Statistics.Sample:robustSumVarWeighted from math-functions-0.1.5.2

Percentage Accurate: 99.9% → 99.9%
Time: 8.7s
Alternatives: 4
Speedup: 1.2×

Specification

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

\\
x + \left(y \cdot z\right) \cdot z
\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: 99.9% accurate, 1.0× speedup?

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

\\
x + \left(y \cdot z\right) \cdot z
\end{array}

Alternative 1: 99.9% accurate, 1.2× speedup?

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

\\
\mathsf{fma}\left(y \cdot z, z, x\right)
\end{array}
Derivation
  1. Initial program 99.9%

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

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

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

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

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

    \[\leadsto \color{blue}{\mathsf{fma}\left(y \cdot z, z, x\right)} \]
  5. Add Preprocessing

Alternative 2: 87.3% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := z \cdot \left(y \cdot z\right)\\ \mathbf{if}\;t\_0 \leq -0.01:\\ \;\;\;\;t\_0\\ \mathbf{elif}\;t\_0 \leq 5 \cdot 10^{-30}:\\ \;\;\;\;x \cdot 1\\ \mathbf{else}:\\ \;\;\;\;t\_0\\ \end{array} \end{array} \]
(FPCore (x y z)
 :precision binary64
 (let* ((t_0 (* z (* y z))))
   (if (<= t_0 -0.01) t_0 (if (<= t_0 5e-30) (* x 1.0) t_0))))
double code(double x, double y, double z) {
	double t_0 = z * (y * z);
	double tmp;
	if (t_0 <= -0.01) {
		tmp = t_0;
	} else if (t_0 <= 5e-30) {
		tmp = x * 1.0;
	} else {
		tmp = t_0;
	}
	return tmp;
}
real(8) function code(x, y, z)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    real(8) :: t_0
    real(8) :: tmp
    t_0 = z * (y * z)
    if (t_0 <= (-0.01d0)) then
        tmp = t_0
    else if (t_0 <= 5d-30) then
        tmp = x * 1.0d0
    else
        tmp = t_0
    end if
    code = tmp
end function
public static double code(double x, double y, double z) {
	double t_0 = z * (y * z);
	double tmp;
	if (t_0 <= -0.01) {
		tmp = t_0;
	} else if (t_0 <= 5e-30) {
		tmp = x * 1.0;
	} else {
		tmp = t_0;
	}
	return tmp;
}
def code(x, y, z):
	t_0 = z * (y * z)
	tmp = 0
	if t_0 <= -0.01:
		tmp = t_0
	elif t_0 <= 5e-30:
		tmp = x * 1.0
	else:
		tmp = t_0
	return tmp
function code(x, y, z)
	t_0 = Float64(z * Float64(y * z))
	tmp = 0.0
	if (t_0 <= -0.01)
		tmp = t_0;
	elseif (t_0 <= 5e-30)
		tmp = Float64(x * 1.0);
	else
		tmp = t_0;
	end
	return tmp
end
function tmp_2 = code(x, y, z)
	t_0 = z * (y * z);
	tmp = 0.0;
	if (t_0 <= -0.01)
		tmp = t_0;
	elseif (t_0 <= 5e-30)
		tmp = x * 1.0;
	else
		tmp = t_0;
	end
	tmp_2 = tmp;
end
code[x_, y_, z_] := Block[{t$95$0 = N[(z * N[(y * z), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[t$95$0, -0.01], t$95$0, If[LessEqual[t$95$0, 5e-30], N[(x * 1.0), $MachinePrecision], t$95$0]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := z \cdot \left(y \cdot z\right)\\
\mathbf{if}\;t\_0 \leq -0.01:\\
\;\;\;\;t\_0\\

\mathbf{elif}\;t\_0 \leq 5 \cdot 10^{-30}:\\
\;\;\;\;x \cdot 1\\

\mathbf{else}:\\
\;\;\;\;t\_0\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (*.f64 (*.f64 y z) z) < -0.0100000000000000002 or 4.99999999999999972e-30 < (*.f64 (*.f64 y z) z)

