NMSE Section 6.1 mentioned, B

Percentage Accurate: 78.6% → 99.7%
Time: 12.0s
Alternatives: 3
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 3 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: 78.6% 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 75.8%

    \[\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
  2. Step-by-step derivation
    1. *-commutative75.8%

      \[\leadsto \color{blue}{\left(\frac{1}{a} - \frac{1}{b}\right) \cdot \left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right)} \]
    2. associate-*r*75.8%

      \[\leadsto \color{blue}{\left(\left(\frac{1}{a} - \frac{1}{b}\right) \cdot \frac{\pi}{2}\right) \cdot \frac{1}{b \cdot b - a \cdot a}} \]
    3. associate-*r/75.9%

      \[\leadsto \color{blue}{\frac{\left(\left(\frac{1}{a} - \frac{1}{b}\right) \cdot \frac{\pi}{2}\right) \cdot 1}{b \cdot b - a \cdot a}} \]
    4. associate-*r*75.9%

      \[\leadsto \frac{\color{blue}{\left(\frac{1}{a} - \frac{1}{b}\right) \cdot \left(\frac{\pi}{2} \cdot 1\right)}}{b \cdot b - a \cdot a} \]
    5. *-rgt-identity75.9%

      \[\leadsto \frac{\left(\frac{1}{a} - \frac{1}{b}\right) \cdot \color{blue}{\frac{\pi}{2}}}{b \cdot b - a \cdot a} \]
    6. sub-neg75.9%

      \[\leadsto \frac{\color{blue}{\left(\frac{1}{a} + \left(-\frac{1}{b}\right)\right)} \cdot \frac{\pi}{2}}{b \cdot b - a \cdot a} \]
    7. distribute-neg-frac75.9%

      \[\leadsto \frac{\left(\frac{1}{a} + \color{blue}{\frac{-1}{b}}\right) \cdot \frac{\pi}{2}}{b \cdot b - a \cdot a} \]
    8. metadata-eval75.9%

      \[\leadsto \frac{\left(\frac{1}{a} + \frac{\color{blue}{-1}}{b}\right) \cdot \frac{\pi}{2}}{b \cdot b - a \cdot a} \]
  3. Simplified75.9%

    \[\leadsto \color{blue}{\frac{\left(\frac{1}{a} + \frac{-1}{b}\right) \cdot \frac{\pi}{2}}{b \cdot b - a \cdot a}} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. *-commutative75.9%

      \[\leadsto \frac{\color{blue}{\frac{\pi}{2} \cdot \left(\frac{1}{a} + \frac{-1}{b}\right)}}{b \cdot b - a \cdot a} \]
    2. difference-of-squares86.8%

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

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

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

      \[\leadsto \frac{\pi \cdot \color{blue}{0.5}}{b + a} \cdot \frac{\frac{1}{a} + \frac{-1}{b}}{b - a} \]
    6. add-sqr-sqrt48.6%

      \[\leadsto \frac{\pi \cdot 0.5}{b + a} \cdot \frac{\frac{1}{a} + \color{blue}{\sqrt{\frac{-1}{b}} \cdot \sqrt{\frac{-1}{b}}}}{b - a} \]
    7. sqrt-unprod67.3%

      \[\leadsto \frac{\pi \cdot 0.5}{b + a} \cdot \frac{\frac{1}{a} + \color{blue}{\sqrt{\frac{-1}{b} \cdot \frac{-1}{b}}}}{b - a} \]
    8. frac-times67.3%

      \[\leadsto \frac{\pi \cdot 0.5}{b + a} \cdot \frac{\frac{1}{a} + \sqrt{\color{blue}{\frac{-1 \cdot -1}{b \cdot b}}}}{b - a} \]
    9. metadata-eval67.3%

      \[\leadsto \frac{\pi \cdot 0.5}{b + a} \cdot \frac{\frac{1}{a} + \sqrt{\frac{\color{blue}{1}}{b \cdot b}}}{b - a} \]
    10. metadata-eval67.3%

      \[\leadsto \frac{\pi \cdot 0.5}{b + a} \cdot \frac{\frac{1}{a} + \sqrt{\frac{\color{blue}{1 \cdot 1}}{b \cdot b}}}{b - a} \]
    11. frac-times67.3%

      \[\leadsto \frac{\pi \cdot 0.5}{b + a} \cdot \frac{\frac{1}{a} + \sqrt{\color{blue}{\frac{1}{b} \cdot \frac{1}{b}}}}{b - a} \]
    12. sqrt-unprod29.6%

