bug500 (missed optimization)

Percentage Accurate: 69.9% → 99.6%
Time: 7.2s
Alternatives: 7
Speedup: 14.7×

Specification

?
\[-1000 < x \land x < 1000\]
\[\begin{array}{l} \\ \sin x - x \end{array} \]
(FPCore (x) :precision binary64 (- (sin x) x))
double code(double x) {
	return sin(x) - x;
}
real(8) function code(x)
    real(8), intent (in) :: x
    code = sin(x) - x
end function
public static double code(double x) {
	return Math.sin(x) - x;
}
def code(x):
	return math.sin(x) - x
function code(x)
	return Float64(sin(x) - x)
end
function tmp = code(x)
	tmp = sin(x) - x;
end
code[x_] := N[(N[Sin[x], $MachinePrecision] - x), $MachinePrecision]
\begin{array}{l}

\\
\sin x - x
\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 7 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: 69.9% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \sin x - x \end{array} \]
(FPCore (x) :precision binary64 (- (sin x) x))
double code(double x) {
	return sin(x) - x;
}
real(8) function code(x)
    real(8), intent (in) :: x
    code = sin(x) - x
end function
public static double code(double x) {
	return Math.sin(x) - x;
}
def code(x):
	return math.sin(x) - x
function code(x)
	return Float64(sin(x) - x)
end
function tmp = code(x)
	tmp = sin(x) - x;
end
code[x_] := N[(N[Sin[x], $MachinePrecision] - x), $MachinePrecision]
\begin{array}{l}

\\
\sin x - x
\end{array}

Alternative 1: 99.6% accurate, 0.5× speedup?

\[\begin{array}{l} x\_m = \left|x\right| \\ x\_s = \mathsf{copysign}\left(1, x\right) \\ \begin{array}{l} t_0 := \sin x\_m - x\_m\\ x\_s \cdot \begin{array}{l} \mathbf{if}\;t\_0 \leq -0.0001:\\ \;\;\;\;t\_0\\ \mathbf{else}:\\ \;\;\;\;{x\_m}^{3} \cdot \left(\left(x\_m \cdot x\_m\right) \cdot 0.008333333333333333 - 0.16666666666666666\right)\\ \end{array} \end{array} \end{array} \]
x\_m = (fabs.f64 x)
x\_s = (copysign.f64 #s(literal 1 binary64) x)
(FPCore (x_s x_m)
 :precision binary64
 (let* ((t_0 (- (sin x_m) x_m)))
   (*
    x_s
    (if (<= t_0 -0.0001)
      t_0
      (*
       (pow x_m 3.0)
       (- (* (* x_m x_m) 0.008333333333333333) 0.16666666666666666))))))
x\_m = fabs(x);
x\_s = copysign(1.0, x);
double code(double x_s, double x_m) {
	double t_0 = sin(x_m) - x_m;
	double tmp;
	if (t_0 <= -0.0001) {
		tmp = t_0;
	} else {
		tmp = pow(x_m, 3.0) * (((x_m * x_m) * 0.008333333333333333) - 0.16666666666666666);
	}
	return x_s * tmp;
}
x\_m = abs(x)
x\_s = copysign(1.0d0, x)
real(8) function code(x_s, x_m)
    real(8), intent (in) :: x_s
    real(8), intent (in) :: x_m
    real(8) :: t_0
    real(8) :: tmp
    t_0 = sin(x_m) - x_m
    if (t_0 <= (-0.0001d0)) then
        tmp = t_0
    else
        tmp = (x_m ** 3.0d0) * (((x_m * x_m) * 0.008333333333333333d0) - 0.16666666666666666d0)
    end if
    code = x_s * tmp
end function
x\_m = Math.abs(x);
x\_s = Math.copySign(1.0, x);
public static double code(double x_s, double x_m) {
	double t_0 = Math.sin(x_m) - x_m;
	double tmp;
	if (t_0 <= -0.0001) {
		tmp = t_0;
	} else {
		tmp = Math.pow(x_m, 3.0) * (((x_m * x_m) * 0.008333333333333333) - 0.16666666666666666);
	}
	return x_s * tmp;
}
x\_m = math.fabs(x)
x\_s = math.copysign(1.0, x)
def code(x_s, x_m):
	t_0 = math.sin(x_m) - x_m
	tmp = 0
	if t_0 <= -0.0001:
		tmp = t_0
	else:
		tmp = math.pow(x_m, 3.0) * (((x_m * x_m) * 0.008333333333333333) - 0.16666666666666666)
	return x_s * tmp
x\_m = abs(x)
x\_s = copysign(1.0, x)
function code(x_s, x_m)
	t_0 = Float64(sin(x_m) - x_m)
	tmp = 0.0
	if (t_0 <= -0.0001)
		tmp = t_0;
	else
		tmp = Float64((x_m ^ 3.0) * Float64(Float64(Float64(x_m * x_m) * 0.008333333333333333) - 0.16666666666666666));
	end
	return Float64(x_s * tmp)
end
x\_m = abs(x);
x\_s = sign(x) * abs(1.0);
function tmp_2 = code(x_s, x_m)
	t_0 = sin(x_m) - x_m;
	tmp = 0.0;
	if (t_0 <= -0.0001)
		tmp = t_0;
	else
		tmp = (x_m ^ 3.0) * (((x_m * x_m) * 0.008333333333333333) - 0.16666666666666666);
	end
	tmp_2 = x_s * tmp;
end
x\_m = N[Abs[x], $MachinePrecision]
x\_s = N[With[{TMP1 = Abs[1.0], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
code[x$95$s_, x$95$m_] := Block[{t$95$0 = N[(N[Sin[x$95$m], $MachinePrecision] - x$95$m), $MachinePrecision]}, N[(x$95$s * If[LessEqual[t$95$0, -0.0001], t$95$0, N[(N[Power[x$95$m, 3.0], $MachinePrecision] * N[(N[(N[(x$95$m * x$95$m), $MachinePrecision] * 0.008333333333333333), $MachinePrecision] - 0.16666666666666666), $MachinePrecision]), $MachinePrecision]]), $MachinePrecision]]
\begin{array}{l}
x\_m = \left|x\right|
\\
x\_s = \mathsf{copysign}\left(1, x\right)