    1. Initial program 99.8%

      \[x + \left(y \cdot z\right) \cdot z \]
    2. Add Preprocessing
    3. Taylor expanded in x around 0

      \[\leadsto \color{blue}{y \cdot {z}^{2}} \]
    4. Step-by-step derivation
      1. lower-*.f64N/A

        \[\leadsto \color{blue}{y \cdot {z}^{2}} \]
      2. unpow2N/A

        \[\leadsto y \cdot \color{blue}{\left(z \cdot z\right)} \]
      3. lower-*.f6480.0

        \[\leadsto y \cdot \color{blue}{\left(z \cdot z\right)} \]
    5. Applied rewrites80.0%

      \[\leadsto \color{blue}{y \cdot \left(z \cdot z\right)} \]
    6. Step-by-step derivation
      1. Applied rewrites89.9%

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

      if -0.0100000000000000002 < (*.f64 (*.f64 y z) z) < 4.99999999999999972e-30

      1. Initial program 100.0%

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

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

          \[\leadsto \color{blue}{\left(y \cdot z\right) \cdot z + x} \]
        3. unpow1N/A

          \[\leadsto \color{blue}{{\left(\left(y \cdot z\right) \cdot z\right)}^{1}} + x \]
        4. sqr-powN/A

          \[\leadsto \color{blue}{{\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)} \cdot {\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}} + x \]
        5. lower-fma.f64N/A

          \[\leadsto \color{blue}{\mathsf{fma}\left({\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}, {\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}, x\right)} \]
        6. lower-pow.f64N/A

          \[\leadsto \mathsf{fma}\left(\color{blue}{{\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}}, {\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}, x\right) \]
        7. lift-*.f64N/A

          \[\leadsto \mathsf{fma}\left({\color{blue}{\left(\left(y \cdot z\right) \cdot z\right)}}^{\left(\frac{1}{2}\right)}, {\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}, x\right) \]
        8. lift-*.f64N/A

          \[\leadsto \mathsf{fma}\left({\left(\color{blue}{\left(y \cdot z\right)} \cdot z\right)}^{\left(\frac{1}{2}\right)}, {\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}, x\right) \]
        9. associate-*l*N/A

          \[\leadsto \mathsf{fma}\left({\color{blue}{\left(y \cdot \left(z \cdot z\right)\right)}}^{\left(\frac{1}{2}\right)}, {\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}, x\right) \]
        10. lower-*.f64N/A

          \[\leadsto \mathsf{fma}\left({\color{blue}{\left(y \cdot \left(z \cdot z\right)\right)}}^{\left(\frac{1}{2}\right)}, {\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}, x\right) \]
        11. lower-*.f64N/A

          \[\leadsto \mathsf{fma}\left({\left(y \cdot \color{blue}{\left(z \cdot z\right)}\right)}^{\left(\frac{1}{2}\right)}, {\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}, x\right) \]
        12. metadata-evalN/A

          \[\leadsto \mathsf{fma}\left({\left(y \cdot \left(z \cdot z\right)\right)}^{\color{blue}{\frac{1}{2}}}, {\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}, x\right) \]
        13. lower-pow.f64N/A

          \[\leadsto \mathsf{fma}\left({\left(y \cdot \left(z \cdot z\right)\right)}^{\frac{1}{2}}, \color{blue}{{\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}}, x\right) \]
        14. lift-*.f64N/A

          \[\leadsto \mathsf{fma}\left({\left(y \cdot \left(z \cdot z\right)\right)}^{\frac{1}{2}}, {\color{blue}{\left(\left(y \cdot z\right) \cdot z\right)}}^{\left(\frac{1}{2}\right)}, x\right) \]
        15. lift-*.f64N/A

          \[\leadsto \mathsf{fma}\left({\left(y \cdot \left(z \cdot z\right)\right)}^{\frac{1}{2}}, {\left(\color{blue}{\left(y \cdot z\right)} \cdot z\right)}^{\left(\frac{1}{2}\right)}, x\right) \]
        16. associate-*l*N/A

          \[\leadsto \mathsf{fma}\left({\left(y \cdot \left(z \cdot z\right)\right)}^{\frac{1}{2}}, {\color{blue}{\left(y \cdot \left(z \cdot z\right)\right)}}^{\left(\frac{1}{2}\right)}, x\right) \]
        17. lower-*.f64N/A

          \[\leadsto \mathsf{fma}\left({\left(y \cdot \left(z \cdot z\right)\right)}^{\frac{1}{2}}, {\color{blue}{\left(y \cdot \left(z \cdot z\right)\right)}}^{\left(\frac{1}{2}\right)}, x\right) \]
        18. lower-*.f64N/A