      \[\leadsto \frac{\pi \cdot 0.5}{b + a} \cdot \frac{\frac{1}{a} + \color{blue}{\sqrt{\frac{1}{b}} \cdot \sqrt{\frac{1}{b}}}}{b - a} \]
    13. add-sqr-sqrt61.0%

      \[\leadsto \frac{\pi \cdot 0.5}{b + a} \cdot \frac{\frac{1}{a} + \color{blue}{\frac{1}{b}}}{b - a} \]
  6. Applied egg-rr61.0%

    \[\leadsto \color{blue}{\frac{\pi \cdot 0.5}{b + a} \cdot \frac{\frac{1}{a} + \frac{1}{b}}{b - a}} \]
  7. Step-by-step derivation
    1. associate-*l/61.0%

      \[\leadsto \color{blue}{\frac{\left(\pi \cdot 0.5\right) \cdot \frac{\frac{1}{a} + \frac{1}{b}}{b - a}}{b + a}} \]
    2. *-commutative61.0%

      \[\leadsto \frac{\color{blue}{\left(0.5 \cdot \pi\right)} \cdot \frac{\frac{1}{a} + \frac{1}{b}}{b - a}}{b + a} \]
    3. +-commutative61.0%

      \[\leadsto \frac{\left(0.5 \cdot \pi\right) \cdot \frac{\color{blue}{\frac{1}{b} + \frac{1}{a}}}{b - a}}{b + a} \]
    4. +-commutative61.0%

      \[\leadsto \frac{\left(0.5 \cdot \pi\right) \cdot \frac{\frac{1}{b} + \frac{1}{a}}{b - a}}{\color{blue}{a + b}} \]
  8. Simplified61.0%

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

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

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

Alternative 2: 99.0% accurate, 1.9× speedup?

\[\begin{array}{l} \\ 0.5 \cdot \frac{\pi}{\left(a \cdot b\right) \cdot \left(a + b\right)} \end{array} \]
(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(0.5 * Float64(pi / Float64(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[(0.5 * N[(Pi / N[(N[(a * b), $MachinePrecision] * N[(a + b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
0.5 \cdot \frac{\pi}{\left(a \cdot b\right) \cdot \left(a + b\right)}
\end{array}
Derivation
  1. Initial program 75.8%

    \[\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
  2. Step-by-step derivation
    1. *-commutative75.8%

      \[\leadsto \color{blue}{\left(\frac{1}{a} - \frac{1}{b}\right) \cdot \left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right)} \]
    2. associate-*r*75.8%

      \[\leadsto \color{blue}{\left(\left(\frac{1}{a} - \frac{1}{b}\right) \cdot \frac{\pi}{2}\right) \cdot \frac{1}{b \cdot b - a \cdot a}} \]
    3. associate-*r/75.9%

      \[\leadsto \color{blue}{\frac{\left(\left(\frac{1}{a} - \frac{1}{b}\right) \cdot \frac{\pi}{2}\right) \cdot 1}{b \cdot b - a \cdot a}} \]
    4. associate-*r*75.9%

      \[\leadsto \frac{\color{blue}{\left(\frac{1}{a} - \frac{1}{b}\right) \cdot \left(\frac{\pi}{2} \cdot 1\right)}}{b \cdot b - a \cdot a} \]
    5. *-rgt-identity75.9%

      \[\leadsto \frac{\left(\frac{1}{a} - \frac{1}{b}\right) \cdot \color{blue}{\frac{\pi}{2}}}{b \cdot b - a \cdot a} \]
    6. sub-neg75.9%

      \[\leadsto \frac{\color{blue}{\left(\frac{1}{a} + \left(-\frac{1}{b}\right)\right)} \cdot \frac{\pi}{2}}{b \cdot b - a \cdot a} \]
    7. distribute-neg-frac75.9%

      \[\leadsto \frac{\left(\frac{1}{a} + \color{blue}{\frac{-1}{b}}\right) \cdot \frac{\pi}{2}}{b \cdot b - a \cdot a} \]
    8. metadata-eval75.9%

      \[\leadsto \frac{\left(\frac{1}{a} + \frac{\color{blue}{-1}}{b}\right) \cdot \frac{\pi}{2}}{b \cdot b - a \cdot a} \]
  3. Simplified75.9%

    \[\leadsto \color{blue}{\frac{\left(\frac{1}{a} + \frac{-1}{b}\right) \cdot \frac{\pi}{2}}{b \cdot b - a \cdot a}} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. *-commutative75.9%

      \[\leadsto \frac{\color{blue}{\frac{\pi}{2} \cdot \left(\frac{1}{a} + \frac{-1}{b}\right)}}{b \cdot b - a \cdot a} \]
    2. difference-of-squares86.8%

