From Rump in a 1983 paper, rewritten

Percentage Accurate: 3.1% → 100.0%
Time: 10.6s
Alternatives: 4
Speedup: 22.8×

Specification

?
\[x = 10864 \land y = 18817\]
\[\begin{array}{l} \\ 9 \cdot {x}^{4} - \left(y \cdot y\right) \cdot \left(y \cdot y - 2\right) \end{array} \]
(FPCore (x y)
 :precision binary64
 (- (* 9.0 (pow x 4.0)) (* (* y y) (- (* y y) 2.0))))
double code(double x, double y) {
	return (9.0 * pow(x, 4.0)) - ((y * y) * ((y * y) - 2.0));
}
real(8) function code(x, y)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    code = (9.0d0 * (x ** 4.0d0)) - ((y * y) * ((y * y) - 2.0d0))
end function
public static double code(double x, double y) {
	return (9.0 * Math.pow(x, 4.0)) - ((y * y) * ((y * y) - 2.0));
}
def code(x, y):
	return (9.0 * math.pow(x, 4.0)) - ((y * y) * ((y * y) - 2.0))
function code(x, y)
	return Float64(Float64(9.0 * (x ^ 4.0)) - Float64(Float64(y * y) * Float64(Float64(y * y) - 2.0)))
end
function tmp = code(x, y)
	tmp = (9.0 * (x ^ 4.0)) - ((y * y) * ((y * y) - 2.0));
end
code[x_, y_] := N[(N[(9.0 * N[Power[x, 4.0], $MachinePrecision]), $MachinePrecision] - N[(N[(y * y), $MachinePrecision] * N[(N[(y * y), $MachinePrecision] - 2.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
9 \cdot {x}^{4} - \left(y \cdot y\right) \cdot \left(y \cdot y - 2\right)
\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 4 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: 3.1% accurate, 1.0× speedup?

\[\begin{array}{l} \\ 9 \cdot {x}^{4} - \left(y \cdot y\right) \cdot \left(y \cdot y - 2\right) \end{array} \]
(FPCore (x y)
 :precision binary64
 (- (* 9.0 (pow x 4.0)) (* (* y y) (- (* y y) 2.0))))
double code(double x, double y) {
	return (9.0 * pow(x, 4.0)) - ((y * y) * ((y * y) - 2.0));
}
real(8) function code(x, y)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    code = (9.0d0 * (x ** 4.0d0)) - ((y * y) * ((y * y) - 2.0d0))
end function
public static double code(double x, double y) {
	return (9.0 * Math.pow(x, 4.0)) - ((y * y) * ((y * y) - 2.0));
}
def code(x, y):
	return (9.0 * math.pow(x, 4.0)) - ((y * y) * ((y * y) - 2.0))
function code(x, y)
	return Float64(Float64(9.0 * (x ^ 4.0)) - Float64(Float64(y * y) * Float64(Float64(y * y) - 2.0)))
end
function tmp = code(x, y)
	tmp = (9.0 * (x ^ 4.0)) - ((y * y) * ((y * y) - 2.0));
end
code[x_, y_] := N[(N[(9.0 * N[Power[x, 4.0], $MachinePrecision]), $MachinePrecision] - N[(N[(y * y), $MachinePrecision] * N[(N[(y * y), $MachinePrecision] - 2.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
9 \cdot {x}^{4} - \left(y \cdot y\right) \cdot \left(y \cdot y - 2\right)
\end{array}

Alternative 1: 100.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \mathsf{fma}\left(2 - y \cdot y, y \cdot y, x \cdot \left(x \cdot \left(9 \cdot \left(x \cdot x\right)\right)\right)\right) \end{array} \]
(FPCore (x y)
 :precision binary64
 (fma (- 2.0 (* y y)) (* y y) (* x (* x (* 9.0 (* x x))))))
double code(double x, double y) {
	return fma((2.0 - (y * y)), (y * y), (x * (x * (9.0 * (x * x)))));
}
function code(x, y)
	return fma(Float64(2.0 - Float64(y * y)), Float64(y * y), Float64(x * Float64(x * Float64(9.0 * Float64(x * x)))))
end
code[x_, y_] := N[(N[(2.0 - N[(y * y), $MachinePrecision]), $MachinePrecision] * N[(y * y), $MachinePrecision] + N[(x * N[(x * N[(9.0 * N[(x * x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\mathsf{fma}\left(2 - y \cdot y, y \cdot y, x \cdot \left(x \cdot \left(9 \cdot \left(x \cdot x\right)\right)\right)\right)
\end{array}
Derivation
  1. Initial program 3.1%

