NMSE Section 6.1 mentioned, B

Percentage Accurate: 78.8% → 99.7%
Time: 9.9s
Alternatives: 5
Speedup: 1.9×

Specification

?
\[\begin{array}{l} \\ \left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \end{array} \]
(FPCore (a b)
 :precision binary64
 (* (* (/ PI 2.0) (/ 1.0 (- (* b b) (* a a)))) (- (/ 1.0 a) (/ 1.0 b))))
double code(double a, double b) {
	return ((((double) M_PI) / 2.0) * (1.0 / ((b * b) - (a * a)))) * ((1.0 / a) - (1.0 / b));
}
public static double code(double a, double b) {
	return ((Math.PI / 2.0) * (1.0 / ((b * b) - (a * a)))) * ((1.0 / a) - (1.0 / b));
}
def code(a, b):
	return ((math.pi / 2.0) * (1.0 / ((b * b) - (a * a)))) * ((1.0 / a) - (1.0 / b))
function code(a, b)
	return Float64(Float64(Float64(pi / 2.0) * Float64(1.0 / Float64(Float64(b * b) - Float64(a * a)))) * Float64(Float64(1.0 / a) - Float64(1.0 / b)))
end
function tmp = code(a, b)
	tmp = ((pi / 2.0) * (1.0 / ((b * b) - (a * a)))) * ((1.0 / a) - (1.0 / b));
end
code[a_, b_] := N[(N[(N[(Pi / 2.0), $MachinePrecision] * N[(1.0 / N[(N[(b * b), $MachinePrecision] - N[(a * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[(N[(1.0 / a), $MachinePrecision] - N[(1.0 / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\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: 78.8% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \end{array} \]
(FPCore (a b)
 :precision binary64
 (* (* (/ PI 2.0) (/ 1.0 (- (* b b) (* a a)))) (- (/ 1.0 a) (/ 1.0 b))))
double code(double a, double b) {
	return ((((double) M_PI) / 2.0) * (1.0 / ((b * b) - (a * a)))) * ((1.0 / a) - (1.0 / b));
}
public static double code(double a, double b) {
	return ((Math.PI / 2.0) * (1.0 / ((b * b) - (a * a)))) * ((1.0 / a) - (1.0 / b));
}
def code(a, b):
	return ((math.pi / 2.0) * (1.0 / ((b * b) - (a * a)))) * ((1.0 / a) - (1.0 / b))
function code(a, b)
	return Float64(Float64(Float64(pi / 2.0) * Float64(1.0 / Float64(Float64(b * b) - Float64(a * a)))) * Float64(Float64(1.0 / a) - Float64(1.0 / b)))
end
function tmp = code(a, b)
	tmp = ((pi / 2.0) * (1.0 / ((b * b) - (a * a)))) * ((1.0 / a) - (1.0 / b));
end
code[a_, b_] := N[(N[(N[(Pi / 2.0), $MachinePrecision] * N[(1.0 / N[(N[(b * b), $MachinePrecision] - N[(a * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[(N[(1.0 / a), $MachinePrecision] - N[(1.0 / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right)
\end{array}

Alternative 1: 99.7% accurate, 1.9× speedup?

\[\begin{array}{l} \\ \frac{0.5 \cdot \frac{\pi}{a \cdot b}}{a + b} \end{array} \]
(FPCore (a b) :precision binary64 (/ (* 0.5 (/ PI (* a b))) (+ a b)))
double code(double a, double b) {
	return (0.5 * (((double) M_PI) / (a * b))) / (a + b);
}
public static double code(double a, double b) {
	return (0.5 * (Math.PI / (a * b))) / (a + b);
}
def code(a, b):
	return (0.5 * (math.pi / (a * b))) / (a + b)
function code(a, b)
	return Float64(Float64(0.5 * Float64(pi / Float64(a * b))) / Float64(a + b))
end
function tmp = code(a, b)
	tmp = (0.5 * (pi / (a * b))) / (a + b);
end
code[a_, b_] := N[(N[(0.5 * N[(Pi / N[(a * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(a + b), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{0.5 \cdot \frac{\pi}{a \cdot b}}{a + b}
\end{array}
Derivation
  1. Initial program 76.9%

    \[\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
  2. Step-by-step derivation
    1. associate-*l*76.9%

      \[\leadsto \color{blue}{\frac{\pi}{2} \cdot \left(\frac{1}{b \cdot b - a \cdot a} \cdot \left(\frac{1}{a} - \frac{1}{b}\right)\right)} \]
    2. associate-*l/76.9%

      \[\leadsto \frac{\pi}{2} \cdot \color{blue}{\frac{1 \cdot \left(\frac{1}{a} - \frac{1}{b}\right)}{b \cdot b - a \cdot a}} \]
    3. *-lft-identity76.9%

      \[\leadsto \frac{\pi}{2} \cdot \frac{\color{blue}{\frac{1}{a} - \frac{1}{b}}}{b \cdot b - a \cdot a} \]
    4. difference-of-squares85.8%

      \[\leadsto \frac{\pi}{2} \cdot \frac{\frac{1}{a} - \frac{1}{b}}{\color{blue}{\left(b + a\right) \cdot \left(b - a\right)}} \]
    5. associate-/l/99.7%

      \[\leadsto \frac{\pi}{2} \cdot \color{blue}{\frac{\frac{\frac{1}{a} - \frac{1}{b}}{b - a}}{b + a}} \]
    6. sub-neg99.7%

      \[\leadsto \frac{\pi}{2} \cdot \frac{\frac{\color{blue}{\frac{1}{a} + \left(-\frac{1}{b}\right)}}{b - a}}{b + a} \]
    7. distribute-neg-frac99.7%

      \[\leadsto \frac{\pi}{2} \cdot \frac{\frac{\frac{1}{a} + \color{blue}{\frac{-1}{b}}}{b - a}}{b + a} \]
    8. metadata-eval99.7%

      \[\leadsto \frac{\pi}{2} \cdot \frac{\frac{\frac{1}{a} + \frac{\color{blue}{-1}}{b}}{b - a}}{b + a} \]
  3. Simplified99.7%

    \[\leadsto \color{blue}{\frac{\pi}{2} \cdot \frac{\frac{\frac{1}{a} + \frac{-1}{b}}{b - a}}{b + a}} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. associate-*r/99.7%

      \[\leadsto \color{blue}{\frac{\frac{\pi}{2} \cdot \frac{\frac{1}{a} + \frac{-1}{b}}{b - a}}{b + a}} \]
    2. div-inv99.7%

      \[\leadsto \frac{\color{blue}{\left(\pi \cdot \frac{1}{2}\right)} \cdot \frac{\frac{1}{a} + \frac{-1}{b}}{b - a}}{b + a} \]
    3. metadata-eval99.7%

      \[\leadsto \frac{\left(\pi \cdot \color{blue}{0.5}\right) \cdot \frac{\frac{1}{a} + \frac{-1}{b}}{b - a}}{b + a} \]
  6. Applied egg-rr99.7%

    \[\leadsto \color{blue}{\frac{\left(\pi \cdot 0.5\right) \cdot \frac{\frac{1}{a} + \frac{-1}{b}}{b - a}}{b + a}} \]
  7. Taylor expanded in a around 0 99.7%

    \[\leadsto \frac{\color{blue}{0.5 \cdot \frac{\pi}{a \cdot b}}}{b + a} \]
  8. Final simplification99.7%

    \[\leadsto \frac{0.5 \cdot \frac{\pi}{a \cdot b}}{a + b} \]
  9. Add Preprocessing

