NMSE Section 6.1 mentioned, B

Percentage Accurate: 78.8% → 99.6%
Time: 4.2s
Alternatives: 7
Speedup: 1.6×

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}

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 7 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: 99.6% accurate, 1.6× speedup?

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

\\
\frac{\pi \cdot \frac{1}{a \cdot b}}{\left(a + b\right) \cdot 2}
\end{array}
Derivation
  1. Initial program 78.8%

    \[\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
  2. Step-by-step derivation
    1. lift-*.f64N/A

      \[\leadsto \color{blue}{\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right)} \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    2. lift-/.f64N/A

      \[\leadsto \left(\frac{\pi}{2} \cdot \color{blue}{\frac{1}{b \cdot b - a \cdot a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    3. lift-*.f64N/A

      \[\leadsto \left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - \color{blue}{a \cdot a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    4. lift--.f64N/A

      \[\leadsto \left(\frac{\pi}{2} \cdot \frac{1}{\color{blue}{b \cdot b - a \cdot a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    5. lift-*.f64N/A

      \[\leadsto \left(\frac{\pi}{2} \cdot \frac{1}{\color{blue}{b \cdot b} - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    6. associate-*r/N/A

      \[\leadsto \color{blue}{\frac{\frac{\pi}{2} \cdot 1}{b \cdot b - a \cdot a}} \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    7. difference-of-squaresN/A

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

      \[\leadsto \color{blue}{\left(\frac{\frac{\pi}{2}}{b + a} \cdot \frac{1}{b - a}\right)} \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    9. lower-*.f64N/A

      \[\leadsto \color{blue}{\left(\frac{\frac{\pi}{2}}{b + a} \cdot \frac{1}{b - a}\right)} \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    10. lower-/.f64N/A

      \[\leadsto \left(\color{blue}{\frac{\frac{\pi}{2}}{b + a}} \cdot \frac{1}{b - a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    11. lower-+.f64N/A

      \[\leadsto \left(\frac{\frac{\pi}{2}}{\color{blue}{b + a}} \cdot \frac{1}{b - a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    12. lower-/.f64N/A

      \[\leadsto \left(\frac{\frac{\pi}{2}}{b + a} \cdot \color{blue}{\frac{1}{b - a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    13. lower--.f6488.0

      \[\leadsto \left(\frac{\frac{\pi}{2}}{b + a} \cdot \frac{1}{\color{blue}{b - a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
  3. Applied rewrites88.0%

    \[\leadsto \color{blue}{\left(\frac{\frac{\pi}{2}}{b + a} \cdot \frac{1}{b - a}\right)} \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
  4. Step-by-step derivation
    1. lift-*.f64N/A

      \[\leadsto \color{blue}{\left(\frac{\frac{\pi}{2}}{b + a} \cdot \frac{1}{b - a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right)} \]
    2. lift-*.f64N/A

      \[\leadsto \color{blue}{\left(\frac{\frac{\pi}{2}}{b + a} \cdot \frac{1}{b - a}\right)} \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    3. lift-+.f64N/A

      \[\leadsto \left(\frac{\frac{\pi}{2}}{\color{blue}{b + a}} \cdot \frac{1}{b - a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    4. lift-/.f64N/A

      \[\leadsto \left(\color{blue}{\frac{\frac{\pi}{2}}{b + a}} \cdot \frac{1}{b - a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    5. lift-PI.f64N/A

      \[\leadsto \left(\frac{\frac{\color{blue}{\mathsf{PI}\left(\right)}}{2}}{b + a} \cdot \frac{1}{b - a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    6. lift-/.f64N/A

      \[\leadsto \left(\frac{\color{blue}{\frac{\mathsf{PI}\left(\right)}{2}}}{b + a} \cdot \frac{1}{b - a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    7. lift--.f64N/A

      \[\leadsto \left(\frac{\frac{\mathsf{PI}\left(\right)}{2}}{b + a} \cdot \frac{1}{\color{blue}{b - a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    8. lift-/.f64N/A

      \[\leadsto \left(\frac{\frac{\mathsf{PI}\left(\right)}{2}}{b + a} \cdot \color{blue}{\frac{1}{b - a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    9. lift--.f64N/A

      \[\leadsto \left(\frac{\frac{\mathsf{PI}\left(\right)}{2}}{b + a} \cdot \frac{1}{b - a}\right) \cdot \color{blue}{\left(\frac{1}{a} - \frac{1}{b}\right)} \]
    10. lift-/.f64N/A

      \[\leadsto \left(\frac{\frac{\mathsf{PI}\left(\right)}{2}}{b + a} \cdot \frac{1}{b - a}\right) \cdot \left(\color{blue}{\frac{1}{a}} - \frac{1}{b}\right) \]
    11. lift-/.f64N/A

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

      \[\leadsto \color{blue}{\frac{\frac{\mathsf{PI}\left(\right)}{2}}{b + a} \cdot \left(\frac{1}{b - a} \cdot \left(\frac{1}{a} - \frac{1}{b}\right)\right)} \]
    13. lower-*.f64N/A

      \[\leadsto \color{blue}{\frac{\frac{\mathsf{PI}\left(\right)}{2}}{b + a} \cdot \left(\frac{1}{b - a} \cdot \left(\frac{1}{a} - \frac{1}{b}\right)\right)} \]
  5. Applied rewrites99.6%

    \[\leadsto \color{blue}{\frac{\pi}{2 \cdot \left(b + a\right)} \cdot \left(\frac{1}{b - a} \cdot \left(\frac{1}{a} - \frac{1}{b}\right)\right)} \]
  6. Taylor expanded in a around 0

    \[\leadsto \frac{\pi}{2 \cdot \left(b + a\right)} \cdot \color{blue}{\frac{1}{a \cdot b}} \]
  7. Step-by-step derivation
    1. lower-/.f64N/A

      \[\leadsto \frac{\pi}{2 \cdot \left(b + a\right)} \cdot \frac{1}{\color{blue}{a \cdot b}} \]
    2. lift-*.f6499.6

      \[\leadsto \frac{\pi}{2 \cdot \left(b + a\right)} \cdot \frac{1}{a \cdot \color{blue}{b}} \]
  8. Applied rewrites99.6%

    \[\leadsto \frac{\pi}{2 \cdot \left(b + a\right)} \cdot \color{blue}{\frac{1}{a \cdot b}} \]
  9. Step-by-step derivation
    1. lift-*.f64N/A

      \[\leadsto \color{blue}{\frac{\pi}{2 \cdot \left(b + a\right)} \cdot \frac{1}{a \cdot b}} \]
    2. lift-PI.f64N/A

      \[\leadsto \frac{\color{blue}{\mathsf{PI}\left(\right)}}{2 \cdot \left(b + a\right)} \cdot \frac{1}{a \cdot b} \]
    3. lift-/.f64N/A

      \[\leadsto \color{blue}{\frac{\mathsf{PI}\left(\right)}{2 \cdot \left(b + a\right)}} \cdot \frac{1}{a \cdot b} \]
    4. lift-*.f64N/A

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

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

      \[\leadsto \color{blue}{\frac{\mathsf{PI}\left(\right) \cdot \frac{1}{a \cdot b}}{2 \cdot \left(b + a\right)}} \]
    7. lower-/.f64N/A

      \[\leadsto \color{blue}{\frac{\mathsf{PI}\left(\right) \cdot \frac{1}{a \cdot b}}{2 \cdot \left(b + a\right)}} \]
    8. lower-*.f64N/A

      \[\leadsto \frac{\color{blue}{\mathsf{PI}\left(\right) \cdot \frac{1}{a \cdot b}}}{2 \cdot \left(b + a\right)} \]
    9. lift-PI.f64N/A

      \[\leadsto \frac{\color{blue}{\pi} \cdot \frac{1}{a \cdot b}}{2 \cdot \left(b + a\right)} \]
    10. *-commutativeN/A

      \[\leadsto \frac{\pi \cdot \frac{1}{a \cdot b}}{\color{blue}{\left(b + a\right) \cdot 2}} \]
    11. lower-*.f64N/A

      \[\leadsto \frac{\pi \cdot \frac{1}{a \cdot b}}{\color{blue}{\left(b + a\right) \cdot 2}} \]
    12. +-commutativeN/A

      \[\leadsto \frac{\pi \cdot \frac{1}{a \cdot b}}{\color{blue}{\left(a + b\right)} \cdot 2} \]
    13. lower-+.f6499.6

      \[\leadsto \frac{\pi \cdot \frac{1}{a \cdot b}}{\color{blue}{\left(a + b\right)} \cdot 2} \]
  10. Applied rewrites99.6%

    \[\leadsto \color{blue}{\frac{\pi \cdot \frac{1}{a \cdot b}}{\left(a + b\right) \cdot 2}} \]
  11. Add Preprocessing

Alternative 2: 99.6% accurate, 1.6× speedup?