    \[9 \cdot {x}^{4} - \left(y \cdot y\right) \cdot \left(y \cdot y - 2\right) \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. sqr-powN/A

      \[\leadsto \mathsf{\_.f64}\left(\left(9 \cdot \left({x}^{\left(\frac{4}{2}\right)} \cdot {x}^{\left(\frac{4}{2}\right)}\right)\right), \mathsf{*.f64}\left(\mathsf{*.f64}\left(y, \color{blue}{y}\right), \mathsf{\_.f64}\left(\mathsf{*.f64}\left(y, y\right), 2\right)\right)\right) \]
    2. associate-*r*N/A

      \[\leadsto \mathsf{\_.f64}\left(\left(\left(9 \cdot {x}^{\left(\frac{4}{2}\right)}\right) \cdot {x}^{\left(\frac{4}{2}\right)}\right), \mathsf{*.f64}\left(\color{blue}{\mathsf{*.f64}\left(y, y\right)}, \mathsf{\_.f64}\left(\mathsf{*.f64}\left(y, y\right), 2\right)\right)\right) \]
    3. metadata-evalN/A

      \[\leadsto \mathsf{\_.f64}\left(\left(\left(9 \cdot {x}^{\left(\frac{4}{2}\right)}\right) \cdot {x}^{2}\right), \mathsf{*.f64}\left(\mathsf{*.f64}\left(y, y\right), \mathsf{\_.f64}\left(\mathsf{*.f64}\left(y, y\right), 2\right)\right)\right) \]
    4. unpow2N/A

      \[\leadsto \mathsf{\_.f64}\left(\left(\left(9 \cdot {x}^{\left(\frac{4}{2}\right)}\right) \cdot \left(x \cdot x\right)\right), \mathsf{*.f64}\left(\mathsf{*.f64}\left(y, \color{blue}{y}\right), \mathsf{\_.f64}\left(\mathsf{*.f64}\left(y, y\right), 2\right)\right)\right) \]
    5. associate-*r*N/A

      \[\leadsto \mathsf{\_.f64}\left(\left(\left(\left(9 \cdot {x}^{\left(\frac{4}{2}\right)}\right) \cdot x\right) \cdot x\right), \mathsf{*.f64}\left(\color{blue}{\mathsf{*.f64}\left(y, y\right)}, \mathsf{\_.f64}\left(\mathsf{*.f64}\left(y, y\right), 2\right)\right)\right) \]
    6. *-lowering-*.f64N/A

      \[\leadsto \mathsf{\_.f64}\left(\mathsf{*.f64}\left(\left(\left(9 \cdot {x}^{\left(\frac{4}{2}\right)}\right) \cdot x\right), x\right), \mathsf{*.f64}\left(\color{blue}{\mathsf{*.f64}\left(y, y\right)}, \mathsf{\_.f64}\left(\mathsf{*.f64}\left(y, y\right), 2\right)\right)\right) \]
    7. *-lowering-*.f64N/A

      \[\leadsto \mathsf{\_.f64}\left(\mathsf{*.f64}\left(\mathsf{*.f64}\left(\left(9 \cdot {x}^{\left(\frac{4}{2}\right)}\right), x\right), x\right), \mathsf{*.f64}\left(\mathsf{*.f64}\left(\color{blue}{y}, y\right), \mathsf{\_.f64}\left(\mathsf{*.f64}\left(y, y\right), 2\right)\right)\right) \]
    8. *-lowering-*.f64N/A

      \[\leadsto \mathsf{\_.f64}\left(\mathsf{*.f64}\left(\mathsf{*.f64}\left(\mathsf{*.f64}\left(9, \left({x}^{\left(\frac{4}{2}\right)}\right)\right), x\right), x\right), \mathsf{*.f64}\left(\mathsf{*.f64}\left(y, y\right), \mathsf{\_.f64}\left(\mathsf{*.f64}\left(y, y\right), 2\right)\right)\right) \]
    9. metadata-evalN/A

      \[\leadsto \mathsf{\_.f64}\left(\mathsf{*.f64}\left(\mathsf{*.f64}\left(\mathsf{*.f64}\left(9, \left({x}^{2}\right)\right), x\right), x\right), \mathsf{*.f64}\left(\mathsf{*.f64}\left(y, y\right), \mathsf{\_.f64}\left(\mathsf{*.f64}\left(y, y\right), 2\right)\right)\right) \]
    10. unpow2N/A

