sintan (problem 3.4.5)

Average Error: 31.6 → 0.0

Time: 18.3s

Precision: binary64

Cost: 13640

Math

\[\frac{x - \sin x}{x - \tan x} \]

↓

\[\begin{array}{l} \mathbf{if}\;x \leq -0.095:\\ \;\;\;\;\frac{x - \sin x}{x - \tan x}\\ \mathbf{elif}\;x \leq 0.085:\\ \;\;\;\;{x}^{4} \cdot \left(\left(x \cdot x\right) \cdot 0.00024107142857142857 + -0.009642857142857142\right) + \left(\left(x \cdot x\right) \cdot 0.225 + -0.5\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{1}{\frac{\tan x - x}{\sin x - x}}\\ \end{array} \]

FPCore

(FPCore (x) :precision binary64 (/ (- x (sin x)) (- x (tan x))))

↓

(FPCore (x)
 :precision binary64
 (if (<= x -0.095)
   (/ (- x (sin x)) (- x (tan x)))
   (if (<= x 0.085)
     (+
      (*
       (pow x 4.0)
       (+ (* (* x x) 0.00024107142857142857) -0.009642857142857142))
      (+ (* (* x x) 0.225) -0.5))
     (/ 1.0 (/ (- (tan x) x) (- (sin x) x))))))

C

double code(double x) {
	return (x - sin(x)) / (x - tan(x));
}

↓

double code(double x) {
	double tmp;
	if (x <= -0.095) {
		tmp = (x - sin(x)) / (x - tan(x));
	} else if (x <= 0.085) {
		tmp = (pow(x, 4.0) * (((x * x) * 0.00024107142857142857) + -0.009642857142857142)) + (((x * x) * 0.225) + -0.5);
	} else {
		tmp = 1.0 / ((tan(x) - x) / (sin(x) - x));
	}
	return tmp;
}

Fortran

real(8) function code(x)
    real(8), intent (in) :: x
    code = (x - sin(x)) / (x - tan(x))
end function

↓

real(8) function code(x)
    real(8), intent (in) :: x
    real(8) :: tmp
    if (x <= (-0.095d0)) then
        tmp = (x - sin(x)) / (x - tan(x))
    else if (x <= 0.085d0) then
        tmp = ((x ** 4.0d0) * (((x * x) * 0.00024107142857142857d0) + (-0.009642857142857142d0))) + (((x * x) * 0.225d0) + (-0.5d0))
    else
        tmp = 1.0d0 / ((tan(x) - x) / (sin(x) - x))
    end if
    code = tmp
end function

Java

public static double code(double x) {
	return (x - Math.sin(x)) / (x - Math.tan(x));
}

↓

public static double code(double x) {
	double tmp;
	if (x <= -0.095) {
		tmp = (x - Math.sin(x)) / (x - Math.tan(x));
	} else if (x <= 0.085) {
		tmp = (Math.pow(x, 4.0) * (((x * x) * 0.00024107142857142857) + -0.009642857142857142)) + (((x * x) * 0.225) + -0.5);
	} else {
		tmp = 1.0 / ((Math.tan(x) - x) / (Math.sin(x) - x));
	}
	return tmp;
}

Python

def code(x):
	return (x - math.sin(x)) / (x - math.tan(x))

↓

def code(x):
	tmp = 0
	if x <= -0.095:
		tmp = (x - math.sin(x)) / (x - math.tan(x))
	elif x <= 0.085:
		tmp = (math.pow(x, 4.0) * (((x * x) * 0.00024107142857142857) + -0.009642857142857142)) + (((x * x) * 0.225) + -0.5)
	else:
		tmp = 1.0 / ((math.tan(x) - x) / (math.sin(x) - x))
	return tmp

Julia

function code(x)
	return Float64(Float64(x - sin(x)) / Float64(x - tan(x)))
end

↓

function code(x)
	tmp = 0.0
	if (x <= -0.095)
		tmp = Float64(Float64(x - sin(x)) / Float64(x - tan(x)));
	elseif (x <= 0.085)
		tmp = Float64(Float64((x ^ 4.0) * Float64(Float64(Float64(x * x) * 0.00024107142857142857) + -0.009642857142857142)) + Float64(Float64(Float64(x * x) * 0.225) + -0.5));
	else
		tmp = Float64(1.0 / Float64(Float64(tan(x) - x) / Float64(sin(x) - x)));
	end
	return tmp
end

