Radioactive exchange between two surfaces

Percentage Accurate: 86.2% → 99.9%
Time: 8.0s
Alternatives: 5
Speedup: 7.4×

Specification

?
\[\begin{array}{l} \\ {x}^{4} - {y}^{4} \end{array} \]
(FPCore (x y) :precision binary64 (- (pow x 4.0) (pow y 4.0)))
double code(double x, double y) {
	return pow(x, 4.0) - pow(y, 4.0);
}
real(8) function code(x, y)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    code = (x ** 4.0d0) - (y ** 4.0d0)
end function
public static double code(double x, double y) {
	return Math.pow(x, 4.0) - Math.pow(y, 4.0);
}
def code(x, y):
	return math.pow(x, 4.0) - math.pow(y, 4.0)
function code(x, y)
	return Float64((x ^ 4.0) - (y ^ 4.0))
end
function tmp = code(x, y)
	tmp = (x ^ 4.0) - (y ^ 4.0);
end
code[x_, y_] := N[(N[Power[x, 4.0], $MachinePrecision] - N[Power[y, 4.0], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
{x}^{4} - {y}^{4}
\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 5 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: 86.2% accurate, 1.0× speedup?

\[\begin{array}{l} \\ {x}^{4} - {y}^{4} \end{array} \]
(FPCore (x y) :precision binary64 (- (pow x 4.0) (pow y 4.0)))
double code(double x, double y) {
	return pow(x, 4.0) - pow(y, 4.0);
}
real(8) function code(x, y)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    code = (x ** 4.0d0) - (y ** 4.0d0)
end function
public static double code(double x, double y) {
	return Math.pow(x, 4.0) - Math.pow(y, 4.0);
}
def code(x, y):
	return math.pow(x, 4.0) - math.pow(y, 4.0)
function code(x, y)
	return Float64((x ^ 4.0) - (y ^ 4.0))
end
function tmp = code(x, y)
	tmp = (x ^ 4.0) - (y ^ 4.0);
end
code[x_, y_] := N[(N[Power[x, 4.0], $MachinePrecision] - N[Power[y, 4.0], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
{x}^{4} - {y}^{4}
\end{array}

Alternative 1: 99.9% accurate, 7.4× speedup?

\[\begin{array}{l} \\ \left(\mathsf{fma}\left(y, y, x \cdot x\right) \cdot \left(y + x\right)\right) \cdot \left(x - y\right) \end{array} \]
(FPCore (x y) :precision binary64 (* (* (fma y y (* x x)) (+ y x)) (- x y)))
double code(double x, double y) {
	return (fma(y, y, (x * x)) * (y + x)) * (x - y);
}
function code(x, y)
	return Float64(Float64(fma(y, y, Float64(x * x)) * Float64(y + x)) * Float64(x - y))
end
code[x_, y_] := N[(N[(N[(y * y + N[(x * x), $MachinePrecision]), $MachinePrecision] * N[(y + x), $MachinePrecision]), $MachinePrecision] * N[(x - y), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\left(\mathsf{fma}\left(y, y, x \cdot x\right) \cdot \left(y + x\right)\right) \cdot \left(x - y\right)
\end{array}
Derivation
  1. Initial program 85.9%

    \[{x}^{4} - {y}^{4} \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. lift--.f64N/A

      \[\leadsto \color{blue}{{x}^{4} - {y}^{4}} \]
    2. lift-pow.f64N/A

      \[\leadsto \color{blue}{{x}^{4}} - {y}^{4} \]
    3. sqr-powN/A

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

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

      \[\leadsto {x}^{\left(\frac{4}{2}\right)} \cdot {x}^{\left(\frac{4}{2}\right)} - \color{blue}{{y}^{\left(\frac{4}{2}\right)} \cdot {y}^{\left(\frac{4}{2}\right)}} \]
    6. difference-of-squaresN/A

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

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

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

      \[\leadsto \left({y}^{\color{blue}{2}} + {x}^{\left(\frac{4}{2}\right)}\right) \cdot \left({x}^{\left(\frac{4}{2}\right)} - {y}^{\left(\frac{4}{2}\right)}\right) \]
    10. unpow2N/A

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

      \[\leadsto \color{blue}{\mathsf{fma}\left(y, y, {x}^{\left(\frac{4}{2}\right)}\right)} \cdot \left({x}^{\left(\frac{4}{2}\right)} - {y}^{\left(\frac{4}{2}\right)}\right) \]
    12. metadata-evalN/A

      \[\leadsto \mathsf{fma}\left(y, y, {x}^{\color{blue}{2}}\right) \cdot \left({x}^{\left(\frac{4}{2}\right)} - {y}^{\left(\frac{4}{2}\right)}\right) \]
    13. unpow2N/A