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

\\
\frac{\pi}{2 \cdot \left(b + a\right)} \cdot \frac{1}{a \cdot b}
\end{array}
Derivation
  1. Initial program 78.8%

    \[\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
  2. Step-by-step derivation
    1. lift-*.f64N/A

      \[\leadsto \color{blue}{\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right)} \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    2. lift-/.f64N/A

      \[\leadsto \left(\frac{\pi}{2} \cdot \color{blue}{\frac{1}{b \cdot b - a \cdot a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    3. lift-*.f64N/A

      \[\leadsto \left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - \color{blue}{a \cdot a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    4. lift--.f64N/A

      \[\leadsto \left(\frac{\pi}{2} \cdot \frac{1}{\color{blue}{b \cdot b - a \cdot a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    5. lift-*.f64N/A

      \[\leadsto \left(\frac{\pi}{2} \cdot \frac{1}{\color{blue}{b \cdot b} - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    6. associate-*r/N/A

      \[\leadsto \color{blue}{\frac{\frac{\pi}{2} \cdot 1}{b \cdot b - a \cdot a}} \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    7. difference-of-squaresN/A

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

      \[\leadsto \color{blue}{\left(\frac{\frac{\pi}{2}}{b + a} \cdot \frac{1}{b - a}\right)} \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    9. lower-*.f64N/A

      \[\leadsto \color{blue}{\left(\frac{\frac{\pi}{2}}{b + a} \cdot \frac{1}{b - a}\right)} \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    10. lower-/.f64N/A

      \[\leadsto \left(\color{blue}{\frac{\frac{\pi}{2}}{b + a}} \cdot \frac{1}{b - a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    11. lower-+.f64N/A

      \[\leadsto \left(\frac{\frac{\pi}{2}}{\color{blue}{b + a}} \cdot \frac{1}{b - a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    12. lower-/.f64N/A

      \[\leadsto \left(\frac{\frac{\pi}{2}}{b + a} \cdot \color{blue}{\frac{1}{b - a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    13. lower--.f6488.0

      \[\leadsto \left(\frac{\frac{\pi}{2}}{b + a} \cdot \frac{1}{\color{blue}{b - a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
  3. Applied rewrites88.0%

    \[\leadsto \color{blue}{\left(\frac{\frac{\pi}{2}}{b + a} \cdot \frac{1}{b - a}\right)} \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
  4. Step-by-step derivation
    1. lift-*.f64N/A

      \[\leadsto \color{blue}{\left(\frac{\frac{\pi}{2}}{b + a} \cdot \frac{1}{b - a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right)} \]
    2. lift-*.f64N/A

      \[\leadsto \color{blue}{\left(\frac{\frac{\pi}{2}}{b + a} \cdot \frac{1}{b - a}\right)} \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    3. lift-+.f64N/A

      \[\leadsto \left(\frac{\frac{\pi}{2}}{\color{blue}{b + a}} \cdot \frac{1}{b - a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    4. lift-/.f64N/A

      \[\leadsto \left(\color{blue}{\frac{\frac{\pi}{2}}{b + a}} \cdot \frac{1}{b - a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    5. lift-PI.f64N/A

      \[\leadsto \left(\frac{\frac{\color{blue}{\mathsf{PI}\left(\right)}}{2}}{b + a} \cdot \frac{1}{b - a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    6. lift-/.f64N/A

      \[\leadsto \left(\frac{\color{blue}{\frac{\mathsf{PI}\left(\right)}{2}}}{b + a} \cdot \frac{1}{b - a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    7. lift--.f64N/A

      \[\leadsto \left(\frac{\frac{\mathsf{PI}\left(\right)}{2}}{b + a} \cdot \frac{1}{\color{blue}{b - a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    8. lift-/.f64N/A

      \[\leadsto \left(\frac{\frac{\mathsf{PI}\left(\right)}{2}}{b + a} \cdot \color{blue}{\frac{1}{b - a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    9. lift--.f64N/A

      \[\leadsto \left(\frac{\frac{\mathsf{PI}\left(\right)}{2}}{b + a} \cdot \frac{1}{b - a}\right) \cdot \color{blue}{\left(\frac{1}{a} - \frac{1}{b}\right)} \]
    10. lift-/.f64N/A

      \[\leadsto \left(\frac{\frac{\mathsf{PI}\left(\right)}{2}}{b + a} \cdot \frac{1}{b - a}\right) \cdot \left(\color{blue}{\frac{1}{a}} - \frac{1}{b}\right) \]
    11. lift-/.f64N/A

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

      \[\leadsto \color{blue}{\frac{\frac{\mathsf{PI}\left(\right)}{2}}{b + a} \cdot \left(\frac{1}{b - a} \cdot \left(\frac{1}{a} - \frac{1}{b}\right)\right)} \]
    13. lower-*.f64N/A

      \[\leadsto \color{blue}{\frac{\frac{\mathsf{PI}\left(\right)}{2}}{b + a} \cdot \left(\frac{1}{b - a} \cdot \left(\frac{1}{a} - \frac{1}{b}\right)\right)} \]
  5. Applied rewrites99.6%

    \[\leadsto \color{blue}{\frac{\pi}{2 \cdot \left(b + a\right)} \cdot \left(\frac{1}{b - a} \cdot \left(\frac{1}{a} - \frac{1}{b}\right)\right)} \]
  6. Taylor expanded in a around 0

    \[\leadsto \frac{\pi}{2 \cdot \left(b + a\right)} \cdot \color{blue}{\frac{1}{a \cdot b}} \]
  7. Step-by-step derivation
    1. lower-/.f64N/A

      \[\leadsto \frac{\pi}{2 \cdot \left(b + a\right)} \cdot \frac{1}{\color{blue}{a \cdot b}} \]
    2. lift-*.f6499.6

      \[\leadsto \frac{\pi}{2 \cdot \left(b + a\right)} \cdot \frac{1}{a \cdot \color{blue}{b}} \]
  8. Applied rewrites99.6%

    \[\leadsto \frac{\pi}{2 \cdot \left(b + a\right)} \cdot \color{blue}{\frac{1}{a \cdot b}} \]
  9. Add Preprocessing

Alternative 3: 74.8% accurate, 1.6× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;a \leq -1.45 \cdot 10^{-44}:\\ \;\;\;\;\frac{\frac{\pi}{a}}{a \cdot b} \cdot 0.5\\ \mathbf{else}:\\ \;\;\;\;\frac{\pi}{b + b} \cdot \frac{1}{a \cdot b}\\ \end{array} \end{array} \]
(FPCore (a b)
 :precision binary64
 (if (<= a -1.45e-44)
   (* (/ (/ PI a) (* a b)) 0.5)
   (* (/ PI (+ b b)) (/ 1.0 (* a b)))))
double code(double a, double b) {
	double tmp;
	if (a <= -1.45e-44) {
		tmp = ((((double) M_PI) / a) / (a * b)) * 0.5;
	} else {
		tmp = (((double) M_PI) / (b + b)) * (1.0 / (a * b));
	}
	return tmp;
}
public static double code(double a, double b) {
	double tmp;
	if (a <= -1.45e-44) {
		tmp = ((Math.PI / a) / (a * b)) * 0.5;
	} else {
		tmp = (Math.PI / (b + b)) * (1.0 / (a * b));
	}
	return tmp;
}
def code(a, b):
	tmp = 0
	if a <= -1.45e-44:
		tmp = ((math.pi / a) / (a * b)) * 0.5
	else:
		tmp = (math.pi / (b + b)) * (1.0 / (a * b))
	return tmp
function code(a, b)
	tmp = 0.0
	if (a <= -1.45e-44)
		tmp = Float64(Float64(Float64(pi / a) / Float64(a * b)) * 0.5);
	else
		tmp = Float64(Float64(pi / Float64(b + b)) * Float64(1.0 / Float64(a * b)));
	end
	return tmp
end
function tmp_2 = code(a, b)
	tmp = 0.0;
	if (a <= -1.45e-44)
		tmp = ((pi / a) / (a * b)) * 0.5;
	else
		tmp = (pi / (b + b)) * (1.0 / (a * b));
	end
	tmp_2 = tmp;
end
code[a_, b_] := If[LessEqual[a, -1.45e-44], N[(N[(N[(Pi / a), $MachinePrecision] / N[(a * b), $MachinePrecision]), $MachinePrecision] * 0.5), $MachinePrecision], N[(N[(Pi / N[(b + b), $MachinePrecision]), $MachinePrecision] * N[(1.0 / N[(a * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;a \leq -1.45 \cdot 10^{-44}:\\
\;\;\;\;\frac{\frac{\pi}{a}}{a \cdot b} \cdot 0.5\\