MATLAB

function tmp = code(x)
	tmp = (x - sin(x)) / (x - tan(x));
end

↓

function tmp_2 = code(x)
	tmp = 0.0;
	if (x <= -0.095)
		tmp = (x - sin(x)) / (x - tan(x));
	elseif (x <= 0.085)
		tmp = ((x ^ 4.0) * (((x * x) * 0.00024107142857142857) + -0.009642857142857142)) + (((x * x) * 0.225) + -0.5);
	else
		tmp = 1.0 / ((tan(x) - x) / (sin(x) - x));
	end
	tmp_2 = tmp;
end

Wolfram

code[x_] := N[(N[(x - N[Sin[x], $MachinePrecision]), $MachinePrecision] / N[(x - N[Tan[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]

↓

code[x_] := If[LessEqual[x, -0.095], N[(N[(x - N[Sin[x], $MachinePrecision]), $MachinePrecision] / N[(x - N[Tan[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], If[LessEqual[x, 0.085], N[(N[(N[Power[x, 4.0], $MachinePrecision] * N[(N[(N[(x * x), $MachinePrecision] * 0.00024107142857142857), $MachinePrecision] + -0.009642857142857142), $MachinePrecision]), $MachinePrecision] + N[(N[(N[(x * x), $MachinePrecision] * 0.225), $MachinePrecision] + -0.5), $MachinePrecision]), $MachinePrecision], N[(1.0 / N[(N[(N[Tan[x], $MachinePrecision] - x), $MachinePrecision] / N[(N[Sin[x], $MachinePrecision] - x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]

Derivation

1. Split input into 3 regimes

2. if x < -0.095000000000000001

   1. Initial program 0.0

      \[\frac{x - \sin x}{x - \tan x} \]

   if -0.095000000000000001 < x < 0.0850000000000000061

   1. Initial program 63.0

      \[\frac{x - \sin x}{x - \tan x} \]

   2. Simplified 63.0

      \[\leadsto \color{blue}{\frac{\sin x - x}{\tan x - x}} \]
      Proof

      [Start] 63.0	\[ \frac{x - \sin x}{x - \tan x} \]
      sub-neg [=>] 63.0	\[ \frac{\color{blue}{x + \left(-\sin x\right)}}{x - \tan x} \]
      +-commutative [=>] 63.0	\[ \frac{\color{blue}{\left(-\sin x\right) + x}}{x - \tan x} \]
      neg-sub0 [=>] 63.0	\[ \frac{\color{blue}{\left(0 - \sin x\right)} + x}{x - \tan x} \]
      associate-+l- [=>] 63.0	\[ \frac{\color{blue}{0 - \left(\sin x - x\right)}}{x - \tan x} \]
      sub0-neg [=>] 63.0	\[ \frac{\color{blue}{-\left(\sin x - x\right)}}{x - \tan x} \]
      neg-mul-1 [=>] 63.0	\[ \frac{\color{blue}{-1 \cdot \left(\sin x - x\right)}}{x - \tan x} \]
      sub-neg [=>] 63.0	\[ \frac{-1 \cdot \left(\sin x - x\right)}{\color{blue}{x + \left(-\tan x\right)}} \]
      +-commutative [=>] 63.0	\[ \frac{-1 \cdot \left(\sin x - x\right)}{\color{blue}{\left(-\tan x\right) + x}} \]
      neg-sub0 [=>] 63.0	\[ \frac{-1 \cdot \left(\sin x - x\right)}{\color{blue}{\left(0 - \tan x\right)} + x} \]
      associate-+l- [=>] 63.0	\[ \frac{-1 \cdot \left(\sin x - x\right)}{\color{blue}{0 - \left(\tan x - x\right)}} \]
      sub0-neg [=>] 63.0	\[ \frac{-1 \cdot \left(\sin x - x\right)}{\color{blue}{-\left(\tan x - x\right)}} \]
      neg-mul-1 [=>] 63.0	\[ \frac{-1 \cdot \left(\sin x - x\right)}{\color{blue}{-1 \cdot \left(\tan x - x\right)}} \]
      times-frac [=>] 63.0	\[ \color{blue}{\frac{-1}{-1} \cdot \frac{\sin x - x}{\tan x - x}} \]
      metadata-eval [=>] 63.0	\[ \color{blue}{1} \cdot \frac{\sin x - x}{\tan x - x} \]
      *-lft-identity [=>] 63.0	\[ \color{blue}{\frac{\sin x - x}{\tan x - x}} \]