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

      \[\leadsto \mathsf{fma}\left(y, y, \color{blue}{x \cdot x}\right) \cdot \left({x}^{\left(\frac{4}{2}\right)} - {y}^{\left(\frac{4}{2}\right)}\right) \]
    15. metadata-evalN/A

      \[\leadsto \mathsf{fma}\left(y, y, x \cdot x\right) \cdot \left({x}^{\color{blue}{2}} - {y}^{\left(\frac{4}{2}\right)}\right) \]
    16. unpow2N/A

      \[\leadsto \mathsf{fma}\left(y, y, x \cdot x\right) \cdot \left(\color{blue}{x \cdot x} - {y}^{\left(\frac{4}{2}\right)}\right) \]
    17. metadata-evalN/A

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

      \[\leadsto \mathsf{fma}\left(y, y, x \cdot x\right) \cdot \left(x \cdot x - \color{blue}{y \cdot y}\right) \]
    19. difference-of-squaresN/A

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

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

      \[\leadsto \mathsf{fma}\left(y, y, x \cdot x\right) \cdot \left(\color{blue}{\left(x + y\right)} \cdot \left(x - y\right)\right) \]
    22. lower--.f6499.8

      \[\leadsto \mathsf{fma}\left(y, y, x \cdot x\right) \cdot \left(\left(x + y\right) \cdot \color{blue}{\left(x - y\right)}\right) \]
  4. Applied rewrites99.8%

    \[\leadsto \color{blue}{\mathsf{fma}\left(y, y, x \cdot x\right) \cdot \left(\left(x + y\right) \cdot \left(x - y\right)\right)} \]
  5. Step-by-step derivation
    1. lift-*.f64N/A

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

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

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

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

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

      \[\leadsto \left(x - y\right) \cdot \color{blue}{\left(\left(x + y\right) \cdot \mathsf{fma}\left(y, y, x \cdot x\right)\right)} \]
    7. lower-*.f6499.9

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

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

      \[\leadsto \left(x - y\right) \cdot \left(\color{blue}{\left(y + x\right)} \cdot \mathsf{fma}\left(y, y, x \cdot x\right)\right) \]
    10. lower-+.f6499.9

      \[\leadsto \left(x - y\right) \cdot \left(\color{blue}{\left(y + x\right)} \cdot \mathsf{fma}\left(y, y, x \cdot x\right)\right) \]
  6. Applied rewrites99.9%

    \[\leadsto \color{blue}{\left(x - y\right) \cdot \left(\left(y + x\right) \cdot \mathsf{fma}\left(y, y, x \cdot x\right)\right)} \]
  7. Final simplification99.9%

    \[\leadsto \left(\mathsf{fma}\left(y, y, x \cdot x\right) \cdot \left(y + x\right)\right) \cdot \left(x - y\right) \]
  8. Add Preprocessing

Alternative 2: 99.3% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;{x}^{4} - {y}^{4} \leq -1 \cdot 10^{-295}:\\ \;\;\;\;\left(\left(y \cdot y\right) \cdot \left(y + x\right)\right) \cdot \left(x - y\right)\\ \mathbf{else}:\\ \;\;\;\;\left(\left(x \cdot x\right) \cdot \left(y + x\right)\right) \cdot \left(x - y\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= (- (pow x 4.0) (pow y 4.0)) -1e-295)
   (* (* (* y y) (+ y x)) (- x y))
   (* (* (* x x) (+ y x)) (- x y))))
double code(double x, double y) {
	double tmp;
	if ((pow(x, 4.0) - pow(y, 4.0)) <= -1e-295) {
		tmp = ((y * y) * (y + x)) * (x - y);
	} else {
		tmp = ((x * x) * (y + x)) * (x - y);
	}
	return tmp;
}
real(8) function code(x, y)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8) :: tmp
    if (((x ** 4.0d0) - (y ** 4.0d0)) <= (-1d-295)) then
        tmp = ((y * y) * (y + x)) * (x - y)
    else
        tmp = ((x * x) * (y + x)) * (x - y)
    end if
    code = tmp
end function
public static double code(double x, double y) {
	double tmp;
	if ((Math.pow(x, 4.0) - Math.pow(y, 4.0)) <= -1e-295) {
		tmp = ((y * y) * (y + x)) * (x - y);
	} else {
		tmp = ((x * x) * (y + x)) * (x - y);
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if (math.pow(x, 4.0) - math.pow(y, 4.0)) <= -1e-295:
		tmp = ((y * y) * (y + x)) * (x - y)
	else:
		tmp = ((x * x) * (y + x)) * (x - y)
	return tmp
function code(x, y)
	tmp = 0.0
	if (Float64((x ^ 4.0) - (y ^ 4.0)) <= -1e-295)
		tmp = Float64(Float64(Float64(y * y) * Float64(y + x)) * Float64(x - y));
	else
		tmp = Float64(Float64(Float64(x * x) * Float64(y + x)) * Float64(x - y));
	end
	return tmp
end
function tmp_2 = code(x, y)
	tmp = 0.0;
	if (((x ^ 4.0) - (y ^ 4.0)) <= -1e-295)
		tmp = ((y * y) * (y + x)) * (x - y);
	else
		tmp = ((x * x) * (y + x)) * (x - y);
	end
	tmp_2 = tmp;
end
code[x_, y_] := If[LessEqual[N[(N[Power[x, 4.0], $MachinePrecision] - N[Power[y, 4.0], $MachinePrecision]), $MachinePrecision], -1e-295], N[(N[(N[(y * y), $MachinePrecision] * N[(y + x), $MachinePrecision]), $MachinePrecision] * N[(x - y), $MachinePrecision]), $MachinePrecision], N[(N[(N[(x * x), $MachinePrecision] * N[(y + x), $MachinePrecision]), $MachinePrecision] * N[(x - y), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;{x}^{4} - {y}^{4} \leq -1 \cdot 10^{-295}:\\
\;\;\;\;\left(\left(y \cdot y\right) \cdot \left(y + x\right)\right) \cdot \left(x - y\right)\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (-.f64 (pow.f64 x #s(literal 4 binary64)) (pow.f64 y #s(literal 4 binary64))) < -1.00000000000000006e-295

