Linear.Projection:perspective from linear-1.19.1.3, B

Percentage Accurate: 76.4% → 98.6%
Time: 7.9s
Alternatives: 6
Speedup: 0.5×

Specification

?
\[\begin{array}{l} \\ \frac{\left(x \cdot 2\right) \cdot y}{x - y} \end{array} \]
(FPCore (x y) :precision binary64 (/ (* (* x 2.0) y) (- x y)))
double code(double x, double y) {
	return ((x * 2.0) * y) / (x - y);
}
real(8) function code(x, y)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    code = ((x * 2.0d0) * y) / (x - y)
end function
public static double code(double x, double y) {
	return ((x * 2.0) * y) / (x - y);
}
def code(x, y):
	return ((x * 2.0) * y) / (x - y)
function code(x, y)
	return Float64(Float64(Float64(x * 2.0) * y) / Float64(x - y))
end
function tmp = code(x, y)
	tmp = ((x * 2.0) * y) / (x - y);
end
code[x_, y_] := N[(N[(N[(x * 2.0), $MachinePrecision] * y), $MachinePrecision] / N[(x - y), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{\left(x \cdot 2\right) \cdot y}{x - y}
\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 6 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: 76.4% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \frac{\left(x \cdot 2\right) \cdot y}{x - y} \end{array} \]
(FPCore (x y) :precision binary64 (/ (* (* x 2.0) y) (- x y)))
double code(double x, double y) {
	return ((x * 2.0) * y) / (x - y);
}
real(8) function code(x, y)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    code = ((x * 2.0d0) * y) / (x - y)
end function
public static double code(double x, double y) {
	return ((x * 2.0) * y) / (x - y);
}
def code(x, y):
	return ((x * 2.0) * y) / (x - y)
function code(x, y)
	return Float64(Float64(Float64(x * 2.0) * y) / Float64(x - y))
end
function tmp = code(x, y)
	tmp = ((x * 2.0) * y) / (x - y);
end
code[x_, y_] := N[(N[(N[(x * 2.0), $MachinePrecision] * y), $MachinePrecision] / N[(x - y), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{\left(x \cdot 2\right) \cdot y}{x - y}
\end{array}

Alternative 1: 98.6% accurate, 0.2× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \frac{\left(x \cdot 2\right) \cdot y}{x - y}\\ \mathbf{if}\;t\_0 \leq -1 \cdot 10^{+51} \lor \neg \left(t\_0 \leq -1 \cdot 10^{-303} \lor \neg \left(t\_0 \leq 5 \cdot 10^{-305} \lor \neg \left(t\_0 \leq 4 \cdot 10^{-86}\right)\right)\right):\\ \;\;\;\;\left(\frac{y}{x - y} \cdot x\right) \cdot 2\\ \mathbf{else}:\\ \;\;\;\;\frac{\left(x + x\right) \cdot y}{x - y}\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (let* ((t_0 (/ (* (* x 2.0) y) (- x y))))
   (if (or (<= t_0 -1e+51)
           (not
            (or (<= t_0 -1e-303)
                (not (or (<= t_0 5e-305) (not (<= t_0 4e-86)))))))
     (* (* (/ y (- x y)) x) 2.0)
     (/ (* (+ x x) y) (- x y)))))
double code(double x, double y) {
	double t_0 = ((x * 2.0) * y) / (x - y);
	double tmp;
	if ((t_0 <= -1e+51) || !((t_0 <= -1e-303) || !((t_0 <= 5e-305) || !(t_0 <= 4e-86)))) {
		tmp = ((y / (x - y)) * x) * 2.0;
	} else {
		tmp = ((x + x) * y) / (x - y);
	}
	return tmp;
}
real(8) function code(x, y)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8) :: t_0
    real(8) :: tmp
    t_0 = ((x * 2.0d0) * y) / (x - y)
    if ((t_0 <= (-1d+51)) .or. (.not. (t_0 <= (-1d-303)) .or. (.not. (t_0 <= 5d-305) .or. (.not. (t_0 <= 4d-86))))) then
        tmp = ((y / (x - y)) * x) * 2.0d0
    else
        tmp = ((x + x) * y) / (x - y)
    end if
    code = tmp
end function
public static double code(double x, double y) {
	double t_0 = ((x * 2.0) * y) / (x - y);
	double tmp;
	if ((t_0 <= -1e+51) || !((t_0 <= -1e-303) || !((t_0 <= 5e-305) || !(t_0 <= 4e-86)))) {
		tmp = ((y / (x - y)) * x) * 2.0;
	} else {
		tmp = ((x + x) * y) / (x - y);
	}
	return tmp;
}
def code(x, y):
	t_0 = ((x * 2.0) * y) / (x - y)
	tmp = 0
	if (t_0 <= -1e+51) or not ((t_0 <= -1e-303) or not ((t_0 <= 5e-305) or not (t_0 <= 4e-86))):
		tmp = ((y / (x - y)) * x) * 2.0
	else:
		tmp = ((x + x) * y) / (x - y)
	return tmp
function code(x, y)
	t_0 = Float64(Float64(Float64(x * 2.0) * y) / Float64(x - y))
	tmp = 0.0
	if ((t_0 <= -1e+51) || !((t_0 <= -1e-303) || !((t_0 <= 5e-305) || !(t_0 <= 4e-86))))
		tmp = Float64(Float64(Float64(y / Float64(x - y)) * x) * 2.0);
	else
		tmp = Float64(Float64(Float64(x + x) * y) / Float64(x - y));
	end
	return tmp
end
function tmp_2 = code(x, y)
	t_0 = ((x * 2.0) * y) / (x - y);
	tmp = 0.0;
	if ((t_0 <= -1e+51) || ~(((t_0 <= -1e-303) || ~(((t_0 <= 5e-305) || ~((t_0 <= 4e-86)))))))
		tmp = ((y / (x - y)) * x) * 2.0;
	else
		tmp = ((x + x) * y) / (x - y);
	end
	tmp_2 = tmp;
end
code[x_, y_] := Block[{t$95$0 = N[(N[(N[(x * 2.0), $MachinePrecision] * y), $MachinePrecision] / N[(x - y), $MachinePrecision]), $MachinePrecision]}, If[Or[LessEqual[t$95$0, -1e+51], N[Not[Or[LessEqual[t$95$0, -1e-303], N[Not[Or[LessEqual[t$95$0, 5e-305], N[Not[LessEqual[t$95$0, 4e-86]], $MachinePrecision]]], $MachinePrecision]]], $MachinePrecision]], N[(N[(N[(y / N[(x - y), $MachinePrecision]), $MachinePrecision] * x), $MachinePrecision] * 2.0), $MachinePrecision], N[(N[(N[(x + x), $MachinePrecision] * y), $MachinePrecision] / N[(x - y), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \frac{\left(x \cdot 2\right) \cdot y}{x - y}\\
\mathbf{if}\;t\_0 \leq -1 \cdot 10^{+51} \lor \neg \left(t\_0 \leq -1 \cdot 10^{-303} \lor \neg \left(t\_0 \leq 5 \cdot 10^{-305} \lor \neg \left(t\_0 \leq 4 \cdot 10^{-86}\right)\right)\right):\\
\;\;\;\;\left(\frac{y}{x - y} \cdot x\right) \cdot 2\\