   3. Taylor expanded in x around 0 0.0

      \[\leadsto \color{blue}{\left(0.225 \cdot {x}^{2} + \left(-0.009642857142857142 \cdot {x}^{4} + 0.00024107142857142857 \cdot {x}^{6}\right)\right) - 0.5} \]

   4. Simplified 0.0

      \[\leadsto \color{blue}{\mathsf{fma}\left(-0.009642857142857142, {x}^{4}, 0.00024107142857142857 \cdot {x}^{6}\right) + \mathsf{fma}\left(0.225, x \cdot x, -0.5\right)} \]
      Proof

      [Start] 0.0	\[ \left(0.225 \cdot {x}^{2} + \left(-0.009642857142857142 \cdot {x}^{4} + 0.00024107142857142857 \cdot {x}^{6}\right)\right) - 0.5 \]
      +-commutative [=>] 0.0	\[ \color{blue}{\left(\left(-0.009642857142857142 \cdot {x}^{4} + 0.00024107142857142857 \cdot {x}^{6}\right) + 0.225 \cdot {x}^{2}\right)} - 0.5 \]
      associate--l+ [=>] 0.0	\[ \color{blue}{\left(-0.009642857142857142 \cdot {x}^{4} + 0.00024107142857142857 \cdot {x}^{6}\right) + \left(0.225 \cdot {x}^{2} - 0.5\right)} \]
      fma-def [=>] 0.0	\[ \color{blue}{\mathsf{fma}\left(-0.009642857142857142, {x}^{4}, 0.00024107142857142857 \cdot {x}^{6}\right)} + \left(0.225 \cdot {x}^{2} - 0.5\right) \]
      unpow2 [=>] 0.0	\[ \mathsf{fma}\left(-0.009642857142857142, {x}^{4}, 0.00024107142857142857 \cdot {x}^{6}\right) + \left(0.225 \cdot \color{blue}{\left(x \cdot x\right)} - 0.5\right) \]
      fma-neg [=>] 0.0	\[ \mathsf{fma}\left(-0.009642857142857142, {x}^{4}, 0.00024107142857142857 \cdot {x}^{6}\right) + \color{blue}{\mathsf{fma}\left(0.225, x \cdot x, -0.5\right)} \]
      metadata-eval [=>] 0.0	\[ \mathsf{fma}\left(-0.009642857142857142, {x}^{4}, 0.00024107142857142857 \cdot {x}^{6}\right) + \mathsf{fma}\left(0.225, x \cdot x, \color{blue}{-0.5}\right) \]

   5. Applied egg-rr 0.0

      \[\leadsto \color{blue}{{x}^{4} \cdot \left(\left(x \cdot x\right) \cdot 0.00024107142857142857 + -0.009642857142857142\right)} + \mathsf{fma}\left(0.225, x \cdot x, -0.5\right) \]

   6. Applied egg-rr 0.0

      \[\leadsto {x}^{4} \cdot \left(\left(x \cdot x\right) \cdot 0.00024107142857142857 + -0.009642857142857142\right) + \color{blue}{\left(\left(0.225 \cdot x\right) \cdot x + -0.5\right)} \]

   7. Taylor expanded in x around 0 0.0

      \[\leadsto {x}^{4} \cdot \left(\left(x \cdot x\right) \cdot 0.00024107142857142857 + -0.009642857142857142\right) + \left(\color{blue}{0.225 \cdot {x}^{2}} + -0.5\right) \]

   8. Simplified 0.0

      \[\leadsto {x}^{4} \cdot \left(\left(x \cdot x\right) \cdot 0.00024107142857142857 + -0.009642857142857142\right) + \left(\color{blue}{0.225 \cdot \left(x \cdot x\right)} + -0.5\right) \]
      Proof

      [Start] 0.0	\[ {x}^{4} \cdot \left(\left(x \cdot x\right) \cdot 0.00024107142857142857 + -0.009642857142857142\right) + \left(0.225 \cdot {x}^{2} + -0.5\right) \]
      unpow2 [=>] 0.0	\[ {x}^{4} \cdot \left(\left(x \cdot x\right) \cdot 0.00024107142857142857 + -0.009642857142857142\right) + \left(0.225 \cdot \color{blue}{\left(x \cdot x\right)} + -0.5\right) \]

   if 0.0850000000000000061 < x

   1. Initial program 0.0

      \[\frac{x - \sin x}{x - \tan x} \]