    1. Initial program 100.0%

      \[{x}^{4} - {y}^{4} \]
    2. Add Preprocessing
    3. Step-by-step derivation
      1. lift--.f64N/A

        \[\leadsto \color{blue}{{x}^{4} - {y}^{4}} \]
      2. lift-pow.f64N/A

        \[\leadsto \color{blue}{{x}^{4}} - {y}^{4} \]
      3. sqr-powN/A

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

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

        \[\leadsto {x}^{\left(\frac{4}{2}\right)} \cdot {x}^{\left(\frac{4}{2}\right)} - \color{blue}{{y}^{\left(\frac{4}{2}\right)} \cdot {y}^{\left(\frac{4}{2}\right)}} \]
      6. difference-of-squaresN/A

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

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

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

        \[\leadsto \left({y}^{\color{blue}{2}} + {x}^{\left(\frac{4}{2}\right)}\right) \cdot \left({x}^{\left(\frac{4}{2}\right)} - {y}^{\left(\frac{4}{2}\right)}\right) \]
      10. unpow2N/A

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

        \[\leadsto \color{blue}{\mathsf{fma}\left(y, y, {x}^{\left(\frac{4}{2}\right)}\right)} \cdot \left({x}^{\left(\frac{4}{2}\right)} - {y}^{\left(\frac{4}{2}\right)}\right) \]
      12. metadata-evalN/A

        \[\leadsto \mathsf{fma}\left(y, y, {x}^{\color{blue}{2}}\right) \cdot \left({x}^{\left(\frac{4}{2}\right)} - {y}^{\left(\frac{4}{2}\right)}\right) \]
      13. unpow2N/A

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

        \[\leadsto \mathsf{fma}\left(y, y, \color{blue}{x \cdot x}\right) \cdot \left({x}^{\left(\frac{4}{2}\right)} - {y}^{\left(\frac{4}{2}\right)}\right) \]
      15. metadata-evalN/A

        \[\leadsto \mathsf{fma}\left(y, y, x \cdot x\right) \cdot \left({x}^{\color{blue}{2}} - {y}^{\left(\frac{4}{2}\right)}\right) \]
      16. unpow2N/A

        \[\leadsto \mathsf{fma}\left(y, y, x \cdot x\right) \cdot \left(\color{blue}{x \cdot x} - {y}^{\left(\frac{4}{2}\right)}\right) \]
      17. metadata-evalN/A

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

        \[\leadsto \mathsf{fma}\left(y, y, x \cdot x\right) \cdot \left(x \cdot x - \color{blue}{y \cdot y}\right) \]
      19. difference-of-squaresN/A

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

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

        \[\leadsto \mathsf{fma}\left(y, y, x \cdot x\right) \cdot \left(\color{blue}{\left(x + y\right)} \cdot \left(x - y\right)\right) \]
      22. lower--.f6499.8

        \[\leadsto \mathsf{fma}\left(y, y, x \cdot x\right) \cdot \left(\left(x + y\right) \cdot \color{blue}{\left(x - y\right)}\right) \]
    4. Applied rewrites99.8%

      \[\leadsto \color{blue}{\mathsf{fma}\left(y, y, x \cdot x\right) \cdot \left(\left(x + y\right) \cdot \left(x - y\right)\right)} \]
    5. Step-by-step derivation
      1. lift-*.f64N/A

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

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

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

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

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

        \[\leadsto \left(x - y\right) \cdot \color{blue}{\left(\left(x + y\right) \cdot \mathsf{fma}\left(y, y, x \cdot x\right)\right)} \]
      7. lower-*.f6499.8