          \[\leadsto \mathsf{fma}\left({\left(y \cdot \left(z \cdot z\right)\right)}^{\frac{1}{2}}, {\left(y \cdot \color{blue}{\left(z \cdot z\right)}\right)}^{\left(\frac{1}{2}\right)}, x\right) \]
        19. metadata-eval71.3

          \[\leadsto \mathsf{fma}\left({\left(y \cdot \left(z \cdot z\right)\right)}^{0.5}, {\left(y \cdot \left(z \cdot z\right)\right)}^{\color{blue}{0.5}}, x\right) \]
      4. Applied rewrites71.3%

        \[\leadsto \color{blue}{\mathsf{fma}\left({\left(y \cdot \left(z \cdot z\right)\right)}^{0.5}, {\left(y \cdot \left(z \cdot z\right)\right)}^{0.5}, x\right)} \]
      5. Taylor expanded in x around inf

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

          \[\leadsto x \cdot \color{blue}{\left(\frac{y \cdot {z}^{2}}{x} + 1\right)} \]
        2. distribute-lft-inN/A

          \[\leadsto \color{blue}{x \cdot \frac{y \cdot {z}^{2}}{x} + x \cdot 1} \]
        3. *-rgt-identityN/A

          \[\leadsto x \cdot \frac{y \cdot {z}^{2}}{x} + \color{blue}{x} \]
        4. associate-/l*N/A

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

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

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

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

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

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

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

          \[\leadsto \mathsf{fma}\left(\frac{z \cdot z}{x}, \color{blue}{y \cdot x}, x\right) \]
        12. lower-*.f6484.5

          \[\leadsto \mathsf{fma}\left(\frac{z \cdot z}{x}, \color{blue}{y \cdot x}, x\right) \]
      7. Applied rewrites84.5%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{z \cdot z}{x}, y \cdot x, x\right)} \]
      8. Step-by-step derivation
        1. Applied rewrites92.0%

          \[\leadsto \mathsf{fma}\left(z \cdot z, \frac{y}{x}, 1\right) \cdot \color{blue}{x} \]
        2. Taylor expanded in z around 0

          \[\leadsto 1 \cdot x \]
        3. Step-by-step derivation
          1. Applied rewrites88.2%

            \[\leadsto 1 \cdot x \]
        4. Recombined 2 regimes into one program.
        5. Final simplification89.1%

          \[\leadsto \begin{array}{l} \mathbf{if}\;z \cdot \left(y \cdot z\right) \leq -0.01:\\ \;\;\;\;z \cdot \left(y \cdot z\right)\\ \mathbf{elif}\;z \cdot \left(y \cdot z\right) \leq 5 \cdot 10^{-30}:\\ \;\;\;\;x \cdot 1\\ \mathbf{else}:\\ \;\;\;\;z \cdot \left(y \cdot z\right)\\ \end{array} \]
        6. Add Preprocessing

        Alternative 3: 82.7% accurate, 0.3× speedup?

        \[\begin{array}{l} \\ \begin{array}{l} t_0 := z \cdot \left(y \cdot z\right)\\ t_1 := y \cdot \left(z \cdot z\right)\\ \mathbf{if}\;t\_0 \leq -0.01:\\ \;\;\;\;t\_1\\ \mathbf{elif}\;t\_0 \leq 5 \cdot 10^{-30}:\\ \;\;\;\;x \cdot 1\\ \mathbf{else}:\\ \;\;\;\;t\_1\\ \end{array} \end{array} \]
        (FPCore (x y z)
         :precision binary64
         (let* ((t_0 (* z (* y z))) (t_1 (* y (* z z))))
           (if (<= t_0 -0.01) t_1 (if (<= t_0 5e-30) (* x 1.0) t_1))))
        double code(double x, double y, double z) {
        	double t_0 = z * (y * z);
        	double t_1 = y * (z * z);
        	double tmp;
        	if (t_0 <= -0.01) {
        		tmp = t_1;
        	} else if (t_0 <= 5e-30) {
        		tmp = x * 1.0;
        	} else {
        		tmp = t_1;
        	}
        	return tmp;
        }
        
        real(8) function code(x, y, z)
            real(8), intent (in) :: x
            real(8), intent (in) :: y
            real(8), intent (in) :: z
            real(8) :: t_0
            real(8) :: t_1
            real(8) :: tmp
            t_0 = z * (y * z)
            t_1 = y * (z * z)
            if (t_0 <= (-0.01d0)) then
                tmp = t_1
            else if (t_0 <= 5d-30) then
                tmp = x * 1.0d0
            else
                tmp = t_1
            end if
            code = tmp
        end function
        