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

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

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

      \[\leadsto \frac{\pi \cdot \color{blue}{0.5}}{b + a} \cdot \frac{\frac{1}{a} + \frac{-1}{b}}{b - a} \]
    6. add-sqr-sqrt48.6%

      \[\leadsto \frac{\pi \cdot 0.5}{b + a} \cdot \frac{\frac{1}{a} + \color{blue}{\sqrt{\frac{-1}{b}} \cdot \sqrt{\frac{-1}{b}}}}{b - a} \]
    7. sqrt-unprod67.3%

      \[\leadsto \frac{\pi \cdot 0.5}{b + a} \cdot \frac{\frac{1}{a} + \color{blue}{\sqrt{\frac{-1}{b} \cdot \frac{-1}{b}}}}{b - a} \]
    8. frac-times67.3%

      \[\leadsto \frac{\pi \cdot 0.5}{b + a} \cdot \frac{\frac{1}{a} + \sqrt{\color{blue}{\frac{-1 \cdot -1}{b \cdot b}}}}{b - a} \]
    9. metadata-eval67.3%

      \[\leadsto \frac{\pi \cdot 0.5}{b + a} \cdot \frac{\frac{1}{a} + \sqrt{\frac{\color{blue}{1}}{b \cdot b}}}{b - a} \]
    10. metadata-eval67.3%

      \[\leadsto \frac{\pi \cdot 0.5}{b + a} \cdot \frac{\frac{1}{a} + \sqrt{\frac{\color{blue}{1 \cdot 1}}{b \cdot b}}}{b - a} \]
    11. frac-times67.3%

      \[\leadsto \frac{\pi \cdot 0.5}{b + a} \cdot \frac{\frac{1}{a} + \sqrt{\color{blue}{\frac{1}{b} \cdot \frac{1}{b}}}}{b - a} \]
    12. sqrt-unprod29.6%

      \[\leadsto \frac{\pi \cdot 0.5}{b + a} \cdot \frac{\frac{1}{a} + \color{blue}{\sqrt{\frac{1}{b}} \cdot \sqrt{\frac{1}{b}}}}{b - a} \]
    13. add-sqr-sqrt61.0%

      \[\leadsto \frac{\pi \cdot 0.5}{b + a} \cdot \frac{\frac{1}{a} + \color{blue}{\frac{1}{b}}}{b - a} \]
  6. Applied egg-rr61.0%

    \[\leadsto \color{blue}{\frac{\pi \cdot 0.5}{b + a} \cdot \frac{\frac{1}{a} + \frac{1}{b}}{b - a}} \]
  7. Step-by-step derivation
    1. associate-*l/61.0%

      \[\leadsto \color{blue}{\frac{\left(\pi \cdot 0.5\right) \cdot \frac{\frac{1}{a} + \frac{1}{b}}{b - a}}{b + a}} \]
    2. *-commutative61.0%

      \[\leadsto \frac{\color{blue}{\left(0.5 \cdot \pi\right)} \cdot \frac{\frac{1}{a} + \frac{1}{b}}{b - a}}{b + a} \]
    3. +-commutative61.0%

      \[\leadsto \frac{\left(0.5 \cdot \pi\right) \cdot \frac{\color{blue}{\frac{1}{b} + \frac{1}{a}}}{b - a}}{b + a} \]
    4. +-commutative61.0%

      \[\leadsto \frac{\left(0.5 \cdot \pi\right) \cdot \frac{\frac{1}{b} + \frac{1}{a}}{b - a}}{\color{blue}{a + b}} \]
  8. Simplified61.0%