      \[\leadsto \mathsf{\_.f64}\left(\mathsf{*.f64}\left(\mathsf{*.f64}\left(\mathsf{*.f64}\left(9, \left(x \cdot x\right)\right), x\right), x\right), \mathsf{*.f64}\left(\mathsf{*.f64}\left(y, y\right), \mathsf{\_.f64}\left(\mathsf{*.f64}\left(y, y\right), 2\right)\right)\right) \]
    11. *-lowering-*.f643.1%

      \[\leadsto \mathsf{\_.f64}\left(\mathsf{*.f64}\left(\mathsf{*.f64}\left(\mathsf{*.f64}\left(9, \mathsf{*.f64}\left(x, x\right)\right), x\right), x\right), \mathsf{*.f64}\left(\mathsf{*.f64}\left(y, y\right), \mathsf{\_.f64}\left(\mathsf{*.f64}\left(y, y\right), 2\right)\right)\right) \]
  4. Applied egg-rr3.1%

    \[\leadsto \color{blue}{\left(\left(9 \cdot \left(x \cdot x\right)\right) \cdot x\right) \cdot x} - \left(y \cdot y\right) \cdot \left(y \cdot y - 2\right) \]
  5. Step-by-step derivation
    1. sub-negN/A

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

      \[\leadsto \left(\left(9 \cdot \left(x \cdot x\right)\right) \cdot x\right) \cdot x - \left(y \cdot y\right) \cdot \left(y \cdot y + -2\right) \]
    3. *-commutativeN/A

      \[\leadsto \left(\left(9 \cdot \left(x \cdot x\right)\right) \cdot x\right) \cdot x - \left(y \cdot y + -2\right) \cdot \color{blue}{\left(y \cdot y\right)} \]
    4. cancel-sign-sub-invN/A

      \[\leadsto \left(\left(9 \cdot \left(x \cdot x\right)\right) \cdot x\right) \cdot x + \color{blue}{\left(\mathsf{neg}\left(\left(y \cdot y + -2\right)\right)\right) \cdot \left(y \cdot y\right)} \]
    5. associate-*l*N/A

      \[\leadsto \left(9 \cdot \left(x \cdot x\right)\right) \cdot \left(x \cdot x\right) + \color{blue}{\left(\mathsf{neg}\left(\left(y \cdot y + -2\right)\right)\right)} \cdot \left(y \cdot y\right) \]
    6. associate-*r*N/A

      \[\leadsto 9 \cdot \left(\left(x \cdot x\right) \cdot \left(x \cdot x\right)\right) + \color{blue}{\left(\mathsf{neg}\left(\left(y \cdot y + -2\right)\right)\right)} \cdot \left(y \cdot y\right) \]
    7. associate-*r*N/A

      \[\leadsto 9 \cdot \left(x \cdot \left(x \cdot \left(x \cdot x\right)\right)\right) + \left(\mathsf{neg}\left(\left(y \cdot y + -2\right)\right)\right) \cdot \left(y \cdot y\right) \]
    8. sub0-negN/A

      \[\leadsto 9 \cdot \left(x \cdot \left(x \cdot \left(x \cdot x\right)\right)\right) + \left(0 - \left(y \cdot y + -2\right)\right) \cdot \left(\color{blue}{y} \cdot y\right) \]
    9. +-commutativeN/A

      \[\leadsto \left(0 - \left(y \cdot y + -2\right)\right) \cdot \left(y \cdot y\right) + \color{blue}{9 \cdot \left(x \cdot \left(x \cdot \left(x \cdot x\right)\right)\right)} \]
    10. accelerator-lowering-fma.f64N/A

      \[\leadsto \mathsf{fma.f64}\left(\left(0 - \left(y \cdot y + -2\right)\right), \color{blue}{\left(y \cdot y\right)}, \left(9 \cdot \left(x \cdot \left(x \cdot \left(x \cdot x\right)\right)\right)\right)\right) \]
    11. +-commutativeN/A

      \[\leadsto \mathsf{fma.f64}\left(\left(0 - \left(-2 + y \cdot y\right)\right), \left(y \cdot y\right), \left(9 \cdot \left(x \cdot \left(x \cdot \left(x \cdot x\right)\right)\right)\right)\right) \]
    12. associate--r+N/A

      \[\leadsto \mathsf{fma.f64}\left(\left(\left(0 - -2\right) - y \cdot y\right), \left(\color{blue}{y} \cdot y\right), \left(9 \cdot \left(x \cdot \left(x \cdot \left(x \cdot x\right)\right)\right)\right)\right) \]
    13. metadata-evalN/A