\\
\begin{array}{l}
t_0 := \sin x\_m - x\_m\\
x\_s \cdot \begin{array}{l}
\mathbf{if}\;t\_0 \leq -0.0001:\\
\;\;\;\;t\_0\\

\mathbf{else}:\\
\;\;\;\;{x\_m}^{3} \cdot \left(\left(x\_m \cdot x\_m\right) \cdot 0.008333333333333333 - 0.16666666666666666\right)\\


\end{array}
\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (-.f64 (sin.f64 x) x) < -1.00000000000000005e-4

    1. Initial program 100.0%

      \[\sin x - x \]
    2. Add Preprocessing

    if -1.00000000000000005e-4 < (-.f64 (sin.f64 x) x)

    1. Initial program 70.1%

      \[\sin x - x \]
    2. Add Preprocessing
    3. Taylor expanded in x around 0 99.0%

      \[\leadsto \color{blue}{{x}^{3} \cdot \left(0.008333333333333333 \cdot {x}^{2} - 0.16666666666666666\right)} \]
    4. Step-by-step derivation
      1. unpow299.0%

        \[\leadsto {x}^{3} \cdot \left(0.008333333333333333 \cdot \color{blue}{\left(x \cdot x\right)} - 0.16666666666666666\right) \]
    5. Applied egg-rr99.0%

      \[\leadsto {x}^{3} \cdot \left(0.008333333333333333 \cdot \color{blue}{\left(x \cdot x\right)} - 0.16666666666666666\right) \]
  3. Recombined 2 regimes into one program.
  4. Final simplification99.1%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\sin x - x \leq -0.0001:\\ \;\;\;\;\sin x - x\\ \mathbf{else}:\\ \;\;\;\;{x}^{3} \cdot \left(\left(x \cdot x\right) \cdot 0.008333333333333333 - 0.16666666666666666\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 2: 99.2% accurate, 0.5× speedup?

