
    \begin{array}{l}
    
    \\
    1 + \frac{-0.5 \cdot \frac{b \cdot b}{a}}{a}
    \end{array}
    
    Derivation
    1. Initial program 73.7%

      \[\sqrt{\left|\frac{a \cdot a - b \cdot b}{a \cdot a}\right|} \]
    2. Step-by-step derivation
      1. sqrt-lowering-sqrt.f64N/A

        \[\leadsto \mathsf{sqrt.f64}\left(\left(\left|\frac{a \cdot a - b \cdot b}{a \cdot a}\right|\right)\right) \]
      2. div-subN/A

        \[\leadsto \mathsf{sqrt.f64}\left(\left(\left|\frac{a \cdot a}{a \cdot a} - \frac{b \cdot b}{a \cdot a}\right|\right)\right) \]
      3. fabs-subN/A

        \[\leadsto \mathsf{sqrt.f64}\left(\left(\left|\frac{b \cdot b}{a \cdot a} - \frac{a \cdot a}{a \cdot a}\right|\right)\right) \]
      4. fabs-lowering-fabs.f64N/A

        \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\left(\frac{b \cdot b}{a \cdot a} - \frac{a \cdot a}{a \cdot a}\right)\right)\right) \]
      5. sub-negN/A

        \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\left(\frac{b \cdot b}{a \cdot a} + \left(\mathsf{neg}\left(\frac{a \cdot a}{a \cdot a}\right)\right)\right)\right)\right) \]
      6. *-inversesN/A

        \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\left(\frac{b \cdot b}{a \cdot a} + \left(\mathsf{neg}\left(1\right)\right)\right)\right)\right) \]
      7. metadata-evalN/A

        \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\left(\frac{b \cdot b}{a \cdot a} + -1\right)\right)\right) \]
      8. +-lowering-+.f64N/A

        \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\mathsf{+.f64}\left(\left(\frac{b \cdot b}{a \cdot a}\right), -1\right)\right)\right) \]
      9. associate-/r*N/A

        \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\mathsf{+.f64}\left(\left(\frac{\frac{b \cdot b}{a}}{a}\right), -1\right)\right)\right) \]
      10. /-lowering-/.f64N/A

        \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\mathsf{+.f64}\left(\mathsf{/.f64}\left(\left(\frac{b \cdot b}{a}\right), a\right), -1\right)\right)\right) \]
      11. associate-/l*N/A

        \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\mathsf{+.f64}\left(\mathsf{/.f64}\left(\left(b \cdot \frac{b}{a}\right), a\right), -1\right)\right)\right) \]
      12. *-lowering-*.f64N/A

        \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\mathsf{+.f64}\left(\mathsf{/.f64}\left(\mathsf{*.f64}\left(b, \left(\frac{b}{a}\right)\right), a\right), -1\right)\right)\right) \]
      13. /-lowering-/.f64100.0%

        \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\mathsf{+.f64}\left(\mathsf{/.f64}\left(\mathsf{*.f64}\left(b, \mathsf{/.f64}\left(b, a\right)\right), a\right), -1\right)\right)\right) \]
    3. Simplified100.0%

      \[\leadsto \color{blue}{\sqrt{\left|\frac{b \cdot \frac{b}{a}}{a} + -1\right|}} \]
    4. Add Preprocessing
    5. Applied egg-rr72.9%

      \[\leadsto \sqrt{\left|\color{blue}{\frac{\frac{\frac{\frac{b}{\frac{a}{b}}}{\frac{a}{b \cdot b}}}{a \cdot a} + 1}{-1 - \frac{b}{\frac{a \cdot a}{b}}}}\right|} \]
    6. Taylor expanded in b around 0