      \[\leadsto \mathsf{fma.f64}\left(\left(2 - y \cdot y\right), \left(y \cdot y\right), \left(9 \cdot \left(x \cdot \left(x \cdot \left(x \cdot x\right)\right)\right)\right)\right) \]
    14. --lowering--.f64N/A

      \[\leadsto \mathsf{fma.f64}\left(\mathsf{\_.f64}\left(2, \left(y \cdot y\right)\right), \left(\color{blue}{y} \cdot y\right), \left(9 \cdot \left(x \cdot \left(x \cdot \left(x \cdot x\right)\right)\right)\right)\right) \]
    15. *-lowering-*.f64N/A

      \[\leadsto \mathsf{fma.f64}\left(\mathsf{\_.f64}\left(2, \mathsf{*.f64}\left(y, y\right)\right), \left(y \cdot y\right), \left(9 \cdot \left(x \cdot \left(x \cdot \left(x \cdot x\right)\right)\right)\right)\right) \]
    16. *-lowering-*.f64N/A

      \[\leadsto \mathsf{fma.f64}\left(\mathsf{\_.f64}\left(2, \mathsf{*.f64}\left(y, y\right)\right), \mathsf{*.f64}\left(y, \color{blue}{y}\right), \left(9 \cdot \left(x \cdot \left(x \cdot \left(x \cdot x\right)\right)\right)\right)\right) \]
    17. associate-*r*N/A

      \[\leadsto \mathsf{fma.f64}\left(\mathsf{\_.f64}\left(2, \mathsf{*.f64}\left(y, y\right)\right), \mathsf{*.f64}\left(y, y\right), \left(9 \cdot \left(\left(x \cdot x\right) \cdot \left(x \cdot x\right)\right)\right)\right) \]
  6. Applied egg-rr100.0%

    \[\leadsto \color{blue}{\mathsf{fma}\left(2 - y \cdot y, y \cdot y, x \cdot \left(x \cdot \left(9 \cdot \left(x \cdot x\right)\right)\right)\right)} \]
  7. Add Preprocessing

Alternative 2: 18.8% accurate, 1.7× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := y \cdot \left(y \cdot \left(y \cdot y\right)\right)\\ t_1 := x \cdot \left(x \cdot \left(9 \cdot \left(x \cdot x\right)\right)\right)\\ t_2 := t\_0 - t\_1\\ \frac{t\_0 \cdot 4 + \left(t\_1 - t\_0\right) \cdot t\_2}{y \cdot \left(2 \cdot y\right) + t\_2} \end{array} \end{array} \]
(FPCore (x y)
 :precision binary64
 (let* ((t_0 (* y (* y (* y y))))
        (t_1 (* x (* x (* 9.0 (* x x)))))
        (t_2 (- t_0 t_1)))
   (/ (+ (* t_0 4.0) (* (- t_1 t_0) t_2)) (+ (* y (* 2.0 y)) t_2))))
double code(double x, double y) {
	double t_0 = y * (y * (y * y));
	double t_1 = x * (x * (9.0 * (x * x)));
	double t_2 = t_0 - t_1;
	return ((t_0 * 4.0) + ((t_1 - t_0) * t_2)) / ((y * (2.0 * y)) + t_2);
}
real(8) function code(x, y)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8) :: t_0
    real(8) :: t_1
    real(8) :: t_2
    t_0 = y * (y * (y * y))
    t_1 = x * (x * (9.0d0 * (x * x)))
    t_2 = t_0 - t_1
    code = ((t_0 * 4.0d0) + ((t_1 - t_0) * t_2)) / ((y * (2.0d0 * y)) + t_2)
end function
public static double code(double x, double y) {
	double t_0 = y * (y * (y * y));
	double t_1 = x * (x * (9.0 * (x * x)));
	double t_2 = t_0 - t_1;
	return ((t_0 * 4.0) + ((t_1 - t_0) * t_2)) / ((y * (2.0 * y)) + t_2);
}
def code(x, y):
	t_0 = y * (y * (y * y))
	t_1 = x * (x * (9.0 * (x * x)))
	t_2 = t_0 - t_1
	return ((t_0 * 4.0) + ((t_1 - t_0) * t_2)) / ((y * (2.0 * y)) + t_2)
function code(x, y)
	t_0 = Float64(y * Float64(y * Float64(y * y)))
	t_1 = Float64(x * Float64(x * Float64(9.0 * Float64(x * x))))
	t_2 = Float64(t_0 - t_1)
	return Float64(Float64(Float64(t_0 * 4.0) + Float64(Float64(t_1 - t_0) * t_2)) / Float64(Float64(y * Float64(2.0 * y)) + t_2))
end
function tmp = code(x, y)
	t_0 = y * (y * (y * y));
	t_1 = x * (x * (9.0 * (x * x)));
	t_2 = t_0 - t_1;
	tmp = ((t_0 * 4.0) + ((t_1 - t_0) * t_2)) / ((y * (2.0 * y)) + t_2);
end
code[x_, y_] := Block[{t$95$0 = N[(y * N[(y * N[(y * y), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[(x * N[(x * N[(9.0 * N[(x * x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$2 = N[(t$95$0 - t$95$1), $MachinePrecision]}, N[(N[(N[(t$95$0 * 4.0), $MachinePrecision] + N[(N[(t$95$1 - t$95$0), $MachinePrecision] * t$95$2), $MachinePrecision]), $MachinePrecision] / N[(N[(y * N[(2.0 * y), $MachinePrecision]), $MachinePrecision] + t$95$2), $MachinePrecision]), $MachinePrecision]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := y \cdot \left(y \cdot \left(y \cdot y\right)\right)\\
t_1 := x \cdot \left(x \cdot \left(9 \cdot \left(x \cdot x\right)\right)\right)\\
t_2 := t\_0 - t\_1\\
\frac{t\_0 \cdot 4 + \left(t\_1 - t\_0\right) \cdot t\_2}{y \cdot \left(2 \cdot y\right) + t\_2}
\end{array}
\end{array}
Derivation
  1. Initial program 3.1%