\mathbf{else}:\\
\;\;\;\;\frac{\pi}{b + b} \cdot \frac{1}{a \cdot b}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if a < -1.4500000000000001e-44

    1. Initial program 78.8%

      \[\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    2. Taylor expanded in a around inf

      \[\leadsto \color{blue}{\frac{1}{2} \cdot \frac{\mathsf{PI}\left(\right)}{{a}^{2} \cdot b}} \]
    3. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \frac{\mathsf{PI}\left(\right)}{{a}^{2} \cdot b} \cdot \color{blue}{\frac{1}{2}} \]
      2. lower-*.f64N/A

        \[\leadsto \frac{\mathsf{PI}\left(\right)}{{a}^{2} \cdot b} \cdot \color{blue}{\frac{1}{2}} \]
      3. lower-/.f64N/A

        \[\leadsto \frac{\mathsf{PI}\left(\right)}{{a}^{2} \cdot b} \cdot \frac{1}{2} \]
      4. lift-PI.f64N/A

        \[\leadsto \frac{\pi}{{a}^{2} \cdot b} \cdot \frac{1}{2} \]
      5. lower-*.f64N/A

        \[\leadsto \frac{\pi}{{a}^{2} \cdot b} \cdot \frac{1}{2} \]
      6. pow2N/A

        \[\leadsto \frac{\pi}{\left(a \cdot a\right) \cdot b} \cdot \frac{1}{2} \]
      7. lift-*.f6456.1

        \[\leadsto \frac{\pi}{\left(a \cdot a\right) \cdot b} \cdot 0.5 \]
    4. Applied rewrites56.1%

      \[\leadsto \color{blue}{\frac{\pi}{\left(a \cdot a\right) \cdot b} \cdot 0.5} \]
    5. Step-by-step derivation
      1. lift-*.f64N/A

        \[\leadsto \frac{\pi}{\left(a \cdot a\right) \cdot b} \cdot \frac{1}{2} \]
      2. lift-*.f64N/A

        \[\leadsto \frac{\pi}{\left(a \cdot a\right) \cdot b} \cdot \frac{1}{2} \]
      3. associate-*l*N/A

        \[\leadsto \frac{\pi}{a \cdot \left(a \cdot b\right)} \cdot \frac{1}{2} \]
      4. lower-*.f64N/A

        \[\leadsto \frac{\pi}{a \cdot \left(a \cdot b\right)} \cdot \frac{1}{2} \]
      5. lower-*.f6462.3

        \[\leadsto \frac{\pi}{a \cdot \left(a \cdot b\right)} \cdot 0.5 \]
    6. Applied rewrites62.3%

      \[\leadsto \frac{\pi}{a \cdot \left(a \cdot b\right)} \cdot 0.5 \]
    7. Step-by-step derivation
      1. lift-PI.f64N/A

        \[\leadsto \frac{\mathsf{PI}\left(\right)}{a \cdot \left(a \cdot b\right)} \cdot \frac{1}{2} \]
      2. lift-/.f64N/A

        \[\leadsto \frac{\mathsf{PI}\left(\right)}{a \cdot \left(a \cdot b\right)} \cdot \frac{1}{2} \]
      3. lift-*.f64N/A

        \[\leadsto \frac{\mathsf{PI}\left(\right)}{a \cdot \left(a \cdot b\right)} \cdot \frac{1}{2} \]
      4. lift-*.f64N/A

        \[\leadsto \frac{\mathsf{PI}\left(\right)}{a \cdot \left(a \cdot b\right)} \cdot \frac{1}{2} \]
      5. associate-/r*N/A

        \[\leadsto \frac{\frac{\mathsf{PI}\left(\right)}{a}}{a \cdot b} \cdot \frac{1}{2} \]
      6. lower-/.f64N/A

        \[\leadsto \frac{\frac{\mathsf{PI}\left(\right)}{a}}{a \cdot b} \cdot \frac{1}{2} \]
      7. lower-/.f64N/A

        \[\leadsto \frac{\frac{\mathsf{PI}\left(\right)}{a}}{a \cdot b} \cdot \frac{1}{2} \]
      8. lift-PI.f64N/A

        \[\leadsto \frac{\frac{\pi}{a}}{a \cdot b} \cdot \frac{1}{2} \]
      9. lift-*.f6462.5

        \[\leadsto \frac{\frac{\pi}{a}}{a \cdot b} \cdot 0.5 \]
    8. Applied rewrites62.5%

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

    if -1.4500000000000001e-44 < a

    1. Initial program 78.8%

      \[\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    2. Step-by-step derivation
      1. lift-*.f64N/A

        \[\leadsto \color{blue}{\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right)} \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      2. lift-/.f64N/A

        \[\leadsto \left(\frac{\pi}{2} \cdot \color{blue}{\frac{1}{b \cdot b - a \cdot a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      3. lift-*.f64N/A

        \[\leadsto \left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - \color{blue}{a \cdot a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      4. lift--.f64N/A

        \[\leadsto \left(\frac{\pi}{2} \cdot \frac{1}{\color{blue}{b \cdot b - a \cdot a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      5. lift-*.f64N/A

        \[\leadsto \left(\frac{\pi}{2} \cdot \frac{1}{\color{blue}{b \cdot b} - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      6. associate-*r/N/A

        \[\leadsto \color{blue}{\frac{\frac{\pi}{2} \cdot 1}{b \cdot b - a \cdot a}} \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      7. difference-of-squaresN/A

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

        \[\leadsto \color{blue}{\left(\frac{\frac{\pi}{2}}{b + a} \cdot \frac{1}{b - a}\right)} \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      9. lower-*.f64N/A

        \[\leadsto \color{blue}{\left(\frac{\frac{\pi}{2}}{b + a} \cdot \frac{1}{b - a}\right)} \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      10. lower-/.f64N/A

        \[\leadsto \left(\color{blue}{\frac{\frac{\pi}{2}}{b + a}} \cdot \frac{1}{b - a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      11. lower-+.f64N/A

        \[\leadsto \left(\frac{\frac{\pi}{2}}{\color{blue}{b + a}} \cdot \frac{1}{b - a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      12. lower-/.f64N/A

        \[\leadsto \left(\frac{\frac{\pi}{2}}{b + a} \cdot \color{blue}{\frac{1}{b - a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      13. lower--.f6488.0

        \[\leadsto \left(\frac{\frac{\pi}{2}}{b + a} \cdot \frac{1}{\color{blue}{b - a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    3. Applied rewrites88.0%

      \[\leadsto \color{blue}{\left(\frac{\frac{\pi}{2}}{b + a} \cdot \frac{1}{b - a}\right)} \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    4. Step-by-step derivation
      1. lift-*.f64N/A

        \[\leadsto \color{blue}{\left(\frac{\frac{\pi}{2}}{b + a} \cdot \frac{1}{b - a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right)} \]
      2. lift-*.f64N/A

        \[\leadsto \color{blue}{\left(\frac{\frac{\pi}{2}}{b + a} \cdot \frac{1}{b - a}\right)} \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      3. lift-+.f64N/A

        \[\leadsto \left(\frac{\frac{\pi}{2}}{\color{blue}{b + a}} \cdot \frac{1}{b - a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      4. lift-/.f64N/A

        \[\leadsto \left(\color{blue}{\frac{\frac{\pi}{2}}{b + a}} \cdot \frac{1}{b - a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      5. lift-PI.f64N/A

