Falkner and Boettcher, Equation (20:1,3)

Percentage Accurate: 99.3% → 99.3%
Time: 8.6s
Alternatives: 6
Speedup: N/A×

Specification

?
\[\begin{array}{l} \\ \frac{1 - 5 \cdot \left(v \cdot v\right)}{\left(\left(\pi \cdot t\right) \cdot \sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)}\right) \cdot \left(1 - v \cdot v\right)} \end{array} \]
(FPCore (v t)
 :precision binary64
 (/
  (- 1.0 (* 5.0 (* v v)))
  (* (* (* PI t) (sqrt (* 2.0 (- 1.0 (* 3.0 (* v v)))))) (- 1.0 (* v v)))))
double code(double v, double t) {
	return (1.0 - (5.0 * (v * v))) / (((((double) M_PI) * t) * sqrt((2.0 * (1.0 - (3.0 * (v * v)))))) * (1.0 - (v * v)));
}
public static double code(double v, double t) {
	return (1.0 - (5.0 * (v * v))) / (((Math.PI * t) * Math.sqrt((2.0 * (1.0 - (3.0 * (v * v)))))) * (1.0 - (v * v)));
}
def code(v, t):
	return (1.0 - (5.0 * (v * v))) / (((math.pi * t) * math.sqrt((2.0 * (1.0 - (3.0 * (v * v)))))) * (1.0 - (v * v)))
function code(v, t)
	return Float64(Float64(1.0 - Float64(5.0 * Float64(v * v))) / Float64(Float64(Float64(pi * t) * sqrt(Float64(2.0 * Float64(1.0 - Float64(3.0 * Float64(v * v)))))) * Float64(1.0 - Float64(v * v))))
end
function tmp = code(v, t)
	tmp = (1.0 - (5.0 * (v * v))) / (((pi * t) * sqrt((2.0 * (1.0 - (3.0 * (v * v)))))) * (1.0 - (v * v)));
end
code[v_, t_] := N[(N[(1.0 - N[(5.0 * N[(v * v), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(N[(N[(Pi * t), $MachinePrecision] * N[Sqrt[N[(2.0 * N[(1.0 - N[(3.0 * N[(v * v), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * N[(1.0 - N[(v * v), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{1 - 5 \cdot \left(v \cdot v\right)}{\left(\left(\pi \cdot t\right) \cdot \sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)}\right) \cdot \left(1 - v \cdot v\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 6 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: 99.3% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \frac{1 - 5 \cdot \left(v \cdot v\right)}{\left(\left(\pi \cdot t\right) \cdot \sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)}\right) \cdot \left(1 - v \cdot v\right)} \end{array} \]
(FPCore (v t)
 :precision binary64
 (/
  (- 1.0 (* 5.0 (* v v)))
  (* (* (* PI t) (sqrt (* 2.0 (- 1.0 (* 3.0 (* v v)))))) (- 1.0 (* v v)))))
double code(double v, double t) {
	return (1.0 - (5.0 * (v * v))) / (((((double) M_PI) * t) * sqrt((2.0 * (1.0 - (3.0 * (v * v)))))) * (1.0 - (v * v)));
}
public static double code(double v, double t) {
	return (1.0 - (5.0 * (v * v))) / (((Math.PI * t) * Math.sqrt((2.0 * (1.0 - (3.0 * (v * v)))))) * (1.0 - (v * v)));
}
def code(v, t):
	return (1.0 - (5.0 * (v * v))) / (((math.pi * t) * math.sqrt((2.0 * (1.0 - (3.0 * (v * v)))))) * (1.0 - (v * v)))
function code(v, t)
	return Float64(Float64(1.0 - Float64(5.0 * Float64(v * v))) / Float64(Float64(Float64(pi * t) * sqrt(Float64(2.0 * Float64(1.0 - Float64(3.0 * Float64(v * v)))))) * Float64(1.0 - Float64(v * v))))
end
function tmp = code(v, t)
	tmp = (1.0 - (5.0 * (v * v))) / (((pi * t) * sqrt((2.0 * (1.0 - (3.0 * (v * v)))))) * (1.0 - (v * v)));
end
code[v_, t_] := N[(N[(1.0 - N[(5.0 * N[(v * v), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(N[(N[(Pi * t), $MachinePrecision] * N[Sqrt[N[(2.0 * N[(1.0 - N[(3.0 * N[(v * v), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * N[(1.0 - N[(v * v), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{1 - 5 \cdot \left(v \cdot v\right)}{\left(\left(\pi \cdot t\right) \cdot \sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)}\right) \cdot \left(1 - v \cdot v\right)}
\end{array}