   2. Simplified 0.0

      \[\leadsto \color{blue}{\frac{\sin x - x}{\tan x - x}} \]
      Proof

      [Start] 0.0	\[ \frac{x - \sin x}{x - \tan x} \]
      sub-neg [=>] 0.0	\[ \frac{\color{blue}{x + \left(-\sin x\right)}}{x - \tan x} \]
      +-commutative [=>] 0.0	\[ \frac{\color{blue}{\left(-\sin x\right) + x}}{x - \tan x} \]
      neg-sub0 [=>] 0.0	\[ \frac{\color{blue}{\left(0 - \sin x\right)} + x}{x - \tan x} \]
      associate-+l- [=>] 0.0	\[ \frac{\color{blue}{0 - \left(\sin x - x\right)}}{x - \tan x} \]
      sub0-neg [=>] 0.0	\[ \frac{\color{blue}{-\left(\sin x - x\right)}}{x - \tan x} \]
      neg-mul-1 [=>] 0.0	\[ \frac{\color{blue}{-1 \cdot \left(\sin x - x\right)}}{x - \tan x} \]
      sub-neg [=>] 0.0	\[ \frac{-1 \cdot \left(\sin x - x\right)}{\color{blue}{x + \left(-\tan x\right)}} \]
      +-commutative [=>] 0.0	\[ \frac{-1 \cdot \left(\sin x - x\right)}{\color{blue}{\left(-\tan x\right) + x}} \]
      neg-sub0 [=>] 0.0	\[ \frac{-1 \cdot \left(\sin x - x\right)}{\color{blue}{\left(0 - \tan x\right)} + x} \]
      associate-+l- [=>] 0.0	\[ \frac{-1 \cdot \left(\sin x - x\right)}{\color{blue}{0 - \left(\tan x - x\right)}} \]
      sub0-neg [=>] 0.0	\[ \frac{-1 \cdot \left(\sin x - x\right)}{\color{blue}{-\left(\tan x - x\right)}} \]
      neg-mul-1 [=>] 0.0	\[ \frac{-1 \cdot \left(\sin x - x\right)}{\color{blue}{-1 \cdot \left(\tan x - x\right)}} \]
      times-frac [=>] 0.0	\[ \color{blue}{\frac{-1}{-1} \cdot \frac{\sin x - x}{\tan x - x}} \]
      metadata-eval [=>] 0.0	\[ \color{blue}{1} \cdot \frac{\sin x - x}{\tan x - x} \]
      *-lft-identity [=>] 0.0	\[ \color{blue}{\frac{\sin x - x}{\tan x - x}} \]

   3. Applied egg-rr 0.0

      \[\leadsto \color{blue}{{\left(\frac{\tan x - x}{\sin x - x}\right)}^{-1}} \]

   4. Applied egg-rr 0.0

      \[\leadsto \color{blue}{\frac{1}{\frac{\tan x - x}{\sin x - x}}} \]
3. Recombined 3 regimes into one program.

4. Final simplification 0.0

   \[\leadsto \begin{array}{l} \mathbf{if}\;x \leq -0.095:\\ \;\;\;\;\frac{x - \sin x}{x - \tan x}\\ \mathbf{elif}\;x \leq 0.085:\\ \;\;\;\;{x}^{4} \cdot \left(\left(x \cdot x\right) \cdot 0.00024107142857142857 + -0.009642857142857142\right) + \left(\left(x \cdot x\right) \cdot 0.225 + -0.5\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{1}{\frac{\tan x - x}{\sin x - x}}\\ \end{array} \]

Alternatives

Alternative 1
Error	0.0
Cost	13513

\[\begin{array}{l} \mathbf{if}\;x \leq -0.095 \lor \neg \left(x \leq 0.085\right):\\ \;\;\;\;\frac{x - \sin x}{x - \tan x}\\ \mathbf{else}:\\ \;\;\;\;{x}^{4} \cdot \left(\left(x \cdot x\right) \cdot 0.00024107142857142857 + -0.009642857142857142\right) + \left(\left(x \cdot x\right) \cdot 0.225 + -0.5\right)\\ \end{array} \]