\mathbf{else}:\\
\;\;\;\;\frac{\left(x + x\right) \cdot y}{x - y}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (/.f64 (*.f64 (*.f64 x #s(literal 2 binary64)) y) (-.f64 x y)) < -1e51 or -9.99999999999999931e-304 < (/.f64 (*.f64 (*.f64 x #s(literal 2 binary64)) y) (-.f64 x y)) < 4.99999999999999985e-305 or 4.00000000000000034e-86 < (/.f64 (*.f64 (*.f64 x #s(literal 2 binary64)) y) (-.f64 x y))

    1. Initial program 50.8%

      \[\frac{\left(x \cdot 2\right) \cdot y}{x - y} \]
    2. Add Preprocessing
    3. Step-by-step derivation
      1. lift-/.f64N/A

        \[\leadsto \color{blue}{\frac{\left(x \cdot 2\right) \cdot y}{x - y}} \]
      2. lift-*.f64N/A

        \[\leadsto \frac{\color{blue}{\left(x \cdot 2\right) \cdot y}}{x - y} \]
      3. associate-/l*N/A

        \[\leadsto \color{blue}{\left(x \cdot 2\right) \cdot \frac{y}{x - y}} \]
      4. lift-*.f64N/A

        \[\leadsto \color{blue}{\left(x \cdot 2\right)} \cdot \frac{y}{x - y} \]
      5. *-commutativeN/A

        \[\leadsto \color{blue}{\left(2 \cdot x\right)} \cdot \frac{y}{x - y} \]
      6. associate-*l*N/A

        \[\leadsto \color{blue}{2 \cdot \left(x \cdot \frac{y}{x - y}\right)} \]
      7. *-commutativeN/A

        \[\leadsto \color{blue}{\left(x \cdot \frac{y}{x - y}\right) \cdot 2} \]
      8. lower-*.f64N/A

        \[\leadsto \color{blue}{\left(x \cdot \frac{y}{x - y}\right) \cdot 2} \]
      9. *-commutativeN/A

        \[\leadsto \color{blue}{\left(\frac{y}{x - y} \cdot x\right)} \cdot 2 \]
      10. lower-*.f64N/A

        \[\leadsto \color{blue}{\left(\frac{y}{x - y} \cdot x\right)} \cdot 2 \]
      11. lower-/.f6499.9

        \[\leadsto \left(\color{blue}{\frac{y}{x - y}} \cdot x\right) \cdot 2 \]
    4. Applied rewrites99.9%

      \[\leadsto \color{blue}{\left(\frac{y}{x - y} \cdot x\right) \cdot 2} \]

    if -1e51 < (/.f64 (*.f64 (*.f64 x #s(literal 2 binary64)) y) (-.f64 x y)) < -9.99999999999999931e-304 or 4.99999999999999985e-305 < (/.f64 (*.f64 (*.f64 x #s(literal 2 binary64)) y) (-.f64 x y)) < 4.00000000000000034e-86

    1. Initial program 98.6%

      \[\frac{\left(x \cdot 2\right) \cdot y}{x - y} \]
    2. Add Preprocessing
    3. Step-by-step derivation
      1. lift-*.f64N/A

        \[\leadsto \frac{\color{blue}{\left(x \cdot 2\right)} \cdot y}{x - y} \]
      2. *-commutativeN/A

        \[\leadsto \frac{\color{blue}{\left(2 \cdot x\right)} \cdot y}{x - y} \]
      3. count-2-revN/A

        \[\leadsto \frac{\color{blue}{\left(x + x\right)} \cdot y}{x - y} \]
      4. lower-+.f6498.6

        \[\leadsto \frac{\color{blue}{\left(x + x\right)} \cdot y}{x - y} \]
    4. Applied rewrites98.6%