Alternative 1: 99.3% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \left(1 + v \cdot \left(v \cdot -5\right)\right) \cdot \frac{1}{\left(1 - v \cdot v\right) \cdot \left(\pi \cdot \left(t \cdot \sqrt{2 \cdot \left(1 + \left(1 + \left(-1 - v \cdot \left(v \cdot 3\right)\right)\right)\right)}\right)\right)} \end{array} \]
(FPCore (v t)
 :precision binary64
 (*
  (+ 1.0 (* v (* v -5.0)))
  (/
   1.0
   (*
    (- 1.0 (* v v))
    (* PI (* t (sqrt (* 2.0 (+ 1.0 (+ 1.0 (- -1.0 (* v (* v 3.0)))))))))))))
double code(double v, double t) {
	return (1.0 + (v * (v * -5.0))) * (1.0 / ((1.0 - (v * v)) * (((double) M_PI) * (t * sqrt((2.0 * (1.0 + (1.0 + (-1.0 - (v * (v * 3.0)))))))))));
}
public static double code(double v, double t) {
	return (1.0 + (v * (v * -5.0))) * (1.0 / ((1.0 - (v * v)) * (Math.PI * (t * Math.sqrt((2.0 * (1.0 + (1.0 + (-1.0 - (v * (v * 3.0)))))))))));
}
def code(v, t):
	return (1.0 + (v * (v * -5.0))) * (1.0 / ((1.0 - (v * v)) * (math.pi * (t * math.sqrt((2.0 * (1.0 + (1.0 + (-1.0 - (v * (v * 3.0)))))))))))
function code(v, t)
	return Float64(Float64(1.0 + Float64(v * Float64(v * -5.0))) * Float64(1.0 / Float64(Float64(1.0 - Float64(v * v)) * Float64(pi * Float64(t * sqrt(Float64(2.0 * Float64(1.0 + Float64(1.0 + Float64(-1.0 - Float64(v * Float64(v * 3.0))))))))))))
end
function tmp = code(v, t)
	tmp = (1.0 + (v * (v * -5.0))) * (1.0 / ((1.0 - (v * v)) * (pi * (t * sqrt((2.0 * (1.0 + (1.0 + (-1.0 - (v * (v * 3.0)))))))))));
end
code[v_, t_] := N[(N[(1.0 + N[(v * N[(v * -5.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[(1.0 / N[(N[(1.0 - N[(v * v), $MachinePrecision]), $MachinePrecision] * N[(Pi * N[(t * N[Sqrt[N[(2.0 * N[(1.0 + N[(1.0 + N[(-1.0 - N[(v * N[(v * 3.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\left(1 + v \cdot \left(v \cdot -5\right)\right) \cdot \frac{1}{\left(1 - v \cdot v\right) \cdot \left(\pi \cdot \left(t \cdot \sqrt{2 \cdot \left(1 + \left(1 + \left(-1 - v \cdot \left(v \cdot 3\right)\right)\right)\right)}\right)\right)}
\end{array}
Derivation
  1. Initial program 99.1%

    \[\frac{1 - 5 \cdot \left(v \cdot v\right)}{\left(\left(\pi \cdot t\right) \cdot \sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)}\right) \cdot \left(1 - v \cdot v\right)} \]
  2. Step-by-step derivation
    1. expm1-log1p-u99.1%

      \[\leadsto \frac{1 - 5 \cdot \left(v \cdot v\right)}{\left(\left(\pi \cdot t\right) \cdot \sqrt{2 \cdot \left(1 - \color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(3 \cdot \left(v \cdot v\right)\right)\right)}\right)}\right) \cdot \left(1 - v \cdot v\right)} \]
    2. expm1-udef99.1%