\[\begin{array}{l} x\_m = \left|x\right| \\ x\_s = \mathsf{copysign}\left(1, x\right) \\ \begin{array}{l} t_0 := \sin x\_m - x\_m\\ x\_s \cdot \begin{array}{l} \mathbf{if}\;t\_0 \leq -0.0001:\\ \;\;\;\;t\_0\\ \mathbf{else}:\\ \;\;\;\;{x\_m}^{3} \cdot -0.16666666666666666\\ \end{array} \end{array} \end{array} \]
x\_m = (fabs.f64 x)
x\_s = (copysign.f64 #s(literal 1 binary64) x)
(FPCore (x_s x_m)
 :precision binary64
 (let* ((t_0 (- (sin x_m) x_m)))
   (* x_s (if (<= t_0 -0.0001) t_0 (* (pow x_m 3.0) -0.16666666666666666)))))
x\_m = fabs(x);
x\_s = copysign(1.0, x);
double code(double x_s, double x_m) {
	double t_0 = sin(x_m) - x_m;
	double tmp;
	if (t_0 <= -0.0001) {
		tmp = t_0;
	} else {
		tmp = pow(x_m, 3.0) * -0.16666666666666666;
	}
	return x_s * tmp;
}
x\_m = abs(x)
x\_s = copysign(1.0d0, x)
real(8) function code(x_s, x_m)
    real(8), intent (in) :: x_s
    real(8), intent (in) :: x_m
    real(8) :: t_0
    real(8) :: tmp
    t_0 = sin(x_m) - x_m
    if (t_0 <= (-0.0001d0)) then
        tmp = t_0
    else
        tmp = (x_m ** 3.0d0) * (-0.16666666666666666d0)
    end if
    code = x_s * tmp
end function
x\_m = Math.abs(x);
x\_s = Math.copySign(1.0, x);
public static double code(double x_s, double x_m) {
	double t_0 = Math.sin(x_m) - x_m;
	double tmp;
	if (t_0 <= -0.0001) {
		tmp = t_0;
	} else {
		tmp = Math.pow(x_m, 3.0) * -0.16666666666666666;
	}
	return x_s * tmp;
}
x\_m = math.fabs(x)
x\_s = math.copysign(1.0, x)
def code(x_s, x_m):
	t_0 = math.sin(x_m) - x_m
	tmp = 0
	if t_0 <= -0.0001:
		tmp = t_0
	else:
		tmp = math.pow(x_m, 3.0) * -0.16666666666666666
	return x_s * tmp
x\_m = abs(x)
x\_s = copysign(1.0, x)
function code(x_s, x_m)
	t_0 = Float64(sin(x_m) - x_m)
	tmp = 0.0
	if (t_0 <= -0.0001)
		tmp = t_0;
	else
		tmp = Float64((x_m ^ 3.0) * -0.16666666666666666);
	end
	return Float64(x_s * tmp)
end
x\_m = abs(x);
x\_s = sign(x) * abs(1.0);
function tmp_2 = code(x_s, x_m)
	t_0 = sin(x_m) - x_m;
	tmp = 0.0;
	if (t_0 <= -0.0001)
		tmp = t_0;
	else
		tmp = (x_m ^ 3.0) * -0.16666666666666666;
	end
	tmp_2 = x_s * tmp;
end
x\_m = N[Abs[x], $MachinePrecision]
x\_s = N[With[{TMP1 = Abs[1.0], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
code[x$95$s_, x$95$m_] := Block[{t$95$0 = N[(N[Sin[x$95$m], $MachinePrecision] - x$95$m), $MachinePrecision]}, N[(x$95$s * If[LessEqual[t$95$0, -0.0001], t$95$0, N[(N[Power[x$95$m, 3.0], $MachinePrecision] * -0.16666666666666666), $MachinePrecision]]), $MachinePrecision]]
\begin{array}{l}
x\_m = \left|x\right|
\\
x\_s = \mathsf{copysign}\left(1, x\right)

\\
\begin{array}{l}
t_0 := \sin x\_m - x\_m\\
x\_s \cdot \begin{array}{l}
\mathbf{if}\;t\_0 \leq -0.0001:\\
\;\;\;\;t\_0\\

\mathbf{else}:\\
\;\;\;\;{x\_m}^{3} \cdot -0.16666666666666666\\


\end{array}
\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (-.f64 (sin.f64 x) x) < -1.00000000000000005e-4

    1. Initial program 100.0%

      \[\sin x - x \]
    2. Add Preprocessing

    if -1.00000000000000005e-4 < (-.f64 (sin.f64 x) x)

    1. Initial program 70.1%

      \[\sin x - x \]
    2. Add Preprocessing
    3. Taylor expanded in x around 0 98.9%

      \[\leadsto \color{blue}{-0.16666666666666666 \cdot {x}^{3}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification98.9%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\sin x - x \leq -0.0001:\\ \;\;\;\;\sin x - x\\ \mathbf{else}:\\ \;\;\;\;{x}^{3} \cdot -0.16666666666666666\\ \end{array} \]
  5. Add Preprocessing

Alternative 3: 99.2% accurate, 0.5× speedup?