Alternative 2: 71.4% accurate, 1.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;a \leq -8.2 \cdot 10^{-22}:\\ \;\;\;\;\frac{\frac{0.5}{a} \cdot \frac{\pi}{a}}{b}\\ \mathbf{else}:\\ \;\;\;\;\frac{\pi}{b} \cdot \frac{0.5}{a \cdot b}\\ \end{array} \end{array} \]
(FPCore (a b)
 :precision binary64
 (if (<= a -8.2e-22)
   (/ (* (/ 0.5 a) (/ PI a)) b)
   (* (/ PI b) (/ 0.5 (* a b)))))
double code(double a, double b) {
	double tmp;
	if (a <= -8.2e-22) {
		tmp = ((0.5 / a) * (((double) M_PI) / a)) / b;
	} else {
		tmp = (((double) M_PI) / b) * (0.5 / (a * b));
	}
	return tmp;
}
public static double code(double a, double b) {
	double tmp;
	if (a <= -8.2e-22) {
		tmp = ((0.5 / a) * (Math.PI / a)) / b;
	} else {
		tmp = (Math.PI / b) * (0.5 / (a * b));
	}
	return tmp;
}
def code(a, b):
	tmp = 0
	if a <= -8.2e-22:
		tmp = ((0.5 / a) * (math.pi / a)) / b
	else:
		tmp = (math.pi / b) * (0.5 / (a * b))
	return tmp
function code(a, b)
	tmp = 0.0
	if (a <= -8.2e-22)
		tmp = Float64(Float64(Float64(0.5 / a) * Float64(pi / a)) / b);
	else
		tmp = Float64(Float64(pi / b) * Float64(0.5 / Float64(a * b)));
	end
	return tmp
end
function tmp_2 = code(a, b)
	tmp = 0.0;
	if (a <= -8.2e-22)
		tmp = ((0.5 / a) * (pi / a)) / b;
	else
		tmp = (pi / b) * (0.5 / (a * b));
	end
	tmp_2 = tmp;
end
code[a_, b_] := If[LessEqual[a, -8.2e-22], N[(N[(N[(0.5 / a), $MachinePrecision] * N[(Pi / a), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision], N[(N[(Pi / b), $MachinePrecision] * N[(0.5 / N[(a * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;a \leq -8.2 \cdot 10^{-22}:\\
\;\;\;\;\frac{\frac{0.5}{a} \cdot \frac{\pi}{a}}{b}\\

\mathbf{else}:\\
\;\;\;\;\frac{\pi}{b} \cdot \frac{0.5}{a \cdot b}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if a < -8.1999999999999999e-22

    1. Initial program 76.2%

      \[\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    2. Step-by-step derivation
      1. associate-*l*76.1%

        \[\leadsto \color{blue}{\frac{\pi}{2} \cdot \left(\frac{1}{b \cdot b - a \cdot a} \cdot \left(\frac{1}{a} - \frac{1}{b}\right)\right)} \]
      2. associate-*l/76.2%

        \[\leadsto \frac{\pi}{2} \cdot \color{blue}{\frac{1 \cdot \left(\frac{1}{a} - \frac{1}{b}\right)}{b \cdot b - a \cdot a}} \]
      3. *-lft-identity76.2%

        \[\leadsto \frac{\pi}{2} \cdot \frac{\color{blue}{\frac{1}{a} - \frac{1}{b}}}{b \cdot b - a \cdot a} \]
      4. difference-of-squares85.9%

        \[\leadsto \frac{\pi}{2} \cdot \frac{\frac{1}{a} - \frac{1}{b}}{\color{blue}{\left(b + a\right) \cdot \left(b - a\right)}} \]
      5. associate-/l/99.6%

        \[\leadsto \frac{\pi}{2} \cdot \color{blue}{\frac{\frac{\frac{1}{a} - \frac{1}{b}}{b - a}}{b + a}} \]
      6. sub-neg99.6%

        \[\leadsto \frac{\pi}{2} \cdot \frac{\frac{\color{blue}{\frac{1}{a} + \left(-\frac{1}{b}\right)}}{b - a}}{b + a} \]
      7. distribute-neg-frac99.6%

        \[\leadsto \frac{\pi}{2} \cdot \frac{\frac{\frac{1}{a} + \color{blue}{\frac{-1}{b}}}{b - a}}{b + a} \]
      8. metadata-eval99.6%

        \[\leadsto \frac{\pi}{2} \cdot \frac{\frac{\frac{1}{a} + \frac{\color{blue}{-1}}{b}}{b - a}}{b + a} \]
    3. Simplified99.6%

      \[\leadsto \color{blue}{\frac{\pi}{2} \cdot \frac{\frac{\frac{1}{a} + \frac{-1}{b}}{b - a}}{b + a}} \]
    4. Add Preprocessing
    5. Taylor expanded in a around 0 99.6%

      \[\leadsto \frac{\pi}{2} \cdot \frac{\color{blue}{\frac{1}{a \cdot b}}}{b + a} \]
    6. Step-by-step derivation
      1. *-commutative99.6%

        \[\leadsto \color{blue}{\frac{\frac{1}{a \cdot b}}{b + a} \cdot \frac{\pi}{2}} \]
      2. associate-/l/97.9%

        \[\leadsto \color{blue}{\frac{1}{\left(b + a\right) \cdot \left(a \cdot b\right)}} \cdot \frac{\pi}{2} \]
      3. frac-times97.9%

        \[\leadsto \color{blue}{\frac{1 \cdot \pi}{\left(\left(b + a\right) \cdot \left(a \cdot b\right)\right) \cdot 2}} \]
      4. *-un-lft-identity97.9%

        \[\leadsto \frac{\color{blue}{\pi}}{\left(\left(b + a\right) \cdot \left(a \cdot b\right)\right) \cdot 2} \]
      5. +-commutative97.9%

        \[\leadsto \frac{\pi}{\left(\color{blue}{\left(a + b\right)} \cdot \left(a \cdot b\right)\right) \cdot 2} \]
    7. Applied egg-rr97.9%

      \[\leadsto \color{blue}{\frac{\pi}{\left(\left(a + b\right) \cdot \left(a \cdot b\right)\right) \cdot 2}} \]
    8. Step-by-step derivation
      1. associate-/l/97.9%

        \[\leadsto \color{blue}{\frac{\frac{\pi}{2}}{\left(a + b\right) \cdot \left(a \cdot b\right)}} \]
      2. associate-*r*86.0%