      \[\leadsto \frac{1 - 5 \cdot \left(v \cdot v\right)}{\left(\left(\pi \cdot t\right) \cdot \sqrt{2 \cdot \left(1 - \color{blue}{\left(e^{\mathsf{log1p}\left(3 \cdot \left(v \cdot v\right)\right)} - 1\right)}\right)}\right) \cdot \left(1 - v \cdot v\right)} \]
    3. log1p-udef99.1%

      \[\leadsto \frac{1 - 5 \cdot \left(v \cdot v\right)}{\left(\left(\pi \cdot t\right) \cdot \sqrt{2 \cdot \left(1 - \left(e^{\color{blue}{\log \left(1 + 3 \cdot \left(v \cdot v\right)\right)}} - 1\right)\right)}\right) \cdot \left(1 - v \cdot v\right)} \]
    4. add-exp-log99.1%

      \[\leadsto \frac{1 - 5 \cdot \left(v \cdot v\right)}{\left(\left(\pi \cdot t\right) \cdot \sqrt{2 \cdot \left(1 - \left(\color{blue}{\left(1 + 3 \cdot \left(v \cdot v\right)\right)} - 1\right)\right)}\right) \cdot \left(1 - v \cdot v\right)} \]
    5. *-commutative99.1%

      \[\leadsto \frac{1 - 5 \cdot \left(v \cdot v\right)}{\left(\left(\pi \cdot t\right) \cdot \sqrt{2 \cdot \left(1 - \left(\left(1 + \color{blue}{\left(v \cdot v\right) \cdot 3}\right) - 1\right)\right)}\right) \cdot \left(1 - v \cdot v\right)} \]
    6. associate-*r*99.1%

      \[\leadsto \frac{1 - 5 \cdot \left(v \cdot v\right)}{\left(\left(\pi \cdot t\right) \cdot \sqrt{2 \cdot \left(1 - \left(\left(1 + \color{blue}{v \cdot \left(v \cdot 3\right)}\right) - 1\right)\right)}\right) \cdot \left(1 - v \cdot v\right)} \]
  3. Applied egg-rr99.1%

    \[\leadsto \frac{1 - 5 \cdot \left(v \cdot v\right)}{\left(\left(\pi \cdot t\right) \cdot \sqrt{2 \cdot \left(1 - \color{blue}{\left(\left(1 + v \cdot \left(v \cdot 3\right)\right) - 1\right)}\right)}\right) \cdot \left(1 - v \cdot v\right)} \]
  4. Step-by-step derivation
    1. div-inv99.1%

      \[\leadsto \color{blue}{\left(1 - 5 \cdot \left(v \cdot v\right)\right) \cdot \frac{1}{\left(\left(\pi \cdot t\right) \cdot \sqrt{2 \cdot \left(1 - \left(\left(1 + v \cdot \left(v \cdot 3\right)\right) - 1\right)\right)}\right) \cdot \left(1 - v \cdot v\right)}} \]
    2. cancel-sign-sub-inv99.1%

      \[\leadsto \color{blue}{\left(1 + \left(-5\right) \cdot \left(v \cdot v\right)\right)} \cdot \frac{1}{\left(\left(\pi \cdot t\right) \cdot \sqrt{2 \cdot \left(1 - \left(\left(1 + v \cdot \left(v \cdot 3\right)\right) - 1\right)\right)}\right) \cdot \left(1 - v \cdot v\right)} \]
    3. metadata-eval99.1%

      \[\leadsto \left(1 + \color{blue}{-5} \cdot \left(v \cdot v\right)\right) \cdot \frac{1}{\left(\left(\pi \cdot t\right) \cdot \sqrt{2 \cdot \left(1 - \left(\left(1 + v \cdot \left(v \cdot 3\right)\right) - 1\right)\right)}\right) \cdot \left(1 - v \cdot v\right)} \]
    4. *-commutative99.1%

      \[\leadsto \left(1 + \color{blue}{\left(v \cdot v\right) \cdot -5}\right) \cdot \frac{1}{\left(\left(\pi \cdot t\right) \cdot \sqrt{2 \cdot \left(1 - \left(\left(1 + v \cdot \left(v \cdot 3\right)\right) - 1\right)\right)}\right) \cdot \left(1 - v \cdot v\right)} \]
    5. associate-*l*99.1%