    \[9 \cdot {x}^{4} - \left(y \cdot y\right) \cdot \left(y \cdot y - 2\right) \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. sqr-powN/A

      \[\leadsto \mathsf{\_.f64}\left(\left(9 \cdot \left({x}^{\left(\frac{4}{2}\right)} \cdot {x}^{\left(\frac{4}{2}\right)}\right)\right), \mathsf{*.f64}\left(\mathsf{*.f64}\left(y, \color{blue}{y}\right), \mathsf{\_.f64}\left(\mathsf{*.f64}\left(y, y\right), 2\right)\right)\right) \]
    2. associate-*r*N/A

      \[\leadsto \mathsf{\_.f64}\left(\left(\left(9 \cdot {x}^{\left(\frac{4}{2}\right)}\right) \cdot {x}^{\left(\frac{4}{2}\right)}\right), \mathsf{*.f64}\left(\color{blue}{\mathsf{*.f64}\left(y, y\right)}, \mathsf{\_.f64}\left(\mathsf{*.f64}\left(y, y\right), 2\right)\right)\right) \]
    3. metadata-evalN/A

      \[\leadsto \mathsf{\_.f64}\left(\left(\left(9 \cdot {x}^{\left(\frac{4}{2}\right)}\right) \cdot {x}^{2}\right), \mathsf{*.f64}\left(\mathsf{*.f64}\left(y, y\right), \mathsf{\_.f64}\left(\mathsf{*.f64}\left(y, y\right), 2\right)\right)\right) \]
    4. unpow2N/A

      \[\leadsto \mathsf{\_.f64}\left(\left(\left(9 \cdot {x}^{\left(\frac{4}{2}\right)}\right) \cdot \left(x \cdot x\right)\right), \mathsf{*.f64}\left(\mathsf{*.f64}\left(y, \color{blue}{y}\right), \mathsf{\_.f64}\left(\mathsf{*.f64}\left(y, y\right), 2\right)\right)\right) \]
    5. associate-*r*N/A

      \[\leadsto \mathsf{\_.f64}\left(\left(\left(\left(9 \cdot {x}^{\left(\frac{4}{2}\right)}\right) \cdot x\right) \cdot x\right), \mathsf{*.f64}\left(\color{blue}{\mathsf{*.f64}\left(y, y\right)}, \mathsf{\_.f64}\left(\mathsf{*.f64}\left(y, y\right), 2\right)\right)\right) \]
    6. *-lowering-*.f64N/A

      \[\leadsto \mathsf{\_.f64}\left(\mathsf{*.f64}\left(\left(\left(9 \cdot {x}^{\left(\frac{4}{2}\right)}\right) \cdot x\right), x\right), \mathsf{*.f64}\left(\color{blue}{\mathsf{*.f64}\left(y, y\right)}, \mathsf{\_.f64}\left(\mathsf{*.f64}\left(y, y\right), 2\right)\right)\right) \]
    7. *-lowering-*.f64N/A