        \[\leadsto \frac{\frac{\pi}{2}}{\color{blue}{\left(\left(a + b\right) \cdot a\right) \cdot b}} \]
      3. *-un-lft-identity86.0%

        \[\leadsto \frac{\color{blue}{1 \cdot \frac{\pi}{2}}}{\left(\left(a + b\right) \cdot a\right) \cdot b} \]
      4. *-commutative86.0%

        \[\leadsto \frac{1 \cdot \frac{\pi}{2}}{\color{blue}{b \cdot \left(\left(a + b\right) \cdot a\right)}} \]
      5. times-frac85.8%

        \[\leadsto \color{blue}{\frac{1}{b} \cdot \frac{\frac{\pi}{2}}{\left(a + b\right) \cdot a}} \]
      6. div-inv85.8%

        \[\leadsto \frac{1}{b} \cdot \frac{\color{blue}{\pi \cdot \frac{1}{2}}}{\left(a + b\right) \cdot a} \]
      7. metadata-eval85.8%

        \[\leadsto \frac{1}{b} \cdot \frac{\pi \cdot \color{blue}{0.5}}{\left(a + b\right) \cdot a} \]
      8. +-commutative85.8%

        \[\leadsto \frac{1}{b} \cdot \frac{\pi \cdot 0.5}{\color{blue}{\left(b + a\right)} \cdot a} \]
      9. times-frac85.8%

        \[\leadsto \frac{1}{b} \cdot \color{blue}{\left(\frac{\pi}{b + a} \cdot \frac{0.5}{a}\right)} \]
      10. +-commutative85.8%

        \[\leadsto \frac{1}{b} \cdot \left(\frac{\pi}{\color{blue}{a + b}} \cdot \frac{0.5}{a}\right) \]
    9. Applied egg-rr85.8%

      \[\leadsto \color{blue}{\frac{1}{b} \cdot \left(\frac{\pi}{a + b} \cdot \frac{0.5}{a}\right)} \]
    10. Step-by-step derivation
      1. associate-*l/85.9%

        \[\leadsto \color{blue}{\frac{1 \cdot \left(\frac{\pi}{a + b} \cdot \frac{0.5}{a}\right)}{b}} \]
      2. *-lft-identity85.9%

        \[\leadsto \frac{\color{blue}{\frac{\pi}{a + b} \cdot \frac{0.5}{a}}}{b} \]
      3. *-commutative85.9%

        \[\leadsto \frac{\color{blue}{\frac{0.5}{a} \cdot \frac{\pi}{a + b}}}{b} \]
    11. Simplified85.9%

      \[\leadsto \color{blue}{\frac{\frac{0.5}{a} \cdot \frac{\pi}{a + b}}{b}} \]
    12. Taylor expanded in a around inf 73.0%

      \[\leadsto \frac{\frac{0.5}{a} \cdot \color{blue}{\frac{\pi}{a}}}{b} \]

    if -8.1999999999999999e-22 < a

    1. Initial program 77.1%

      \[\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    2. Step-by-step derivation
      1. associate-*l*77.1%

        \[\leadsto \color{blue}{\frac{\pi}{2} \cdot \left(\frac{1}{b \cdot b - a \cdot a} \cdot \left(\frac{1}{a} - \frac{1}{b}\right)\right)} \]
      2. associate-*l/77.1%

        \[\leadsto \frac{\pi}{2} \cdot \color{blue}{\frac{1 \cdot \left(\frac{1}{a} - \frac{1}{b}\right)}{b \cdot b - a \cdot a}} \]
      3. *-lft-identity77.1%

        \[\leadsto \frac{\pi}{2} \cdot \frac{\color{blue}{\frac{1}{a} - \frac{1}{b}}}{b \cdot b - a \cdot a} \]
      4. difference-of-squares85.8%

        \[\leadsto \frac{\pi}{2} \cdot \frac{\frac{1}{a} - \frac{1}{b}}{\color{blue}{\left(b + a\right) \cdot \left(b - a\right)}} \]
      5. associate-/l/99.7%

        \[\leadsto \frac{\pi}{2} \cdot \color{blue}{\frac{\frac{\frac{1}{a} - \frac{1}{b}}{b - a}}{b + a}} \]
      6. sub-neg99.7%

        \[\leadsto \frac{\pi}{2} \cdot \frac{\frac{\color{blue}{\frac{1}{a} + \left(-\frac{1}{b}\right)}}{b - a}}{b + a} \]
      7. distribute-neg-frac99.7%

        \[\leadsto \frac{\pi}{2} \cdot \frac{\frac{\frac{1}{a} + \color{blue}{\frac{-1}{b}}}{b - a}}{b + a} \]
      8. metadata-eval99.7%

        \[\leadsto \frac{\pi}{2} \cdot \frac{\frac{\frac{1}{a} + \frac{\color{blue}{-1}}{b}}{b - a}}{b + a} \]
    3. Simplified99.7%

      \[\leadsto \color{blue}{\frac{\pi}{2} \cdot \frac{\frac{\frac{1}{a} + \frac{-1}{b}}{b - a}}{b + a}} \]
    4. Add Preprocessing
    5. Taylor expanded in a around 0 99.7%

      \[\leadsto \frac{\pi}{2} \cdot \frac{\color{blue}{\frac{1}{a \cdot b}}}{b + a} \]
    6. Step-by-step derivation
      1. expm1-log1p-u81.2%

        \[\leadsto \color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\frac{\pi}{2} \cdot \frac{\frac{1}{a \cdot b}}{b + a}\right)\right)} \]
      2. expm1-udef52.1%

        \[\leadsto \color{blue}{e^{\mathsf{log1p}\left(\frac{\pi}{2} \cdot \frac{\frac{1}{a \cdot b}}{b + a}\right)} - 1} \]
      3. *-commutative52.1%

        \[\leadsto e^{\mathsf{log1p}\left(\color{blue}{\frac{\frac{1}{a \cdot b}}{b + a} \cdot \frac{\pi}{2}}\right)} - 1 \]
      4. associate-/l/52.1%

        \[\leadsto e^{\mathsf{log1p}\left(\color{blue}{\frac{1}{\left(b + a\right) \cdot \left(a \cdot b\right)}} \cdot \frac{\pi}{2}\right)} - 1 \]
      5. frac-times52.1%

        \[\leadsto e^{\mathsf{log1p}\left(\color{blue}{\frac{1 \cdot \pi}{\left(\left(b + a\right) \cdot \left(a \cdot b\right)\right) \cdot 2}}\right)} - 1 \]
      6. *-un-lft-identity52.1%

        \[\leadsto e^{\mathsf{log1p}\left(\frac{\color{blue}{\pi}}{\left(\left(b + a\right) \cdot \left(a \cdot b\right)\right) \cdot 2}\right)} - 1 \]
      7. +-commutative52.1%