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

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

        \[\leadsto \left(x - y\right) \cdot \left(\color{blue}{\left(y + x\right)} \cdot \mathsf{fma}\left(y, y, x \cdot x\right)\right) \]
      10. lower-+.f6499.8

        \[\leadsto \left(x - y\right) \cdot \left(\color{blue}{\left(y + x\right)} \cdot \mathsf{fma}\left(y, y, x \cdot x\right)\right) \]
    6. Applied rewrites99.8%

      \[\leadsto \color{blue}{\left(x - y\right) \cdot \left(\left(y + x\right) \cdot \mathsf{fma}\left(y, y, x \cdot x\right)\right)} \]
    7. Taylor expanded in y around inf

      \[\leadsto \left(x - y\right) \cdot \left(\left(y + x\right) \cdot \color{blue}{{y}^{2}}\right) \]
    8. Step-by-step derivation
      1. unpow2N/A

        \[\leadsto \left(x - y\right) \cdot \left(\left(y + x\right) \cdot \color{blue}{\left(y \cdot y\right)}\right) \]
      2. lower-*.f6499.8

        \[\leadsto \left(x - y\right) \cdot \left(\left(y + x\right) \cdot \color{blue}{\left(y \cdot y\right)}\right) \]
    9. Applied rewrites99.8%

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

    if -1.00000000000000006e-295 < (-.f64 (pow.f64 x #s(literal 4 binary64)) (pow.f64 y #s(literal 4 binary64)))

    1. Initial program 78.2%

      \[{x}^{4} - {y}^{4} \]
    2. Add Preprocessing
    3. Step-by-step derivation
      1. lift--.f64N/A

        \[\leadsto \color{blue}{{x}^{4} - {y}^{4}} \]
      2. lift-pow.f64N/A

        \[\leadsto \color{blue}{{x}^{4}} - {y}^{4} \]
      3. sqr-powN/A

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

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

        \[\leadsto {x}^{\left(\frac{4}{2}\right)} \cdot {x}^{\left(\frac{4}{2}\right)} - \color{blue}{{y}^{\left(\frac{4}{2}\right)} \cdot {y}^{\left(\frac{4}{2}\right)}} \]
      6. difference-of-squaresN/A

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

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

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

        \[\leadsto \left({y}^{\color{blue}{2}} + {x}^{\left(\frac{4}{2}\right)}\right) \cdot \left({x}^{\left(\frac{4}{2}\right)} - {y}^{\left(\frac{4}{2}\right)}\right) \]
      10. unpow2N/A

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

        \[\leadsto \color{blue}{\mathsf{fma}\left(y, y, {x}^{\left(\frac{4}{2}\right)}\right)} \cdot \left({x}^{\left(\frac{4}{2}\right)} - {y}^{\left(\frac{4}{2}\right)}\right) \]
      12. metadata-evalN/A

        \[\leadsto \mathsf{fma}\left(y, y, {x}^{\color{blue}{2}}\right) \cdot \left({x}^{\left(\frac{4}{2}\right)} - {y}^{\left(\frac{4}{2}\right)}\right) \]
      13. unpow2N/A

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

        \[\leadsto \mathsf{fma}\left(y, y, \color{blue}{x \cdot x}\right) \cdot \left({x}^{\left(\frac{4}{2}\right)} - {y}^{\left(\frac{4}{2}\right)}\right) \]
      15. metadata-evalN/A

        \[\leadsto \mathsf{fma}\left(y, y, x \cdot x\right) \cdot \left({x}^{\color{blue}{2}} - {y}^{\left(\frac{4}{2}\right)}\right) \]
      16. unpow2N/A

        \[\leadsto \mathsf{fma}\left(y, y, x \cdot x\right) \cdot \left(\color{blue}{x \cdot x} - {y}^{\left(\frac{4}{2}\right)}\right) \]
      17. metadata-evalN/A

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

        \[\leadsto \mathsf{fma}\left(y, y, x \cdot x\right) \cdot \left(x \cdot x - \color{blue}{y \cdot y}\right) \]
      19. difference-of-squaresN/A

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

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

        \[\leadsto \mathsf{fma}\left(y, y, x \cdot x\right) \cdot \left(\color{blue}{\left(x + y\right)} \cdot \left(x - y\right)\right) \]
      22. lower--.f6499.9

        \[\leadsto \mathsf{fma}\left(y, y, x \cdot x\right) \cdot \left(\left(x + y\right) \cdot \color{blue}{\left(x - y\right)}\right) \]
    4. Applied rewrites99.9%

      \[\leadsto \color{blue}{\mathsf{fma}\left(y, y, x \cdot x\right) \cdot \left(\left(x + y\right) \cdot \left(x - y\right)\right)} \]
    5. Step-by-step derivation
      1. lift-*.f64N/A