\[\begin{array}{l} x\_m = \left|x\right| \\ x\_s = \mathsf{copysign}\left(1, x\right) \\ \begin{array}{l} t_0 := \sin x\_m - x\_m\\ x\_s \cdot \begin{array}{l} \mathbf{if}\;t\_0 \leq -0.0001:\\ \;\;\;\;t\_0\\ \mathbf{else}:\\ \;\;\;\;x\_m \cdot \left(\left(x\_m \cdot x\_m\right) \cdot -0.16666666666666666\right)\\ \end{array} \end{array} \end{array} \]
x\_m = (fabs.f64 x)
x\_s = (copysign.f64 #s(literal 1 binary64) x)
(FPCore (x_s x_m)
 :precision binary64
 (let* ((t_0 (- (sin x_m) x_m)))
   (*
    x_s
    (if (<= t_0 -0.0001) t_0 (* x_m (* (* x_m x_m) -0.16666666666666666))))))
x\_m = fabs(x);
x\_s = copysign(1.0, x);
double code(double x_s, double x_m) {
	double t_0 = sin(x_m) - x_m;
	double tmp;
	if (t_0 <= -0.0001) {
		tmp = t_0;
	} else {
		tmp = x_m * ((x_m * x_m) * -0.16666666666666666);
	}
	return x_s * tmp;
}
x\_m = abs(x)
x\_s = copysign(1.0d0, x)
real(8) function code(x_s, x_m)
    real(8), intent (in) :: x_s
    real(8), intent (in) :: x_m
    real(8) :: t_0
    real(8) :: tmp
    t_0 = sin(x_m) - x_m
    if (t_0 <= (-0.0001d0)) then
        tmp = t_0
    else
        tmp = x_m * ((x_m * x_m) * (-0.16666666666666666d0))
    end if
    code = x_s * tmp
end function
x\_m = Math.abs(x);
x\_s = Math.copySign(1.0, x);
public static double code(double x_s, double x_m) {
	double t_0 = Math.sin(x_m) - x_m;
	double tmp;
	if (t_0 <= -0.0001) {
		tmp = t_0;
	} else {
		tmp = x_m * ((x_m * x_m) * -0.16666666666666666);
	}
	return x_s * tmp;
}
x\_m = math.fabs(x)
x\_s = math.copysign(1.0, x)
def code(x_s, x_m):
	t_0 = math.sin(x_m) - x_m
	tmp = 0
	if t_0 <= -0.0001:
		tmp = t_0
	else:
		tmp = x_m * ((x_m * x_m) * -0.16666666666666666)
	return x_s * tmp
x\_m = abs(x)
x\_s = copysign(1.0, x)
function code(x_s, x_m)
	t_0 = Float64(sin(x_m) - x_m)
	tmp = 0.0
	if (t_0 <= -0.0001)
		tmp = t_0;
	else
		tmp = Float64(x_m * Float64(Float64(x_m * x_m) * -0.16666666666666666));
	end
	return Float64(x_s * tmp)
end
x\_m = abs(x);
x\_s = sign(x) * abs(1.0);
function tmp_2 = code(x_s, x_m)
	t_0 = sin(x_m) - x_m;
	tmp = 0.0;
	if (t_0 <= -0.0001)
		tmp = t_0;
	else
		tmp = x_m * ((x_m * x_m) * -0.16666666666666666);
	end
	tmp_2 = x_s * tmp;
end
x\_m = N[Abs[x], $MachinePrecision]
x\_s = N[With[{TMP1 = Abs[1.0], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
code[x$95$s_, x$95$m_] := Block[{t$95$0 = N[(N[Sin[x$95$m], $MachinePrecision] - x$95$m), $MachinePrecision]}, N[(x$95$s * If[LessEqual[t$95$0, -0.0001], t$95$0, N[(x$95$m * N[(N[(x$95$m * x$95$m), $MachinePrecision] * -0.16666666666666666), $MachinePrecision]), $MachinePrecision]]), $MachinePrecision]]
\begin{array}{l}
x\_m = \left|x\right|
\\
x\_s = \mathsf{copysign}\left(1, x\right)

\\
\begin{array}{l}
t_0 := \sin x\_m - x\_m\\
x\_s \cdot \begin{array}{l}
\mathbf{if}\;t\_0 \leq -0.0001:\\
\;\;\;\;t\_0\\

\mathbf{else}:\\
\;\;\;\;x\_m \cdot \left(\left(x\_m \cdot x\_m\right) \cdot -0.16666666666666666\right)\\


\end{array}
\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (-.f64 (sin.f64 x) x) < -1.00000000000000005e-4

    1. Initial program 100.0%

      \[\sin x - x \]
    2. Add Preprocessing

    if -1.00000000000000005e-4 < (-.f64 (sin.f64 x) x)

    1. Initial program 70.1%

      \[\sin x - x \]
    2. Add Preprocessing
    3. Taylor expanded in x around inf 70.1%

      \[\leadsto \color{blue}{x \cdot \left(\frac{\sin x}{x} - 1\right)} \]
    4. Taylor expanded in x around 0 98.8%

      \[\leadsto x \cdot \color{blue}{\left(-0.16666666666666666 \cdot {x}^{2}\right)} \]
    5. Step-by-step derivation
      1. *-commutative98.8%

        \[\leadsto x \cdot \color{blue}{\left({x}^{2} \cdot -0.16666666666666666\right)} \]
    6. Simplified98.8%

      \[\leadsto x \cdot \color{blue}{\left({x}^{2} \cdot -0.16666666666666666\right)} \]
    7. Step-by-step derivation
      1. unpow299.0%

        \[\leadsto {x}^{3} \cdot \left(0.008333333333333333 \cdot \color{blue}{\left(x \cdot x\right)} - 0.16666666666666666\right) \]
    8. Applied egg-rr98.8%

      \[\leadsto x \cdot \left(\color{blue}{\left(x \cdot x\right)} \cdot -0.16666666666666666\right) \]
  3. Recombined 2 regimes into one program.
  4. Final simplification98.8%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\sin x - x \leq -0.0001:\\ \;\;\;\;\sin x - x\\ \mathbf{else}:\\ \;\;\;\;x \cdot \left(\left(x \cdot x\right) \cdot -0.16666666666666666\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 4: 98.8% accurate, 0.8× speedup?