        public static double code(double x, double y, double z) {
        	double t_0 = z * (y * z);
        	double t_1 = y * (z * z);
        	double tmp;
        	if (t_0 <= -0.01) {
        		tmp = t_1;
        	} else if (t_0 <= 5e-30) {
        		tmp = x * 1.0;
        	} else {
        		tmp = t_1;
        	}
        	return tmp;
        }
        
        def code(x, y, z):
        	t_0 = z * (y * z)
        	t_1 = y * (z * z)
        	tmp = 0
        	if t_0 <= -0.01:
        		tmp = t_1
        	elif t_0 <= 5e-30:
        		tmp = x * 1.0
        	else:
        		tmp = t_1
        	return tmp
        
        function code(x, y, z)
        	t_0 = Float64(z * Float64(y * z))
        	t_1 = Float64(y * Float64(z * z))
        	tmp = 0.0
        	if (t_0 <= -0.01)
        		tmp = t_1;
        	elseif (t_0 <= 5e-30)
        		tmp = Float64(x * 1.0);
        	else
        		tmp = t_1;
        	end
        	return tmp
        end
        
        function tmp_2 = code(x, y, z)
        	t_0 = z * (y * z);
        	t_1 = y * (z * z);
        	tmp = 0.0;
        	if (t_0 <= -0.01)
        		tmp = t_1;
        	elseif (t_0 <= 5e-30)
        		tmp = x * 1.0;
        	else
        		tmp = t_1;
        	end
        	tmp_2 = tmp;
        end
        
        code[x_, y_, z_] := Block[{t$95$0 = N[(z * N[(y * z), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[(y * N[(z * z), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[t$95$0, -0.01], t$95$1, If[LessEqual[t$95$0, 5e-30], N[(x * 1.0), $MachinePrecision], t$95$1]]]]
        
        \begin{array}{l}
        
        \\
        \begin{array}{l}
        t_0 := z \cdot \left(y \cdot z\right)\\
        t_1 := y \cdot \left(z \cdot z\right)\\
        \mathbf{if}\;t\_0 \leq -0.01:\\
        \;\;\;\;t\_1\\
        
        \mathbf{elif}\;t\_0 \leq 5 \cdot 10^{-30}:\\
        \;\;\;\;x \cdot 1\\
        
        \mathbf{else}:\\
        \;\;\;\;t\_1\\
        
        
        \end{array}
        \end{array}
        
        Derivation
        1. Split input into 2 regimes
        2. if (*.f64 (*.f64 y z) z) < -0.0100000000000000002 or 4.99999999999999972e-30 < (*.f64 (*.f64 y z) z)

          1. Initial program 99.8%

            \[x + \left(y \cdot z\right) \cdot z \]
          2. Add Preprocessing
          3. Taylor expanded in x around 0

            \[\leadsto \color{blue}{y \cdot {z}^{2}} \]
          4. Step-by-step derivation
            1. lower-*.f64N/A

              \[\leadsto \color{blue}{y \cdot {z}^{2}} \]
            2. unpow2N/A

              \[\leadsto y \cdot \color{blue}{\left(z \cdot z\right)} \]
            3. lower-*.f6480.0

              \[\leadsto y \cdot \color{blue}{\left(z \cdot z\right)} \]
          5. Applied rewrites80.0%

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

          if -0.0100000000000000002 < (*.f64 (*.f64 y z) z) < 4.99999999999999972e-30

          1. Initial program 100.0%

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

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

              \[\leadsto \color{blue}{\left(y \cdot z\right) \cdot z + x} \]
            3. unpow1N/A

              \[\leadsto \color{blue}{{\left(\left(y \cdot z\right) \cdot z\right)}^{1}} + x \]
            4. sqr-powN/A

              \[\leadsto \color{blue}{{\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)} \cdot {\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}} + x \]
            5. lower-fma.f64N/A

              \[\leadsto \color{blue}{\mathsf{fma}\left({\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}, {\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}, x\right)} \]
            6. lower-pow.f64N/A

              \[\leadsto \mathsf{fma}\left(\color{blue}{{\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}}, {\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}, x\right) \]
            7. lift-*.f64N/A