        \[\leadsto e^{\mathsf{log1p}\left(\frac{\pi}{\left(\color{blue}{\left(a + b\right)} \cdot \left(a \cdot b\right)\right) \cdot 2}\right)} - 1 \]
    7. Applied egg-rr52.1%

      \[\leadsto \color{blue}{e^{\mathsf{log1p}\left(\frac{\pi}{\left(\left(a + b\right) \cdot \left(a \cdot b\right)\right) \cdot 2}\right)} - 1} \]
    8. Step-by-step derivation
      1. expm1-def79.7%

        \[\leadsto \color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\frac{\pi}{\left(\left(a + b\right) \cdot \left(a \cdot b\right)\right) \cdot 2}\right)\right)} \]
      2. expm1-log1p98.2%

        \[\leadsto \color{blue}{\frac{\pi}{\left(\left(a + b\right) \cdot \left(a \cdot b\right)\right) \cdot 2}} \]
      3. *-commutative98.2%

        \[\leadsto \frac{\pi}{\color{blue}{2 \cdot \left(\left(a + b\right) \cdot \left(a \cdot b\right)\right)}} \]
      4. associate-/r*98.2%

        \[\leadsto \color{blue}{\frac{\frac{\pi}{2}}{\left(a + b\right) \cdot \left(a \cdot b\right)}} \]
      5. associate-*r*93.8%

        \[\leadsto \frac{\frac{\pi}{2}}{\color{blue}{\left(\left(a + b\right) \cdot a\right) \cdot b}} \]
    9. Simplified93.8%

      \[\leadsto \color{blue}{\frac{\frac{\pi}{2}}{\left(\left(a + b\right) \cdot a\right) \cdot b}} \]
    10. Taylor expanded in a around 0 69.2%

      \[\leadsto \frac{\frac{\pi}{2}}{\color{blue}{\left(a \cdot b\right)} \cdot b} \]
    11. Step-by-step derivation
      1. div-inv69.2%

        \[\leadsto \frac{\color{blue}{\pi \cdot \frac{1}{2}}}{\left(a \cdot b\right) \cdot b} \]
      2. metadata-eval69.2%

        \[\leadsto \frac{\pi \cdot \color{blue}{0.5}}{\left(a \cdot b\right) \cdot b} \]
      3. *-commutative69.2%

        \[\leadsto \frac{\pi \cdot 0.5}{\color{blue}{b \cdot \left(a \cdot b\right)}} \]
      4. times-frac69.8%

        \[\leadsto \color{blue}{\frac{\pi}{b} \cdot \frac{0.5}{a \cdot b}} \]
    12. Applied egg-rr69.8%

      \[\leadsto \color{blue}{\frac{\pi}{b} \cdot \frac{0.5}{a \cdot b}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification70.5%

    \[\leadsto \begin{array}{l} \mathbf{if}\;a \leq -8.2 \cdot 10^{-22}:\\ \;\;\;\;\frac{\frac{0.5}{a} \cdot \frac{\pi}{a}}{b}\\ \mathbf{else}:\\ \;\;\;\;\frac{\pi}{b} \cdot \frac{0.5}{a \cdot b}\\ \end{array} \]
  5. Add Preprocessing

Alternative 3: 71.4% accurate, 1.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;a \leq -7.5 \cdot 10^{-22}:\\ \;\;\;\;\frac{\frac{0.5}{a} \cdot \frac{\pi}{a}}{b}\\ \mathbf{else}:\\ \;\;\;\;\frac{\frac{0.5}{a} \cdot \frac{\pi}{b}}{b}\\ \end{array} \end{array} \]
(FPCore (a b)
 :precision binary64
 (if (<= a -7.5e-22)
   (/ (* (/ 0.5 a) (/ PI a)) b)
   (/ (* (/ 0.5 a) (/ PI b)) b)))
double code(double a, double b) {
	double tmp;
	if (a <= -7.5e-22) {
		tmp = ((0.5 / a) * (((double) M_PI) / a)) / b;
	} else {
		tmp = ((0.5 / a) * (((double) M_PI) / b)) / b;
	}
	return tmp;
}
public static double code(double a, double b) {
	double tmp;
	if (a <= -7.5e-22) {
		tmp = ((0.5 / a) * (Math.PI / a)) / b;
	} else {
		tmp = ((0.5 / a) * (Math.PI / b)) / b;
	}
	return tmp;
}
def code(a, b):
	tmp = 0
	if a <= -7.5e-22:
		tmp = ((0.5 / a) * (math.pi / a)) / b
	else:
		tmp = ((0.5 / a) * (math.pi / b)) / b
	return tmp
function code(a, b)
	tmp = 0.0
	if (a <= -7.5e-22)
		tmp = Float64(Float64(Float64(0.5 / a) * Float64(pi / a)) / b);
	else
		tmp = Float64(Float64(Float64(0.5 / a) * Float64(pi / b)) / b);
	end
	return tmp
end
function tmp_2 = code(a, b)
	tmp = 0.0;
	if (a <= -7.5e-22)
		tmp = ((0.5 / a) * (pi / a)) / b;
	else
		tmp = ((0.5 / a) * (pi / b)) / b;
	end
	tmp_2 = tmp;
end
code[a_, b_] := If[LessEqual[a, -7.5e-22], N[(N[(N[(0.5 / a), $MachinePrecision] * N[(Pi / a), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision], N[(N[(N[(0.5 / a), $MachinePrecision] * N[(Pi / b), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;a \leq -7.5 \cdot 10^{-22}:\\
\;\;\;\;\frac{\frac{0.5}{a} \cdot \frac{\pi}{a}}{b}\\

\mathbf{else}:\\
\;\;\;\;\frac{\frac{0.5}{a} \cdot \frac{\pi}{b}}{b}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if a < -7.49999999999999978e-22

    1. Initial program 76.2%

      \[\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    2. Step-by-step derivation
      1. associate-*l*76.1%

        \[\leadsto \color{blue}{\frac{\pi}{2} \cdot \left(\frac{1}{b \cdot b - a \cdot a} \cdot \left(\frac{1}{a} - \frac{1}{b}\right)\right)} \]
      2. associate-*l/76.2%

        \[\leadsto \frac{\pi}{2} \cdot \color{blue}{\frac{1 \cdot \left(\frac{1}{a} - \frac{1}{b}\right)}{b \cdot b - a \cdot a}} \]
      3. *-lft-identity76.2%

        \[\leadsto \frac{\pi}{2} \cdot \frac{\color{blue}{\frac{1}{a} - \frac{1}{b}}}{b \cdot b - a \cdot a} \]
      4. difference-of-squares85.9%

        \[\leadsto \frac{\pi}{2} \cdot \frac{\frac{1}{a} - \frac{1}{b}}{\color{blue}{\left(b + a\right) \cdot \left(b - a\right)}} \]
      5. associate-/l/99.6%

        \[\leadsto \frac{\pi}{2} \cdot \color{blue}{\frac{\frac{\frac{1}{a} - \frac{1}{b}}{b - a}}{b + a}} \]
      6. sub-neg99.6%