        \[\leadsto \left(\frac{\frac{\color{blue}{\mathsf{PI}\left(\right)}}{2}}{b + a} \cdot \frac{1}{b - a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      6. lift-/.f64N/A

        \[\leadsto \left(\frac{\color{blue}{\frac{\mathsf{PI}\left(\right)}{2}}}{b + a} \cdot \frac{1}{b - a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      7. lift--.f64N/A

        \[\leadsto \left(\frac{\frac{\mathsf{PI}\left(\right)}{2}}{b + a} \cdot \frac{1}{\color{blue}{b - a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      8. lift-/.f64N/A

        \[\leadsto \left(\frac{\frac{\mathsf{PI}\left(\right)}{2}}{b + a} \cdot \color{blue}{\frac{1}{b - a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      9. lift--.f64N/A

        \[\leadsto \left(\frac{\frac{\mathsf{PI}\left(\right)}{2}}{b + a} \cdot \frac{1}{b - a}\right) \cdot \color{blue}{\left(\frac{1}{a} - \frac{1}{b}\right)} \]
      10. lift-/.f64N/A

        \[\leadsto \left(\frac{\frac{\mathsf{PI}\left(\right)}{2}}{b + a} \cdot \frac{1}{b - a}\right) \cdot \left(\color{blue}{\frac{1}{a}} - \frac{1}{b}\right) \]
      11. lift-/.f64N/A

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

        \[\leadsto \color{blue}{\frac{\frac{\mathsf{PI}\left(\right)}{2}}{b + a} \cdot \left(\frac{1}{b - a} \cdot \left(\frac{1}{a} - \frac{1}{b}\right)\right)} \]
      13. lower-*.f64N/A

        \[\leadsto \color{blue}{\frac{\frac{\mathsf{PI}\left(\right)}{2}}{b + a} \cdot \left(\frac{1}{b - a} \cdot \left(\frac{1}{a} - \frac{1}{b}\right)\right)} \]
    5. Applied rewrites99.6%

      \[\leadsto \color{blue}{\frac{\pi}{2 \cdot \left(b + a\right)} \cdot \left(\frac{1}{b - a} \cdot \left(\frac{1}{a} - \frac{1}{b}\right)\right)} \]
    6. Taylor expanded in a around 0

      \[\leadsto \frac{\pi}{2 \cdot \left(b + a\right)} \cdot \color{blue}{\frac{1}{a \cdot b}} \]
    7. Step-by-step derivation
      1. lower-/.f64N/A

        \[\leadsto \frac{\pi}{2 \cdot \left(b + a\right)} \cdot \frac{1}{\color{blue}{a \cdot b}} \]
      2. lift-*.f6499.6

        \[\leadsto \frac{\pi}{2 \cdot \left(b + a\right)} \cdot \frac{1}{a \cdot \color{blue}{b}} \]
    8. Applied rewrites99.6%

      \[\leadsto \frac{\pi}{2 \cdot \left(b + a\right)} \cdot \color{blue}{\frac{1}{a \cdot b}} \]
    9. Taylor expanded in a around 0

      \[\leadsto \frac{\pi}{\color{blue}{2 \cdot b}} \cdot \frac{1}{a \cdot b} \]
    10. Step-by-step derivation
      1. count-2-revN/A

        \[\leadsto \frac{\pi}{b + \color{blue}{b}} \cdot \frac{1}{a \cdot b} \]
      2. lower-+.f6463.0

        \[\leadsto \frac{\pi}{b + \color{blue}{b}} \cdot \frac{1}{a \cdot b} \]
    11. Applied rewrites63.0%

      \[\leadsto \frac{\pi}{\color{blue}{b + b}} \cdot \frac{1}{a \cdot b} \]
  3. Recombined 2 regimes into one program.
  4. Add Preprocessing

Alternative 4: 74.6% accurate, 1.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;a \leq -1.45 \cdot 10^{-44}:\\ \;\;\;\;\frac{\frac{\pi}{a}}{a \cdot b} \cdot 0.5\\ \mathbf{else}:\\ \;\;\;\;\frac{\pi}{b \cdot \left(a \cdot b\right)} \cdot 0.5\\ \end{array} \end{array} \]
(FPCore (a b)
 :precision binary64
 (if (<= a -1.45e-44)
   (* (/ (/ PI a) (* a b)) 0.5)
   (* (/ PI (* b (* a b))) 0.5)))
double code(double a, double b) {
	double tmp;
	if (a <= -1.45e-44) {
		tmp = ((((double) M_PI) / a) / (a * b)) * 0.5;
	} else {
		tmp = (((double) M_PI) / (b * (a * b))) * 0.5;
	}
	return tmp;
}
public static double code(double a, double b) {
	double tmp;
	if (a <= -1.45e-44) {
		tmp = ((Math.PI / a) / (a * b)) * 0.5;
	} else {
		tmp = (Math.PI / (b * (a * b))) * 0.5;
	}
	return tmp;
}
def code(a, b):
	tmp = 0
	if a <= -1.45e-44:
		tmp = ((math.pi / a) / (a * b)) * 0.5
	else:
		tmp = (math.pi / (b * (a * b))) * 0.5
	return tmp
function code(a, b)
	tmp = 0.0
	if (a <= -1.45e-44)
		tmp = Float64(Float64(Float64(pi / a) / Float64(a * b)) * 0.5);
	else
		tmp = Float64(Float64(pi / Float64(b * Float64(a * b))) * 0.5);
	end
	return tmp
end
function tmp_2 = code(a, b)
	tmp = 0.0;
	if (a <= -1.45e-44)
		tmp = ((pi / a) / (a * b)) * 0.5;
	else
		tmp = (pi / (b * (a * b))) * 0.5;
	end
	tmp_2 = tmp;
end
code[a_, b_] := If[LessEqual[a, -1.45e-44], N[(N[(N[(Pi / a), $MachinePrecision] / N[(a * b), $MachinePrecision]), $MachinePrecision] * 0.5), $MachinePrecision], N[(N[(Pi / N[(b * N[(a * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * 0.5), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;a \leq -1.45 \cdot 10^{-44}:\\
\;\;\;\;\frac{\frac{\pi}{a}}{a \cdot b} \cdot 0.5\\

\mathbf{else}:\\
\;\;\;\;\frac{\pi}{b \cdot \left(a \cdot b\right)} \cdot 0.5\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if a < -1.4500000000000001e-44

    1. Initial program 78.8%

      \[\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    2. Taylor expanded in a around inf

      \[\leadsto \color{blue}{\frac{1}{2} \cdot \frac{\mathsf{PI}\left(\right)}{{a}^{2} \cdot b}} \]
    3. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \frac{\mathsf{PI}\left(\right)}{{a}^{2} \cdot b} \cdot \color{blue}{\frac{1}{2}} \]
      2. lower-*.f64N/A

        \[\leadsto \frac{\mathsf{PI}\left(\right)}{{a}^{2} \cdot b} \cdot \color{blue}{\frac{1}{2}} \]
      3. lower-/.f64N/A

        \[\leadsto \frac{\mathsf{PI}\left(\right)}{{a}^{2} \cdot b} \cdot \frac{1}{2} \]
      4. lift-PI.f64N/A

        \[\leadsto \frac{\pi}{{a}^{2} \cdot b} \cdot \frac{1}{2} \]
      5. lower-*.f64N/A

        \[\leadsto \frac{\pi}{{a}^{2} \cdot b} \cdot \frac{1}{2} \]
      6. pow2N/A

        \[\leadsto \frac{\pi}{\left(a \cdot a\right) \cdot b} \cdot \frac{1}{2} \]
      7. lift-*.f6456.1

        \[\leadsto \frac{\pi}{\left(a \cdot a\right) \cdot b} \cdot 0.5 \]
    4. Applied rewrites56.1%

      \[\leadsto \color{blue}{\frac{\pi}{\left(a \cdot a\right) \cdot b} \cdot 0.5} \]
    5. Step-by-step derivation
      1. lift-*.f64N/A

        \[\leadsto \frac{\pi}{\left(a \cdot a\right) \cdot b} \cdot \frac{1}{2} \]
      2. lift-*.f64N/A

        \[\leadsto \frac{\pi}{\left(a \cdot a\right) \cdot b} \cdot \frac{1}{2} \]
      3. associate-*l*N/A