              \[\leadsto \mathsf{fma}\left({\color{blue}{\left(\left(y \cdot z\right) \cdot z\right)}}^{\left(\frac{1}{2}\right)}, {\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}, x\right) \]
            8. lift-*.f64N/A

              \[\leadsto \mathsf{fma}\left({\left(\color{blue}{\left(y \cdot z\right)} \cdot z\right)}^{\left(\frac{1}{2}\right)}, {\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}, x\right) \]
            9. associate-*l*N/A

              \[\leadsto \mathsf{fma}\left({\color{blue}{\left(y \cdot \left(z \cdot z\right)\right)}}^{\left(\frac{1}{2}\right)}, {\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}, x\right) \]
            10. lower-*.f64N/A

              \[\leadsto \mathsf{fma}\left({\color{blue}{\left(y \cdot \left(z \cdot z\right)\right)}}^{\left(\frac{1}{2}\right)}, {\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}, x\right) \]
            11. lower-*.f64N/A

              \[\leadsto \mathsf{fma}\left({\left(y \cdot \color{blue}{\left(z \cdot z\right)}\right)}^{\left(\frac{1}{2}\right)}, {\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}, x\right) \]
            12. metadata-evalN/A

              \[\leadsto \mathsf{fma}\left({\left(y \cdot \left(z \cdot z\right)\right)}^{\color{blue}{\frac{1}{2}}}, {\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}, x\right) \]
            13. lower-pow.f64N/A

              \[\leadsto \mathsf{fma}\left({\left(y \cdot \left(z \cdot z\right)\right)}^{\frac{1}{2}}, \color{blue}{{\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}}, x\right) \]
            14. lift-*.f64N/A

              \[\leadsto \mathsf{fma}\left({\left(y \cdot \left(z \cdot z\right)\right)}^{\frac{1}{2}}, {\color{blue}{\left(\left(y \cdot z\right) \cdot z\right)}}^{\left(\frac{1}{2}\right)}, x\right) \]
            15. lift-*.f64N/A

              \[\leadsto \mathsf{fma}\left({\left(y \cdot \left(z \cdot z\right)\right)}^{\frac{1}{2}}, {\left(\color{blue}{\left(y \cdot z\right)} \cdot z\right)}^{\left(\frac{1}{2}\right)}, x\right) \]
            16. associate-*l*N/A

              \[\leadsto \mathsf{fma}\left({\left(y \cdot \left(z \cdot z\right)\right)}^{\frac{1}{2}}, {\color{blue}{\left(y \cdot \left(z \cdot z\right)\right)}}^{\left(\frac{1}{2}\right)}, x\right) \]
            17. lower-*.f64N/A

              \[\leadsto \mathsf{fma}\left({\left(y \cdot \left(z \cdot z\right)\right)}^{\frac{1}{2}}, {\color{blue}{\left(y \cdot \left(z \cdot z\right)\right)}}^{\left(\frac{1}{2}\right)}, x\right) \]
            18. lower-*.f64N/A

              \[\leadsto \mathsf{fma}\left({\left(y \cdot \left(z \cdot z\right)\right)}^{\frac{1}{2}}, {\left(y \cdot \color{blue}{\left(z \cdot z\right)}\right)}^{\left(\frac{1}{2}\right)}, x\right) \]
            19. metadata-eval71.3

              \[\leadsto \mathsf{fma}\left({\left(y \cdot \left(z \cdot z\right)\right)}^{0.5}, {\left(y \cdot \left(z \cdot z\right)\right)}^{\color{blue}{0.5}}, x\right) \]
          4. Applied rewrites71.3%

            \[\leadsto \color{blue}{\mathsf{fma}\left({\left(y \cdot \left(z \cdot z\right)\right)}^{0.5}, {\left(y \cdot \left(z \cdot z\right)\right)}^{0.5}, x\right)} \]
          5. Taylor expanded in x around inf

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

              \[\leadsto x \cdot \color{blue}{\left(\frac{y \cdot {z}^{2}}{x} + 1\right)} \]
            2. distribute-lft-inN/A

              \[\leadsto \color{blue}{x \cdot \frac{y \cdot {z}^{2}}{x} + x \cdot 1} \]
            3. *-rgt-identityN/A

              \[\leadsto x \cdot \frac{y \cdot {z}^{2}}{x} + \color{blue}{x} \]
            4. associate-/l*N/A