      \[\leadsto \mathsf{\_.f64}\left(\mathsf{*.f64}\left(\mathsf{*.f64}\left(\left(9 \cdot {x}^{\left(\frac{4}{2}\right)}\right), x\right), x\right), \mathsf{*.f64}\left(\mathsf{*.f64}\left(\color{blue}{y}, y\right), \mathsf{\_.f64}\left(\mathsf{*.f64}\left(y, y\right), 2\right)\right)\right) \]
    8. *-lowering-*.f64N/A

      \[\leadsto \mathsf{\_.f64}\left(\mathsf{*.f64}\left(\mathsf{*.f64}\left(\mathsf{*.f64}\left(9, \left({x}^{\left(\frac{4}{2}\right)}\right)\right), x\right), x\right), \mathsf{*.f64}\left(\mathsf{*.f64}\left(y, y\right), \mathsf{\_.f64}\left(\mathsf{*.f64}\left(y, y\right), 2\right)\right)\right) \]
    9. metadata-evalN/A

      \[\leadsto \mathsf{\_.f64}\left(\mathsf{*.f64}\left(\mathsf{*.f64}\left(\mathsf{*.f64}\left(9, \left({x}^{2}\right)\right), x\right), x\right), \mathsf{*.f64}\left(\mathsf{*.f64}\left(y, y\right), \mathsf{\_.f64}\left(\mathsf{*.f64}\left(y, y\right), 2\right)\right)\right) \]
    10. unpow2N/A

      \[\leadsto \mathsf{\_.f64}\left(\mathsf{*.f64}\left(\mathsf{*.f64}\left(\mathsf{*.f64}\left(9, \left(x \cdot x\right)\right), x\right), x\right), \mathsf{*.f64}\left(\mathsf{*.f64}\left(y, y\right), \mathsf{\_.f64}\left(\mathsf{*.f64}\left(y, y\right), 2\right)\right)\right) \]
    11. *-lowering-*.f643.1%

      \[\leadsto \mathsf{\_.f64}\left(\mathsf{*.f64}\left(\mathsf{*.f64}\left(\mathsf{*.f64}\left(9, \mathsf{*.f64}\left(x, x\right)\right), x\right), x\right), \mathsf{*.f64}\left(\mathsf{*.f64}\left(y, y\right), \mathsf{\_.f64}\left(\mathsf{*.f64}\left(y, y\right), 2\right)\right)\right) \]
  4. Applied egg-rr3.1%

    \[\leadsto \color{blue}{\left(\left(9 \cdot \left(x \cdot x\right)\right) \cdot x\right) \cdot x} - \left(y \cdot y\right) \cdot \left(y \cdot y - 2\right) \]
  5. Applied egg-rr18.8%

    \[\leadsto \color{blue}{\frac{\left(y \cdot \left(y \cdot \left(y \cdot y\right)\right)\right) \cdot 4 - \left(x \cdot \left(x \cdot \left(9 \cdot \left(x \cdot x\right)\right)\right) - y \cdot \left(y \cdot \left(y \cdot y\right)\right)\right) \cdot \left(x \cdot \left(x \cdot \left(9 \cdot \left(x \cdot x\right)\right)\right) - y \cdot \left(y \cdot \left(y \cdot y\right)\right)\right)}{y \cdot \left(y \cdot 2\right) - \left(x \cdot \left(x \cdot \left(9 \cdot \left(x \cdot x\right)\right)\right) - y \cdot \left(y \cdot \left(y \cdot y\right)\right)\right)}} \]
  6. Final simplification18.8%

    \[\leadsto \frac{\left(y \cdot \left(y \cdot \left(y \cdot y\right)\right)\right) \cdot 4 + \left(x \cdot \left(x \cdot \left(9 \cdot \left(x \cdot x\right)\right)\right) - y \cdot \left(y \cdot \left(y \cdot y\right)\right)\right) \cdot \left(y \cdot \left(y \cdot \left(y \cdot y\right)\right) - x \cdot \left(x \cdot \left(9 \cdot \left(x \cdot x\right)\right)\right)\right)}{y \cdot \left(2 \cdot y\right) + \left(y \cdot \left(y \cdot \left(y \cdot y\right)\right) - x \cdot \left(x \cdot \left(9 \cdot \left(x \cdot x\right)\right)\right)\right)} \]
  7. Add Preprocessing

Alternative 3: 18.8% accurate, 5.0× speedup?