      \[\leadsto \left(1 + \color{blue}{v \cdot \left(v \cdot -5\right)}\right) \cdot \frac{1}{\left(\left(\pi \cdot t\right) \cdot \sqrt{2 \cdot \left(1 - \left(\left(1 + v \cdot \left(v \cdot 3\right)\right) - 1\right)\right)}\right) \cdot \left(1 - v \cdot v\right)} \]
    6. *-commutative99.1%

      \[\leadsto \left(1 + v \cdot \left(v \cdot -5\right)\right) \cdot \frac{1}{\color{blue}{\left(1 - v \cdot v\right) \cdot \left(\left(\pi \cdot t\right) \cdot \sqrt{2 \cdot \left(1 - \left(\left(1 + v \cdot \left(v \cdot 3\right)\right) - 1\right)\right)}\right)}} \]
    7. associate-*l*99.1%

      \[\leadsto \left(1 + v \cdot \left(v \cdot -5\right)\right) \cdot \frac{1}{\left(1 - v \cdot v\right) \cdot \color{blue}{\left(\pi \cdot \left(t \cdot \sqrt{2 \cdot \left(1 - \left(\left(1 + v \cdot \left(v \cdot 3\right)\right) - 1\right)\right)}\right)\right)}} \]
    8. associate--r-99.1%

      \[\leadsto \left(1 + v \cdot \left(v \cdot -5\right)\right) \cdot \frac{1}{\left(1 - v \cdot v\right) \cdot \left(\pi \cdot \left(t \cdot \sqrt{2 \cdot \color{blue}{\left(\left(1 - \left(1 + v \cdot \left(v \cdot 3\right)\right)\right) + 1\right)}}\right)\right)} \]
  5. Applied egg-rr99.1%

    \[\leadsto \color{blue}{\left(1 + v \cdot \left(v \cdot -5\right)\right) \cdot \frac{1}{\left(1 - v \cdot v\right) \cdot \left(\pi \cdot \left(t \cdot \sqrt{2 \cdot \left(\left(1 - \left(1 + v \cdot \left(v \cdot 3\right)\right)\right) + 1\right)}\right)\right)}} \]
  6. Final simplification99.1%

    \[\leadsto \left(1 + v \cdot \left(v \cdot -5\right)\right) \cdot \frac{1}{\left(1 - v \cdot v\right) \cdot \left(\pi \cdot \left(t \cdot \sqrt{2 \cdot \left(1 + \left(1 + \left(-1 - v \cdot \left(v \cdot 3\right)\right)\right)\right)}\right)\right)} \]

Alternative 2: 99.3% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \frac{1 + -5 \cdot \left(v \cdot v\right)}{\pi \cdot \left(t \cdot \left(\left(1 - v \cdot v\right) \cdot \sqrt{2 \cdot \left(1 - v \cdot \left(v \cdot 3\right)\right)}\right)\right)} \end{array} \]
(FPCore (v t)
 :precision binary64
 (/
  (+ 1.0 (* -5.0 (* v v)))
  (* PI (* t (* (- 1.0 (* v v)) (sqrt (* 2.0 (- 1.0 (* v (* v 3.0))))))))))
double code(double v, double t) {
	return (1.0 + (-5.0 * (v * v))) / (((double) M_PI) * (t * ((1.0 - (v * v)) * sqrt((2.0 * (1.0 - (v * (v * 3.0))))))));
}
public static double code(double v, double t) {
	return (1.0 + (-5.0 * (v * v))) / (Math.PI * (t * ((1.0 - (v * v)) * Math.sqrt((2.0 * (1.0 - (v * (v * 3.0))))))));
}
def code(v, t):
	return (1.0 + (-5.0 * (v * v))) / (math.pi * (t * ((1.0 - (v * v)) * math.sqrt((2.0 * (1.0 - (v * (v * 3.0))))))))
function code(v, t)
	return Float64(Float64(1.0 + Float64(-5.0 * Float64(v * v))) / Float64(pi * Float64(t * Float64(Float64(1.0 - Float64(v * v)) * sqrt(Float64(2.0 * Float64(1.0 - Float64(v * Float64(v * 3.0)))))))))
end
function tmp = code(v, t)
	tmp = (1.0 + (-5.0 * (v * v))) / (pi * (t * ((1.0 - (v * v)) * sqrt((2.0 * (1.0 - (v * (v * 3.0))))))));
end
code[v_, t_] := N[(N[(1.0 + N[(-5.0 * N[(v * v), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(Pi * N[(t * N[(N[(1.0 - N[(v * v), $MachinePrecision]), $MachinePrecision] * N[Sqrt[N[(2.0 * N[(1.0 - N[(v * N[(v * 3.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{1 + -5 \cdot \left(v \cdot v\right)}{\pi \cdot \left(t \cdot \left(\left(1 - v \cdot v\right) \cdot \sqrt{2 \cdot \left(1 - v \cdot \left(v \cdot 3\right)\right)}\right)\right)}
\end{array}
Derivation
  1. Initial program 99.1%

