VandenBroeck and Keller, Equation (6)

Average Error: 16.4 → 0.8

Time: 9.6s

Precision: binary64

Cost: 32968

Math

\[\pi \cdot \ell - \frac{1}{F \cdot F} \cdot \tan \left(\pi \cdot \ell\right) \]

↓

\[\begin{array}{l} \mathbf{if}\;\pi \cdot \ell \leq -4 \cdot 10^{+20}:\\ \;\;\;\;\pi \cdot \ell\\ \mathbf{elif}\;\pi \cdot \ell \leq 2 \cdot 10^{-6}:\\ \;\;\;\;\pi \cdot \ell - \frac{\frac{\tan \left(\pi \cdot \ell\right)}{F}}{F}\\ \mathbf{else}:\\ \;\;\;\;\pi \cdot \ell\\ \end{array} \]

FPCore

(FPCore (F l)
 :precision binary64
 (- (* PI l) (* (/ 1.0 (* F F)) (tan (* PI l)))))

↓

(FPCore (F l)
 :precision binary64
 (if (<= (* PI l) -4e+20)
   (* PI l)
   (if (<= (* PI l) 2e-6) (- (* PI l) (/ (/ (tan (* PI l)) F) F)) (* PI l))))

C

double code(double F, double l) {
	return (((double) M_PI) * l) - ((1.0 / (F * F)) * tan((((double) M_PI) * l)));
}

↓

double code(double F, double l) {
	double tmp;
	if ((((double) M_PI) * l) <= -4e+20) {
		tmp = ((double) M_PI) * l;
	} else if ((((double) M_PI) * l) <= 2e-6) {
		tmp = (((double) M_PI) * l) - ((tan((((double) M_PI) * l)) / F) / F);
	} else {
		tmp = ((double) M_PI) * l;
	}
	return tmp;
}

Java

public static double code(double F, double l) {
	return (Math.PI * l) - ((1.0 / (F * F)) * Math.tan((Math.PI * l)));
}

↓

public static double code(double F, double l) {
	double tmp;
	if ((Math.PI * l) <= -4e+20) {
		tmp = Math.PI * l;
	} else if ((Math.PI * l) <= 2e-6) {
		tmp = (Math.PI * l) - ((Math.tan((Math.PI * l)) / F) / F);
	} else {
		tmp = Math.PI * l;
	}
	return tmp;
}

Python

def code(F, l):
	return (math.pi * l) - ((1.0 / (F * F)) * math.tan((math.pi * l)))

↓

def code(F, l):
	tmp = 0
	if (math.pi * l) <= -4e+20:
		tmp = math.pi * l
	elif (math.pi * l) <= 2e-6:
		tmp = (math.pi * l) - ((math.tan((math.pi * l)) / F) / F)
	else:
		tmp = math.pi * l
	return tmp

Julia

function code(F, l)
	return Float64(Float64(pi * l) - Float64(Float64(1.0 / Float64(F * F)) * tan(Float64(pi * l))))
end

↓

function code(F, l)
	tmp = 0.0
	if (Float64(pi * l) <= -4e+20)
		tmp = Float64(pi * l);
	elseif (Float64(pi * l) <= 2e-6)
		tmp = Float64(Float64(pi * l) - Float64(Float64(tan(Float64(pi * l)) / F) / F));
	else
		tmp = Float64(pi * l);
	end
	return tmp
end

MATLAB

function tmp = code(F, l)
	tmp = (pi * l) - ((1.0 / (F * F)) * tan((pi * l)));
end

↓

function tmp_2 = code(F, l)
	tmp = 0.0;
	if ((pi * l) <= -4e+20)
		tmp = pi * l;
	elseif ((pi * l) <= 2e-6)
		tmp = (pi * l) - ((tan((pi * l)) / F) / F);
	else
		tmp = pi * l;
	end
	tmp_2 = tmp;
end

Wolfram

code[F_, l_] := N[(N[(Pi * l), $MachinePrecision] - N[(N[(1.0 / N[(F * F), $MachinePrecision]), $MachinePrecision] * N[Tan[N[(Pi * l), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]

↓

code[F_, l_] := If[LessEqual[N[(Pi * l), $MachinePrecision], -4e+20], N[(Pi * l), $MachinePrecision], If[LessEqual[N[(Pi * l), $MachinePrecision], 2e-6], N[(N[(Pi * l), $MachinePrecision] - N[(N[(N[Tan[N[(Pi * l), $MachinePrecision]], $MachinePrecision] / F), $MachinePrecision] / F), $MachinePrecision]), $MachinePrecision], N[(Pi * l), $MachinePrecision]]]