        \[\leadsto \frac{\pi}{2} \cdot \frac{\frac{\color{blue}{\frac{1}{a} + \left(-\frac{1}{b}\right)}}{b - a}}{b + a} \]
      7. distribute-neg-frac99.6%

        \[\leadsto \frac{\pi}{2} \cdot \frac{\frac{\frac{1}{a} + \color{blue}{\frac{-1}{b}}}{b - a}}{b + a} \]
      8. metadata-eval99.6%

        \[\leadsto \frac{\pi}{2} \cdot \frac{\frac{\frac{1}{a} + \frac{\color{blue}{-1}}{b}}{b - a}}{b + a} \]
    3. Simplified99.6%

      \[\leadsto \color{blue}{\frac{\pi}{2} \cdot \frac{\frac{\frac{1}{a} + \frac{-1}{b}}{b - a}}{b + a}} \]
    4. Add Preprocessing
    5. Taylor expanded in a around 0 99.6%

      \[\leadsto \frac{\pi}{2} \cdot \frac{\color{blue}{\frac{1}{a \cdot b}}}{b + a} \]
    6. Step-by-step derivation
      1. *-commutative99.6%

        \[\leadsto \color{blue}{\frac{\frac{1}{a \cdot b}}{b + a} \cdot \frac{\pi}{2}} \]
      2. associate-/l/97.9%

        \[\leadsto \color{blue}{\frac{1}{\left(b + a\right) \cdot \left(a \cdot b\right)}} \cdot \frac{\pi}{2} \]
      3. frac-times97.9%

        \[\leadsto \color{blue}{\frac{1 \cdot \pi}{\left(\left(b + a\right) \cdot \left(a \cdot b\right)\right) \cdot 2}} \]
      4. *-un-lft-identity97.9%

        \[\leadsto \frac{\color{blue}{\pi}}{\left(\left(b + a\right) \cdot \left(a \cdot b\right)\right) \cdot 2} \]
      5. +-commutative97.9%

        \[\leadsto \frac{\pi}{\left(\color{blue}{\left(a + b\right)} \cdot \left(a \cdot b\right)\right) \cdot 2} \]
    7. Applied egg-rr97.9%

      \[\leadsto \color{blue}{\frac{\pi}{\left(\left(a + b\right) \cdot \left(a \cdot b\right)\right) \cdot 2}} \]
    8. Step-by-step derivation
      1. associate-/l/97.9%

        \[\leadsto \color{blue}{\frac{\frac{\pi}{2}}{\left(a + b\right) \cdot \left(a \cdot b\right)}} \]
      2. associate-*r*86.0%

        \[\leadsto \frac{\frac{\pi}{2}}{\color{blue}{\left(\left(a + b\right) \cdot a\right) \cdot b}} \]
      3. *-un-lft-identity86.0%

        \[\leadsto \frac{\color{blue}{1 \cdot \frac{\pi}{2}}}{\left(\left(a + b\right) \cdot a\right) \cdot b} \]
      4. *-commutative86.0%

        \[\leadsto \frac{1 \cdot \frac{\pi}{2}}{\color{blue}{b \cdot \left(\left(a + b\right) \cdot a\right)}} \]
      5. times-frac85.8%

        \[\leadsto \color{blue}{\frac{1}{b} \cdot \frac{\frac{\pi}{2}}{\left(a + b\right) \cdot a}} \]
      6. div-inv85.8%

        \[\leadsto \frac{1}{b} \cdot \frac{\color{blue}{\pi \cdot \frac{1}{2}}}{\left(a + b\right) \cdot a} \]
      7. metadata-eval85.8%

        \[\leadsto \frac{1}{b} \cdot \frac{\pi \cdot \color{blue}{0.5}}{\left(a + b\right) \cdot a} \]
      8. +-commutative85.8%

        \[\leadsto \frac{1}{b} \cdot \frac{\pi \cdot 0.5}{\color{blue}{\left(b + a\right)} \cdot a} \]
      9. times-frac85.8%

        \[\leadsto \frac{1}{b} \cdot \color{blue}{\left(\frac{\pi}{b + a} \cdot \frac{0.5}{a}\right)} \]
      10. +-commutative85.8%

        \[\leadsto \frac{1}{b} \cdot \left(\frac{\pi}{\color{blue}{a + b}} \cdot \frac{0.5}{a}\right) \]
    9. Applied egg-rr85.8%

      \[\leadsto \color{blue}{\frac{1}{b} \cdot \left(\frac{\pi}{a + b} \cdot \frac{0.5}{a}\right)} \]
    10. Step-by-step derivation
      1. associate-*l/85.9%

        \[\leadsto \color{blue}{\frac{1 \cdot \left(\frac{\pi}{a + b} \cdot \frac{0.5}{a}\right)}{b}} \]
      2. *-lft-identity85.9%

        \[\leadsto \frac{\color{blue}{\frac{\pi}{a + b} \cdot \frac{0.5}{a}}}{b} \]
      3. *-commutative85.9%

        \[\leadsto \frac{\color{blue}{\frac{0.5}{a} \cdot \frac{\pi}{a + b}}}{b} \]
    11. Simplified85.9%

      \[\leadsto \color{blue}{\frac{\frac{0.5}{a} \cdot \frac{\pi}{a + b}}{b}} \]
    12. Taylor expanded in a around inf 73.0%

      \[\leadsto \frac{\frac{0.5}{a} \cdot \color{blue}{\frac{\pi}{a}}}{b} \]

    if -7.49999999999999978e-22 < a

    1. Initial program 77.1%

      \[\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    2. Step-by-step derivation
      1. associate-*l*77.1%

        \[\leadsto \color{blue}{\frac{\pi}{2} \cdot \left(\frac{1}{b \cdot b - a \cdot a} \cdot \left(\frac{1}{a} - \frac{1}{b}\right)\right)} \]
      2. associate-*l/77.1%

        \[\leadsto \frac{\pi}{2} \cdot \color{blue}{\frac{1 \cdot \left(\frac{1}{a} - \frac{1}{b}\right)}{b \cdot b - a \cdot a}} \]
      3. *-lft-identity77.1%

        \[\leadsto \frac{\pi}{2} \cdot \frac{\color{blue}{\frac{1}{a} - \frac{1}{b}}}{b \cdot b - a \cdot a} \]
      4. difference-of-squares85.8%

        \[\leadsto \frac{\pi}{2} \cdot \frac{\frac{1}{a} - \frac{1}{b}}{\color{blue}{\left(b + a\right) \cdot \left(b - a\right)}} \]
      5. associate-/l/99.7%

        \[\leadsto \frac{\pi}{2} \cdot \color{blue}{\frac{\frac{\frac{1}{a} - \frac{1}{b}}{b - a}}{b + a}} \]
      6. sub-neg99.7%

        \[\leadsto \frac{\pi}{2} \cdot \frac{\frac{\color{blue}{\frac{1}{a} + \left(-\frac{1}{b}\right)}}{b - a}}{b + a} \]
      7. distribute-neg-frac99.7%

