Linear.Quaternion:$ctanh from linear-1.19.1.3

Average Error: 2.8 → 0.7

Time: 10.2s

Precision: binary64

Cost: 7113

Math

\[\frac{x \cdot \frac{\sin y}{y}}{z} \]

↓

\[\begin{array}{l} t_0 := \frac{\sin y}{y}\\ \mathbf{if}\;z \leq -8.5 \cdot 10^{+81} \lor \neg \left(z \leq 4.9 \cdot 10^{-174}\right):\\ \;\;\;\;\frac{x \cdot t_0}{z}\\ \mathbf{else}:\\ \;\;\;\;\frac{x}{\frac{z}{t_0}}\\ \end{array} \]

FPCore

(FPCore (x y z) :precision binary64 (/ (* x (/ (sin y) y)) z))

↓

(FPCore (x y z)
 :precision binary64
 (let* ((t_0 (/ (sin y) y)))
   (if (or (<= z -8.5e+81) (not (<= z 4.9e-174)))
     (/ (* x t_0) z)
     (/ x (/ z t_0)))))

C

double code(double x, double y, double z) {
	return (x * (sin(y) / y)) / z;
}

↓

double code(double x, double y, double z) {
	double t_0 = sin(y) / y;
	double tmp;
	if ((z <= -8.5e+81) || !(z <= 4.9e-174)) {
		tmp = (x * t_0) / z;
	} else {
		tmp = x / (z / t_0);
	}
	return tmp;
}

Fortran

real(8) function code(x, y, z)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    code = (x * (sin(y) / y)) / z
end function

↓

real(8) function code(x, y, z)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    real(8) :: t_0
    real(8) :: tmp
    t_0 = sin(y) / y
    if ((z <= (-8.5d+81)) .or. (.not. (z <= 4.9d-174))) then
        tmp = (x * t_0) / z
    else
        tmp = x / (z / t_0)
    end if
    code = tmp
end function

Java

public static double code(double x, double y, double z) {
	return (x * (Math.sin(y) / y)) / z;
}

↓

public static double code(double x, double y, double z) {
	double t_0 = Math.sin(y) / y;
	double tmp;
	if ((z <= -8.5e+81) || !(z <= 4.9e-174)) {
		tmp = (x * t_0) / z;
	} else {
		tmp = x / (z / t_0);
	}
	return tmp;
}

Python

def code(x, y, z):
	return (x * (math.sin(y) / y)) / z

↓

def code(x, y, z):
	t_0 = math.sin(y) / y
	tmp = 0
	if (z <= -8.5e+81) or not (z <= 4.9e-174):
		tmp = (x * t_0) / z
	else:
		tmp = x / (z / t_0)
	return tmp

Julia

function code(x, y, z)
	return Float64(Float64(x * Float64(sin(y) / y)) / z)
end

↓

function code(x, y, z)
	t_0 = Float64(sin(y) / y)
	tmp = 0.0
	if ((z <= -8.5e+81) || !(z <= 4.9e-174))
		tmp = Float64(Float64(x * t_0) / z);
	else
		tmp = Float64(x / Float64(z / t_0));
	end
	return tmp
end

MATLAB

function tmp = code(x, y, z)
	tmp = (x * (sin(y) / y)) / z;
end

↓

function tmp_2 = code(x, y, z)
	t_0 = sin(y) / y;
	tmp = 0.0;
	if ((z <= -8.5e+81) || ~((z <= 4.9e-174)))
		tmp = (x * t_0) / z;
	else
		tmp = x / (z / t_0);
	end
	tmp_2 = tmp;
end

Wolfram

code[x_, y_, z_] := N[(N[(x * N[(N[Sin[y], $MachinePrecision] / y), $MachinePrecision]), $MachinePrecision] / z), $MachinePrecision]

↓

code[x_, y_, z_] := Block[{t$95$0 = N[(N[Sin[y], $MachinePrecision] / y), $MachinePrecision]}, If[Or[LessEqual[z, -8.5e+81], N[Not[LessEqual[z, 4.9e-174]], $MachinePrecision]], N[(N[(x * t$95$0), $MachinePrecision] / z), $MachinePrecision], N[(x / N[(z / t$95$0), $MachinePrecision]), $MachinePrecision]]]

Target

Original	2.8
Target	0.2
Herbie	0.7

\[\begin{array}{l} \mathbf{if}\;z < -4.2173720203427147 \cdot 10^{-29}:\\ \;\;\;\;\frac{x \cdot \frac{1}{\frac{y}{\sin y}}}{z}\\ \mathbf{elif}\;z < 4.446702369113811 \cdot 10^{+64}:\\ \;\;\;\;\frac{x}{z \cdot \frac{y}{\sin y}}\\ \mathbf{else}:\\ \;\;\;\;\frac{x \cdot \frac{1}{\frac{y}{\sin y}}}{z}\\ \end{array} \]

Derivation

1. Split input into 2 regimes

2. if z < -8.49999999999999986e81 or 4.90000000000000009e-174 < z

   1. Initial program 0.9

      \[\frac{x \cdot \frac{\sin y}{y}}{z} \]

   if -8.49999999999999986e81 < z < 4.90000000000000009e-174

   1. Initial program 5.6

      \[\frac{x \cdot \frac{\sin y}{y}}{z} \]