\[\begin{array}{l} \\ \left(9 \cdot \left(x \cdot \left(x \cdot \left(x \cdot x\right)\right)\right) - y \cdot \left(y \cdot \left(y \cdot y\right)\right)\right) - \left(y \cdot y\right) \cdot -2 \end{array} \]
(FPCore (x y)
 :precision binary64
 (- (- (* 9.0 (* x (* x (* x x)))) (* y (* y (* y y)))) (* (* y y) -2.0)))
double code(double x, double y) {
	return ((9.0 * (x * (x * (x * x)))) - (y * (y * (y * y)))) - ((y * y) * -2.0);
}
real(8) function code(x, y)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    code = ((9.0d0 * (x * (x * (x * x)))) - (y * (y * (y * y)))) - ((y * y) * (-2.0d0))
end function
public static double code(double x, double y) {
	return ((9.0 * (x * (x * (x * x)))) - (y * (y * (y * y)))) - ((y * y) * -2.0);
}
def code(x, y):
	return ((9.0 * (x * (x * (x * x)))) - (y * (y * (y * y)))) - ((y * y) * -2.0)
function code(x, y)
	return Float64(Float64(Float64(9.0 * Float64(x * Float64(x * Float64(x * x)))) - Float64(y * Float64(y * Float64(y * y)))) - Float64(Float64(y * y) * -2.0))
end
function tmp = code(x, y)
	tmp = ((9.0 * (x * (x * (x * x)))) - (y * (y * (y * y)))) - ((y * y) * -2.0);
end
code[x_, y_] := N[(N[(N[(9.0 * N[(x * N[(x * N[(x * x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(y * N[(y * N[(y * y), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(N[(y * y), $MachinePrecision] * -2.0), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\left(9 \cdot \left(x \cdot \left(x \cdot \left(x \cdot x\right)\right)\right) - y \cdot \left(y \cdot \left(y \cdot y\right)\right)\right) - \left(y \cdot y\right) \cdot -2
\end{array}
Derivation
  1. Initial program 3.1%

    \[9 \cdot {x}^{4} - \left(y \cdot y\right) \cdot \left(y \cdot y - 2\right) \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. sub-negN/A

      \[\leadsto 9 \cdot {x}^{4} - \left(y \cdot y\right) \cdot \left(y \cdot y + \color{blue}{\left(\mathsf{neg}\left(2\right)\right)}\right) \]
    2. distribute-lft-inN/A

      \[\leadsto 9 \cdot {x}^{4} - \left(\left(y \cdot y\right) \cdot \left(y \cdot y\right) + \color{blue}{\left(y \cdot y\right) \cdot \left(\mathsf{neg}\left(2\right)\right)}\right) \]
    3. associate--r+N/A

      \[\leadsto \left(9 \cdot {x}^{4} - \left(y \cdot y\right) \cdot \left(y \cdot y\right)\right) - \color{blue}{\left(y \cdot y\right) \cdot \left(\mathsf{neg}\left(2\right)\right)} \]
    4. --lowering--.f64N/A

      \[\leadsto \mathsf{\_.f64}\left(\left(9 \cdot {x}^{4} - \left(y \cdot y\right) \cdot \left(y \cdot y\right)\right), \color{blue}{\left(\left(y \cdot y\right) \cdot \left(\mathsf{neg}\left(2\right)\right)\right)}\right) \]
  4. Applied egg-rr18.8%

    \[\leadsto \color{blue}{\left(9 \cdot \left(x \cdot \left(x \cdot \left(x \cdot x\right)\right)\right) - y \cdot \left(y \cdot \left(y \cdot y\right)\right)\right) - \left(y \cdot y\right) \cdot -2} \]
  5. Add Preprocessing

Alternative 4: 11.1% accurate, 22.8× speedup?

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

\\
y \cdot \left(2 \cdot y\right)
\end{array}
Derivation
  1. Initial program 3.1%

    \[9 \cdot {x}^{4} - \left(y \cdot y\right) \cdot \left(y \cdot y - 2\right) \]
  2. Add Preprocessing
  3. Taylor expanded in x around 0

    \[\leadsto \color{blue}{-1 \cdot \left({y}^{2} \cdot \left({y}^{2} - 2\right)\right)} \]
  4. Step-by-step derivation
    1. mul-1-negN/A

      \[\leadsto \mathsf{neg}\left({y}^{2} \cdot \left({y}^{2} - 2\right)\right) \]
    2. distribute-rgt-neg-inN/A

      \[\leadsto {y}^{2} \cdot \color{blue}{\left(\mathsf{neg}\left(\left({y}^{2} - 2\right)\right)\right)} \]
    3. unpow2N/A

      \[\leadsto \left(y \cdot y\right) \cdot \left(\mathsf{neg}\left(\color{blue}{\left({y}^{2} - 2\right)}\right)\right) \]
    4. associate-*r*N/A