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

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

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

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

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

        \[\leadsto \left(x - y\right) \cdot \color{blue}{\left(\left(x + y\right) \cdot \mathsf{fma}\left(y, y, x \cdot x\right)\right)} \]
      7. lower-*.f6499.9

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

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

        \[\leadsto \left(x - y\right) \cdot \left(\color{blue}{\left(y + x\right)} \cdot \mathsf{fma}\left(y, y, x \cdot x\right)\right) \]
      10. lower-+.f6499.9

        \[\leadsto \left(x - y\right) \cdot \left(\color{blue}{\left(y + x\right)} \cdot \mathsf{fma}\left(y, y, x \cdot x\right)\right) \]
    6. Applied rewrites99.9%

      \[\leadsto \color{blue}{\left(x - y\right) \cdot \left(\left(y + x\right) \cdot \mathsf{fma}\left(y, y, x \cdot x\right)\right)} \]
    7. Taylor expanded in y around 0

      \[\leadsto \left(x - y\right) \cdot \left(\left(y + x\right) \cdot \color{blue}{{x}^{2}}\right) \]
    8. Step-by-step derivation
      1. unpow2N/A

        \[\leadsto \left(x - y\right) \cdot \left(\left(y + x\right) \cdot \color{blue}{\left(x \cdot x\right)}\right) \]
      2. lower-*.f6499.7

        \[\leadsto \left(x - y\right) \cdot \left(\left(y + x\right) \cdot \color{blue}{\left(x \cdot x\right)}\right) \]
    9. Applied rewrites99.7%

      \[\leadsto \left(x - y\right) \cdot \left(\left(y + x\right) \cdot \color{blue}{\left(x \cdot x\right)}\right) \]
  3. Recombined 2 regimes into one program.
  4. Final simplification99.7%

    \[\leadsto \begin{array}{l} \mathbf{if}\;{x}^{4} - {y}^{4} \leq -1 \cdot 10^{-295}:\\ \;\;\;\;\left(\left(y \cdot y\right) \cdot \left(y + x\right)\right) \cdot \left(x - y\right)\\ \mathbf{else}:\\ \;\;\;\;\left(\left(x \cdot x\right) \cdot \left(y + x\right)\right) \cdot \left(x - y\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 3: 99.4% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;{x}^{4} - {y}^{4} \leq -1 \cdot 10^{-295}:\\ \;\;\;\;\left(\left(-y\right) \cdot y\right) \cdot \left(y \cdot y\right)\\ \mathbf{else}:\\ \;\;\;\;\left(\left(x \cdot x\right) \cdot \left(y + x\right)\right) \cdot \left(x - y\right)\\ \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (if (<= (- (pow x 4.0) (pow y 4.0)) -1e-295)
   (* (* (- y) y) (* y y))
   (* (* (* x x) (+ y x)) (- x y))))
double code(double x, double y) {
	double tmp;
	if ((pow(x, 4.0) - pow(y, 4.0)) <= -1e-295) {
		tmp = (-y * y) * (y * y);
	} else {
		tmp = ((x * x) * (y + x)) * (x - y);
	}
	return tmp;
}
real(8) function code(x, y)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8) :: tmp
    if (((x ** 4.0d0) - (y ** 4.0d0)) <= (-1d-295)) then
        tmp = (-y * y) * (y * y)
    else
        tmp = ((x * x) * (y + x)) * (x - y)
    end if
    code = tmp
end function
public static double code(double x, double y) {
	double tmp;
	if ((Math.pow(x, 4.0) - Math.pow(y, 4.0)) <= -1e-295) {
		tmp = (-y * y) * (y * y);
	} else {
		tmp = ((x * x) * (y + x)) * (x - y);
	}
	return tmp;
}
def code(x, y):
	tmp = 0
	if (math.pow(x, 4.0) - math.pow(y, 4.0)) <= -1e-295:
		tmp = (-y * y) * (y * y)
	else:
		tmp = ((x * x) * (y + x)) * (x - y)
	return tmp
function code(x, y)
	tmp = 0.0
	if (Float64((x ^ 4.0) - (y ^ 4.0)) <= -1e-295)
		tmp = Float64(Float64(Float64(-y) * y) * Float64(y * y));
	else
		tmp = Float64(Float64(Float64(x * x) * Float64(y + x)) * Float64(x - y));
	end
	return tmp
end
function tmp_2 = code(x, y)
	tmp = 0.0;
	if (((x ^ 4.0) - (y ^ 4.0)) <= -1e-295)
		tmp = (-y * y) * (y * y);
	else
		tmp = ((x * x) * (y + x)) * (x - y);
	end
	tmp_2 = tmp;
end
code[x_, y_] := If[LessEqual[N[(N[Power[x, 4.0], $MachinePrecision] - N[Power[y, 4.0], $MachinePrecision]), $MachinePrecision], -1e-295], N[(N[((-y) * y), $MachinePrecision] * N[(y * y), $MachinePrecision]), $MachinePrecision], N[(N[(N[(x * x), $MachinePrecision] * N[(y + x), $MachinePrecision]), $MachinePrecision] * N[(x - y), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;{x}^{4} - {y}^{4} \leq -1 \cdot 10^{-295}:\\
\;\;\;\;\left(\left(-y\right) \cdot y\right) \cdot \left(y \cdot y\right)\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (-.f64 (pow.f64 x #s(literal 4 binary64)) (pow.f64 y #s(literal 4 binary64))) < -1.00000000000000006e-295