    \[\frac{1 - 5 \cdot \left(v \cdot v\right)}{\left(\left(\pi \cdot t\right) \cdot \sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)}\right) \cdot \left(1 - v \cdot v\right)} \]
  2. Simplified99.1%

    \[\leadsto \color{blue}{\frac{1 + \left(v \cdot v\right) \cdot -5}{\pi \cdot \left(t \cdot \left(\sqrt{2 \cdot \left(1 - v \cdot \left(v \cdot 3\right)\right)} \cdot \left(1 - v \cdot v\right)\right)\right)}} \]
  3. Final simplification99.1%

    \[\leadsto \frac{1 + -5 \cdot \left(v \cdot v\right)}{\pi \cdot \left(t \cdot \left(\left(1 - v \cdot v\right) \cdot \sqrt{2 \cdot \left(1 - v \cdot \left(v \cdot 3\right)\right)}\right)\right)} \]

Alternative 3: 98.3% accurate, 1.1× speedup?

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

\\
\frac{1}{t \cdot \left(\pi \cdot \sqrt{2}\right)}
\end{array}
Derivation
  1. Initial program 99.1%

    \[\frac{1 - 5 \cdot \left(v \cdot v\right)}{\left(\left(\pi \cdot t\right) \cdot \sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)}\right) \cdot \left(1 - v \cdot v\right)} \]
  2. Simplified99.1%

    \[\leadsto \color{blue}{\frac{1 + \left(v \cdot v\right) \cdot -5}{\pi \cdot \left(t \cdot \left(\sqrt{2 \cdot \left(1 - v \cdot \left(v \cdot 3\right)\right)} \cdot \left(1 - v \cdot v\right)\right)\right)}} \]
  3. Taylor expanded in v around 0 98.4%

    \[\leadsto \color{blue}{\frac{1}{t \cdot \left(\pi \cdot \sqrt{2}\right)}} \]
  4. Final simplification98.4%

    \[\leadsto \frac{1}{t \cdot \left(\pi \cdot \sqrt{2}\right)} \]

Alternative 4: 98.4% accurate, 1.1× speedup?

\[\begin{array}{l} \\ \frac{\frac{1}{t}}{\pi \cdot \sqrt{2}} \end{array} \]
(FPCore (v t) :precision binary64 (/ (/ 1.0 t) (* PI (sqrt 2.0))))
double code(double v, double t) {
	return (1.0 / t) / (((double) M_PI) * sqrt(2.0));
}
public static double code(double v, double t) {
	return (1.0 / t) / (Math.PI * Math.sqrt(2.0));
}
def code(v, t):
	return (1.0 / t) / (math.pi * math.sqrt(2.0))
function code(v, t)
	return Float64(Float64(1.0 / t) / Float64(pi * sqrt(2.0)))
end
function tmp = code(v, t)
	tmp = (1.0 / t) / (pi * sqrt(2.0));
end
code[v_, t_] := N[(N[(1.0 / t), $MachinePrecision] / N[(Pi * N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{\frac{1}{t}}{\pi \cdot \sqrt{2}}
\end{array}
Derivation
  1. Initial program 99.1%