\[\begin{array}{l} x\_m = \left|x\right| \\ x\_s = \mathsf{copysign}\left(1, x\right) \\ x\_s \cdot \left({x\_m}^{3} \cdot \left(\left(x\_m \cdot x\_m\right) \cdot \left(0.008333333333333333 + \left(x\_m \cdot x\_m\right) \cdot \left(\left(x\_m \cdot x\_m\right) \cdot 2.7557319223985893 \cdot 10^{-6} - 0.0001984126984126984\right)\right) - 0.16666666666666666\right)\right) \end{array} \]
x\_m = (fabs.f64 x)
x\_s = (copysign.f64 #s(literal 1 binary64) x)
(FPCore (x_s x_m)
 :precision binary64
 (*
  x_s
  (*
   (pow x_m 3.0)
   (-
    (*
     (* x_m x_m)
     (+
      0.008333333333333333
      (*
       (* x_m x_m)
       (- (* (* x_m x_m) 2.7557319223985893e-6) 0.0001984126984126984))))
    0.16666666666666666))))
x\_m = fabs(x);
x\_s = copysign(1.0, x);
double code(double x_s, double x_m) {
	return x_s * (pow(x_m, 3.0) * (((x_m * x_m) * (0.008333333333333333 + ((x_m * x_m) * (((x_m * x_m) * 2.7557319223985893e-6) - 0.0001984126984126984)))) - 0.16666666666666666));
}
x\_m = abs(x)
x\_s = copysign(1.0d0, x)
real(8) function code(x_s, x_m)
    real(8), intent (in) :: x_s
    real(8), intent (in) :: x_m
    code = x_s * ((x_m ** 3.0d0) * (((x_m * x_m) * (0.008333333333333333d0 + ((x_m * x_m) * (((x_m * x_m) * 2.7557319223985893d-6) - 0.0001984126984126984d0)))) - 0.16666666666666666d0))
end function
x\_m = Math.abs(x);
x\_s = Math.copySign(1.0, x);
public static double code(double x_s, double x_m) {
	return x_s * (Math.pow(x_m, 3.0) * (((x_m * x_m) * (0.008333333333333333 + ((x_m * x_m) * (((x_m * x_m) * 2.7557319223985893e-6) - 0.0001984126984126984)))) - 0.16666666666666666));
}
x\_m = math.fabs(x)
x\_s = math.copysign(1.0, x)
def code(x_s, x_m):
	return x_s * (math.pow(x_m, 3.0) * (((x_m * x_m) * (0.008333333333333333 + ((x_m * x_m) * (((x_m * x_m) * 2.7557319223985893e-6) - 0.0001984126984126984)))) - 0.16666666666666666))
x\_m = abs(x)
x\_s = copysign(1.0, x)
function code(x_s, x_m)
	return Float64(x_s * Float64((x_m ^ 3.0) * Float64(Float64(Float64(x_m * x_m) * Float64(0.008333333333333333 + Float64(Float64(x_m * x_m) * Float64(Float64(Float64(x_m * x_m) * 2.7557319223985893e-6) - 0.0001984126984126984)))) - 0.16666666666666666)))
end
x\_m = abs(x);
x\_s = sign(x) * abs(1.0);
function tmp = code(x_s, x_m)
	tmp = x_s * ((x_m ^ 3.0) * (((x_m * x_m) * (0.008333333333333333 + ((x_m * x_m) * (((x_m * x_m) * 2.7557319223985893e-6) - 0.0001984126984126984)))) - 0.16666666666666666));
end
x\_m = N[Abs[x], $MachinePrecision]
x\_s = N[With[{TMP1 = Abs[1.0], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
code[x$95$s_, x$95$m_] := N[(x$95$s * N[(N[Power[x$95$m, 3.0], $MachinePrecision] * N[(N[(N[(x$95$m * x$95$m), $MachinePrecision] * N[(0.008333333333333333 + N[(N[(x$95$m * x$95$m), $MachinePrecision] * N[(N[(N[(x$95$m * x$95$m), $MachinePrecision] * 2.7557319223985893e-6), $MachinePrecision] - 0.0001984126984126984), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - 0.16666666666666666), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
x\_m = \left|x\right|
\\
x\_s = \mathsf{copysign}\left(1, x\right)

\\
x\_s \cdot \left({x\_m}^{3} \cdot \left(\left(x\_m \cdot x\_m\right) \cdot \left(0.008333333333333333 + \left(x\_m \cdot x\_m\right) \cdot \left(\left(x\_m \cdot x\_m\right) \cdot 2.7557319223985893 \cdot 10^{-6} - 0.0001984126984126984\right)\right) - 0.16666666666666666\right)\right)
\end{array}
Derivation
  1. Initial program 70.5%

    \[\sin x - x \]
  2. Add Preprocessing
  3. Taylor expanded in x around 0 98.3%

    \[\leadsto \color{blue}{{x}^{3} \cdot \left({x}^{2} \cdot \left(0.008333333333333333 + {x}^{2} \cdot \left(2.7557319223985893 \cdot 10^{-6} \cdot {x}^{2} - 0.0001984126984126984\right)\right) - 0.16666666666666666\right)} \]
  4. Step-by-step derivation
    1. unpow298.0%