    1. Initial program 100.0%

      \[{x}^{4} - {y}^{4} \]
    2. Add Preprocessing
    3. Taylor expanded in y around inf

      \[\leadsto \color{blue}{-1 \cdot {y}^{4}} \]
    4. Step-by-step derivation
      1. mul-1-negN/A

        \[\leadsto \color{blue}{\mathsf{neg}\left({y}^{4}\right)} \]
      2. lower-neg.f64N/A

        \[\leadsto \color{blue}{-{y}^{4}} \]
      3. lower-pow.f64100.0

        \[\leadsto -\color{blue}{{y}^{4}} \]
    5. Applied rewrites100.0%

      \[\leadsto \color{blue}{-{y}^{4}} \]
    6. Step-by-step derivation
      1. Applied rewrites99.8%

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

      if -1.00000000000000006e-295 < (-.f64 (pow.f64 x #s(literal 4 binary64)) (pow.f64 y #s(literal 4 binary64)))

      1. Initial program 78.2%

        \[{x}^{4} - {y}^{4} \]
      2. Add Preprocessing
      3. Step-by-step derivation
        1. lift--.f64N/A

          \[\leadsto \color{blue}{{x}^{4} - {y}^{4}} \]
        2. lift-pow.f64N/A

          \[\leadsto \color{blue}{{x}^{4}} - {y}^{4} \]
        3. sqr-powN/A

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

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

          \[\leadsto {x}^{\left(\frac{4}{2}\right)} \cdot {x}^{\left(\frac{4}{2}\right)} - \color{blue}{{y}^{\left(\frac{4}{2}\right)} \cdot {y}^{\left(\frac{4}{2}\right)}} \]
        6. difference-of-squaresN/A

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

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

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

          \[\leadsto \left({y}^{\color{blue}{2}} + {x}^{\left(\frac{4}{2}\right)}\right) \cdot \left({x}^{\left(\frac{4}{2}\right)} - {y}^{\left(\frac{4}{2}\right)}\right) \]
        10. unpow2N/A

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

          \[\leadsto \color{blue}{\mathsf{fma}\left(y, y, {x}^{\left(\frac{4}{2}\right)}\right)} \cdot \left({x}^{\left(\frac{4}{2}\right)} - {y}^{\left(\frac{4}{2}\right)}\right) \]
        12. metadata-evalN/A

          \[\leadsto \mathsf{fma}\left(y, y, {x}^{\color{blue}{2}}\right) \cdot \left({x}^{\left(\frac{4}{2}\right)} - {y}^{\left(\frac{4}{2}\right)}\right) \]
        13. unpow2N/A

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

          \[\leadsto \mathsf{fma}\left(y, y, \color{blue}{x \cdot x}\right) \cdot \left({x}^{\left(\frac{4}{2}\right)} - {y}^{\left(\frac{4}{2}\right)}\right) \]
        15. metadata-evalN/A

          \[\leadsto \mathsf{fma}\left(y, y, x \cdot x\right) \cdot \left({x}^{\color{blue}{2}} - {y}^{\left(\frac{4}{2}\right)}\right) \]
        16. unpow2N/A

          \[\leadsto \mathsf{fma}\left(y, y, x \cdot x\right) \cdot \left(\color{blue}{x \cdot x} - {y}^{\left(\frac{4}{2}\right)}\right) \]
        17. metadata-evalN/A

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

          \[\leadsto \mathsf{fma}\left(y, y, x \cdot x\right) \cdot \left(x \cdot x - \color{blue}{y \cdot y}\right) \]
        19. difference-of-squaresN/A

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

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

          \[\leadsto \mathsf{fma}\left(y, y, x \cdot x\right) \cdot \left(\color{blue}{\left(x + y\right)} \cdot \left(x - y\right)\right) \]
        22. lower--.f6499.9

          \[\leadsto \mathsf{fma}\left(y, y, x \cdot x\right) \cdot \left(\left(x + y\right) \cdot \color{blue}{\left(x - y\right)}\right) \]
      4. Applied rewrites99.9%

        \[\leadsto \color{blue}{\mathsf{fma}\left(y, y, x \cdot x\right) \cdot \left(\left(x + y\right) \cdot \left(x - y\right)\right)} \]
      5. Step-by-step derivation
        1. lift-*.f64N/A