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

    \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{\left(x \cdot 2\right) \cdot y}{x - y} \leq -1 \cdot 10^{+51} \lor \neg \left(\frac{\left(x \cdot 2\right) \cdot y}{x - y} \leq -1 \cdot 10^{-303} \lor \neg \left(\frac{\left(x \cdot 2\right) \cdot y}{x - y} \leq 5 \cdot 10^{-305} \lor \neg \left(\frac{\left(x \cdot 2\right) \cdot y}{x - y} \leq 4 \cdot 10^{-86}\right)\right)\right):\\ \;\;\;\;\left(\frac{y}{x - y} \cdot x\right) \cdot 2\\ \mathbf{else}:\\ \;\;\;\;\frac{\left(x + x\right) \cdot y}{x - y}\\ \end{array} \]
  5. Add Preprocessing

Alternative 2: 86.0% accurate, 0.2× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \frac{\left(x \cdot 2\right) \cdot y}{x - y}\\ \mathbf{if}\;t\_0 \leq -\infty \lor \neg \left(t\_0 \leq -1 \cdot 10^{-303} \lor \neg \left(t\_0 \leq 5 \cdot 10^{-305} \lor \neg \left(t\_0 \leq 4 \cdot 10^{+80}\right)\right)\right):\\ \;\;\;\;-2 \cdot x\\ \mathbf{else}:\\ \;\;\;\;\frac{\left(x + x\right) \cdot y}{x - y}\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (let* ((t_0 (/ (* (* x 2.0) y) (- x y))))
   (if (or (<= t_0 (- INFINITY))
           (not
            (or (<= t_0 -1e-303)
                (not (or (<= t_0 5e-305) (not (<= t_0 4e+80)))))))
     (* -2.0 x)
     (/ (* (+ x x) y) (- x y)))))
double code(double x, double y) {
	double t_0 = ((x * 2.0) * y) / (x - y);
	double tmp;
	if ((t_0 <= -((double) INFINITY)) || !((t_0 <= -1e-303) || !((t_0 <= 5e-305) || !(t_0 <= 4e+80)))) {
		tmp = -2.0 * x;
	} else {
		tmp = ((x + x) * y) / (x - y);
	}
	return tmp;
}
public static double code(double x, double y) {
	double t_0 = ((x * 2.0) * y) / (x - y);
	double tmp;
	if ((t_0 <= -Double.POSITIVE_INFINITY) || !((t_0 <= -1e-303) || !((t_0 <= 5e-305) || !(t_0 <= 4e+80)))) {
		tmp = -2.0 * x;
	} else {
		tmp = ((x + x) * y) / (x - y);
	}
	return tmp;
}
def code(x, y):
	t_0 = ((x * 2.0) * y) / (x - y)
	tmp = 0
	if (t_0 <= -math.inf) or not ((t_0 <= -1e-303) or not ((t_0 <= 5e-305) or not (t_0 <= 4e+80))):
		tmp = -2.0 * x
	else:
		tmp = ((x + x) * y) / (x - y)
	return tmp
function code(x, y)
	t_0 = Float64(Float64(Float64(x * 2.0) * y) / Float64(x - y))
	tmp = 0.0
	if ((t_0 <= Float64(-Inf)) || !((t_0 <= -1e-303) || !((t_0 <= 5e-305) || !(t_0 <= 4e+80))))
		tmp = Float64(-2.0 * x);
	else
		tmp = Float64(Float64(Float64(x + x) * y) / Float64(x - y));
	end
	return tmp
end
function tmp_2 = code(x, y)
	t_0 = ((x * 2.0) * y) / (x - y);
	tmp = 0.0;
	if ((t_0 <= -Inf) || ~(((t_0 <= -1e-303) || ~(((t_0 <= 5e-305) || ~((t_0 <= 4e+80)))))))
		tmp = -2.0 * x;
	else
		tmp = ((x + x) * y) / (x - y);
	end
	tmp_2 = tmp;
end
code[x_, y_] := Block[{t$95$0 = N[(N[(N[(x * 2.0), $MachinePrecision] * y), $MachinePrecision] / N[(x - y), $MachinePrecision]), $MachinePrecision]}, If[Or[LessEqual[t$95$0, (-Infinity)], N[Not[Or[LessEqual[t$95$0, -1e-303], N[Not[Or[LessEqual[t$95$0, 5e-305], N[Not[LessEqual[t$95$0, 4e+80]], $MachinePrecision]]], $MachinePrecision]]], $MachinePrecision]], N[(-2.0 * x), $MachinePrecision], N[(N[(N[(x + x), $MachinePrecision] * y), $MachinePrecision] / N[(x - y), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \frac{\left(x \cdot 2\right) \cdot y}{x - y}\\
\mathbf{if}\;t\_0 \leq -\infty \lor \neg \left(t\_0 \leq -1 \cdot 10^{-303} \lor \neg \left(t\_0 \leq 5 \cdot 10^{-305} \lor \neg \left(t\_0 \leq 4 \cdot 10^{+80}\right)\right)\right):\\
\;\;\;\;-2 \cdot x\\

\mathbf{else}:\\
\;\;\;\;\frac{\left(x + x\right) \cdot y}{x - y}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (/.f64 (*.f64 (*.f64 x #s(literal 2 binary64)) y) (-.f64 x y)) < -inf.0 or -9.99999999999999931e-304 < (/.f64 (*.f64 (*.f64 x #s(literal 2 binary64)) y) (-.f64 x y)) < 4.99999999999999985e-305 or 4e80 < (/.f64 (*.f64 (*.f64 x #s(literal 2 binary64)) y) (-.f64 x y))