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

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

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

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

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

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

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

              \[\leadsto \mathsf{fma}\left(\frac{z \cdot z}{x}, \color{blue}{y \cdot x}, x\right) \]
            12. lower-*.f6484.5

              \[\leadsto \mathsf{fma}\left(\frac{z \cdot z}{x}, \color{blue}{y \cdot x}, x\right) \]
          7. Applied rewrites84.5%

            \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{z \cdot z}{x}, y \cdot x, x\right)} \]
          8. Step-by-step derivation
            1. Applied rewrites92.0%

              \[\leadsto \mathsf{fma}\left(z \cdot z, \frac{y}{x}, 1\right) \cdot \color{blue}{x} \]
            2. Taylor expanded in z around 0

              \[\leadsto 1 \cdot x \]
            3. Step-by-step derivation
              1. Applied rewrites88.2%

                \[\leadsto 1 \cdot x \]
            4. Recombined 2 regimes into one program.
            5. Final simplification84.0%

              \[\leadsto \begin{array}{l} \mathbf{if}\;z \cdot \left(y \cdot z\right) \leq -0.01:\\ \;\;\;\;y \cdot \left(z \cdot z\right)\\ \mathbf{elif}\;z \cdot \left(y \cdot z\right) \leq 5 \cdot 10^{-30}:\\ \;\;\;\;x \cdot 1\\ \mathbf{else}:\\ \;\;\;\;y \cdot \left(z \cdot z\right)\\ \end{array} \]
            6. Add Preprocessing

            Alternative 4: 50.4% accurate, 2.3× speedup?

            \[\begin{array}{l} \\ x \cdot 1 \end{array} \]
            (FPCore (x y z) :precision binary64 (* x 1.0))
            double code(double x, double y, double z) {
            	return x * 1.0;
            }
            
            real(8) function code(x, y, z)
                real(8), intent (in) :: x
                real(8), intent (in) :: y
                real(8), intent (in) :: z
                code = x * 1.0d0
            end function
            
            public static double code(double x, double y, double z) {
            	return x * 1.0;
            }
            
            def code(x, y, z):
            	return x * 1.0
            
            function code(x, y, z)
            	return Float64(x * 1.0)
            end
            
            function tmp = code(x, y, z)
            	tmp = x * 1.0;
            end
            
            code[x_, y_, z_] := N[(x * 1.0), $MachinePrecision]
            
            \begin{array}{l}
            
            \\
            x \cdot 1
            \end{array}
            
            Derivation
            1. Initial program 99.9%

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

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

                \[\leadsto \color{blue}{\left(y \cdot z\right) \cdot z + x} \]
              3. unpow1N/A

                \[\leadsto \color{blue}{{\left(\left(y \cdot z\right) \cdot z\right)}^{1}} + x \]
              4. sqr-powN/A

                \[\leadsto \color{blue}{{\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)} \cdot {\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}} + x \]
              5. lower-fma.f64N/A

                \[\leadsto \color{blue}{\mathsf{fma}\left({\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}, {\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}, x\right)} \]
              6. lower-pow.f64N/A

                \[\leadsto \mathsf{fma}\left(\color{blue}{{\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}}, {\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}, x\right) \]
              7. lift-*.f64N/A

                \[\leadsto \mathsf{fma}\left({\color{blue}{\left(\left(y \cdot z\right) \cdot z\right)}}^{\left(\frac{1}{2}\right)}, {\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}, x\right) \]
              8. lift-*.f64N/A

                \[\leadsto \mathsf{fma}\left({\left(\color{blue}{\left(y \cdot z\right)} \cdot z\right)}^{\left(\frac{1}{2}\right)}, {\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}, x\right) \]
              9. associate-*l*N/A

                \[\leadsto \mathsf{fma}\left({\color{blue}{\left(y \cdot \left(z \cdot z\right)\right)}}^{\left(\frac{1}{2}\right)}, {\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}, x\right) \]
              10. lower-*.f64N/A

                \[\leadsto \mathsf{fma}\left({\color{blue}{\left(y \cdot \left(z \cdot z\right)\right)}}^{\left(\frac{1}{2}\right)}, {\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}, x\right) \]
              11. lower-*.f64N/A

                \[\leadsto \mathsf{fma}\left({\left(y \cdot \color{blue}{\left(z \cdot z\right)}\right)}^{\left(\frac{1}{2}\right)}, {\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}, x\right) \]
              12. metadata-evalN/A