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

    \[\leadsto \frac{\color{blue}{0.5 \cdot \frac{\pi}{a \cdot b}}}{a + b} \]
  10. Step-by-step derivation
    1. associate-/l*99.7%

      \[\leadsto \color{blue}{0.5 \cdot \frac{\frac{\pi}{a \cdot b}}{a + b}} \]
  11. Applied egg-rr99.7%

    \[\leadsto \color{blue}{0.5 \cdot \frac{\frac{\pi}{a \cdot b}}{a + b}} \]
  12. Step-by-step derivation
    1. associate-/l/98.6%

      \[\leadsto 0.5 \cdot \color{blue}{\frac{\pi}{\left(a + b\right) \cdot \left(a \cdot b\right)}} \]
    2. *-commutative98.6%

      \[\leadsto 0.5 \cdot \frac{\pi}{\color{blue}{\left(a \cdot b\right) \cdot \left(a + b\right)}} \]
  13. Simplified98.6%

    \[\leadsto \color{blue}{0.5 \cdot \frac{\pi}{\left(a \cdot b\right) \cdot \left(a + b\right)}} \]
  14. Final simplification98.6%

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

Alternative 3: 99.6% accurate, 1.9× speedup?

\[\begin{array}{l} \\ \frac{\pi}{a + b} \cdot \frac{0.5}{a \cdot b} \end{array} \]
(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 + b} \cdot \frac{0.5}{a \cdot b}
\end{array}
Derivation
  1. Initial program 75.8%

    \[\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right) \]
  2. Step-by-step derivation
    1. *-commutative75.8%

      \[\leadsto \color{blue}{\left(\frac{1}{a} - \frac{1}{b}\right) \cdot \left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right)} \]
    2. associate-*r*75.8%

      \[\leadsto \color{blue}{\left(\left(\frac{1}{a} - \frac{1}{b}\right) \cdot \frac{\pi}{2}\right) \cdot \frac{1}{b \cdot b - a \cdot a}} \]
    3. associate-*r/75.9%

      \[\leadsto \color{blue}{\frac{\left(\left(\frac{1}{a} - \frac{1}{b}\right) \cdot \frac{\pi}{2}\right) \cdot 1}{b \cdot b - a \cdot a}} \]
    4. associate-*r*75.9%

      \[\leadsto \frac{\color{blue}{\left(\frac{1}{a} - \frac{1}{b}\right) \cdot \left(\frac{\pi}{2} \cdot 1\right)}}{b \cdot b - a \cdot a} \]
    5. *-rgt-identity75.9%

      \[\leadsto \frac{\left(\frac{1}{a} - \frac{1}{b}\right) \cdot \color{blue}{\frac{\pi}{2}}}{b \cdot b - a \cdot a} \]
    6. sub-neg75.9%

      \[\leadsto \frac{\color{blue}{\left(\frac{1}{a} + \left(-\frac{1}{b}\right)\right)} \cdot \frac{\pi}{2}}{b \cdot b - a \cdot a} \]
    7. distribute-neg-frac75.9%

      \[\leadsto \frac{\left(\frac{1}{a} + \color{blue}{\frac{-1}{b}}\right) \cdot \frac{\pi}{2}}{b \cdot b - a \cdot a} \]
    8. metadata-eval75.9%

      \[\leadsto \frac{\left(\frac{1}{a} + \frac{\color{blue}{-1}}{b}\right) \cdot \frac{\pi}{2}}{b \cdot b - a \cdot a} \]
  3. Simplified75.9%

    \[\leadsto \color{blue}{\frac{\left(\frac{1}{a} + \frac{-1}{b}\right) \cdot \frac{\pi}{2}}{b \cdot b - a \cdot a}} \]
  4. Add Preprocessing
  5. Step-by-step derivation
    1. *-commutative75.9%

      \[\leadsto \frac{\color{blue}{\frac{\pi}{2} \cdot \left(\frac{1}{a} + \frac{-1}{b}\right)}}{b \cdot b - a \cdot a} \]
    2. difference-of-squares86.8%

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

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

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

      \[\leadsto \frac{\pi \cdot \color{blue}{0.5}}{b + a} \cdot \frac{\frac{1}{a} + \frac{-1}{b}}{b - a} \]
    6. add-sqr-sqrt48.6%

      \[\leadsto \frac{\pi \cdot 0.5}{b + a} \cdot \frac{\frac{1}{a} + \color{blue}{\sqrt{\frac{-1}{b}} \cdot \sqrt{\frac{-1}{b}}}}{b - a} \]
    7. sqrt-unprod67.3%

      \[\leadsto \frac{\pi \cdot 0.5}{b + a} \cdot \frac{\frac{1}{a} + \color{blue}{\sqrt{\frac{-1}{b} \cdot \frac{-1}{b}}}}{b - a} \]
    8. frac-times67.3%

      \[\leadsto \frac{\pi \cdot 0.5}{b + a} \cdot \frac{\frac{1}{a} + \sqrt{\color{blue}{\frac{-1 \cdot -1}{b \cdot b}}}}{b - a} \]
    9. metadata-eval67.3%