        \[\leadsto \frac{\pi}{2} \cdot \frac{\frac{\frac{1}{a} + \color{blue}{\frac{-1}{b}}}{b - a}}{b + a} \]
      8. metadata-eval99.7%

        \[\leadsto \frac{\pi}{2} \cdot \frac{\frac{\frac{1}{a} + \frac{\color{blue}{-1}}{b}}{b - a}}{b + a} \]
    3. Simplified99.7%

      \[\leadsto \color{blue}{\frac{\pi}{2} \cdot \frac{\frac{\frac{1}{a} + \frac{-1}{b}}{b - a}}{b + a}} \]
    4. Add Preprocessing
    5. Taylor expanded in a around 0 99.7%

      \[\leadsto \frac{\pi}{2} \cdot \frac{\color{blue}{\frac{1}{a \cdot b}}}{b + a} \]
    6. Step-by-step derivation
      1. *-commutative99.7%

        \[\leadsto \color{blue}{\frac{\frac{1}{a \cdot b}}{b + a} \cdot \frac{\pi}{2}} \]
      2. associate-/l/98.2%

        \[\leadsto \color{blue}{\frac{1}{\left(b + a\right) \cdot \left(a \cdot b\right)}} \cdot \frac{\pi}{2} \]
      3. frac-times98.2%

        \[\leadsto \color{blue}{\frac{1 \cdot \pi}{\left(\left(b + a\right) \cdot \left(a \cdot b\right)\right) \cdot 2}} \]
      4. *-un-lft-identity98.2%

        \[\leadsto \frac{\color{blue}{\pi}}{\left(\left(b + a\right) \cdot \left(a \cdot b\right)\right) \cdot 2} \]
      5. +-commutative98.2%

        \[\leadsto \frac{\pi}{\left(\color{blue}{\left(a + b\right)} \cdot \left(a \cdot b\right)\right) \cdot 2} \]
    7. Applied egg-rr98.2%

      \[\leadsto \color{blue}{\frac{\pi}{\left(\left(a + b\right) \cdot \left(a \cdot b\right)\right) \cdot 2}} \]
    8. Step-by-step derivation
      1. associate-/l/98.2%

        \[\leadsto \color{blue}{\frac{\frac{\pi}{2}}{\left(a + b\right) \cdot \left(a \cdot b\right)}} \]
      2. associate-*r*93.8%

        \[\leadsto \frac{\frac{\pi}{2}}{\color{blue}{\left(\left(a + b\right) \cdot a\right) \cdot b}} \]
      3. *-un-lft-identity93.8%

        \[\leadsto \frac{\color{blue}{1 \cdot \frac{\pi}{2}}}{\left(\left(a + b\right) \cdot a\right) \cdot b} \]
      4. *-commutative93.8%

        \[\leadsto \frac{1 \cdot \frac{\pi}{2}}{\color{blue}{b \cdot \left(\left(a + b\right) \cdot a\right)}} \]
      5. times-frac94.4%

        \[\leadsto \color{blue}{\frac{1}{b} \cdot \frac{\frac{\pi}{2}}{\left(a + b\right) \cdot a}} \]
      6. div-inv94.4%

        \[\leadsto \frac{1}{b} \cdot \frac{\color{blue}{\pi \cdot \frac{1}{2}}}{\left(a + b\right) \cdot a} \]
      7. metadata-eval94.4%

        \[\leadsto \frac{1}{b} \cdot \frac{\pi \cdot \color{blue}{0.5}}{\left(a + b\right) \cdot a} \]
      8. +-commutative94.4%

        \[\leadsto \frac{1}{b} \cdot \frac{\pi \cdot 0.5}{\color{blue}{\left(b + a\right)} \cdot a} \]
      9. times-frac94.4%

        \[\leadsto \frac{1}{b} \cdot \color{blue}{\left(\frac{\pi}{b + a} \cdot \frac{0.5}{a}\right)} \]
      10. +-commutative94.4%

        \[\leadsto \frac{1}{b} \cdot \left(\frac{\pi}{\color{blue}{a + b}} \cdot \frac{0.5}{a}\right) \]
    9. Applied egg-rr94.4%

      \[\leadsto \color{blue}{\frac{1}{b} \cdot \left(\frac{\pi}{a + b} \cdot \frac{0.5}{a}\right)} \]
    10. Step-by-step derivation
      1. associate-*l/94.5%

        \[\leadsto \color{blue}{\frac{1 \cdot \left(\frac{\pi}{a + b} \cdot \frac{0.5}{a}\right)}{b}} \]
      2. *-lft-identity94.5%

        \[\leadsto \frac{\color{blue}{\frac{\pi}{a + b} \cdot \frac{0.5}{a}}}{b} \]
      3. *-commutative94.5%

        \[\leadsto \frac{\color{blue}{\frac{0.5}{a} \cdot \frac{\pi}{a + b}}}{b} \]
    11. Simplified94.5%

      \[\leadsto \color{blue}{\frac{\frac{0.5}{a} \cdot \frac{\pi}{a + b}}{b}} \]
    12. Taylor expanded in a around 0 69.9%

      \[\leadsto \frac{\frac{0.5}{a} \cdot \color{blue}{\frac{\pi}{b}}}{b} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification70.6%

    \[\leadsto \begin{array}{l} \mathbf{if}\;a \leq -7.5 \cdot 10^{-22}:\\ \;\;\;\;\frac{\frac{0.5}{a} \cdot \frac{\pi}{a}}{b}\\ \mathbf{else}:\\ \;\;\;\;\frac{\frac{0.5}{a} \cdot \frac{\pi}{b}}{b}\\ \end{array} \]
  5. Add Preprocessing

Alternative 4: 99.6% accurate, 1.9× speedup?

\[\begin{array}{l} \\ \frac{\pi}{a \cdot b} \cdot \frac{0.5}{a + b} \end{array} \]
(FPCore (a b) :precision binary64 (* (/ PI (* a b)) (/ 0.5 (+ a b))))
double code(double a, double b) {
	return (((double) M_PI) / (a * b)) * (0.5 / (a + b));
}
public static double code(double a, double b) {
	return (Math.PI / (a * b)) * (0.5 / (a + b));
}
def code(a, b):
	return (math.pi / (a * b)) * (0.5 / (a + b))
function code(a, b)
	return Float64(Float64(pi / Float64(a * b)) * Float64(0.5 / Float64(a + b)))
end
function tmp = code(a, b)
	tmp = (pi / (a * b)) * (0.5 / (a + b));
end
code[a_, b_] := N[(N[(Pi / N[(a * b), $MachinePrecision]), $MachinePrecision] * N[(0.5 / N[(a + b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{\pi}{a \cdot b} \cdot \frac{0.5}{a + b}
\end{array}
Derivation
  1. Initial program 76.9%

    \[\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
  2. Step-by-step derivation
    1. associate-*l*76.9%