    1. Initial program 9.7%

      \[\frac{\left(x \cdot 2\right) \cdot y}{x - y} \]
    2. Add Preprocessing
    3. Taylor expanded in x around 0

      \[\leadsto \color{blue}{-2 \cdot x} \]
    4. Step-by-step derivation
      1. lower-*.f6464.4

        \[\leadsto \color{blue}{-2 \cdot x} \]
    5. Applied rewrites64.4%

      \[\leadsto \color{blue}{-2 \cdot x} \]

    if -inf.0 < (/.f64 (*.f64 (*.f64 x #s(literal 2 binary64)) y) (-.f64 x y)) < -9.99999999999999931e-304 or 4.99999999999999985e-305 < (/.f64 (*.f64 (*.f64 x #s(literal 2 binary64)) y) (-.f64 x y)) < 4e80

    1. Initial program 98.8%

      \[\frac{\left(x \cdot 2\right) \cdot y}{x - y} \]
    2. Add Preprocessing
    3. Step-by-step derivation
      1. lift-*.f64N/A

        \[\leadsto \frac{\color{blue}{\left(x \cdot 2\right)} \cdot y}{x - y} \]
      2. *-commutativeN/A

        \[\leadsto \frac{\color{blue}{\left(2 \cdot x\right)} \cdot y}{x - y} \]
      3. count-2-revN/A

        \[\leadsto \frac{\color{blue}{\left(x + x\right)} \cdot y}{x - y} \]
      4. lower-+.f6498.8

        \[\leadsto \frac{\color{blue}{\left(x + x\right)} \cdot y}{x - y} \]
    4. Applied rewrites98.8%

      \[\leadsto \frac{\color{blue}{\left(x + x\right)} \cdot y}{x - y} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification92.1%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{\left(x \cdot 2\right) \cdot y}{x - y} \leq -\infty \lor \neg \left(\frac{\left(x \cdot 2\right) \cdot y}{x - y} \leq -1 \cdot 10^{-303} \lor \neg \left(\frac{\left(x \cdot 2\right) \cdot y}{x - y} \leq 5 \cdot 10^{-305} \lor \neg \left(\frac{\left(x \cdot 2\right) \cdot y}{x - y} \leq 4 \cdot 10^{+80}\right)\right)\right):\\ \;\;\;\;-2 \cdot x\\ \mathbf{else}:\\ \;\;\;\;\frac{\left(x + x\right) \cdot y}{x - y}\\ \end{array} \]
  5. Add Preprocessing

Alternative 3: 94.0% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -2.9 \cdot 10^{-109} \lor \neg \left(y \leq 3.2 \cdot 10^{-147}\right):\\ \;\;\;\;\left(\frac{y}{x - y} \cdot x\right) \cdot 2\\ \mathbf{else}:\\ \;\;\;\;2 \cdot \mathsf{fma}\left(\frac{y}{x}, \mathsf{fma}\left(\frac{y}{x}, y, y\right), y\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (or (<= y -2.9e-109) (not (<= y 3.2e-147)))
   (* (* (/ y (- x y)) x) 2.0)
   (* 2.0 (fma (/ y x) (fma (/ y x) y y) y))))
double code(double x, double y) {
	double tmp;
	if ((y <= -2.9e-109) || !(y <= 3.2e-147)) {
		tmp = ((y / (x - y)) * x) * 2.0;
	} else {
		tmp = 2.0 * fma((y / x), fma((y / x), y, y), y);
	}
	return tmp;
}
function code(x, y)
	tmp = 0.0
	if ((y <= -2.9e-109) || !(y <= 3.2e-147))
		tmp = Float64(Float64(Float64(y / Float64(x - y)) * x) * 2.0);
	else
		tmp = Float64(2.0 * fma(Float64(y / x), fma(Float64(y / x), y, y), y));
	end
	return tmp
end
code[x_, y_] := If[Or[LessEqual[y, -2.9e-109], N[Not[LessEqual[y, 3.2e-147]], $MachinePrecision]], N[(N[(N[(y / N[(x - y), $MachinePrecision]), $MachinePrecision] * x), $MachinePrecision] * 2.0), $MachinePrecision], N[(2.0 * N[(N[(y / x), $MachinePrecision] * N[(N[(y / x), $MachinePrecision] * y + y), $MachinePrecision] + y), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq -2.9 \cdot 10^{-109} \lor \neg \left(y \leq 3.2 \cdot 10^{-147}\right):\\
\;\;\;\;\left(\frac{y}{x - y} \cdot x\right) \cdot 2\\

\mathbf{else}:\\
\;\;\;\;2 \cdot \mathsf{fma}\left(\frac{y}{x}, \mathsf{fma}\left(\frac{y}{x}, y, y\right), y\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if y < -2.9e-109 or 3.19999999999999979e-147 < y

