fabs fraction 1

Percentage Accurate: 91.5% → 99.7%
Time: 6.8s
Alternatives: 7
Speedup: 1.6×

Specification

?
\[\begin{array}{l} \\ \left|\frac{x + 4}{y} - \frac{x}{y} \cdot z\right| \end{array} \]
(FPCore (x y z) :precision binary64 (fabs (- (/ (+ x 4.0) y) (* (/ x y) z))))
double code(double x, double y, double z) {
	return fabs((((x + 4.0) / y) - ((x / y) * z)));
}
real(8) function code(x, y, z)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    code = abs((((x + 4.0d0) / y) - ((x / y) * z)))
end function
public static double code(double x, double y, double z) {
	return Math.abs((((x + 4.0) / y) - ((x / y) * z)));
}
def code(x, y, z):
	return math.fabs((((x + 4.0) / y) - ((x / y) * z)))
function code(x, y, z)
	return abs(Float64(Float64(Float64(x + 4.0) / y) - Float64(Float64(x / y) * z)))
end
function tmp = code(x, y, z)
	tmp = abs((((x + 4.0) / y) - ((x / y) * z)));
end
code[x_, y_, z_] := N[Abs[N[(N[(N[(x + 4.0), $MachinePrecision] / y), $MachinePrecision] - N[(N[(x / y), $MachinePrecision] * z), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
\left|\frac{x + 4}{y} - \frac{x}{y} \cdot z\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 7 alternatives:

AlternativeAccuracySpeedup
The accuracy (vertical axis) and speed (horizontal axis) of each alternatives. Up and to the right is better. The red square shows the initial program, and each blue circle shows an alternative.The line shows the best available speed-accuracy tradeoffs.

Initial Program: 91.5% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \left|\frac{x + 4}{y} - \frac{x}{y} \cdot z\right| \end{array} \]
(FPCore (x y z) :precision binary64 (fabs (- (/ (+ x 4.0) y) (* (/ x y) z))))
double code(double x, double y, double z) {
	return fabs((((x + 4.0) / y) - ((x / y) * z)));
}
real(8) function code(x, y, z)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    code = abs((((x + 4.0d0) / y) - ((x / y) * z)))
end function
public static double code(double x, double y, double z) {
	return Math.abs((((x + 4.0) / y) - ((x / y) * z)));
}
def code(x, y, z):
	return math.fabs((((x + 4.0) / y) - ((x / y) * z)))
function code(x, y, z)
	return abs(Float64(Float64(Float64(x + 4.0) / y) - Float64(Float64(x / y) * z)))
end
function tmp = code(x, y, z)
	tmp = abs((((x + 4.0) / y) - ((x / y) * z)));
end
code[x_, y_, z_] := N[Abs[N[(N[(N[(x + 4.0), $MachinePrecision] / y), $MachinePrecision] - N[(N[(x / y), $MachinePrecision] * z), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}

\\
\left|\frac{x + 4}{y} - \frac{x}{y} \cdot z\right|
\end{array}

Alternative 1: 99.7% accurate, 0.9× speedup?

\[\begin{array}{l} y_m = \left|y\right| \\ \begin{array}{l} \mathbf{if}\;y\_m \leq 1.38 \cdot 10^{+51}:\\ \;\;\;\;\left|\frac{\mathsf{fma}\left(z, x, -4 - x\right)}{y\_m}\right|\\ \mathbf{else}:\\ \;\;\;\;\left|\mathsf{fma}\left(-x, \frac{z}{y\_m}, \frac{4 + x}{y\_m}\right)\right|\\ \end{array} \end{array} \]
y_m = (fabs.f64 y)
(FPCore (x y_m z)
 :precision binary64
 (if (<= y_m 1.38e+51)
   (fabs (/ (fma z x (- -4.0 x)) y_m))
   (fabs (fma (- x) (/ z y_m) (/ (+ 4.0 x) y_m)))))
y_m = fabs(y);
double code(double x, double y_m, double z) {
	double tmp;
	if (y_m <= 1.38e+51) {
		tmp = fabs((fma(z, x, (-4.0 - x)) / y_m));
	} else {
		tmp = fabs(fma(-x, (z / y_m), ((4.0 + x) / y_m)));
	}
	return tmp;
}
y_m = abs(y)
function code(x, y_m, z)
	tmp = 0.0
	if (y_m <= 1.38e+51)
		tmp = abs(Float64(fma(z, x, Float64(-4.0 - x)) / y_m));
	else
		tmp = abs(fma(Float64(-x), Float64(z / y_m), Float64(Float64(4.0 + x) / y_m)));
	end
	return tmp
end
y_m = N[Abs[y], $MachinePrecision]
code[x_, y$95$m_, z_] := If[LessEqual[y$95$m, 1.38e+51], N[Abs[N[(N[(z * x + N[(-4.0 - x), $MachinePrecision]), $MachinePrecision] / y$95$m), $MachinePrecision]], $MachinePrecision], N[Abs[N[((-x) * N[(z / y$95$m), $MachinePrecision] + N[(N[(4.0 + x), $MachinePrecision] / y$95$m), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]]
\begin{array}{l}
y_m = \left|y\right|