      \[\leadsto \color{blue}{\frac{\pi}{2} \cdot \left(\frac{1}{b \cdot b - a \cdot a} \cdot \left(\frac{1}{a} - \frac{1}{b}\right)\right)} \]
    2. associate-*l/76.9%

      \[\leadsto \frac{\pi}{2} \cdot \color{blue}{\frac{1 \cdot \left(\frac{1}{a} - \frac{1}{b}\right)}{b \cdot b - a \cdot a}} \]
    3. *-lft-identity76.9%

      \[\leadsto \frac{\pi}{2} \cdot \frac{\color{blue}{\frac{1}{a} - \frac{1}{b}}}{b \cdot b - a \cdot a} \]
    4. difference-of-squares85.8%

      \[\leadsto \frac{\pi}{2} \cdot \frac{\frac{1}{a} - \frac{1}{b}}{\color{blue}{\left(b + a\right) \cdot \left(b - a\right)}} \]
    5. associate-/l/99.7%

      \[\leadsto \frac{\pi}{2} \cdot \color{blue}{\frac{\frac{\frac{1}{a} - \frac{1}{b}}{b - a}}{b + a}} \]
    6. sub-neg99.7%

      \[\leadsto \frac{\pi}{2} \cdot \frac{\frac{\color{blue}{\frac{1}{a} + \left(-\frac{1}{b}\right)}}{b - a}}{b + a} \]
    7. distribute-neg-frac99.7%

      \[\leadsto \frac{\pi}{2} \cdot \frac{\frac{\frac{1}{a} + \color{blue}{\frac{-1}{b}}}{b - a}}{b + a} \]
    8. metadata-eval99.7%

      \[\leadsto \frac{\pi}{2} \cdot \frac{\frac{\frac{1}{a} + \frac{\color{blue}{-1}}{b}}{b - a}}{b + a} \]
  3. Simplified99.7%

    \[\leadsto \color{blue}{\frac{\pi}{2} \cdot \frac{\frac{\frac{1}{a} + \frac{-1}{b}}{b - a}}{b + a}} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. associate-*r/99.7%

      \[\leadsto \color{blue}{\frac{\frac{\pi}{2} \cdot \frac{\frac{1}{a} + \frac{-1}{b}}{b - a}}{b + a}} \]
    2. div-inv99.7%

      \[\leadsto \frac{\color{blue}{\left(\pi \cdot \frac{1}{2}\right)} \cdot \frac{\frac{1}{a} + \frac{-1}{b}}{b - a}}{b + a} \]
    3. metadata-eval99.7%

      \[\leadsto \frac{\left(\pi \cdot \color{blue}{0.5}\right) \cdot \frac{\frac{1}{a} + \frac{-1}{b}}{b - a}}{b + a} \]
  6. Applied egg-rr99.7%

    \[\leadsto \color{blue}{\frac{\left(\pi \cdot 0.5\right) \cdot \frac{\frac{1}{a} + \frac{-1}{b}}{b - a}}{b + a}} \]
  7. Taylor expanded in a around 0 99.7%

    \[\leadsto \frac{\color{blue}{0.5 \cdot \frac{\pi}{a \cdot b}}}{b + a} \]
  8. Step-by-step derivation
    1. expm1-log1p-u83.0%

      \[\leadsto \color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\frac{0.5 \cdot \frac{\pi}{a \cdot b}}{b + a}\right)\right)} \]
    2. expm1-udef52.7%

      \[\leadsto \color{blue}{e^{\mathsf{log1p}\left(\frac{0.5 \cdot \frac{\pi}{a \cdot b}}{b + a}\right)} - 1} \]
    3. *-un-lft-identity52.7%

      \[\leadsto e^{\mathsf{log1p}\left(\frac{0.5 \cdot \frac{\pi}{a \cdot b}}{\color{blue}{1 \cdot \left(b + a\right)}}\right)} - 1 \]
    4. times-frac52.7%

      \[\leadsto e^{\mathsf{log1p}\left(\color{blue}{\frac{0.5}{1} \cdot \frac{\frac{\pi}{a \cdot b}}{b + a}}\right)} - 1 \]
    5. metadata-eval52.7%

      \[\leadsto e^{\mathsf{log1p}\left(\color{blue}{0.5} \cdot \frac{\frac{\pi}{a \cdot b}}{b + a}\right)} - 1 \]
    6. +-commutative52.7%

      \[\leadsto e^{\mathsf{log1p}\left(0.5 \cdot \frac{\frac{\pi}{a \cdot b}}{\color{blue}{a + b}}\right)} - 1 \]
  9. Applied egg-rr52.7%

    \[\leadsto \color{blue}{e^{\mathsf{log1p}\left(0.5 \cdot \frac{\frac{\pi}{a \cdot b}}{a + b}\right)} - 1} \]
  10. Step-by-step derivation
    1. expm1-def82.9%

      \[\leadsto \color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(0.5 \cdot \frac{\frac{\pi}{a \cdot b}}{a + b}\right)\right)} \]
    2. expm1-log1p99.7%

      \[\leadsto \color{blue}{0.5 \cdot \frac{\frac{\pi}{a \cdot b}}{a + b}} \]
    3. associate-*r/99.7%

      \[\leadsto \color{blue}{\frac{0.5 \cdot \frac{\pi}{a \cdot b}}{a + b}} \]
    4. *-commutative99.7%

      \[\leadsto \frac{\color{blue}{\frac{\pi}{a \cdot b} \cdot 0.5}}{a + b} \]
    5. associate-*r/99.6%

      \[\leadsto \color{blue}{\frac{\pi}{a \cdot b} \cdot \frac{0.5}{a + b}} \]
  11. Simplified99.6%

    \[\leadsto \color{blue}{\frac{\pi}{a \cdot b} \cdot \frac{0.5}{a + b}} \]
  12. Final simplification99.6%

    \[\leadsto \frac{\pi}{a \cdot b} \cdot \frac{0.5}{a + b} \]
  13. Add Preprocessing

Alternative 5: 62.3% accurate, 2.3× speedup?

\[\begin{array}{l} \\ \frac{\pi}{b} \cdot \frac{0.5}{a \cdot b} \end{array} \]
(FPCore (a b) :precision binary64 (* (/ PI b) (/ 0.5 (* a b))))
double code(double a, double b) {
	return (((double) M_PI) / b) * (0.5 / (a * b));
}
public static double code(double a, double b) {
	return (Math.PI / b) * (0.5 / (a * b));
}
def code(a, b):
	return (math.pi / b) * (0.5 / (a * b))
function code(a, b)
	return Float64(Float64(pi / b) * Float64(0.5 / Float64(a * b)))
end
function tmp = code(a, b)
	tmp = (pi / b) * (0.5 / (a * b));
end
code[a_, b_] := N[(N[(Pi / b), $MachinePrecision] * N[(0.5 / N[(a * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{\pi}{b} \cdot \frac{0.5}{a \cdot b}
\end{array}
Derivation
  1. Initial program 76.9%

    \[\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
  2. Step-by-step derivation
    1. associate-*l*76.9%