    1. Initial program 82.5%

      \[\frac{\left(x \cdot 2\right) \cdot y}{x - y} \]
    2. Add Preprocessing
    3. Step-by-step derivation
      1. lift-/.f64N/A

        \[\leadsto \color{blue}{\frac{\left(x \cdot 2\right) \cdot y}{x - y}} \]
      2. lift-*.f64N/A

        \[\leadsto \frac{\color{blue}{\left(x \cdot 2\right) \cdot y}}{x - y} \]
      3. associate-/l*N/A

        \[\leadsto \color{blue}{\left(x \cdot 2\right) \cdot \frac{y}{x - y}} \]
      4. lift-*.f64N/A

        \[\leadsto \color{blue}{\left(x \cdot 2\right)} \cdot \frac{y}{x - y} \]
      5. *-commutativeN/A

        \[\leadsto \color{blue}{\left(2 \cdot x\right)} \cdot \frac{y}{x - y} \]
      6. associate-*l*N/A

        \[\leadsto \color{blue}{2 \cdot \left(x \cdot \frac{y}{x - y}\right)} \]
      7. *-commutativeN/A

        \[\leadsto \color{blue}{\left(x \cdot \frac{y}{x - y}\right) \cdot 2} \]
      8. lower-*.f64N/A

        \[\leadsto \color{blue}{\left(x \cdot \frac{y}{x - y}\right) \cdot 2} \]
      9. *-commutativeN/A

        \[\leadsto \color{blue}{\left(\frac{y}{x - y} \cdot x\right)} \cdot 2 \]
      10. lower-*.f64N/A

        \[\leadsto \color{blue}{\left(\frac{y}{x - y} \cdot x\right)} \cdot 2 \]
      11. lower-/.f6499.2

        \[\leadsto \left(\color{blue}{\frac{y}{x - y}} \cdot x\right) \cdot 2 \]
    4. Applied rewrites99.2%

      \[\leadsto \color{blue}{\left(\frac{y}{x - y} \cdot x\right) \cdot 2} \]

    if -2.9e-109 < y < 3.19999999999999979e-147

    1. Initial program 79.3%

      \[\frac{\left(x \cdot 2\right) \cdot y}{x - y} \]
    2. Add Preprocessing
    3. Taylor expanded in x around inf

      \[\leadsto \color{blue}{2 \cdot y + \left(2 \cdot \frac{{y}^{2}}{x} + 2 \cdot \frac{{y}^{3}}{{x}^{2}}\right)} \]
    4. Step-by-step derivation
      1. +-commutativeN/A

        \[\leadsto \color{blue}{\left(2 \cdot \frac{{y}^{2}}{x} + 2 \cdot \frac{{y}^{3}}{{x}^{2}}\right) + 2 \cdot y} \]
      2. distribute-lft-outN/A

        \[\leadsto \color{blue}{2 \cdot \left(\frac{{y}^{2}}{x} + \frac{{y}^{3}}{{x}^{2}}\right)} + 2 \cdot y \]
      3. distribute-lft-outN/A

        \[\leadsto \color{blue}{2 \cdot \left(\left(\frac{{y}^{2}}{x} + \frac{{y}^{3}}{{x}^{2}}\right) + y\right)} \]
      4. lower-*.f64N/A

        \[\leadsto \color{blue}{2 \cdot \left(\left(\frac{{y}^{2}}{x} + \frac{{y}^{3}}{{x}^{2}}\right) + y\right)} \]
      5. unpow2N/A

        \[\leadsto 2 \cdot \left(\left(\frac{\color{blue}{y \cdot y}}{x} + \frac{{y}^{3}}{{x}^{2}}\right) + y\right) \]
      6. associate-/l*N/A

        \[\leadsto 2 \cdot \left(\left(\color{blue}{y \cdot \frac{y}{x}} + \frac{{y}^{3}}{{x}^{2}}\right) + y\right) \]
      7. unpow3N/A

        \[\leadsto 2 \cdot \left(\left(y \cdot \frac{y}{x} + \frac{\color{blue}{\left(y \cdot y\right) \cdot y}}{{x}^{2}}\right) + y\right) \]
      8. unpow2N/A

        \[\leadsto 2 \cdot \left(\left(y \cdot \frac{y}{x} + \frac{\color{blue}{{y}^{2}} \cdot y}{{x}^{2}}\right) + y\right) \]
      9. unpow2N/A

        \[\leadsto 2 \cdot \left(\left(y \cdot \frac{y}{x} + \frac{{y}^{2} \cdot y}{\color{blue}{x \cdot x}}\right) + y\right) \]
      10. times-fracN/A

        \[\leadsto 2 \cdot \left(\left(y \cdot \frac{y}{x} + \color{blue}{\frac{{y}^{2}}{x} \cdot \frac{y}{x}}\right) + y\right) \]
      11. distribute-rgt-outN/A

        \[\leadsto 2 \cdot \left(\color{blue}{\frac{y}{x} \cdot \left(y + \frac{{y}^{2}}{x}\right)} + y\right) \]
      12. lower-fma.f64N/A

        \[\leadsto 2 \cdot \color{blue}{\mathsf{fma}\left(\frac{y}{x}, y + \frac{{y}^{2}}{x}, y\right)} \]
      13. lower-/.f64N/A

        \[\leadsto 2 \cdot \mathsf{fma}\left(\color{blue}{\frac{y}{x}}, y + \frac{{y}^{2}}{x}, y\right) \]
      14. +-commutativeN/A

        \[\leadsto 2 \cdot \mathsf{fma}\left(\frac{y}{x}, \color{blue}{\frac{{y}^{2}}{x} + y}, y\right) \]
      15. unpow2N/A

        \[\leadsto 2 \cdot \mathsf{fma}\left(\frac{y}{x}, \frac{\color{blue}{y \cdot y}}{x} + y, y\right) \]
      16. associate-*l/N/A

        \[\leadsto 2 \cdot \mathsf{fma}\left(\frac{y}{x}, \color{blue}{\frac{y}{x} \cdot y} + y, y\right) \]
      17. lower-fma.f64N/A

        \[\leadsto 2 \cdot \mathsf{fma}\left(\frac{y}{x}, \color{blue}{\mathsf{fma}\left(\frac{y}{x}, y, y\right)}, y\right) \]
      18. lower-/.f6489.4