    \[\frac{1 - 5 \cdot \left(v \cdot v\right)}{\left(\left(\pi \cdot t\right) \cdot \sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)}\right) \cdot \left(1 - v \cdot v\right)} \]
  2. Simplified99.1%

    \[\leadsto \color{blue}{\frac{1 + \left(v \cdot v\right) \cdot -5}{\pi \cdot \left(t \cdot \left(\sqrt{2 \cdot \left(1 - v \cdot \left(v \cdot 3\right)\right)} \cdot \left(1 - v \cdot v\right)\right)\right)}} \]
  3. Taylor expanded in v around 0 98.4%

    \[\leadsto \color{blue}{\frac{1}{t \cdot \left(\pi \cdot \sqrt{2}\right)}} \]
  4. Step-by-step derivation
    1. expm1-log1p-u71.4%

      \[\leadsto \color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\frac{1}{t \cdot \left(\pi \cdot \sqrt{2}\right)}\right)\right)} \]
    2. expm1-udef31.1%

      \[\leadsto \color{blue}{e^{\mathsf{log1p}\left(\frac{1}{t \cdot \left(\pi \cdot \sqrt{2}\right)}\right)} - 1} \]
  5. Applied egg-rr31.1%

    \[\leadsto \color{blue}{e^{\mathsf{log1p}\left(\frac{1}{t \cdot \left(\pi \cdot \sqrt{2}\right)}\right)} - 1} \]
  6. Step-by-step derivation
    1. expm1-def71.4%

      \[\leadsto \color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\frac{1}{t \cdot \left(\pi \cdot \sqrt{2}\right)}\right)\right)} \]
    2. expm1-log1p98.4%

      \[\leadsto \color{blue}{\frac{1}{t \cdot \left(\pi \cdot \sqrt{2}\right)}} \]
    3. associate-/r*98.7%

      \[\leadsto \color{blue}{\frac{\frac{1}{t}}{\pi \cdot \sqrt{2}}} \]
  7. Simplified98.7%

    \[\leadsto \color{blue}{\frac{\frac{1}{t}}{\pi \cdot \sqrt{2}}} \]
  8. Final simplification98.7%

    \[\leadsto \frac{\frac{1}{t}}{\pi \cdot \sqrt{2}} \]

Alternative 5: 97.7% accurate, 1.1× speedup?

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

\\
\frac{\sqrt{0.5}}{\pi \cdot t}
\end{array}
Derivation
  1. Initial program 99.1%

    \[\frac{1 - 5 \cdot \left(v \cdot v\right)}{\left(\left(\pi \cdot t\right) \cdot \sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)}\right) \cdot \left(1 - v \cdot v\right)} \]
  2. Step-by-step derivation
    1. associate-*l*99.1%

      \[\leadsto \frac{1 - 5 \cdot \left(v \cdot v\right)}{\color{blue}{\left(\pi \cdot t\right) \cdot \left(\sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)} \cdot \left(1 - v \cdot v\right)\right)}} \]
    2. associate-/r*99.1%

      \[\leadsto \color{blue}{\frac{\frac{1 - 5 \cdot \left(v \cdot v\right)}{\pi \cdot t}}{\sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)} \cdot \left(1 - v \cdot v\right)}} \]
    3. sub-neg99.1%

      \[\leadsto \frac{\frac{\color{blue}{1 + \left(-5 \cdot \left(v \cdot v\right)\right)}}{\pi \cdot t}}{\sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)} \cdot \left(1 - v \cdot v\right)} \]
    4. +-commutative99.1%

      \[\leadsto \frac{\frac{\color{blue}{\left(-5 \cdot \left(v \cdot v\right)\right) + 1}}{\pi \cdot t}}{\sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)} \cdot \left(1 - v \cdot v\right)} \]
    5. sqr-neg99.1%

      \[\leadsto \frac{\frac{\left(-5 \cdot \color{blue}{\left(\left(-v\right) \cdot \left(-v\right)\right)}\right) + 1}{\pi \cdot t}}{\sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)} \cdot \left(1 - v \cdot v\right)} \]
    6. *-commutative99.1%