      \[\leadsto \frac{\pi \cdot 0.5}{b + a} \cdot \frac{\frac{1}{a} + \sqrt{\frac{\color{blue}{1}}{b \cdot b}}}{b - a} \]
    10. metadata-eval67.3%

      \[\leadsto \frac{\pi \cdot 0.5}{b + a} \cdot \frac{\frac{1}{a} + \sqrt{\frac{\color{blue}{1 \cdot 1}}{b \cdot b}}}{b - a} \]
    11. frac-times67.3%

      \[\leadsto \frac{\pi \cdot 0.5}{b + a} \cdot \frac{\frac{1}{a} + \sqrt{\color{blue}{\frac{1}{b} \cdot \frac{1}{b}}}}{b - a} \]
    12. sqrt-unprod29.6%

      \[\leadsto \frac{\pi \cdot 0.5}{b + a} \cdot \frac{\frac{1}{a} + \color{blue}{\sqrt{\frac{1}{b}} \cdot \sqrt{\frac{1}{b}}}}{b - a} \]
    13. add-sqr-sqrt61.0%

      \[\leadsto \frac{\pi \cdot 0.5}{b + a} \cdot \frac{\frac{1}{a} + \color{blue}{\frac{1}{b}}}{b - a} \]
  6. Applied egg-rr61.0%

    \[\leadsto \color{blue}{\frac{\pi \cdot 0.5}{b + a} \cdot \frac{\frac{1}{a} + \frac{1}{b}}{b - a}} \]
  7. Step-by-step derivation
    1. associate-*l/61.0%

      \[\leadsto \color{blue}{\frac{\left(\pi \cdot 0.5\right) \cdot \frac{\frac{1}{a} + \frac{1}{b}}{b - a}}{b + a}} \]
    2. *-commutative61.0%

      \[\leadsto \frac{\color{blue}{\left(0.5 \cdot \pi\right)} \cdot \frac{\frac{1}{a} + \frac{1}{b}}{b - a}}{b + a} \]
    3. +-commutative61.0%

      \[\leadsto \frac{\left(0.5 \cdot \pi\right) \cdot \frac{\color{blue}{\frac{1}{b} + \frac{1}{a}}}{b - a}}{b + a} \]
    4. +-commutative61.0%

      \[\leadsto \frac{\left(0.5 \cdot \pi\right) \cdot \frac{\frac{1}{b} + \frac{1}{a}}{b - a}}{\color{blue}{a + b}} \]
  8. Simplified61.0%

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

    \[\leadsto \frac{\left(0.5 \cdot \pi\right) \cdot \color{blue}{\frac{1}{a \cdot b}}}{a + b} \]
  10. Step-by-step derivation
    1. associate-/r*99.6%

      \[\leadsto \frac{\left(0.5 \cdot \pi\right) \cdot \color{blue}{\frac{\frac{1}{a}}{b}}}{a + b} \]
  11. Simplified99.6%

    \[\leadsto \frac{\left(0.5 \cdot \pi\right) \cdot \color{blue}{\frac{\frac{1}{a}}{b}}}{a + b} \]
  12. Step-by-step derivation
    1. associate-/r*99.7%

      \[\leadsto \frac{\left(0.5 \cdot \pi\right) \cdot \color{blue}{\frac{1}{a \cdot b}}}{a + b} \]
    2. un-div-inv99.7%

      \[\leadsto \frac{\color{blue}{\frac{0.5 \cdot \pi}{a \cdot b}}}{a + b} \]
    3. associate-/r*98.6%

      \[\leadsto \color{blue}{\frac{0.5 \cdot \pi}{\left(a \cdot b\right) \cdot \left(a + b\right)}} \]
    4. *-commutative98.6%

      \[\leadsto \frac{\color{blue}{\pi \cdot 0.5}}{\left(a \cdot b\right) \cdot \left(a + b\right)} \]
    5. *-commutative98.6%

      \[\leadsto \frac{\pi \cdot 0.5}{\color{blue}{\left(a + b\right) \cdot \left(a \cdot b\right)}} \]
    6. times-frac99.7%

      \[\leadsto \color{blue}{\frac{\pi}{a + b} \cdot \frac{0.5}{a \cdot b}} \]
  13. Applied egg-rr99.7%

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

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

Reproduce

?
herbie shell --seed 2024066 
(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))))