        \[\leadsto 2 \cdot \mathsf{fma}\left(\frac{y}{x}, \mathsf{fma}\left(\color{blue}{\frac{y}{x}}, y, y\right), y\right) \]
    5. Applied rewrites89.4%

      \[\leadsto \color{blue}{2 \cdot \mathsf{fma}\left(\frac{y}{x}, \mathsf{fma}\left(\frac{y}{x}, y, y\right), y\right)} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification96.0%

    \[\leadsto \begin{array}{l} \mathbf{if}\;y \leq -2.9 \cdot 10^{-109} \lor \neg \left(y \leq 3.2 \cdot 10^{-147}\right):\\ \;\;\;\;\left(\frac{y}{x - y} \cdot x\right) \cdot 2\\ \mathbf{else}:\\ \;\;\;\;2 \cdot \mathsf{fma}\left(\frac{y}{x}, \mathsf{fma}\left(\frac{y}{x}, y, y\right), y\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 4: 73.9% accurate, 0.7× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -7 \cdot 10^{-21}:\\ \;\;\;\;-2 \cdot x\\ \mathbf{elif}\;y \leq 3 \cdot 10^{-79}:\\ \;\;\;\;y + y\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(x, \frac{x}{y}, x\right) \cdot -2\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= y -7e-21)
   (* -2.0 x)
   (if (<= y 3e-79) (+ y y) (* (fma x (/ x y) x) -2.0))))
double code(double x, double y) {
	double tmp;
	if (y <= -7e-21) {
		tmp = -2.0 * x;
	} else if (y <= 3e-79) {
		tmp = y + y;
	} else {
		tmp = fma(x, (x / y), x) * -2.0;
	}
	return tmp;
}
function code(x, y)
	tmp = 0.0
	if (y <= -7e-21)
		tmp = Float64(-2.0 * x);
	elseif (y <= 3e-79)
		tmp = Float64(y + y);
	else
		tmp = Float64(fma(x, Float64(x / y), x) * -2.0);
	end
	return tmp
end
code[x_, y_] := If[LessEqual[y, -7e-21], N[(-2.0 * x), $MachinePrecision], If[LessEqual[y, 3e-79], N[(y + y), $MachinePrecision], N[(N[(x * N[(x / y), $MachinePrecision] + x), $MachinePrecision] * -2.0), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq -7 \cdot 10^{-21}:\\
\;\;\;\;-2 \cdot x\\

\mathbf{elif}\;y \leq 3 \cdot 10^{-79}:\\
\;\;\;\;y + y\\

\mathbf{else}:\\
\;\;\;\;\mathsf{fma}\left(x, \frac{x}{y}, x\right) \cdot -2\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if y < -7.0000000000000007e-21

    1. Initial program 82.9%

      \[\frac{\left(x \cdot 2\right) \cdot y}{x - y} \]
    2. Add Preprocessing
    3. Taylor expanded in x around 0

      \[\leadsto \color{blue}{-2 \cdot x} \]
    4. Step-by-step derivation
      1. lower-*.f6473.1

        \[\leadsto \color{blue}{-2 \cdot x} \]
    5. Applied rewrites73.1%

      \[\leadsto \color{blue}{-2 \cdot x} \]

    if -7.0000000000000007e-21 < y < 3e-79

    1. Initial program 81.7%

      \[\frac{\left(x \cdot 2\right) \cdot y}{x - y} \]
    2. Add Preprocessing
    3. Taylor expanded in x around inf

      \[\leadsto \color{blue}{2 \cdot y} \]
    4. Step-by-step derivation
      1. lower-*.f6483.5

        \[\leadsto \color{blue}{2 \cdot y} \]
    5. Applied rewrites83.5%

      \[\leadsto \color{blue}{2 \cdot y} \]
    6. Step-by-step derivation
      1. Applied rewrites83.5%

        \[\leadsto y + \color{blue}{y} \]

      if 3e-79 < y

      1. Initial program 79.6%

        \[\frac{\left(x \cdot 2\right) \cdot y}{x - y} \]
      2. Add Preprocessing
      3. Taylor expanded in y around inf

        \[\leadsto \color{blue}{-2 \cdot x + -2 \cdot \frac{{x}^{2}}{y}} \]
      4. Step-by-step derivation
        1. distribute-lft-outN/A

          \[\leadsto \color{blue}{-2 \cdot \left(x + \frac{{x}^{2}}{y}\right)} \]
        2. *-commutativeN/A

          \[\leadsto \color{blue}{\left(x + \frac{{x}^{2}}{y}\right) \cdot -2} \]
        3. lower-*.f64N/A

          \[\leadsto \color{blue}{\left(x + \frac{{x}^{2}}{y}\right) \cdot -2} \]
        4. +-commutativeN/A

          \[\leadsto \color{blue}{\left(\frac{{x}^{2}}{y} + x\right)} \cdot -2 \]
        5. unpow2N/A

          \[\leadsto \left(\frac{\color{blue}{x \cdot x}}{y} + x\right) \cdot -2 \]
        6. associate-/l*N/A

          \[\leadsto \left(\color{blue}{x \cdot \frac{x}{y}} + x\right) \cdot -2 \]
        7. lower-fma.f64N/A

          \[\leadsto \color{blue}{\mathsf{fma}\left(x, \frac{x}{y}, x\right)} \cdot -2 \]
        8. lower-/.f6480.6

          \[\leadsto \mathsf{fma}\left(x, \color{blue}{\frac{x}{y}}, x\right) \cdot -2 \]
      5. Applied rewrites80.6%

        \[\leadsto \color{blue}{\mathsf{fma}\left(x, \frac{x}{y}, x\right) \cdot -2} \]
    7. Recombined 3 regimes into one program.
    8. Add Preprocessing

    Alternative 5: 74.0% accurate, 1.4× speedup?