      \[\leadsto \frac{\frac{\left(-\color{blue}{\left(\left(-v\right) \cdot \left(-v\right)\right) \cdot 5}\right) + 1}{\pi \cdot t}}{\sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)} \cdot \left(1 - v \cdot v\right)} \]
    7. distribute-rgt-neg-in99.1%

      \[\leadsto \frac{\frac{\color{blue}{\left(\left(-v\right) \cdot \left(-v\right)\right) \cdot \left(-5\right)} + 1}{\pi \cdot t}}{\sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)} \cdot \left(1 - v \cdot v\right)} \]
    8. fma-def99.1%

      \[\leadsto \frac{\frac{\color{blue}{\mathsf{fma}\left(\left(-v\right) \cdot \left(-v\right), -5, 1\right)}}{\pi \cdot t}}{\sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)} \cdot \left(1 - v \cdot v\right)} \]
    9. sqr-neg99.1%

      \[\leadsto \frac{\frac{\mathsf{fma}\left(\color{blue}{v \cdot v}, -5, 1\right)}{\pi \cdot t}}{\sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)} \cdot \left(1 - v \cdot v\right)} \]
    10. metadata-eval99.1%

      \[\leadsto \frac{\frac{\mathsf{fma}\left(v \cdot v, \color{blue}{-5}, 1\right)}{\pi \cdot t}}{\sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)} \cdot \left(1 - v \cdot v\right)} \]
  3. Simplified99.1%

    \[\leadsto \color{blue}{\frac{\frac{\mathsf{fma}\left(v \cdot v, -5, 1\right)}{\pi \cdot t}}{\sqrt{2 + \left(v \cdot v\right) \cdot -6} \cdot \left(1 - v \cdot v\right)}} \]
  4. Taylor expanded in v around 0 97.9%

    \[\leadsto \color{blue}{\frac{\sqrt{0.5}}{t \cdot \pi}} \]
  5. Final simplification97.9%

    \[\leadsto \frac{\sqrt{0.5}}{\pi \cdot t} \]

Alternative 6: 97.8% accurate, 1.1× speedup?

\[\begin{array}{l} \\ \frac{\frac{\sqrt{0.5}}{t}}{\pi} \end{array} \]
(FPCore (v t) :precision binary64 (/ (/ (sqrt 0.5) t) PI))
double code(double v, double t) {
	return (sqrt(0.5) / t) / ((double) M_PI);
}
public static double code(double v, double t) {
	return (Math.sqrt(0.5) / t) / Math.PI;
}
def code(v, t):
	return (math.sqrt(0.5) / t) / math.pi
function code(v, t)
	return Float64(Float64(sqrt(0.5) / t) / pi)
end
function tmp = code(v, t)
	tmp = (sqrt(0.5) / t) / pi;
end
code[v_, t_] := N[(N[(N[Sqrt[0.5], $MachinePrecision] / t), $MachinePrecision] / Pi), $MachinePrecision]
\begin{array}{l}

\\
\frac{\frac{\sqrt{0.5}}{t}}{\pi}
\end{array}
Derivation
  1. Initial program 99.1%

    \[\frac{1 - 5 \cdot \left(v \cdot v\right)}{\left(\left(\pi \cdot t\right) \cdot \sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)}\right) \cdot \left(1 - v \cdot v\right)} \]
  2. Step-by-step derivation
    1. associate-*l*99.1%

      \[\leadsto \frac{1 - 5 \cdot \left(v \cdot v\right)}{\color{blue}{\left(\pi \cdot t\right) \cdot \left(\sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)} \cdot \left(1 - v \cdot v\right)\right)}} \]
    2. associate-/r*99.1%

      \[\leadsto \color{blue}{\frac{\frac{1 - 5 \cdot \left(v \cdot v\right)}{\pi \cdot t}}{\sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)} \cdot \left(1 - v \cdot v\right)}} \]
    3. sub-neg99.1%

      \[\leadsto \frac{\frac{\color{blue}{1 + \left(-5 \cdot \left(v \cdot v\right)\right)}}{\pi \cdot t}}{\sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)} \cdot \left(1 - v \cdot v\right)} \]
    4. +-commutative99.1%