        \[\leadsto \frac{\pi}{a \cdot \left(a \cdot b\right)} \cdot \frac{1}{2} \]
      4. lower-*.f64N/A

        \[\leadsto \frac{\pi}{a \cdot \left(a \cdot b\right)} \cdot \frac{1}{2} \]
      5. lower-*.f6462.3

        \[\leadsto \frac{\pi}{a \cdot \left(a \cdot b\right)} \cdot 0.5 \]
    6. Applied rewrites62.3%

      \[\leadsto \frac{\pi}{a \cdot \left(a \cdot b\right)} \cdot 0.5 \]
    7. Step-by-step derivation
      1. lift-PI.f64N/A

        \[\leadsto \frac{\mathsf{PI}\left(\right)}{a \cdot \left(a \cdot b\right)} \cdot \frac{1}{2} \]
      2. lift-/.f64N/A

        \[\leadsto \frac{\mathsf{PI}\left(\right)}{a \cdot \left(a \cdot b\right)} \cdot \frac{1}{2} \]
      3. lift-*.f64N/A

        \[\leadsto \frac{\mathsf{PI}\left(\right)}{a \cdot \left(a \cdot b\right)} \cdot \frac{1}{2} \]
      4. lift-*.f64N/A

        \[\leadsto \frac{\mathsf{PI}\left(\right)}{a \cdot \left(a \cdot b\right)} \cdot \frac{1}{2} \]
      5. associate-/r*N/A

        \[\leadsto \frac{\frac{\mathsf{PI}\left(\right)}{a}}{a \cdot b} \cdot \frac{1}{2} \]
      6. lower-/.f64N/A

        \[\leadsto \frac{\frac{\mathsf{PI}\left(\right)}{a}}{a \cdot b} \cdot \frac{1}{2} \]
      7. lower-/.f64N/A

        \[\leadsto \frac{\frac{\mathsf{PI}\left(\right)}{a}}{a \cdot b} \cdot \frac{1}{2} \]
      8. lift-PI.f64N/A

        \[\leadsto \frac{\frac{\pi}{a}}{a \cdot b} \cdot \frac{1}{2} \]
      9. lift-*.f6462.5

        \[\leadsto \frac{\frac{\pi}{a}}{a \cdot b} \cdot 0.5 \]
    8. Applied rewrites62.5%

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

    if -1.4500000000000001e-44 < a

    1. Initial program 78.8%

      \[\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    2. Step-by-step derivation
      1. lift-*.f64N/A

        \[\leadsto \color{blue}{\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right)} \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      2. lift-/.f64N/A

        \[\leadsto \left(\frac{\pi}{2} \cdot \color{blue}{\frac{1}{b \cdot b - a \cdot a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      3. lift-*.f64N/A

        \[\leadsto \left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - \color{blue}{a \cdot a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      4. lift--.f64N/A

        \[\leadsto \left(\frac{\pi}{2} \cdot \frac{1}{\color{blue}{b \cdot b - a \cdot a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      5. lift-*.f64N/A

        \[\leadsto \left(\frac{\pi}{2} \cdot \frac{1}{\color{blue}{b \cdot b} - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      6. associate-*r/N/A

        \[\leadsto \color{blue}{\frac{\frac{\pi}{2} \cdot 1}{b \cdot b - a \cdot a}} \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      7. difference-of-squaresN/A

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

        \[\leadsto \color{blue}{\left(\frac{\frac{\pi}{2}}{b + a} \cdot \frac{1}{b - a}\right)} \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      9. lower-*.f64N/A

        \[\leadsto \color{blue}{\left(\frac{\frac{\pi}{2}}{b + a} \cdot \frac{1}{b - a}\right)} \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      10. lower-/.f64N/A

        \[\leadsto \left(\color{blue}{\frac{\frac{\pi}{2}}{b + a}} \cdot \frac{1}{b - a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      11. lower-+.f64N/A

        \[\leadsto \left(\frac{\frac{\pi}{2}}{\color{blue}{b + a}} \cdot \frac{1}{b - a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      12. lower-/.f64N/A

        \[\leadsto \left(\frac{\frac{\pi}{2}}{b + a} \cdot \color{blue}{\frac{1}{b - a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      13. lower--.f6488.0

        \[\leadsto \left(\frac{\frac{\pi}{2}}{b + a} \cdot \frac{1}{\color{blue}{b - a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    3. Applied rewrites88.0%

      \[\leadsto \color{blue}{\left(\frac{\frac{\pi}{2}}{b + a} \cdot \frac{1}{b - a}\right)} \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    4. Step-by-step derivation
      1. lift-*.f64N/A

        \[\leadsto \color{blue}{\left(\frac{\frac{\pi}{2}}{b + a} \cdot \frac{1}{b - a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right)} \]
      2. lift-*.f64N/A

        \[\leadsto \color{blue}{\left(\frac{\frac{\pi}{2}}{b + a} \cdot \frac{1}{b - a}\right)} \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      3. lift-+.f64N/A

        \[\leadsto \left(\frac{\frac{\pi}{2}}{\color{blue}{b + a}} \cdot \frac{1}{b - a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      4. lift-/.f64N/A

        \[\leadsto \left(\color{blue}{\frac{\frac{\pi}{2}}{b + a}} \cdot \frac{1}{b - a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      5. lift-PI.f64N/A

        \[\leadsto \left(\frac{\frac{\color{blue}{\mathsf{PI}\left(\right)}}{2}}{b + a} \cdot \frac{1}{b - a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      6. lift-/.f64N/A

        \[\leadsto \left(\frac{\color{blue}{\frac{\mathsf{PI}\left(\right)}{2}}}{b + a} \cdot \frac{1}{b - a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      7. lift--.f64N/A

        \[\leadsto \left(\frac{\frac{\mathsf{PI}\left(\right)}{2}}{b + a} \cdot \frac{1}{\color{blue}{b - a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      8. lift-/.f64N/A

        \[\leadsto \left(\frac{\frac{\mathsf{PI}\left(\right)}{2}}{b + a} \cdot \color{blue}{\frac{1}{b - a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      9. lift--.f64N/A

        \[\leadsto \left(\frac{\frac{\mathsf{PI}\left(\right)}{2}}{b + a} \cdot \frac{1}{b - a}\right) \cdot \color{blue}{\left(\frac{1}{a} - \frac{1}{b}\right)} \]
      10. lift-/.f64N/A

        \[\leadsto \left(\frac{\frac{\mathsf{PI}\left(\right)}{2}}{b + a} \cdot \frac{1}{b - a}\right) \cdot \left(\color{blue}{\frac{1}{a}} - \frac{1}{b}\right) \]
      11. lift-/.f64N/A

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

        \[\leadsto \color{blue}{\frac{\frac{\mathsf{PI}\left(\right)}{2}}{b + a} \cdot \left(\frac{1}{b - a} \cdot \left(\frac{1}{a} - \frac{1}{b}\right)\right)} \]
      13. lower-*.f64N/A

        \[\leadsto \color{blue}{\frac{\frac{\mathsf{PI}\left(\right)}{2}}{b + a} \cdot \left(\frac{1}{b - a} \cdot \left(\frac{1}{a} - \frac{1}{b}\right)\right)} \]
    5. Applied rewrites99.6%

      \[\leadsto \color{blue}{\frac{\pi}{2 \cdot \left(b + a\right)} \cdot \left(\frac{1}{b - a} \cdot \left(\frac{1}{a} - \frac{1}{b}\right)\right)} \]
    6. Taylor expanded in a around 0

      \[\leadsto \color{blue}{\frac{1}{2} \cdot \frac{\mathsf{PI}\left(\right)}{a \cdot {b}^{2}}} \]
    7. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \frac{\mathsf{PI}\left(\right)}{a \cdot {b}^{2}} \cdot \color{blue}{\frac{1}{2}} \]
      2. lower-*.f64N/A

        \[\leadsto \frac{\mathsf{PI}\left(\right)}{a \cdot {b}^{2}} \cdot \color{blue}{\frac{1}{2}} \]
      3. lower-/.f64N/A

        \[\leadsto \frac{\mathsf{PI}\left(\right)}{a \cdot {b}^{2}} \cdot \frac{1}{2} \]
      4. lift-PI.f64N/A

        \[\leadsto \frac{\pi}{a \cdot {b}^{2}} \cdot \frac{1}{2} \]
      5. *-commutativeN/A