      \[\leadsto {x}^{3} \cdot \left(0.008333333333333333 \cdot \color{blue}{\left(x \cdot x\right)} - 0.16666666666666666\right) \]
  5. Applied egg-rr98.3%

    \[\leadsto {x}^{3} \cdot \left({x}^{2} \cdot \left(0.008333333333333333 + {x}^{2} \cdot \left(2.7557319223985893 \cdot 10^{-6} \cdot \color{blue}{\left(x \cdot x\right)} - 0.0001984126984126984\right)\right) - 0.16666666666666666\right) \]
  6. Step-by-step derivation
    1. unpow298.0%

      \[\leadsto {x}^{3} \cdot \left(0.008333333333333333 \cdot \color{blue}{\left(x \cdot x\right)} - 0.16666666666666666\right) \]
  7. Applied egg-rr98.3%

    \[\leadsto {x}^{3} \cdot \left({x}^{2} \cdot \left(0.008333333333333333 + \color{blue}{\left(x \cdot x\right)} \cdot \left(2.7557319223985893 \cdot 10^{-6} \cdot \left(x \cdot x\right) - 0.0001984126984126984\right)\right) - 0.16666666666666666\right) \]
  8. Step-by-step derivation
    1. unpow298.0%

      \[\leadsto {x}^{3} \cdot \left(0.008333333333333333 \cdot \color{blue}{\left(x \cdot x\right)} - 0.16666666666666666\right) \]
  9. Applied egg-rr98.3%

    \[\leadsto {x}^{3} \cdot \left(\color{blue}{\left(x \cdot x\right)} \cdot \left(0.008333333333333333 + \left(x \cdot x\right) \cdot \left(2.7557319223985893 \cdot 10^{-6} \cdot \left(x \cdot x\right) - 0.0001984126984126984\right)\right) - 0.16666666666666666\right) \]
  10. Final simplification98.3%

    \[\leadsto {x}^{3} \cdot \left(\left(x \cdot x\right) \cdot \left(0.008333333333333333 + \left(x \cdot x\right) \cdot \left(\left(x \cdot x\right) \cdot 2.7557319223985893 \cdot 10^{-6} - 0.0001984126984126984\right)\right) - 0.16666666666666666\right) \]
  11. Add Preprocessing

Alternative 5: 98.0% accurate, 14.7× speedup?

\[\begin{array}{l} x\_m = \left|x\right| \\ x\_s = \mathsf{copysign}\left(1, x\right) \\ x\_s \cdot \left(x\_m \cdot \left(\left(x\_m \cdot x\_m\right) \cdot -0.16666666666666666\right)\right) \end{array} \]
x\_m = (fabs.f64 x)
x\_s = (copysign.f64 #s(literal 1 binary64) x)
(FPCore (x_s x_m)
 :precision binary64
 (* x_s (* x_m (* (* x_m x_m) -0.16666666666666666))))
x\_m = fabs(x);
x\_s = copysign(1.0, x);
double code(double x_s, double x_m) {
	return x_s * (x_m * ((x_m * x_m) * -0.16666666666666666));
}
x\_m = abs(x)
x\_s = copysign(1.0d0, x)
real(8) function code(x_s, x_m)
    real(8), intent (in) :: x_s
    real(8), intent (in) :: x_m
    code = x_s * (x_m * ((x_m * x_m) * (-0.16666666666666666d0)))
end function
x\_m = Math.abs(x);
x\_s = Math.copySign(1.0, x);
public static double code(double x_s, double x_m) {
	return x_s * (x_m * ((x_m * x_m) * -0.16666666666666666));
}
x\_m = math.fabs(x)
x\_s = math.copysign(1.0, x)
def code(x_s, x_m):
	return x_s * (x_m * ((x_m * x_m) * -0.16666666666666666))
x\_m = abs(x)
x\_s = copysign(1.0, x)
function code(x_s, x_m)
	return Float64(x_s * Float64(x_m * Float64(Float64(x_m * x_m) * -0.16666666666666666)))
end
x\_m = abs(x);
x\_s = sign(x) * abs(1.0);
function tmp = code(x_s, x_m)
	tmp = x_s * (x_m * ((x_m * x_m) * -0.16666666666666666));
end
x\_m = N[Abs[x], $MachinePrecision]
x\_s = N[With[{TMP1 = Abs[1.0], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
code[x$95$s_, x$95$m_] := N[(x$95$s * N[(x$95$m * N[(N[(x$95$m * x$95$m), $MachinePrecision] * -0.16666666666666666), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
x\_m = \left|x\right|
\\
x\_s = \mathsf{copysign}\left(1, x\right)