      \[\leadsto \frac{\frac{\color{blue}{\left(-5 \cdot \left(v \cdot v\right)\right) + 1}}{\pi \cdot t}}{\sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)} \cdot \left(1 - v \cdot v\right)} \]
    5. sqr-neg99.1%

      \[\leadsto \frac{\frac{\left(-5 \cdot \color{blue}{\left(\left(-v\right) \cdot \left(-v\right)\right)}\right) + 1}{\pi \cdot t}}{\sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)} \cdot \left(1 - v \cdot v\right)} \]
    6. *-commutative99.1%

      \[\leadsto \frac{\frac{\left(-\color{blue}{\left(\left(-v\right) \cdot \left(-v\right)\right) \cdot 5}\right) + 1}{\pi \cdot t}}{\sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)} \cdot \left(1 - v \cdot v\right)} \]
    7. distribute-rgt-neg-in99.1%

      \[\leadsto \frac{\frac{\color{blue}{\left(\left(-v\right) \cdot \left(-v\right)\right) \cdot \left(-5\right)} + 1}{\pi \cdot t}}{\sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)} \cdot \left(1 - v \cdot v\right)} \]
    8. fma-def99.1%

      \[\leadsto \frac{\frac{\color{blue}{\mathsf{fma}\left(\left(-v\right) \cdot \left(-v\right), -5, 1\right)}}{\pi \cdot t}}{\sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)} \cdot \left(1 - v \cdot v\right)} \]
    9. sqr-neg99.1%

      \[\leadsto \frac{\frac{\mathsf{fma}\left(\color{blue}{v \cdot v}, -5, 1\right)}{\pi \cdot t}}{\sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)} \cdot \left(1 - v \cdot v\right)} \]
    10. metadata-eval99.1%

      \[\leadsto \frac{\frac{\mathsf{fma}\left(v \cdot v, \color{blue}{-5}, 1\right)}{\pi \cdot t}}{\sqrt{2 \cdot \left(1 - 3 \cdot \left(v \cdot v\right)\right)} \cdot \left(1 - v \cdot v\right)} \]
  3. Simplified99.1%

    \[\leadsto \color{blue}{\frac{\frac{\mathsf{fma}\left(v \cdot v, -5, 1\right)}{\pi \cdot t}}{\sqrt{2 + \left(v \cdot v\right) \cdot -6} \cdot \left(1 - v \cdot v\right)}} \]
  4. Taylor expanded in v around 0 97.9%

    \[\leadsto \color{blue}{\frac{\sqrt{0.5}}{t \cdot \pi}} \]
  5. Step-by-step derivation
    1. div-inv97.9%

      \[\leadsto \color{blue}{\sqrt{0.5} \cdot \frac{1}{t \cdot \pi}} \]
    2. associate-/r*98.1%

      \[\leadsto \sqrt{0.5} \cdot \color{blue}{\frac{\frac{1}{t}}{\pi}} \]
  6. Applied egg-rr98.1%

    \[\leadsto \color{blue}{\sqrt{0.5} \cdot \frac{\frac{1}{t}}{\pi}} \]
  7. Taylor expanded in t around 0 97.9%

    \[\leadsto \color{blue}{\frac{\sqrt{0.5}}{t \cdot \pi}} \]
  8. Step-by-step derivation
    1. associate-/r*98.2%

      \[\leadsto \color{blue}{\frac{\frac{\sqrt{0.5}}{t}}{\pi}} \]
  9. Simplified98.2%

    \[\leadsto \color{blue}{\frac{\frac{\sqrt{0.5}}{t}}{\pi}} \]
  10. Final simplification98.2%

    \[\leadsto \frac{\frac{\sqrt{0.5}}{t}}{\pi} \]

Reproduce

?
herbie shell --seed 2023271 
(FPCore (v t)
  :name "Falkner and Boettcher, Equation (20:1,3)"
  :precision binary64
  (/ (- 1.0 (* 5.0 (* v v))) (* (* (* PI t) (sqrt (* 2.0 (- 1.0 (* 3.0 (* v v)))))) (- 1.0 (* v v)))))