      \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\mathsf{/.f64}\left(\color{blue}{1}, \mathsf{\_.f64}\left(-1, \mathsf{/.f64}\left(b, \mathsf{/.f64}\left(\mathsf{*.f64}\left(a, a\right), b\right)\right)\right)\right)\right)\right) \]
    7. Step-by-step derivation
      1. Simplified73.8%

        \[\leadsto \sqrt{\left|\frac{\color{blue}{1}}{-1 - \frac{b}{\frac{a \cdot a}{b}}}\right|} \]
      2. Step-by-step derivation
        1. pow1/2N/A

          \[\leadsto {\left(\left|\frac{1}{-1 - \frac{b}{\frac{a \cdot a}{b}}}\right|\right)}^{\color{blue}{\frac{1}{2}}} \]
        2. sqr-powN/A

          \[\leadsto {\left(\left|\frac{1}{-1 - \frac{b}{\frac{a \cdot a}{b}}}\right|\right)}^{\left(\frac{\frac{1}{2}}{2}\right)} \cdot \color{blue}{{\left(\left|\frac{1}{-1 - \frac{b}{\frac{a \cdot a}{b}}}\right|\right)}^{\left(\frac{\frac{1}{2}}{2}\right)}} \]
        3. pow-prod-downN/A

          \[\leadsto {\left(\left|\frac{1}{-1 - \frac{b}{\frac{a \cdot a}{b}}}\right| \cdot \left|\frac{1}{-1 - \frac{b}{\frac{a \cdot a}{b}}}\right|\right)}^{\color{blue}{\left(\frac{\frac{1}{2}}{2}\right)}} \]
      3. Applied egg-rr73.8%

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

        \[\leadsto \color{blue}{1 + \frac{-1}{2} \cdot \frac{{b}^{2}}{{a}^{2}}} \]
      5. Step-by-step derivation
        1. +-lowering-+.f64N/A

          \[\leadsto \mathsf{+.f64}\left(1, \color{blue}{\left(\frac{-1}{2} \cdot \frac{{b}^{2}}{{a}^{2}}\right)}\right) \]
        2. associate-*r/N/A

          \[\leadsto \mathsf{+.f64}\left(1, \left(\frac{\frac{-1}{2} \cdot {b}^{2}}{\color{blue}{{a}^{2}}}\right)\right) \]
        3. unpow2N/A

          \[\leadsto \mathsf{+.f64}\left(1, \left(\frac{\frac{-1}{2} \cdot {b}^{2}}{a \cdot \color{blue}{a}}\right)\right) \]
        4. associate-/r*N/A

          \[\leadsto \mathsf{+.f64}\left(1, \left(\frac{\frac{\frac{-1}{2} \cdot {b}^{2}}{a}}{\color{blue}{a}}\right)\right) \]
        5. /-lowering-/.f64N/A

          \[\leadsto \mathsf{+.f64}\left(1, \mathsf{/.f64}\left(\left(\frac{\frac{-1}{2} \cdot {b}^{2}}{a}\right), \color{blue}{a}\right)\right) \]
        6. associate-/l*N/A

          \[\leadsto \mathsf{+.f64}\left(1, \mathsf{/.f64}\left(\left(\frac{-1}{2} \cdot \frac{{b}^{2}}{a}\right), a\right)\right) \]
        7. *-lowering-*.f64N/A

          \[\leadsto \mathsf{+.f64}\left(1, \mathsf{/.f64}\left(\mathsf{*.f64}\left(\frac{-1}{2}, \left(\frac{{b}^{2}}{a}\right)\right), a\right)\right) \]
        8. /-lowering-/.f64N/A

          \[\leadsto \mathsf{+.f64}\left(1, \mathsf{/.f64}\left(\mathsf{*.f64}\left(\frac{-1}{2}, \mathsf{/.f64}\left(\left({b}^{2}\right), a\right)\right), a\right)\right) \]
        9. unpow2N/A

          \[\leadsto \mathsf{+.f64}\left(1, \mathsf{/.f64}\left(\mathsf{*.f64}\left(\frac{-1}{2}, \mathsf{/.f64}\left(\left(b \cdot b\right), a\right)\right), a\right)\right) \]
        10. *-lowering-*.f6497.9%

          \[\leadsto \mathsf{+.f64}\left(1, \mathsf{/.f64}\left(\mathsf{*.f64}\left(\frac{-1}{2}, \mathsf{/.f64}\left(\mathsf{*.f64}\left(b, b\right), a\right)\right), a\right)\right) \]
      6. Simplified97.9%

        \[\leadsto \color{blue}{1 + \frac{-0.5 \cdot \frac{b \cdot b}{a}}{a}} \]
      7. Add Preprocessing