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

      \[\leadsto y \cdot \left(\left(\mathsf{neg}\left(\left({y}^{2} - 2\right)\right)\right) \cdot \color{blue}{y}\right) \]
    6. *-lowering-*.f64N/A

      \[\leadsto \mathsf{*.f64}\left(y, \color{blue}{\left(\left(\mathsf{neg}\left(\left({y}^{2} - 2\right)\right)\right) \cdot y\right)}\right) \]
    7. *-commutativeN/A

      \[\leadsto \mathsf{*.f64}\left(y, \left(y \cdot \color{blue}{\left(\mathsf{neg}\left(\left({y}^{2} - 2\right)\right)\right)}\right)\right) \]
    8. *-lowering-*.f64N/A

      \[\leadsto \mathsf{*.f64}\left(y, \mathsf{*.f64}\left(y, \color{blue}{\left(\mathsf{neg}\left(\left({y}^{2} - 2\right)\right)\right)}\right)\right) \]
    9. neg-sub0N/A

      \[\leadsto \mathsf{*.f64}\left(y, \mathsf{*.f64}\left(y, \left(0 - \color{blue}{\left({y}^{2} - 2\right)}\right)\right)\right) \]
    10. sub-negN/A

      \[\leadsto \mathsf{*.f64}\left(y, \mathsf{*.f64}\left(y, \left(0 - \left({y}^{2} + \color{blue}{\left(\mathsf{neg}\left(2\right)\right)}\right)\right)\right)\right) \]
    11. metadata-evalN/A

      \[\leadsto \mathsf{*.f64}\left(y, \mathsf{*.f64}\left(y, \left(0 - \left({y}^{2} + -2\right)\right)\right)\right) \]
    12. +-commutativeN/A

      \[\leadsto \mathsf{*.f64}\left(y, \mathsf{*.f64}\left(y, \left(0 - \left(-2 + \color{blue}{{y}^{2}}\right)\right)\right)\right) \]
    13. associate--r+N/A

      \[\leadsto \mathsf{*.f64}\left(y, \mathsf{*.f64}\left(y, \left(\left(0 - -2\right) - \color{blue}{{y}^{2}}\right)\right)\right) \]
    14. metadata-evalN/A

      \[\leadsto \mathsf{*.f64}\left(y, \mathsf{*.f64}\left(y, \left(2 - {\color{blue}{y}}^{2}\right)\right)\right) \]
    15. --lowering--.f64N/A

      \[\leadsto \mathsf{*.f64}\left(y, \mathsf{*.f64}\left(y, \mathsf{\_.f64}\left(2, \color{blue}{\left({y}^{2}\right)}\right)\right)\right) \]
    16. unpow2N/A

      \[\leadsto \mathsf{*.f64}\left(y, \mathsf{*.f64}\left(y, \mathsf{\_.f64}\left(2, \left(y \cdot \color{blue}{y}\right)\right)\right)\right) \]
    17. *-lowering-*.f641.5%

      \[\leadsto \mathsf{*.f64}\left(y, \mathsf{*.f64}\left(y, \mathsf{\_.f64}\left(2, \mathsf{*.f64}\left(y, \color{blue}{y}\right)\right)\right)\right) \]
  5. Simplified1.5%

    \[\leadsto \color{blue}{y \cdot \left(y \cdot \left(2 - y \cdot y\right)\right)} \]
  6. Taylor expanded in y around 0

    \[\leadsto \mathsf{*.f64}\left(y, \mathsf{*.f64}\left(y, \color{blue}{2}\right)\right) \]
  7. Step-by-step derivation
    1. Simplified11.1%

      \[\leadsto y \cdot \left(y \cdot \color{blue}{2}\right) \]
    2. Final simplification11.1%

      \[\leadsto y \cdot \left(2 \cdot y\right) \]
    3. Add Preprocessing

    Reproduce

    ?
    herbie shell --seed 2024191 
    (FPCore (x y)
      :name "From Rump in a 1983 paper, rewritten"
      :precision binary64
      :pre (and (== x 10864.0) (== y 18817.0))
      (- (* 9.0 (pow x 4.0)) (* (* y y) (- (* y y) 2.0))))