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

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

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

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

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

          \[\leadsto \left(x - y\right) \cdot \color{blue}{\left(\left(x + y\right) \cdot \mathsf{fma}\left(y, y, x \cdot x\right)\right)} \]
        7. lower-*.f6499.9

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

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

          \[\leadsto \left(x - y\right) \cdot \left(\color{blue}{\left(y + x\right)} \cdot \mathsf{fma}\left(y, y, x \cdot x\right)\right) \]
        10. lower-+.f6499.9

          \[\leadsto \left(x - y\right) \cdot \left(\color{blue}{\left(y + x\right)} \cdot \mathsf{fma}\left(y, y, x \cdot x\right)\right) \]
      6. Applied rewrites99.9%

        \[\leadsto \color{blue}{\left(x - y\right) \cdot \left(\left(y + x\right) \cdot \mathsf{fma}\left(y, y, x \cdot x\right)\right)} \]
      7. Taylor expanded in y around 0

        \[\leadsto \left(x - y\right) \cdot \left(\left(y + x\right) \cdot \color{blue}{{x}^{2}}\right) \]
      8. Step-by-step derivation
        1. unpow2N/A

          \[\leadsto \left(x - y\right) \cdot \left(\left(y + x\right) \cdot \color{blue}{\left(x \cdot x\right)}\right) \]
        2. lower-*.f6499.7

          \[\leadsto \left(x - y\right) \cdot \left(\left(y + x\right) \cdot \color{blue}{\left(x \cdot x\right)}\right) \]
      9. Applied rewrites99.7%

        \[\leadsto \left(x - y\right) \cdot \left(\left(y + x\right) \cdot \color{blue}{\left(x \cdot x\right)}\right) \]
    7. Recombined 2 regimes into one program.
    8. Final simplification99.7%

      \[\leadsto \begin{array}{l} \mathbf{if}\;{x}^{4} - {y}^{4} \leq -1 \cdot 10^{-295}:\\ \;\;\;\;\left(\left(-y\right) \cdot y\right) \cdot \left(y \cdot y\right)\\ \mathbf{else}:\\ \;\;\;\;\left(\left(x \cdot x\right) \cdot \left(y + x\right)\right) \cdot \left(x - y\right)\\ \end{array} \]
    9. Add Preprocessing

    Alternative 4: 92.7% accurate, 0.9× speedup?

    \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;{x}^{4} - {y}^{4} \leq -1 \cdot 10^{-295}:\\ \;\;\;\;\left(\left(-y\right) \cdot y\right) \cdot \left(y \cdot y\right)\\ \mathbf{else}:\\ \;\;\;\;\left(x \cdot x\right) \cdot \left(x \cdot x\right)\\ \end{array} \end{array} \]
    (FPCore (x y)
     :precision binary64
     (if (<= (- (pow x 4.0) (pow y 4.0)) -1e-295)
       (* (* (- y) y) (* y y))
       (* (* x x) (* x x))))
    double code(double x, double y) {
    	double tmp;
    	if ((pow(x, 4.0) - pow(y, 4.0)) <= -1e-295) {
    		tmp = (-y * y) * (y * y);
    	} else {
    		tmp = (x * x) * (x * x);
    	}
    	return tmp;
    }
    
    real(8) function code(x, y)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        real(8) :: tmp
        if (((x ** 4.0d0) - (y ** 4.0d0)) <= (-1d-295)) then
            tmp = (-y * y) * (y * y)
        else
            tmp = (x * x) * (x * x)
        end if
        code = tmp
    end function
    
    public static double code(double x, double y) {
    	double tmp;
    	if ((Math.pow(x, 4.0) - Math.pow(y, 4.0)) <= -1e-295) {
    		tmp = (-y * y) * (y * y);
    	} else {
    		tmp = (x * x) * (x * x);
    	}
    	return tmp;
    }
    
    def code(x, y):
    	tmp = 0
    	if (math.pow(x, 4.0) - math.pow(y, 4.0)) <= -1e-295:
    		tmp = (-y * y) * (y * y)
    	else:
    		tmp = (x * x) * (x * x)
    	return tmp
    
    function code(x, y)
    	tmp = 0.0
    	if (Float64((x ^ 4.0) - (y ^ 4.0)) <= -1e-295)
    		tmp = Float64(Float64(Float64(-y) * y) * Float64(y * y));
    	else
    		tmp = Float64(Float64(x * x) * Float64(x * x));
    	end
    	return tmp
    end
    
    function tmp_2 = code(x, y)
    	tmp = 0.0;
    	if (((x ^ 4.0) - (y ^ 4.0)) <= -1e-295)
    		tmp = (-y * y) * (y * y);
    	else
    		tmp = (x * x) * (x * x);
    	end
    	tmp_2 = tmp;
    end
    
    code[x_, y_] := If[LessEqual[N[(N[Power[x, 4.0], $MachinePrecision] - N[Power[y, 4.0], $MachinePrecision]), $MachinePrecision], -1e-295], N[(N[((-y) * y), $MachinePrecision] * N[(y * y), $MachinePrecision]), $MachinePrecision], N[(N[(x * x), $MachinePrecision] * N[(x * x), $MachinePrecision]), $MachinePrecision]]
    
    \begin{array}{l}
    
    \\
    \begin{array}{l}
    \mathbf{if}\;{x}^{4} - {y}^{4} \leq -1 \cdot 10^{-295}:\\
    \;\;\;\;\left(\left(-y\right) \cdot y\right) \cdot \left(y \cdot y\right)\\
    