Alternative 2
Error	0.7
Cost	13316

\[\begin{array}{l} t_0 := x - \tan x\\ t_1 := x \cdot \left(x \cdot 0.225\right)\\ \mathbf{if}\;x \leq -4.2:\\ \;\;\;\;{\left(\frac{t_0}{x}\right)}^{-1}\\ \mathbf{elif}\;x \leq 4.2:\\ \;\;\;\;{x}^{4} \cdot \left(\left(x \cdot x\right) \cdot 0.00024107142857142857 + -0.009642857142857142\right) + \frac{t_1 \cdot t_1 + -0.25}{t_1 + 0.5}\\ \mathbf{else}:\\ \;\;\;\;\frac{x}{t_0}\\ \end{array} \]

Alternative 3
Error	0.7
Cost	8713

\[\begin{array}{l} t_0 := x \cdot \left(x \cdot 0.225\right)\\ \mathbf{if}\;x \leq -4.2 \lor \neg \left(x \leq 4.2\right):\\ \;\;\;\;\frac{x}{x - \tan x}\\ \mathbf{else}:\\ \;\;\;\;{x}^{4} \cdot \left(\left(x \cdot x\right) \cdot 0.00024107142857142857 + -0.009642857142857142\right) + \frac{t_0 \cdot t_0 + -0.25}{t_0 + 0.5}\\ \end{array} \]

Alternative 4
Error	0.7
Cost	7817

\[\begin{array}{l} \mathbf{if}\;x \leq -4.2 \lor \neg \left(x \leq 4.2\right):\\ \;\;\;\;\frac{x}{x - \tan x}\\ \mathbf{else}:\\ \;\;\;\;{x}^{4} \cdot \left(\left(x \cdot x\right) \cdot 0.00024107142857142857 + -0.009642857142857142\right) + \left(\left(x \cdot x\right) \cdot 0.225 + -0.5\right)\\ \end{array} \]

Alternative 5
Error	0.7
Cost	7433

\[\begin{array}{l} \mathbf{if}\;x \leq -2.8 \lor \neg \left(x \leq 2.8\right):\\ \;\;\;\;\frac{x}{x - \tan x}\\ \mathbf{else}:\\ \;\;\;\;{x}^{4} \cdot -0.009642857142857142 + \left(-0.5 + x \cdot \left(x \cdot 0.225\right)\right)\\ \end{array} \]

Alternative 6
Error	0.8
Cost	6985

\[\begin{array}{l} t_0 := x \cdot \left(x \cdot 0.225\right)\\ \mathbf{if}\;x \leq -2.3 \lor \neg \left(x \leq 1.45\right):\\ \;\;\;\;\frac{x}{x - \tan x}\\ \mathbf{else}:\\ \;\;\;\;\frac{t_0 \cdot t_0 + -0.25}{t_0 + 0.5}\\ \end{array} \]

Alternative 7
Error	0.8
Cost	1608

\[\begin{array}{l} t_0 := x \cdot \left(x \cdot 0.225\right)\\ \mathbf{if}\;x \leq -2.6:\\ \;\;\;\;1\\ \mathbf{elif}\;x \leq 2.6:\\ \;\;\;\;\frac{t_0 \cdot t_0 + -0.25}{t_0 + 0.5}\\ \mathbf{else}:\\ \;\;\;\;1\\ \end{array} \]

Alternative 8
Error	0.8
Cost	712

\[\begin{array}{l} \mathbf{if}\;x \leq -2.6:\\ \;\;\;\;1\\ \mathbf{elif}\;x \leq 2.6:\\ \;\;\;\;-0.5 + x \cdot \left(x \cdot 0.225\right)\\ \mathbf{else}:\\ \;\;\;\;1\\ \end{array} \]

Alternative 9
Error	1.0
Cost	328

\[\begin{array}{l} \mathbf{if}\;x \leq -1.58:\\ \;\;\;\;1\\ \mathbf{elif}\;x \leq 1.56:\\ \;\;\;\;-0.5\\ \mathbf{else}:\\ \;\;\;\;1\\ \end{array} \]

Alternative 10
Error	31.7
Cost	64

\[-0.5 \]

Reproduce

herbie shell --seed 2023016 
(FPCore (x)
  :name "sintan (problem 3.4.5)"
  :precision binary64
  (/ (- x (sin x)) (- x (tan x))))