    \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq -7 \cdot 10^{-21} \lor \neg \left(y \leq 3 \cdot 10^{-79}\right):\\ \;\;\;\;-2 \cdot x\\ \mathbf{else}:\\ \;\;\;\;y + y\\ \end{array} \end{array} \]
    (FPCore (x y)
     :precision binary64
     (if (or (<= y -7e-21) (not (<= y 3e-79))) (* -2.0 x) (+ y y)))
    double code(double x, double y) {
    	double tmp;
    	if ((y <= -7e-21) || !(y <= 3e-79)) {
    		tmp = -2.0 * x;
    	} else {
    		tmp = y + y;
    	}
    	return tmp;
    }
    
    real(8) function code(x, y)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        real(8) :: tmp
        if ((y <= (-7d-21)) .or. (.not. (y <= 3d-79))) then
            tmp = (-2.0d0) * x
        else
            tmp = y + y
        end if
        code = tmp
    end function
    
    public static double code(double x, double y) {
    	double tmp;
    	if ((y <= -7e-21) || !(y <= 3e-79)) {
    		tmp = -2.0 * x;
    	} else {
    		tmp = y + y;
    	}
    	return tmp;
    }
    
    def code(x, y):
    	tmp = 0
    	if (y <= -7e-21) or not (y <= 3e-79):
    		tmp = -2.0 * x
    	else:
    		tmp = y + y
    	return tmp
    
    function code(x, y)
    	tmp = 0.0
    	if ((y <= -7e-21) || !(y <= 3e-79))
    		tmp = Float64(-2.0 * x);
    	else
    		tmp = Float64(y + y);
    	end
    	return tmp
    end
    
    function tmp_2 = code(x, y)
    	tmp = 0.0;
    	if ((y <= -7e-21) || ~((y <= 3e-79)))
    		tmp = -2.0 * x;
    	else
    		tmp = y + y;
    	end
    	tmp_2 = tmp;
    end
    
    code[x_, y_] := If[Or[LessEqual[y, -7e-21], N[Not[LessEqual[y, 3e-79]], $MachinePrecision]], N[(-2.0 * x), $MachinePrecision], N[(y + y), $MachinePrecision]]
    
    \begin{array}{l}
    
    \\
    \begin{array}{l}
    \mathbf{if}\;y \leq -7 \cdot 10^{-21} \lor \neg \left(y \leq 3 \cdot 10^{-79}\right):\\
    \;\;\;\;-2 \cdot x\\
    
    \mathbf{else}:\\
    \;\;\;\;y + y\\
    
    
    \end{array}
    \end{array}
    
    Derivation
    1. Split input into 2 regimes
    2. if y < -7.0000000000000007e-21 or 3e-79 < y

      1. Initial program 81.2%

        \[\frac{\left(x \cdot 2\right) \cdot y}{x - y} \]
      2. Add Preprocessing
      3. Taylor expanded in x around 0

        \[\leadsto \color{blue}{-2 \cdot x} \]
      4. Step-by-step derivation
        1. lower-*.f6476.8

          \[\leadsto \color{blue}{-2 \cdot x} \]
      5. Applied rewrites76.8%

        \[\leadsto \color{blue}{-2 \cdot x} \]

      if -7.0000000000000007e-21 < y < 3e-79

      1. Initial program 81.7%

        \[\frac{\left(x \cdot 2\right) \cdot y}{x - y} \]
      2. Add Preprocessing
      3. Taylor expanded in x around inf

        \[\leadsto \color{blue}{2 \cdot y} \]
      4. Step-by-step derivation
        1. lower-*.f6483.5

          \[\leadsto \color{blue}{2 \cdot y} \]
      5. Applied rewrites83.5%

        \[\leadsto \color{blue}{2 \cdot y} \]
      6. Step-by-step derivation
        1. Applied rewrites83.5%

          \[\leadsto y + \color{blue}{y} \]
      7. Recombined 2 regimes into one program.
      8. Final simplification79.7%

        \[\leadsto \begin{array}{l} \mathbf{if}\;y \leq -7 \cdot 10^{-21} \lor \neg \left(y \leq 3 \cdot 10^{-79}\right):\\ \;\;\;\;-2 \cdot x\\ \mathbf{else}:\\ \;\;\;\;y + y\\ \end{array} \]
      9. Add Preprocessing

      Alternative 6: 50.8% accurate, 6.3× speedup?

      \[\begin{array}{l} \\ y + y \end{array} \]
      (FPCore (x y) :precision binary64 (+ y y))
      double code(double x, double y) {
      	return y + y;
      }
      
      real(8) function code(x, y)
          real(8), intent (in) :: x
          real(8), intent (in) :: y
          code = y + y
      end function
      
      public static double code(double x, double y) {
      	return y + y;
      }
      
      def code(x, y):
      	return y + y
      
      function code(x, y)
      	return Float64(y + y)
      end
      
      function tmp = code(x, y)
      	tmp = y + y;
      end
      
      code[x_, y_] := N[(y + y), $MachinePrecision]
      
      \begin{array}{l}
      
      \\
      y + y
      \end{array}
      
      Derivation
      1. Initial program 81.4%

        \[\frac{\left(x \cdot 2\right) \cdot y}{x - y} \]
      2. Add Preprocessing
      3. Taylor expanded in x around inf

        \[\leadsto \color{blue}{2 \cdot y} \]
      4. Step-by-step derivation
        1. lower-*.f6449.4

          \[\leadsto \color{blue}{2 \cdot y} \]
      5. Applied rewrites49.4%

        \[\leadsto \color{blue}{2 \cdot y} \]
      6. Step-by-step derivation
        1. Applied rewrites49.4%

          \[\leadsto y + \color{blue}{y} \]
        2. Add Preprocessing

        Developer Target 1: 99.5% accurate, 0.6× speedup?