    \mathbf{else}:\\
    \;\;\;\;\left(x \cdot x\right) \cdot \left(x \cdot x\right)\\
    
    
    \end{array}
    \end{array}
    
    Derivation
    1. Split input into 2 regimes
    2. if (-.f64 (pow.f64 x #s(literal 4 binary64)) (pow.f64 y #s(literal 4 binary64))) < -1.00000000000000006e-295

      1. Initial program 100.0%

        \[{x}^{4} - {y}^{4} \]
      2. Add Preprocessing
      3. Taylor expanded in y around inf

        \[\leadsto \color{blue}{-1 \cdot {y}^{4}} \]
      4. Step-by-step derivation
        1. mul-1-negN/A

          \[\leadsto \color{blue}{\mathsf{neg}\left({y}^{4}\right)} \]
        2. lower-neg.f64N/A

          \[\leadsto \color{blue}{-{y}^{4}} \]
        3. lower-pow.f64100.0

          \[\leadsto -\color{blue}{{y}^{4}} \]
      5. Applied rewrites100.0%

        \[\leadsto \color{blue}{-{y}^{4}} \]
      6. Step-by-step derivation
        1. Applied rewrites99.8%

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

        if -1.00000000000000006e-295 < (-.f64 (pow.f64 x #s(literal 4 binary64)) (pow.f64 y #s(literal 4 binary64)))

        1. Initial program 78.2%

          \[{x}^{4} - {y}^{4} \]
        2. Add Preprocessing
        3. Taylor expanded in y around 0

          \[\leadsto \color{blue}{{x}^{4}} \]
        4. Step-by-step derivation
          1. lower-pow.f6488.5

            \[\leadsto \color{blue}{{x}^{4}} \]
        5. Applied rewrites88.5%

          \[\leadsto \color{blue}{{x}^{4}} \]
        6. Step-by-step derivation
          1. Applied rewrites88.4%

            \[\leadsto \left(x \cdot x\right) \cdot \color{blue}{\left(x \cdot x\right)} \]
        7. Recombined 2 regimes into one program.
        8. Add Preprocessing

        Alternative 5: 57.9% accurate, 12.9× speedup?

        \[\begin{array}{l} \\ \left(x \cdot x\right) \cdot \left(x \cdot x\right) \end{array} \]
        (FPCore (x y) :precision binary64 (* (* x x) (* x x)))
        double code(double x, double y) {
        	return (x * x) * (x * x);
        }
        
        real(8) function code(x, y)
            real(8), intent (in) :: x
            real(8), intent (in) :: y
            code = (x * x) * (x * x)
        end function
        
        public static double code(double x, double y) {
        	return (x * x) * (x * x);
        }
        
        def code(x, y):
        	return (x * x) * (x * x)
        
        function code(x, y)
        	return Float64(Float64(x * x) * Float64(x * x))
        end
        
        function tmp = code(x, y)
        	tmp = (x * x) * (x * x);
        end
        
        code[x_, y_] := N[(N[(x * x), $MachinePrecision] * N[(x * x), $MachinePrecision]), $MachinePrecision]
        
        \begin{array}{l}
        
        \\
        \left(x \cdot x\right) \cdot \left(x \cdot x\right)
        \end{array}
        
        Derivation
        1. Initial program 85.9%

          \[{x}^{4} - {y}^{4} \]
        2. Add Preprocessing
        3. Taylor expanded in y around 0

          \[\leadsto \color{blue}{{x}^{4}} \]
        4. Step-by-step derivation
          1. lower-pow.f6457.7

            \[\leadsto \color{blue}{{x}^{4}} \]
        5. Applied rewrites57.7%

          \[\leadsto \color{blue}{{x}^{4}} \]
        6. Step-by-step derivation
          1. Applied rewrites57.6%

            \[\leadsto \left(x \cdot x\right) \cdot \color{blue}{\left(x \cdot x\right)} \]
          2. Add Preprocessing

          Reproduce

          ?
          herbie shell --seed 2024267 
          (FPCore (x y)
            :name "Radioactive exchange between two surfaces"
            :precision binary64
            (- (pow x 4.0) (pow y 4.0)))