Derivation

1. Split input into 2 regimes

2. if (*.f64 (PI.f64) l) < -4e20 or 1.99999999999999991e-6 < (*.f64 (PI.f64) l)

   1. Initial program 23.2

      \[\pi \cdot \ell - \frac{1}{F \cdot F} \cdot \tan \left(\pi \cdot \ell\right) \]

   2. Simplified 23.2

      \[\leadsto \color{blue}{\pi \cdot \ell - \frac{\tan \left(\pi \cdot \ell\right)}{F \cdot F}} \]

   3. Taylor expanded in l around inf 0.9

      \[\leadsto \color{blue}{\ell \cdot \pi} \]

   if -4e20 < (*.f64 (PI.f64) l) < 1.99999999999999991e-6

   1. Initial program 9.2

      \[\pi \cdot \ell - \frac{1}{F \cdot F} \cdot \tan \left(\pi \cdot \ell\right) \]

   2. Taylor expanded in F around 0 9.2

      \[\leadsto \pi \cdot \ell - \color{blue}{\frac{1}{{F}^{2}}} \cdot \tan \left(\pi \cdot \ell\right) \]

   3. Simplified 9.2

      \[\leadsto \pi \cdot \ell - \color{blue}{\frac{\frac{1}{F}}{F}} \cdot \tan \left(\pi \cdot \ell\right) \]

   4. Applied egg-rr 0.7

      \[\leadsto \pi \cdot \ell - \color{blue}{\frac{\frac{\tan \left(\pi \cdot \ell\right)}{F}}{F}} \]
3. Recombined 2 regimes into one program.

4. Final simplification 0.8

   \[\leadsto \begin{array}{l} \mathbf{if}\;\pi \cdot \ell \leq -4 \cdot 10^{+20}:\\ \;\;\;\;\pi \cdot \ell\\ \mathbf{elif}\;\pi \cdot \ell \leq 2 \cdot 10^{-6}:\\ \;\;\;\;\pi \cdot \ell - \frac{\frac{\tan \left(\pi \cdot \ell\right)}{F}}{F}\\ \mathbf{else}:\\ \;\;\;\;\pi \cdot \ell\\ \end{array} \]

Alternatives

Alternative 1
Error	0.9
Cost	13640

\[\begin{array}{l} \mathbf{if}\;\ell \leq -92000000:\\ \;\;\;\;\pi \cdot \ell\\ \mathbf{elif}\;\ell \leq 4.4 \cdot 10^{-7}:\\ \;\;\;\;\pi \cdot \ell - \frac{\pi}{\frac{F}{\frac{\ell}{F}}}\\ \mathbf{else}:\\ \;\;\;\;\pi \cdot \ell\\ \end{array} \]

Alternative 2
Error	14.0
Cost	7376

\[\begin{array}{l} t_0 := \frac{\ell}{F} \cdot \frac{-\pi}{F}\\ \mathbf{if}\;\ell \leq -4.287248385977879 \cdot 10^{-210}:\\ \;\;\;\;\pi \cdot \ell\\ \mathbf{elif}\;\ell \leq -1.004418434814658 \cdot 10^{-288}:\\ \;\;\;\;t_0\\ \mathbf{elif}\;\ell \leq 4.11000928044673 \cdot 10^{-216}:\\ \;\;\;\;\pi \cdot \ell\\ \mathbf{elif}\;\ell \leq 2.25 \cdot 10^{-147}:\\ \;\;\;\;t_0\\ \mathbf{else}:\\ \;\;\;\;\pi \cdot \ell\\ \end{array} \]

Alternative 3
Error	0.9
Cost	7176

\[\begin{array}{l} \mathbf{if}\;\ell \leq -92000000:\\ \;\;\;\;\pi \cdot \ell\\ \mathbf{elif}\;\ell \leq 4.4 \cdot 10^{-7}:\\ \;\;\;\;\pi \cdot \left(\ell - \frac{\frac{\ell}{F}}{F}\right)\\ \mathbf{else}:\\ \;\;\;\;\pi \cdot \ell\\ \end{array} \]

Alternative 4
Error	13.7
Cost	6528

\[\pi \cdot \ell \]

Reproduce

herbie shell --seed 2022228 
(FPCore (F l)
  :name "VandenBroeck and Keller, Equation (6)"
  :precision binary64
  (- (* PI l) (* (/ 1.0 (* F F)) (tan (* PI l)))))