        \[\leadsto \frac{\pi}{{b}^{2} \cdot a} \cdot \frac{1}{2} \]
      6. lower-*.f64N/A

        \[\leadsto \frac{\pi}{{b}^{2} \cdot a} \cdot \frac{1}{2} \]
      7. pow2N/A

        \[\leadsto \frac{\pi}{\left(b \cdot b\right) \cdot a} \cdot \frac{1}{2} \]
      8. lift-*.f6457.1

        \[\leadsto \frac{\pi}{\left(b \cdot b\right) \cdot a} \cdot 0.5 \]
    8. Applied rewrites57.1%

      \[\leadsto \color{blue}{\frac{\pi}{\left(b \cdot b\right) \cdot a} \cdot 0.5} \]
    9. Step-by-step derivation
      1. lift-*.f64N/A

        \[\leadsto \frac{\pi}{\left(b \cdot b\right) \cdot a} \cdot \frac{1}{2} \]
      2. lift-*.f64N/A

        \[\leadsto \frac{\pi}{\left(b \cdot b\right) \cdot a} \cdot \frac{1}{2} \]
      3. associate-*l*N/A

        \[\leadsto \frac{\pi}{b \cdot \left(b \cdot a\right)} \cdot \frac{1}{2} \]
      4. *-commutativeN/A

        \[\leadsto \frac{\pi}{b \cdot \left(a \cdot b\right)} \cdot \frac{1}{2} \]
      5. lower-*.f64N/A

        \[\leadsto \frac{\pi}{b \cdot \left(a \cdot b\right)} \cdot \frac{1}{2} \]
      6. lift-*.f6462.8

        \[\leadsto \frac{\pi}{b \cdot \left(a \cdot b\right)} \cdot 0.5 \]
    10. Applied rewrites62.8%

      \[\leadsto \frac{\pi}{b \cdot \left(a \cdot b\right)} \cdot 0.5 \]
  3. Recombined 2 regimes into one program.
  4. Add Preprocessing

Alternative 5: 74.4% accurate, 1.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;a \leq -1.45 \cdot 10^{-44}:\\ \;\;\;\;\frac{\pi}{a \cdot \left(a \cdot b\right)} \cdot 0.5\\ \mathbf{else}:\\ \;\;\;\;\frac{\pi}{b \cdot \left(a \cdot b\right)} \cdot 0.5\\ \end{array} \end{array} \]
(FPCore (a b)
 :precision binary64
 (if (<= a -1.45e-44)
   (* (/ PI (* a (* a b))) 0.5)
   (* (/ PI (* b (* a b))) 0.5)))
double code(double a, double b) {
	double tmp;
	if (a <= -1.45e-44) {
		tmp = (((double) M_PI) / (a * (a * b))) * 0.5;
	} else {
		tmp = (((double) M_PI) / (b * (a * b))) * 0.5;
	}
	return tmp;
}
public static double code(double a, double b) {
	double tmp;
	if (a <= -1.45e-44) {
		tmp = (Math.PI / (a * (a * b))) * 0.5;
	} else {
		tmp = (Math.PI / (b * (a * b))) * 0.5;
	}
	return tmp;
}
def code(a, b):
	tmp = 0
	if a <= -1.45e-44:
		tmp = (math.pi / (a * (a * b))) * 0.5
	else:
		tmp = (math.pi / (b * (a * b))) * 0.5
	return tmp
function code(a, b)
	tmp = 0.0
	if (a <= -1.45e-44)
		tmp = Float64(Float64(pi / Float64(a * Float64(a * b))) * 0.5);
	else
		tmp = Float64(Float64(pi / Float64(b * Float64(a * b))) * 0.5);
	end
	return tmp
end
function tmp_2 = code(a, b)
	tmp = 0.0;
	if (a <= -1.45e-44)
		tmp = (pi / (a * (a * b))) * 0.5;
	else
		tmp = (pi / (b * (a * b))) * 0.5;
	end
	tmp_2 = tmp;
end
code[a_, b_] := If[LessEqual[a, -1.45e-44], N[(N[(Pi / N[(a * N[(a * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * 0.5), $MachinePrecision], N[(N[(Pi / N[(b * N[(a * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * 0.5), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;a \leq -1.45 \cdot 10^{-44}:\\
\;\;\;\;\frac{\pi}{a \cdot \left(a \cdot b\right)} \cdot 0.5\\

\mathbf{else}:\\
\;\;\;\;\frac{\pi}{b \cdot \left(a \cdot b\right)} \cdot 0.5\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if a < -1.4500000000000001e-44

    1. Initial program 78.8%

      \[\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    2. Taylor expanded in a around inf

      \[\leadsto \color{blue}{\frac{1}{2} \cdot \frac{\mathsf{PI}\left(\right)}{{a}^{2} \cdot b}} \]
    3. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \frac{\mathsf{PI}\left(\right)}{{a}^{2} \cdot b} \cdot \color{blue}{\frac{1}{2}} \]
      2. lower-*.f64N/A

        \[\leadsto \frac{\mathsf{PI}\left(\right)}{{a}^{2} \cdot b} \cdot \color{blue}{\frac{1}{2}} \]
      3. lower-/.f64N/A

        \[\leadsto \frac{\mathsf{PI}\left(\right)}{{a}^{2} \cdot b} \cdot \frac{1}{2} \]
      4. lift-PI.f64N/A

        \[\leadsto \frac{\pi}{{a}^{2} \cdot b} \cdot \frac{1}{2} \]
      5. lower-*.f64N/A

        \[\leadsto \frac{\pi}{{a}^{2} \cdot b} \cdot \frac{1}{2} \]
      6. pow2N/A

        \[\leadsto \frac{\pi}{\left(a \cdot a\right) \cdot b} \cdot \frac{1}{2} \]
      7. lift-*.f6456.1

        \[\leadsto \frac{\pi}{\left(a \cdot a\right) \cdot b} \cdot 0.5 \]
    4. Applied rewrites56.1%

      \[\leadsto \color{blue}{\frac{\pi}{\left(a \cdot a\right) \cdot b} \cdot 0.5} \]
    5. Step-by-step derivation
      1. lift-*.f64N/A

        \[\leadsto \frac{\pi}{\left(a \cdot a\right) \cdot b} \cdot \frac{1}{2} \]
      2. lift-*.f64N/A

        \[\leadsto \frac{\pi}{\left(a \cdot a\right) \cdot b} \cdot \frac{1}{2} \]
      3. associate-*l*N/A

        \[\leadsto \frac{\pi}{a \cdot \left(a \cdot b\right)} \cdot \frac{1}{2} \]
      4. lower-*.f64N/A

        \[\leadsto \frac{\pi}{a \cdot \left(a \cdot b\right)} \cdot \frac{1}{2} \]
      5. lower-*.f6462.3

        \[\leadsto \frac{\pi}{a \cdot \left(a \cdot b\right)} \cdot 0.5 \]
    6. Applied rewrites62.3%

      \[\leadsto \frac{\pi}{a \cdot \left(a \cdot b\right)} \cdot 0.5 \]

    if -1.4500000000000001e-44 < a

    1. Initial program 78.8%

      \[\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    2. Step-by-step derivation
      1. lift-*.f64N/A

        \[\leadsto \color{blue}{\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right)} \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      2. lift-/.f64N/A

        \[\leadsto \left(\frac{\pi}{2} \cdot \color{blue}{\frac{1}{b \cdot b - a \cdot a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      3. lift-*.f64N/A

        \[\leadsto \left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - \color{blue}{a \cdot a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      4. lift--.f64N/A

        \[\leadsto \left(\frac{\pi}{2} \cdot \frac{1}{\color{blue}{b \cdot b - a \cdot a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      5. lift-*.f64N/A

        \[\leadsto \left(\frac{\pi}{2} \cdot \frac{1}{\color{blue}{b \cdot b} - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      6. associate-*r/N/A

        \[\leadsto \color{blue}{\frac{\frac{\pi}{2} \cdot 1}{b \cdot b - a \cdot a}} \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      7. difference-of-squaresN/A