        \[\begin{array}{l} \\ \begin{array}{l} t_0 := \frac{2 \cdot x}{x - y} \cdot y\\ \mathbf{if}\;x < -1.7210442634149447 \cdot 10^{+81}:\\ \;\;\;\;t\_0\\ \mathbf{elif}\;x < 83645045635564430:\\ \;\;\;\;\frac{x \cdot 2}{\frac{x - y}{y}}\\ \mathbf{else}:\\ \;\;\;\;t\_0\\ \end{array} \end{array} \]
        (FPCore (x y)
         :precision binary64
         (let* ((t_0 (* (/ (* 2.0 x) (- x y)) y)))
           (if (< x -1.7210442634149447e+81)
             t_0
             (if (< x 83645045635564430.0) (/ (* x 2.0) (/ (- x y) y)) t_0))))
        double code(double x, double y) {
        	double t_0 = ((2.0 * x) / (x - y)) * y;
        	double tmp;
        	if (x < -1.7210442634149447e+81) {
        		tmp = t_0;
        	} else if (x < 83645045635564430.0) {
        		tmp = (x * 2.0) / ((x - y) / y);
        	} else {
        		tmp = t_0;
        	}
        	return tmp;
        }
        
        real(8) function code(x, y)
            real(8), intent (in) :: x
            real(8), intent (in) :: y
            real(8) :: t_0
            real(8) :: tmp
            t_0 = ((2.0d0 * x) / (x - y)) * y
            if (x < (-1.7210442634149447d+81)) then
                tmp = t_0
            else if (x < 83645045635564430.0d0) then
                tmp = (x * 2.0d0) / ((x - y) / y)
            else
                tmp = t_0
            end if
            code = tmp
        end function
        
        public static double code(double x, double y) {
        	double t_0 = ((2.0 * x) / (x - y)) * y;
        	double tmp;
        	if (x < -1.7210442634149447e+81) {
        		tmp = t_0;
        	} else if (x < 83645045635564430.0) {
        		tmp = (x * 2.0) / ((x - y) / y);
        	} else {
        		tmp = t_0;
        	}
        	return tmp;
        }
        
        def code(x, y):
        	t_0 = ((2.0 * x) / (x - y)) * y
        	tmp = 0
        	if x < -1.7210442634149447e+81:
        		tmp = t_0
        	elif x < 83645045635564430.0:
        		tmp = (x * 2.0) / ((x - y) / y)
        	else:
        		tmp = t_0
        	return tmp
        
        function code(x, y)
        	t_0 = Float64(Float64(Float64(2.0 * x) / Float64(x - y)) * y)
        	tmp = 0.0
        	if (x < -1.7210442634149447e+81)
        		tmp = t_0;
        	elseif (x < 83645045635564430.0)
        		tmp = Float64(Float64(x * 2.0) / Float64(Float64(x - y) / y));
        	else
        		tmp = t_0;
        	end
        	return tmp
        end
        
        function tmp_2 = code(x, y)
        	t_0 = ((2.0 * x) / (x - y)) * y;
        	tmp = 0.0;
        	if (x < -1.7210442634149447e+81)
        		tmp = t_0;
        	elseif (x < 83645045635564430.0)
        		tmp = (x * 2.0) / ((x - y) / y);
        	else
        		tmp = t_0;
        	end
        	tmp_2 = tmp;
        end
        
        code[x_, y_] := Block[{t$95$0 = N[(N[(N[(2.0 * x), $MachinePrecision] / N[(x - y), $MachinePrecision]), $MachinePrecision] * y), $MachinePrecision]}, If[Less[x, -1.7210442634149447e+81], t$95$0, If[Less[x, 83645045635564430.0], N[(N[(x * 2.0), $MachinePrecision] / N[(N[(x - y), $MachinePrecision] / y), $MachinePrecision]), $MachinePrecision], t$95$0]]]
        
        \begin{array}{l}
        
        \\
        \begin{array}{l}
        t_0 := \frac{2 \cdot x}{x - y} \cdot y\\
        \mathbf{if}\;x < -1.7210442634149447 \cdot 10^{+81}:\\
        \;\;\;\;t\_0\\
        
        \mathbf{elif}\;x < 83645045635564430:\\
        \;\;\;\;\frac{x \cdot 2}{\frac{x - y}{y}}\\
        
        \mathbf{else}:\\
        \;\;\;\;t\_0\\
        
        
        \end{array}
        \end{array}
        

        Reproduce

        ?
        herbie shell --seed 2024329 
        (FPCore (x y)
          :name "Linear.Projection:perspective from linear-1.19.1.3, B"
          :precision binary64
        
          :alt
          (! :herbie-platform default (if (< x -1721044263414944700000000000000000000000000000000000000000000000000000000000000000) (* (/ (* 2 x) (- x y)) y) (if (< x 83645045635564430) (/ (* x 2) (/ (- x y) y)) (* (/ (* 2 x) (- x y)) y))))
        
          (/ (* (* x 2.0) y) (- x y)))