      \[\leadsto \color{blue}{\frac{\pi}{2} \cdot \left(\frac{1}{b \cdot b - a \cdot a} \cdot \left(\frac{1}{a} - \frac{1}{b}\right)\right)} \]
    2. associate-*l/76.9%

      \[\leadsto \frac{\pi}{2} \cdot \color{blue}{\frac{1 \cdot \left(\frac{1}{a} - \frac{1}{b}\right)}{b \cdot b - a \cdot a}} \]
    3. *-lft-identity76.9%

      \[\leadsto \frac{\pi}{2} \cdot \frac{\color{blue}{\frac{1}{a} - \frac{1}{b}}}{b \cdot b - a \cdot a} \]
    4. difference-of-squares85.8%

      \[\leadsto \frac{\pi}{2} \cdot \frac{\frac{1}{a} - \frac{1}{b}}{\color{blue}{\left(b + a\right) \cdot \left(b - a\right)}} \]
    5. associate-/l/99.7%

      \[\leadsto \frac{\pi}{2} \cdot \color{blue}{\frac{\frac{\frac{1}{a} - \frac{1}{b}}{b - a}}{b + a}} \]
    6. sub-neg99.7%

      \[\leadsto \frac{\pi}{2} \cdot \frac{\frac{\color{blue}{\frac{1}{a} + \left(-\frac{1}{b}\right)}}{b - a}}{b + a} \]
    7. distribute-neg-frac99.7%

      \[\leadsto \frac{\pi}{2} \cdot \frac{\frac{\frac{1}{a} + \color{blue}{\frac{-1}{b}}}{b - a}}{b + a} \]
    8. metadata-eval99.7%

      \[\leadsto \frac{\pi}{2} \cdot \frac{\frac{\frac{1}{a} + \frac{\color{blue}{-1}}{b}}{b - a}}{b + a} \]
  3. Simplified99.7%

    \[\leadsto \color{blue}{\frac{\pi}{2} \cdot \frac{\frac{\frac{1}{a} + \frac{-1}{b}}{b - a}}{b + a}} \]
  4. Add Preprocessing
  5. Taylor expanded in a around 0 99.6%

    \[\leadsto \frac{\pi}{2} \cdot \frac{\color{blue}{\frac{1}{a \cdot b}}}{b + a} \]
  6. Step-by-step derivation
    1. expm1-log1p-u82.9%

      \[\leadsto \color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\frac{\pi}{2} \cdot \frac{\frac{1}{a \cdot b}}{b + a}\right)\right)} \]
    2. expm1-udef52.7%

      \[\leadsto \color{blue}{e^{\mathsf{log1p}\left(\frac{\pi}{2} \cdot \frac{\frac{1}{a \cdot b}}{b + a}\right)} - 1} \]
    3. *-commutative52.7%

      \[\leadsto e^{\mathsf{log1p}\left(\color{blue}{\frac{\frac{1}{a \cdot b}}{b + a} \cdot \frac{\pi}{2}}\right)} - 1 \]
    4. associate-/l/52.7%

      \[\leadsto e^{\mathsf{log1p}\left(\color{blue}{\frac{1}{\left(b + a\right) \cdot \left(a \cdot b\right)}} \cdot \frac{\pi}{2}\right)} - 1 \]
    5. frac-times52.7%

      \[\leadsto e^{\mathsf{log1p}\left(\color{blue}{\frac{1 \cdot \pi}{\left(\left(b + a\right) \cdot \left(a \cdot b\right)\right) \cdot 2}}\right)} - 1 \]
    6. *-un-lft-identity52.7%

      \[\leadsto e^{\mathsf{log1p}\left(\frac{\color{blue}{\pi}}{\left(\left(b + a\right) \cdot \left(a \cdot b\right)\right) \cdot 2}\right)} - 1 \]
    7. +-commutative52.7%

      \[\leadsto e^{\mathsf{log1p}\left(\frac{\pi}{\left(\color{blue}{\left(a + b\right)} \cdot \left(a \cdot b\right)\right) \cdot 2}\right)} - 1 \]
  7. Applied egg-rr52.7%

    \[\leadsto \color{blue}{e^{\mathsf{log1p}\left(\frac{\pi}{\left(\left(a + b\right) \cdot \left(a \cdot b\right)\right) \cdot 2}\right)} - 1} \]
  8. Step-by-step derivation
    1. expm1-def81.4%

      \[\leadsto \color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\frac{\pi}{\left(\left(a + b\right) \cdot \left(a \cdot b\right)\right) \cdot 2}\right)\right)} \]
    2. expm1-log1p98.1%

      \[\leadsto \color{blue}{\frac{\pi}{\left(\left(a + b\right) \cdot \left(a \cdot b\right)\right) \cdot 2}} \]
    3. *-commutative98.1%

      \[\leadsto \frac{\pi}{\color{blue}{2 \cdot \left(\left(a + b\right) \cdot \left(a \cdot b\right)\right)}} \]
    4. associate-/r*98.1%

      \[\leadsto \color{blue}{\frac{\frac{\pi}{2}}{\left(a + b\right) \cdot \left(a \cdot b\right)}} \]
    5. associate-*r*91.9%

      \[\leadsto \frac{\frac{\pi}{2}}{\color{blue}{\left(\left(a + b\right) \cdot a\right) \cdot b}} \]
  9. Simplified91.9%

    \[\leadsto \color{blue}{\frac{\frac{\pi}{2}}{\left(\left(a + b\right) \cdot a\right) \cdot b}} \]
  10. Taylor expanded in a around 0 63.1%

    \[\leadsto \frac{\frac{\pi}{2}}{\color{blue}{\left(a \cdot b\right)} \cdot b} \]
  11. Step-by-step derivation
    1. div-inv63.1%

      \[\leadsto \frac{\color{blue}{\pi \cdot \frac{1}{2}}}{\left(a \cdot b\right) \cdot b} \]
    2. metadata-eval63.1%

      \[\leadsto \frac{\pi \cdot \color{blue}{0.5}}{\left(a \cdot b\right) \cdot b} \]
    3. *-commutative63.1%

      \[\leadsto \frac{\pi \cdot 0.5}{\color{blue}{b \cdot \left(a \cdot b\right)}} \]
    4. times-frac63.6%

      \[\leadsto \color{blue}{\frac{\pi}{b} \cdot \frac{0.5}{a \cdot b}} \]
  12. Applied egg-rr63.6%

    \[\leadsto \color{blue}{\frac{\pi}{b} \cdot \frac{0.5}{a \cdot b}} \]
  13. Final simplification63.6%

    \[\leadsto \frac{\pi}{b} \cdot \frac{0.5}{a \cdot b} \]
  14. Add Preprocessing

Reproduce

?
herbie shell --seed 2024026 
(FPCore (a b)
  :name "NMSE Section 6.1 mentioned, B"
  :precision binary64
  (* (* (/ PI 2.0) (/ 1.0 (- (* b b) (* a a)))) (- (/ 1.0 a) (/ 1.0 b))))