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

        \[\leadsto \color{blue}{\left(\frac{\frac{\pi}{2}}{b + a} \cdot \frac{1}{b - a}\right)} \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      9. lower-*.f64N/A

        \[\leadsto \color{blue}{\left(\frac{\frac{\pi}{2}}{b + a} \cdot \frac{1}{b - a}\right)} \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      10. lower-/.f64N/A

        \[\leadsto \left(\color{blue}{\frac{\frac{\pi}{2}}{b + a}} \cdot \frac{1}{b - a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      11. lower-+.f64N/A

        \[\leadsto \left(\frac{\frac{\pi}{2}}{\color{blue}{b + a}} \cdot \frac{1}{b - a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      12. lower-/.f64N/A

        \[\leadsto \left(\frac{\frac{\pi}{2}}{b + a} \cdot \color{blue}{\frac{1}{b - a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      13. lower--.f6488.0

        \[\leadsto \left(\frac{\frac{\pi}{2}}{b + a} \cdot \frac{1}{\color{blue}{b - a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    3. Applied rewrites88.0%

      \[\leadsto \color{blue}{\left(\frac{\frac{\pi}{2}}{b + a} \cdot \frac{1}{b - a}\right)} \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    4. Step-by-step derivation
      1. lift-*.f64N/A

        \[\leadsto \color{blue}{\left(\frac{\frac{\pi}{2}}{b + a} \cdot \frac{1}{b - a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right)} \]
      2. lift-*.f64N/A

        \[\leadsto \color{blue}{\left(\frac{\frac{\pi}{2}}{b + a} \cdot \frac{1}{b - a}\right)} \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      3. lift-+.f64N/A

        \[\leadsto \left(\frac{\frac{\pi}{2}}{\color{blue}{b + a}} \cdot \frac{1}{b - a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      4. lift-/.f64N/A

        \[\leadsto \left(\color{blue}{\frac{\frac{\pi}{2}}{b + a}} \cdot \frac{1}{b - a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      5. lift-PI.f64N/A

        \[\leadsto \left(\frac{\frac{\color{blue}{\mathsf{PI}\left(\right)}}{2}}{b + a} \cdot \frac{1}{b - a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      6. lift-/.f64N/A

        \[\leadsto \left(\frac{\color{blue}{\frac{\mathsf{PI}\left(\right)}{2}}}{b + a} \cdot \frac{1}{b - a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      7. lift--.f64N/A

        \[\leadsto \left(\frac{\frac{\mathsf{PI}\left(\right)}{2}}{b + a} \cdot \frac{1}{\color{blue}{b - a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      8. lift-/.f64N/A

        \[\leadsto \left(\frac{\frac{\mathsf{PI}\left(\right)}{2}}{b + a} \cdot \color{blue}{\frac{1}{b - a}}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
      9. lift--.f64N/A

        \[\leadsto \left(\frac{\frac{\mathsf{PI}\left(\right)}{2}}{b + a} \cdot \frac{1}{b - a}\right) \cdot \color{blue}{\left(\frac{1}{a} - \frac{1}{b}\right)} \]
      10. lift-/.f64N/A

        \[\leadsto \left(\frac{\frac{\mathsf{PI}\left(\right)}{2}}{b + a} \cdot \frac{1}{b - a}\right) \cdot \left(\color{blue}{\frac{1}{a}} - \frac{1}{b}\right) \]
      11. lift-/.f64N/A

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

        \[\leadsto \color{blue}{\frac{\frac{\mathsf{PI}\left(\right)}{2}}{b + a} \cdot \left(\frac{1}{b - a} \cdot \left(\frac{1}{a} - \frac{1}{b}\right)\right)} \]
      13. lower-*.f64N/A

        \[\leadsto \color{blue}{\frac{\frac{\mathsf{PI}\left(\right)}{2}}{b + a} \cdot \left(\frac{1}{b - a} \cdot \left(\frac{1}{a} - \frac{1}{b}\right)\right)} \]
    5. Applied rewrites99.6%

      \[\leadsto \color{blue}{\frac{\pi}{2 \cdot \left(b + a\right)} \cdot \left(\frac{1}{b - a} \cdot \left(\frac{1}{a} - \frac{1}{b}\right)\right)} \]
    6. Taylor expanded in a around 0

      \[\leadsto \color{blue}{\frac{1}{2} \cdot \frac{\mathsf{PI}\left(\right)}{a \cdot {b}^{2}}} \]
    7. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \frac{\mathsf{PI}\left(\right)}{a \cdot {b}^{2}} \cdot \color{blue}{\frac{1}{2}} \]
      2. lower-*.f64N/A

        \[\leadsto \frac{\mathsf{PI}\left(\right)}{a \cdot {b}^{2}} \cdot \color{blue}{\frac{1}{2}} \]
      3. lower-/.f64N/A

        \[\leadsto \frac{\mathsf{PI}\left(\right)}{a \cdot {b}^{2}} \cdot \frac{1}{2} \]
      4. lift-PI.f64N/A

        \[\leadsto \frac{\pi}{a \cdot {b}^{2}} \cdot \frac{1}{2} \]
      5. *-commutativeN/A

        \[\leadsto \frac{\pi}{{b}^{2} \cdot a} \cdot \frac{1}{2} \]
      6. lower-*.f64N/A

        \[\leadsto \frac{\pi}{{b}^{2} \cdot a} \cdot \frac{1}{2} \]
      7. pow2N/A

        \[\leadsto \frac{\pi}{\left(b \cdot b\right) \cdot a} \cdot \frac{1}{2} \]
      8. lift-*.f6457.1

        \[\leadsto \frac{\pi}{\left(b \cdot b\right) \cdot a} \cdot 0.5 \]
    8. Applied rewrites57.1%

      \[\leadsto \color{blue}{\frac{\pi}{\left(b \cdot b\right) \cdot a} \cdot 0.5} \]
    9. Step-by-step derivation
      1. lift-*.f64N/A

        \[\leadsto \frac{\pi}{\left(b \cdot b\right) \cdot a} \cdot \frac{1}{2} \]
      2. lift-*.f64N/A

        \[\leadsto \frac{\pi}{\left(b \cdot b\right) \cdot a} \cdot \frac{1}{2} \]
      3. associate-*l*N/A

        \[\leadsto \frac{\pi}{b \cdot \left(b \cdot a\right)} \cdot \frac{1}{2} \]
      4. *-commutativeN/A

        \[\leadsto \frac{\pi}{b \cdot \left(a \cdot b\right)} \cdot \frac{1}{2} \]
      5. lower-*.f64N/A

        \[\leadsto \frac{\pi}{b \cdot \left(a \cdot b\right)} \cdot \frac{1}{2} \]
      6. lift-*.f6462.8

        \[\leadsto \frac{\pi}{b \cdot \left(a \cdot b\right)} \cdot 0.5 \]
    10. Applied rewrites62.8%

      \[\leadsto \frac{\pi}{b \cdot \left(a \cdot b\right)} \cdot 0.5 \]
  3. Recombined 2 regimes into one program.
  4. Add Preprocessing

Alternative 6: 68.8% accurate, 1.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;a \leq -9.8 \cdot 10^{-45}:\\ \;\;\;\;\frac{\pi}{a \cdot \left(a \cdot b\right)} \cdot 0.5\\ \mathbf{else}:\\ \;\;\;\;\frac{\pi}{\left(b \cdot b\right) \cdot a} \cdot 0.5\\ \end{array} \end{array} \]
(FPCore (a b)
 :precision binary64
 (if (<= a -9.8e-45)
   (* (/ PI (* a (* a b))) 0.5)
   (* (/ PI (* (* b b) a)) 0.5)))
double code(double a, double b) {
	double tmp;
	if (a <= -9.8e-45) {
		tmp = (((double) M_PI) / (a * (a * b))) * 0.5;
	} else {
		tmp = (((double) M_PI) / ((b * b) * a)) * 0.5;
	}
	return tmp;
}
public static double code(double a, double b) {
	double tmp;
	if (a <= -9.8e-45) {
		tmp = (Math.PI / (a * (a * b))) * 0.5;
	} else {
		tmp = (Math.PI / ((b * b) * a)) * 0.5;
	}
	return tmp;
}
def code(a, b):
	tmp = 0
	if a <= -9.8e-45:
		tmp = (math.pi / (a * (a * b))) * 0.5
	else:
		tmp = (math.pi / ((b * b) * a)) * 0.5
	return tmp
function code(a, b)
	tmp = 0.0
	if (a <= -9.8e-45)
		tmp = Float64(Float64(pi / Float64(a * Float64(a * b))) * 0.5);
	else
		tmp = Float64(Float64(pi / Float64(Float64(b * b) * a)) * 0.5);
	end
	return tmp
end
function tmp_2 = code(a, b)
	tmp = 0.0;
	if (a <= -9.8e-45)
		tmp = (pi / (a * (a * b))) * 0.5;
	else
		tmp = (pi / ((b * b) * a)) * 0.5;
	end
	tmp_2 = tmp;
end
code[a_, b_] := If[LessEqual[a, -9.8e-45], N[(N[(Pi / N[(a * N[(a * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * 0.5), $MachinePrecision], N[(N[(Pi / N[(N[(b * b), $MachinePrecision] * a), $MachinePrecision]), $MachinePrecision] * 0.5), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;a \leq -9.8 \cdot 10^{-45}:\\
\;\;\;\;\frac{\pi}{a \cdot \left(a \cdot b\right)} \cdot 0.5\\

