VandenBroeck and Keller, Equation (6)

Average Error: 16.6 → 0.7

Time: 12.9s

Precision: binary64

Cost: 32968

Math

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

↓

\[\begin{array}{l} \mathbf{if}\;\pi \cdot \ell \leq -5 \cdot 10^{+19}:\\ \;\;\;\;\pi \cdot \ell\\ \mathbf{elif}\;\pi \cdot \ell \leq 5 \cdot 10^{-7}:\\ \;\;\;\;\pi \cdot \ell - \frac{\frac{\tan \left(\pi \cdot \ell\right)}{F}}{F}\\ \mathbf{else}:\\ \;\;\;\;\pi \cdot \ell\\ \end{array} \]

FPCore

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

↓

(FPCore (F l)
 :precision binary64
 (if (<= (* PI l) -5e+19)
   (* PI l)
   (if (<= (* PI l) 5e-7) (- (* 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) <= -5e+19) {
		tmp = ((double) M_PI) * l;
	} else if ((((double) M_PI) * l) <= 5e-7) {
		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) <= -5e+19) {
		tmp = Math.PI * l;
	} else if ((Math.PI * l) <= 5e-7) {
		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) <= -5e+19:
		tmp = math.pi * l
	elif (math.pi * l) <= 5e-7:
		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) <= -5e+19)
		tmp = Float64(pi * l);
	elseif (Float64(pi * l) <= 5e-7)
		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) <= -5e+19)
		tmp = pi * l;
	elseif ((pi * l) <= 5e-7)
		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], -5e+19], N[(Pi * l), $MachinePrecision], If[LessEqual[N[(Pi * l), $MachinePrecision], 5e-7], 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) < -5e19 or 4.99999999999999977e-7 < (*.f64 (PI.f64) l)

   1. Initial program 23.0

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

   2. Simplified 23.0

      \[\leadsto \color{blue}{\pi \cdot \ell - \frac{\tan \left(\pi \cdot \ell\right)}{F \cdot F}} \]
      Proof
      (-.f64 (*.f64 (PI.f64) l) (/.f64 (tan.f64 (*.f64 (PI.f64) l)) (*.f64 F F))): 0 points increase in error, 0 points decrease in error
      (-.f64 (*.f64 (PI.f64) l) (/.f64 (Rewrite<= *-lft-identity_binary64 (*.f64 1 (tan.f64 (*.f64 (PI.f64) l)))) (*.f64 F F))): 0 points increase in error, 0 points decrease in error
      (-.f64 (*.f64 (PI.f64) l) (Rewrite<= associate-*l/_binary64 (*.f64 (/.f64 1 (*.f64 F F)) (tan.f64 (*.f64 (PI.f64) l))))): 1 points increase in error, 5 points decrease in error

   3. Taylor expanded in l around inf 0.8

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

   if -5e19 < (*.f64 (PI.f64) l) < 4.99999999999999977e-7

   1. Initial program 9.7

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

   2. Applied egg-rr 0.6

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

4. Final simplification 0.7

   \[\leadsto \begin{array}{l} \mathbf{if}\;\pi \cdot \ell \leq -5 \cdot 10^{+19}:\\ \;\;\;\;\pi \cdot \ell\\ \mathbf{elif}\;\pi \cdot \ell \leq 5 \cdot 10^{-7}:\\ \;\;\;\;\pi \cdot \ell - \frac{\frac{\tan \left(\pi \cdot \ell\right)}{F}}{F}\\ \mathbf{else}:\\ \;\;\;\;\pi \cdot \ell\\ \end{array} \]

Alternatives

Alternative 1
Error	0.8
Cost	13640

\[\begin{array}{l} \mathbf{if}\;\ell \leq -22484240992040042000:\\ \;\;\;\;\pi \cdot \ell\\ \mathbf{elif}\;\ell \leq 9.2 \cdot 10^{-8}:\\ \;\;\;\;\pi \cdot \ell - \frac{\frac{\pi \cdot \ell}{F}}{F}\\ \mathbf{else}:\\ \;\;\;\;\pi \cdot \ell\\ \end{array} \]

Alternative 2
Error	0.8
Cost	13640

\[\begin{array}{l} \mathbf{if}\;\ell \leq -22484240992040042000:\\ \;\;\;\;\pi \cdot \ell\\ \mathbf{elif}\;\ell \leq 9.2 \cdot 10^{-8}:\\ \;\;\;\;\pi \cdot \ell - \frac{\frac{\pi}{\frac{F}{\ell}}}{F}\\ \mathbf{else}:\\ \;\;\;\;\pi \cdot \ell\\ \end{array} \]

Alternative 3
Error	5.2
Cost	7368

\[\begin{array}{l} \mathbf{if}\;\ell \leq -22484240992040042000:\\ \;\;\;\;\pi \cdot \ell\\ \mathbf{elif}\;\ell \leq 9.2 \cdot 10^{-8}:\\ \;\;\;\;\pi \cdot \left(\ell + \ell \cdot \frac{1}{F \cdot \left(-F\right)}\right)\\ \mathbf{else}:\\ \;\;\;\;\pi \cdot \ell\\ \end{array} \]

Alternative 4
Error	4.9
Cost	7176

\[\begin{array}{l} \mathbf{if}\;\ell \leq -22484240992040042000:\\ \;\;\;\;\pi \cdot \ell\\ \mathbf{elif}\;\ell \leq 9.2 \cdot 10^{-8}:\\ \;\;\;\;\pi \cdot \left(\ell - \frac{\ell}{F \cdot F}\right)\\ \mathbf{else}:\\ \;\;\;\;\pi \cdot \ell\\ \end{array} \]

Alternative 5
Error	13.5
Cost	7112

\[\begin{array}{l} \mathbf{if}\;F \leq 7.5 \cdot 10^{-208}:\\ \;\;\;\;\pi \cdot \ell\\ \mathbf{elif}\;F \leq 8.182058973613726 \cdot 10^{-123}:\\ \;\;\;\;\frac{\frac{\ell}{F}}{F} \cdot \left(-\pi\right)\\ \mathbf{else}:\\ \;\;\;\;\pi \cdot \ell\\ \end{array} \]

Alternative 6
Error	13.3
Cost	6528

\[\pi \cdot \ell \]

Reproduce

herbie shell --seed 2022310 
(FPCore (F l)
  :name "VandenBroeck and Keller, Equation (6)"
  :precision binary64
  (- (* PI l) (* (/ 1.0 (* F F)) (tan (* PI l)))))