\\
x\_s \cdot \left(x\_m \cdot \left(\left(x\_m \cdot x\_m\right) \cdot -0.16666666666666666\right)\right)
\end{array}
Derivation
  1. Initial program 70.5%

    \[\sin x - x \]
  2. Add Preprocessing
  3. Taylor expanded in x around inf 70.4%

    \[\leadsto \color{blue}{x \cdot \left(\frac{\sin x}{x} - 1\right)} \]
  4. Taylor expanded in x around 0 97.8%

    \[\leadsto x \cdot \color{blue}{\left(-0.16666666666666666 \cdot {x}^{2}\right)} \]
  5. Step-by-step derivation
    1. *-commutative97.8%

      \[\leadsto x \cdot \color{blue}{\left({x}^{2} \cdot -0.16666666666666666\right)} \]
  6. Simplified97.8%

    \[\leadsto x \cdot \color{blue}{\left({x}^{2} \cdot -0.16666666666666666\right)} \]
  7. Step-by-step derivation
    1. unpow298.0%

      \[\leadsto {x}^{3} \cdot \left(0.008333333333333333 \cdot \color{blue}{\left(x \cdot x\right)} - 0.16666666666666666\right) \]
  8. Applied egg-rr97.8%

    \[\leadsto x \cdot \left(\color{blue}{\left(x \cdot x\right)} \cdot -0.16666666666666666\right) \]
  9. Final simplification97.8%

    \[\leadsto x \cdot \left(\left(x \cdot x\right) \cdot -0.16666666666666666\right) \]
  10. Add Preprocessing

Alternative 6: 67.5% accurate, 34.3× speedup?

\[\begin{array}{l} x\_m = \left|x\right| \\ x\_s = \mathsf{copysign}\left(1, x\right) \\ x\_s \cdot \left(x\_m \cdot 0\right) \end{array} \]
x\_m = (fabs.f64 x)
x\_s = (copysign.f64 #s(literal 1 binary64) x)
(FPCore (x_s x_m) :precision binary64 (* x_s (* x_m 0.0)))
x\_m = fabs(x);
x\_s = copysign(1.0, x);
double code(double x_s, double x_m) {
	return x_s * (x_m * 0.0);
}
x\_m = abs(x)
x\_s = copysign(1.0d0, x)
real(8) function code(x_s, x_m)
    real(8), intent (in) :: x_s
    real(8), intent (in) :: x_m
    code = x_s * (x_m * 0.0d0)
end function
x\_m = Math.abs(x);
x\_s = Math.copySign(1.0, x);
public static double code(double x_s, double x_m) {
	return x_s * (x_m * 0.0);
}
x\_m = math.fabs(x)
x\_s = math.copysign(1.0, x)
def code(x_s, x_m):
	return x_s * (x_m * 0.0)
x\_m = abs(x)
x\_s = copysign(1.0, x)
function code(x_s, x_m)
	return Float64(x_s * Float64(x_m * 0.0))
end
x\_m = abs(x);
x\_s = sign(x) * abs(1.0);
function tmp = code(x_s, x_m)
	tmp = x_s * (x_m * 0.0);
end
x\_m = N[Abs[x], $MachinePrecision]
x\_s = N[With[{TMP1 = Abs[1.0], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
code[x$95$s_, x$95$m_] := N[(x$95$s * N[(x$95$m * 0.0), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
x\_m = \left|x\right|
\\
x\_s = \mathsf{copysign}\left(1, x\right)

\\
x\_s \cdot \left(x\_m \cdot 0\right)
\end{array}
Derivation
  1. Initial program 70.5%

    \[\sin x - x \]
  2. Add Preprocessing
  3. Taylor expanded in x around inf 70.4%

    \[\leadsto \color{blue}{x \cdot \left(\frac{\sin x}{x} - 1\right)} \]
  4. Taylor expanded in x around 0 67.9%

    \[\leadsto x \cdot \left(\color{blue}{1} - 1\right) \]
  5. Final simplification67.9%

    \[\leadsto x \cdot 0 \]
  6. Add Preprocessing

Alternative 7: 6.5% accurate, 51.5× speedup?

\[\begin{array}{l} x\_m = \left|x\right| \\ x\_s = \mathsf{copysign}\left(1, x\right) \\ x\_s \cdot \left(-x\_m\right) \end{array} \]
x\_m = (fabs.f64 x)
x\_s = (copysign.f64 #s(literal 1 binary64) x)
(FPCore (x_s x_m) :precision binary64 (* x_s (- x_m)))
x\_m = fabs(x);
x\_s = copysign(1.0, x);
double code(double x_s, double x_m) {
	return x_s * -x_m;
}
x\_m = abs(x)
x\_s = copysign(1.0d0, x)
real(8) function code(x_s, x_m)
    real(8), intent (in) :: x_s
    real(8), intent (in) :: x_m
    code = x_s * -x_m
end function
x\_m = Math.abs(x);
x\_s = Math.copySign(1.0, x);
public static double code(double x_s, double x_m) {
	return x_s * -x_m;
}
x\_m = math.fabs(x)
x\_s = math.copysign(1.0, x)
def code(x_s, x_m):
	return x_s * -x_m
x\_m = abs(x)
x\_s = copysign(1.0, x)
function code(x_s, x_m)
	return Float64(x_s * Float64(-x_m))
end
x\_m = abs(x);
x\_s = sign(x) * abs(1.0);
function tmp = code(x_s, x_m)
	tmp = x_s * -x_m;
end
x\_m = N[Abs[x], $MachinePrecision]
x\_s = N[With[{TMP1 = Abs[1.0], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
code[x$95$s_, x$95$m_] := N[(x$95$s * (-x$95$m)), $MachinePrecision]
\begin{array}{l}
x\_m = \left|x\right|
\\
x\_s = \mathsf{copysign}\left(1, x\right)