\mathbf{else}:\\
\;\;\;\;\frac{\pi}{\left(b \cdot b\right) \cdot a} \cdot 0.5\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if a < -9.7999999999999996e-45

    1. Initial program 78.8%

      \[\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    2. Taylor expanded in a around inf

      \[\leadsto \color{blue}{\frac{1}{2} \cdot \frac{\mathsf{PI}\left(\right)}{{a}^{2} \cdot b}} \]
    3. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \frac{\mathsf{PI}\left(\right)}{{a}^{2} \cdot b} \cdot \color{blue}{\frac{1}{2}} \]
      2. lower-*.f64N/A

        \[\leadsto \frac{\mathsf{PI}\left(\right)}{{a}^{2} \cdot b} \cdot \color{blue}{\frac{1}{2}} \]
      3. lower-/.f64N/A

        \[\leadsto \frac{\mathsf{PI}\left(\right)}{{a}^{2} \cdot b} \cdot \frac{1}{2} \]
      4. lift-PI.f64N/A

        \[\leadsto \frac{\pi}{{a}^{2} \cdot b} \cdot \frac{1}{2} \]
      5. lower-*.f64N/A

        \[\leadsto \frac{\pi}{{a}^{2} \cdot b} \cdot \frac{1}{2} \]
      6. pow2N/A

        \[\leadsto \frac{\pi}{\left(a \cdot a\right) \cdot b} \cdot \frac{1}{2} \]
      7. lift-*.f6456.1

        \[\leadsto \frac{\pi}{\left(a \cdot a\right) \cdot b} \cdot 0.5 \]
    4. Applied rewrites56.1%

      \[\leadsto \color{blue}{\frac{\pi}{\left(a \cdot a\right) \cdot b} \cdot 0.5} \]
    5. Step-by-step derivation
      1. lift-*.f64N/A

        \[\leadsto \frac{\pi}{\left(a \cdot a\right) \cdot b} \cdot \frac{1}{2} \]
      2. lift-*.f64N/A

        \[\leadsto \frac{\pi}{\left(a \cdot a\right) \cdot b} \cdot \frac{1}{2} \]
      3. associate-*l*N/A

        \[\leadsto \frac{\pi}{a \cdot \left(a \cdot b\right)} \cdot \frac{1}{2} \]
      4. lower-*.f64N/A

        \[\leadsto \frac{\pi}{a \cdot \left(a \cdot b\right)} \cdot \frac{1}{2} \]
      5. lower-*.f6462.3

        \[\leadsto \frac{\pi}{a \cdot \left(a \cdot b\right)} \cdot 0.5 \]
    6. Applied rewrites62.3%

      \[\leadsto \frac{\pi}{a \cdot \left(a \cdot b\right)} \cdot 0.5 \]

    if -9.7999999999999996e-45 < a

    1. Initial program 78.8%

      \[\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
    2. Taylor expanded in a around 0

      \[\leadsto \color{blue}{\frac{1}{2} \cdot \frac{\mathsf{PI}\left(\right)}{a \cdot {b}^{2}}} \]
    3. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \frac{\mathsf{PI}\left(\right)}{a \cdot {b}^{2}} \cdot \color{blue}{\frac{1}{2}} \]
      2. lower-*.f64N/A

        \[\leadsto \frac{\mathsf{PI}\left(\right)}{a \cdot {b}^{2}} \cdot \color{blue}{\frac{1}{2}} \]
      3. lower-/.f64N/A

        \[\leadsto \frac{\mathsf{PI}\left(\right)}{a \cdot {b}^{2}} \cdot \frac{1}{2} \]
      4. lift-PI.f64N/A

        \[\leadsto \frac{\pi}{a \cdot {b}^{2}} \cdot \frac{1}{2} \]
      5. *-commutativeN/A

        \[\leadsto \frac{\pi}{{b}^{2} \cdot a} \cdot \frac{1}{2} \]
      6. lower-*.f64N/A

        \[\leadsto \frac{\pi}{{b}^{2} \cdot a} \cdot \frac{1}{2} \]
      7. pow2N/A

        \[\leadsto \frac{\pi}{\left(b \cdot b\right) \cdot a} \cdot \frac{1}{2} \]
      8. lift-*.f6457.1

        \[\leadsto \frac{\pi}{\left(b \cdot b\right) \cdot a} \cdot 0.5 \]
    4. Applied rewrites57.1%

      \[\leadsto \color{blue}{\frac{\pi}{\left(b \cdot b\right) \cdot a} \cdot 0.5} \]
  3. Recombined 2 regimes into one program.
  4. Add Preprocessing

Alternative 7: 62.3% accurate, 2.4× speedup?

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

\\
\frac{\pi}{a \cdot \left(a \cdot b\right)} \cdot 0.5
\end{array}
Derivation
  1. Initial program 78.8%

    \[\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
  2. Taylor expanded in a around inf

    \[\leadsto \color{blue}{\frac{1}{2} \cdot \frac{\mathsf{PI}\left(\right)}{{a}^{2} \cdot b}} \]
  3. Step-by-step derivation
    1. *-commutativeN/A

      \[\leadsto \frac{\mathsf{PI}\left(\right)}{{a}^{2} \cdot b} \cdot \color{blue}{\frac{1}{2}} \]
    2. lower-*.f64N/A

      \[\leadsto \frac{\mathsf{PI}\left(\right)}{{a}^{2} \cdot b} \cdot \color{blue}{\frac{1}{2}} \]
    3. lower-/.f64N/A

      \[\leadsto \frac{\mathsf{PI}\left(\right)}{{a}^{2} \cdot b} \cdot \frac{1}{2} \]
    4. lift-PI.f64N/A

      \[\leadsto \frac{\pi}{{a}^{2} \cdot b} \cdot \frac{1}{2} \]
    5. lower-*.f64N/A

      \[\leadsto \frac{\pi}{{a}^{2} \cdot b} \cdot \frac{1}{2} \]
    6. pow2N/A

      \[\leadsto \frac{\pi}{\left(a \cdot a\right) \cdot b} \cdot \frac{1}{2} \]
    7. lift-*.f6456.1

      \[\leadsto \frac{\pi}{\left(a \cdot a\right) \cdot b} \cdot 0.5 \]
  4. Applied rewrites56.1%

    \[\leadsto \color{blue}{\frac{\pi}{\left(a \cdot a\right) \cdot b} \cdot 0.5} \]
  5. Step-by-step derivation
    1. lift-*.f64N/A

      \[\leadsto \frac{\pi}{\left(a \cdot a\right) \cdot b} \cdot \frac{1}{2} \]
    2. lift-*.f64N/A

      \[\leadsto \frac{\pi}{\left(a \cdot a\right) \cdot b} \cdot \frac{1}{2} \]
    3. associate-*l*N/A

      \[\leadsto \frac{\pi}{a \cdot \left(a \cdot b\right)} \cdot \frac{1}{2} \]
    4. lower-*.f64N/A

      \[\leadsto \frac{\pi}{a \cdot \left(a \cdot b\right)} \cdot \frac{1}{2} \]
    5. lower-*.f6462.3

      \[\leadsto \frac{\pi}{a \cdot \left(a \cdot b\right)} \cdot 0.5 \]
  6. Applied rewrites62.3%

    \[\leadsto \frac{\pi}{a \cdot \left(a \cdot b\right)} \cdot 0.5 \]
  7. Add Preprocessing

Reproduce

?
herbie shell --seed 2025139 
(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))))