      Alternative 4: 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 73.7%

        \[\sqrt{\left|\frac{a \cdot a - b \cdot b}{a \cdot a}\right|} \]
      2. Step-by-step derivation
        1. sqrt-lowering-sqrt.f64N/A

          \[\leadsto \mathsf{sqrt.f64}\left(\left(\left|\frac{a \cdot a - b \cdot b}{a \cdot a}\right|\right)\right) \]
        2. div-subN/A

          \[\leadsto \mathsf{sqrt.f64}\left(\left(\left|\frac{a \cdot a}{a \cdot a} - \frac{b \cdot b}{a \cdot a}\right|\right)\right) \]
        3. fabs-subN/A

          \[\leadsto \mathsf{sqrt.f64}\left(\left(\left|\frac{b \cdot b}{a \cdot a} - \frac{a \cdot a}{a \cdot a}\right|\right)\right) \]
        4. fabs-lowering-fabs.f64N/A

          \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\left(\frac{b \cdot b}{a \cdot a} - \frac{a \cdot a}{a \cdot a}\right)\right)\right) \]
        5. sub-negN/A

          \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\left(\frac{b \cdot b}{a \cdot a} + \left(\mathsf{neg}\left(\frac{a \cdot a}{a \cdot a}\right)\right)\right)\right)\right) \]
        6. *-inversesN/A

          \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\left(\frac{b \cdot b}{a \cdot a} + \left(\mathsf{neg}\left(1\right)\right)\right)\right)\right) \]
        7. metadata-evalN/A

          \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\left(\frac{b \cdot b}{a \cdot a} + -1\right)\right)\right) \]
        8. +-lowering-+.f64N/A

          \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\mathsf{+.f64}\left(\left(\frac{b \cdot b}{a \cdot a}\right), -1\right)\right)\right) \]
        9. associate-/r*N/A

          \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\mathsf{+.f64}\left(\left(\frac{\frac{b \cdot b}{a}}{a}\right), -1\right)\right)\right) \]
        10. /-lowering-/.f64N/A

          \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\mathsf{+.f64}\left(\mathsf{/.f64}\left(\left(\frac{b \cdot b}{a}\right), a\right), -1\right)\right)\right) \]
        11. associate-/l*N/A

          \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\mathsf{+.f64}\left(\mathsf{/.f64}\left(\left(b \cdot \frac{b}{a}\right), a\right), -1\right)\right)\right) \]
        12. *-lowering-*.f64N/A

          \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\mathsf{+.f64}\left(\mathsf{/.f64}\left(\mathsf{*.f64}\left(b, \left(\frac{b}{a}\right)\right), a\right), -1\right)\right)\right) \]
        13. /-lowering-/.f64100.0%

          \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\mathsf{+.f64}\left(\mathsf{/.f64}\left(\mathsf{*.f64}\left(b, \mathsf{/.f64}\left(b, a\right)\right), a\right), -1\right)\right)\right) \]
      3. Simplified100.0%

        \[\leadsto \color{blue}{\sqrt{\left|\frac{b \cdot \frac{b}{a}}{a} + -1\right|}} \]
      4. Add Preprocessing
      5. Taylor expanded in b around 0

        \[\leadsto \mathsf{sqrt.f64}\left(\mathsf{fabs.f64}\left(\color{blue}{-1}\right)\right) \]
      6. Step-by-step derivation
        1. Simplified97.3%

          \[\leadsto \sqrt{\left|\color{blue}{-1}\right|} \]
        2. Step-by-step derivation
          1. metadata-evalN/A

            \[\leadsto \sqrt{1} \]
          2. metadata-eval97.3%

            \[\leadsto 1 \]
        3. Applied egg-rr97.3%

          \[\leadsto \color{blue}{1} \]
        4. Add Preprocessing

        Reproduce

        ?
        herbie shell --seed 2024155 
        (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)))))