\\
x\_s \cdot \left(-x\_m\right)
\end{array}
Derivation
  1. Initial program 70.5%

    \[\sin x - x \]
  2. Add Preprocessing
  3. Taylor expanded in x around inf 6.4%

    \[\leadsto \color{blue}{-1 \cdot x} \]
  4. Step-by-step derivation
    1. neg-mul-16.4%

      \[\leadsto \color{blue}{-x} \]
  5. Simplified6.4%

    \[\leadsto \color{blue}{-x} \]
  6. Final simplification6.4%

    \[\leadsto -x \]
  7. Add Preprocessing

Developer target: 99.8% accurate, 0.2× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\left|x\right| < 0.07:\\ \;\;\;\;-\left(\left(\frac{{x}^{3}}{6} - \frac{{x}^{5}}{120}\right) + \frac{{x}^{7}}{5040}\right)\\ \mathbf{else}:\\ \;\;\;\;\sin x - x\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (if (< (fabs x) 0.07)
   (- (+ (- (/ (pow x 3.0) 6.0) (/ (pow x 5.0) 120.0)) (/ (pow x 7.0) 5040.0)))
   (- (sin x) x)))
double code(double x) {
	double tmp;
	if (fabs(x) < 0.07) {
		tmp = -(((pow(x, 3.0) / 6.0) - (pow(x, 5.0) / 120.0)) + (pow(x, 7.0) / 5040.0));
	} else {
		tmp = sin(x) - x;
	}
	return tmp;
}
real(8) function code(x)
    real(8), intent (in) :: x
    real(8) :: tmp
    if (abs(x) < 0.07d0) then
        tmp = -((((x ** 3.0d0) / 6.0d0) - ((x ** 5.0d0) / 120.0d0)) + ((x ** 7.0d0) / 5040.0d0))
    else
        tmp = sin(x) - x
    end if
    code = tmp
end function
public static double code(double x) {
	double tmp;
	if (Math.abs(x) < 0.07) {
		tmp = -(((Math.pow(x, 3.0) / 6.0) - (Math.pow(x, 5.0) / 120.0)) + (Math.pow(x, 7.0) / 5040.0));
	} else {
		tmp = Math.sin(x) - x;
	}
	return tmp;
}
def code(x):
	tmp = 0
	if math.fabs(x) < 0.07:
		tmp = -(((math.pow(x, 3.0) / 6.0) - (math.pow(x, 5.0) / 120.0)) + (math.pow(x, 7.0) / 5040.0))
	else:
		tmp = math.sin(x) - x
	return tmp
function code(x)
	tmp = 0.0
	if (abs(x) < 0.07)
		tmp = Float64(-Float64(Float64(Float64((x ^ 3.0) / 6.0) - Float64((x ^ 5.0) / 120.0)) + Float64((x ^ 7.0) / 5040.0)));
	else
		tmp = Float64(sin(x) - x);
	end
	return tmp
end
function tmp_2 = code(x)
	tmp = 0.0;
	if (abs(x) < 0.07)
		tmp = -((((x ^ 3.0) / 6.0) - ((x ^ 5.0) / 120.0)) + ((x ^ 7.0) / 5040.0));
	else
		tmp = sin(x) - x;
	end
	tmp_2 = tmp;
end
code[x_] := If[Less[N[Abs[x], $MachinePrecision], 0.07], (-N[(N[(N[(N[Power[x, 3.0], $MachinePrecision] / 6.0), $MachinePrecision] - N[(N[Power[x, 5.0], $MachinePrecision] / 120.0), $MachinePrecision]), $MachinePrecision] + N[(N[Power[x, 7.0], $MachinePrecision] / 5040.0), $MachinePrecision]), $MachinePrecision]), N[(N[Sin[x], $MachinePrecision] - x), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\left|x\right| < 0.07:\\
\;\;\;\;-\left(\left(\frac{{x}^{3}}{6} - \frac{{x}^{5}}{120}\right) + \frac{{x}^{7}}{5040}\right)\\

\mathbf{else}:\\
\;\;\;\;\sin x - x\\


\end{array}
\end{array}

Reproduce

?
herbie shell --seed 2024080 
(FPCore (x)
  :name "bug500 (missed optimization)"
  :precision binary64
  :pre (and (< -1000.0 x) (< x 1000.0))

  :alt
  (if (< (fabs x) 0.07) (- (+ (- (/ (pow x 3.0) 6.0) (/ (pow x 5.0) 120.0)) (/ (pow x 7.0) 5040.0))) (- (sin x) x))

  (- (sin x) x))