   2. Simplified 0.4

      \[\leadsto \color{blue}{\frac{x}{\frac{z}{\frac{\sin y}{y}}}} \]
      Proof

      [Start] 5.6	\[ \frac{x \cdot \frac{\sin y}{y}}{z} \]
      associate-/l* [=>] 0.4	\[ \color{blue}{\frac{x}{\frac{z}{\frac{\sin y}{y}}}} \]

3. Recombined 2 regimes into one program.

4. Final simplification 0.7

   \[\leadsto \begin{array}{l} \mathbf{if}\;z \leq -8.5 \cdot 10^{+81} \lor \neg \left(z \leq 4.9 \cdot 10^{-174}\right):\\ \;\;\;\;\frac{x \cdot \frac{\sin y}{y}}{z}\\ \mathbf{else}:\\ \;\;\;\;\frac{x}{\frac{z}{\frac{\sin y}{y}}}\\ \end{array} \]

Alternatives

Alternative 1
Error	3.1
Cost	7113

\[\begin{array}{l} \mathbf{if}\;y \leq -0.00033 \lor \neg \left(y \leq 1.6 \cdot 10^{-46}\right):\\ \;\;\;\;x \cdot \frac{\sin y}{z \cdot y}\\ \mathbf{else}:\\ \;\;\;\;\frac{x}{\frac{z}{1 + y \cdot \left(y \cdot -0.16666666666666666\right)}}\\ \end{array} \]

Alternative 2
Error	1.2
Cost	7113

\[\begin{array}{l} \mathbf{if}\;z \leq -1.8 \cdot 10^{+60} \lor \neg \left(z \leq 3.4 \cdot 10^{+39}\right):\\ \;\;\;\;\sin y \cdot \frac{\frac{x}{z}}{y}\\ \mathbf{else}:\\ \;\;\;\;\frac{x}{y \cdot \frac{z}{\sin y}}\\ \end{array} \]

Alternative 3
Error	2.9
Cost	7112

\[\begin{array}{l} \mathbf{if}\;y \leq -0.00033:\\ \;\;\;\;x \cdot \frac{\sin y}{z \cdot y}\\ \mathbf{elif}\;y \leq 0.00026:\\ \;\;\;\;\frac{x}{\frac{z}{1 + y \cdot \left(y \cdot -0.16666666666666666\right)}}\\ \mathbf{else}:\\ \;\;\;\;\sin y \cdot \frac{\frac{x}{y}}{z}\\ \end{array} \]

Alternative 4
Error	3.0
Cost	7112

\[\begin{array}{l} \mathbf{if}\;y \leq -0.00034:\\ \;\;\;\;x \cdot \frac{\sin y}{z \cdot y}\\ \mathbf{elif}\;y \leq 0.00065:\\ \;\;\;\;\frac{x}{\frac{z}{1 + y \cdot \left(y \cdot -0.16666666666666666\right)}}\\ \mathbf{else}:\\ \;\;\;\;\sin y \cdot \frac{\frac{x}{z}}{y}\\ \end{array} \]

Alternative 5
Error	1.9
Cost	6980

\[\begin{array}{l} \mathbf{if}\;z \leq -1.9 \cdot 10^{+82}:\\ \;\;\;\;\sin y \cdot \frac{\frac{x}{z}}{y}\\ \mathbf{else}:\\ \;\;\;\;\frac{x}{\frac{z}{\frac{\sin y}{y}}}\\ \end{array} \]

Alternative 6
Error	22.7
Cost	1097

\[\begin{array}{l} \mathbf{if}\;y \leq -3800 \lor \neg \left(y \leq 1600000000000\right):\\ \;\;\;\;\frac{x}{y \cdot \left(\left(z \cdot y\right) \cdot 0.16666666666666666 + \frac{z}{y}\right)}\\ \mathbf{else}:\\ \;\;\;\;\frac{x}{\frac{z}{1 + y \cdot \left(y \cdot -0.16666666666666666\right)}}\\ \end{array} \]

Alternative 7
Error	22.9
Cost	969

\[\begin{array}{l} \mathbf{if}\;y \leq -3800 \lor \neg \left(y \leq 1600000000000\right):\\ \;\;\;\;\left(\frac{x}{z} + 1\right) + -1\\ \mathbf{else}:\\ \;\;\;\;\frac{x}{\frac{z}{1 + y \cdot \left(y \cdot -0.16666666666666666\right)}}\\ \end{array} \]

Alternative 8
Error	23.1
Cost	713

\[\begin{array}{l} \mathbf{if}\;y \leq -1.3 \cdot 10^{+23} \lor \neg \left(y \leq 6 \cdot 10^{+36}\right):\\ \;\;\;\;\left(\frac{x}{z} + 1\right) + -1\\ \mathbf{else}:\\ \;\;\;\;\frac{x}{z}\\ \end{array} \]

Alternative 9
Error	28.7
Cost	320

\[\frac{1}{\frac{z}{x}} \]

Alternative 10
Error	28.6
Cost	192

\[\frac{x}{z} \]

Reproduce

herbie shell --seed 2022354 
(FPCore (x y z)
  :name "Linear.Quaternion:$ctanh from linear-1.19.1.3"
  :precision binary64

  :herbie-target
  (if (< z -4.2173720203427147e-29) (/ (* x (/ 1.0 (/ y (sin y)))) z) (if (< z 4.446702369113811e+64) (/ x (* z (/ y (sin y)))) (/ (* x (/ 1.0 (/ y (sin y)))) z)))

  (/ (* x (/ (sin y) y)) z))