                \[\leadsto \mathsf{fma}\left({\left(y \cdot \left(z \cdot z\right)\right)}^{\color{blue}{\frac{1}{2}}}, {\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}, x\right) \]
              13. lower-pow.f64N/A

                \[\leadsto \mathsf{fma}\left({\left(y \cdot \left(z \cdot z\right)\right)}^{\frac{1}{2}}, \color{blue}{{\left(\left(y \cdot z\right) \cdot z\right)}^{\left(\frac{1}{2}\right)}}, x\right) \]
              14. lift-*.f64N/A

                \[\leadsto \mathsf{fma}\left({\left(y \cdot \left(z \cdot z\right)\right)}^{\frac{1}{2}}, {\color{blue}{\left(\left(y \cdot z\right) \cdot z\right)}}^{\left(\frac{1}{2}\right)}, x\right) \]
              15. lift-*.f64N/A

                \[\leadsto \mathsf{fma}\left({\left(y \cdot \left(z \cdot z\right)\right)}^{\frac{1}{2}}, {\left(\color{blue}{\left(y \cdot z\right)} \cdot z\right)}^{\left(\frac{1}{2}\right)}, x\right) \]
              16. associate-*l*N/A

                \[\leadsto \mathsf{fma}\left({\left(y \cdot \left(z \cdot z\right)\right)}^{\frac{1}{2}}, {\color{blue}{\left(y \cdot \left(z \cdot z\right)\right)}}^{\left(\frac{1}{2}\right)}, x\right) \]
              17. lower-*.f64N/A

                \[\leadsto \mathsf{fma}\left({\left(y \cdot \left(z \cdot z\right)\right)}^{\frac{1}{2}}, {\color{blue}{\left(y \cdot \left(z \cdot z\right)\right)}}^{\left(\frac{1}{2}\right)}, x\right) \]
              18. lower-*.f64N/A

                \[\leadsto \mathsf{fma}\left({\left(y \cdot \left(z \cdot z\right)\right)}^{\frac{1}{2}}, {\left(y \cdot \color{blue}{\left(z \cdot z\right)}\right)}^{\left(\frac{1}{2}\right)}, x\right) \]
              19. metadata-eval59.7

                \[\leadsto \mathsf{fma}\left({\left(y \cdot \left(z \cdot z\right)\right)}^{0.5}, {\left(y \cdot \left(z \cdot z\right)\right)}^{\color{blue}{0.5}}, x\right) \]
            4. Applied rewrites59.7%

              \[\leadsto \color{blue}{\mathsf{fma}\left({\left(y \cdot \left(z \cdot z\right)\right)}^{0.5}, {\left(y \cdot \left(z \cdot z\right)\right)}^{0.5}, x\right)} \]
            5. Taylor expanded in x around inf

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

                \[\leadsto x \cdot \color{blue}{\left(\frac{y \cdot {z}^{2}}{x} + 1\right)} \]
              2. distribute-lft-inN/A

                \[\leadsto \color{blue}{x \cdot \frac{y \cdot {z}^{2}}{x} + x \cdot 1} \]
              3. *-rgt-identityN/A

                \[\leadsto x \cdot \frac{y \cdot {z}^{2}}{x} + \color{blue}{x} \]
              4. associate-/l*N/A

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

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

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

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

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

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

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

                \[\leadsto \mathsf{fma}\left(\frac{z \cdot z}{x}, \color{blue}{y \cdot x}, x\right) \]
              12. lower-*.f6480.0

                \[\leadsto \mathsf{fma}\left(\frac{z \cdot z}{x}, \color{blue}{y \cdot x}, x\right) \]
            7. Applied rewrites80.0%

              \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{z \cdot z}{x}, y \cdot x, x\right)} \]
            8. Step-by-step derivation
              1. Applied rewrites84.7%

                \[\leadsto \mathsf{fma}\left(z \cdot z, \frac{y}{x}, 1\right) \cdot \color{blue}{x} \]
              2. Taylor expanded in z around 0

                \[\leadsto 1 \cdot x \]
              3. Step-by-step derivation
                1. Applied rewrites48.4%

                  \[\leadsto 1 \cdot x \]
                2. Final simplification48.4%

                  \[\leadsto x \cdot 1 \]
                3. Add Preprocessing

                Reproduce

                ?
                herbie shell --seed 2024220 
                (FPCore (x y z)
                  :name "Statistics.Sample:robustSumVarWeighted from math-functions-0.1.5.2"
                  :precision binary64
                  (+ x (* (* y z) z)))