\\
\begin{array}{l}
\mathbf{if}\;y\_m \leq 1.38 \cdot 10^{+51}:\\
\;\;\;\;\left|\frac{\mathsf{fma}\left(z, x, -4 - x\right)}{y\_m}\right|\\

\mathbf{else}:\\
\;\;\;\;\left|\mathsf{fma}\left(-x, \frac{z}{y\_m}, \frac{4 + x}{y\_m}\right)\right|\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if y < 1.38000000000000006e51

    1. Initial program 93.2%

      \[\left|\frac{x + 4}{y} - \frac{x}{y} \cdot z\right| \]
    2. Add Preprocessing
    3. Step-by-step derivation
      1. lift-fabs.f64N/A

        \[\leadsto \color{blue}{\left|\frac{x + 4}{y} - \frac{x}{y} \cdot z\right|} \]
      2. lift--.f64N/A

        \[\leadsto \left|\color{blue}{\frac{x + 4}{y} - \frac{x}{y} \cdot z}\right| \]
      3. fabs-subN/A

        \[\leadsto \color{blue}{\left|\frac{x}{y} \cdot z - \frac{x + 4}{y}\right|} \]
      4. lower-fabs.f64N/A

        \[\leadsto \color{blue}{\left|\frac{x}{y} \cdot z - \frac{x + 4}{y}\right|} \]
      5. lift-*.f64N/A

        \[\leadsto \left|\color{blue}{\frac{x}{y} \cdot z} - \frac{x + 4}{y}\right| \]
      6. lift-/.f64N/A

        \[\leadsto \left|\color{blue}{\frac{x}{y}} \cdot z - \frac{x + 4}{y}\right| \]
      7. associate-*l/N/A

        \[\leadsto \left|\color{blue}{\frac{x \cdot z}{y}} - \frac{x + 4}{y}\right| \]
      8. lift-/.f64N/A

        \[\leadsto \left|\frac{x \cdot z}{y} - \color{blue}{\frac{x + 4}{y}}\right| \]
      9. sub-divN/A

        \[\leadsto \left|\color{blue}{\frac{x \cdot z - \left(x + 4\right)}{y}}\right| \]
      10. lower-/.f64N/A

        \[\leadsto \left|\color{blue}{\frac{x \cdot z - \left(x + 4\right)}{y}}\right| \]
      11. sub-negN/A

        \[\leadsto \left|\frac{\color{blue}{x \cdot z + \left(\mathsf{neg}\left(\left(x + 4\right)\right)\right)}}{y}\right| \]
      12. *-commutativeN/A

        \[\leadsto \left|\frac{\color{blue}{z \cdot x} + \left(\mathsf{neg}\left(\left(x + 4\right)\right)\right)}{y}\right| \]
      13. lower-fma.f64N/A

        \[\leadsto \left|\frac{\color{blue}{\mathsf{fma}\left(z, x, \mathsf{neg}\left(\left(x + 4\right)\right)\right)}}{y}\right| \]
      14. lift-+.f64N/A

        \[\leadsto \left|\frac{\mathsf{fma}\left(z, x, \mathsf{neg}\left(\color{blue}{\left(x + 4\right)}\right)\right)}{y}\right| \]
      15. +-commutativeN/A

        \[\leadsto \left|\frac{\mathsf{fma}\left(z, x, \mathsf{neg}\left(\color{blue}{\left(4 + x\right)}\right)\right)}{y}\right| \]
      16. distribute-neg-inN/A

        \[\leadsto \left|\frac{\mathsf{fma}\left(z, x, \color{blue}{\left(\mathsf{neg}\left(4\right)\right) + \left(\mathsf{neg}\left(x\right)\right)}\right)}{y}\right| \]
      17. unsub-negN/A

        \[\leadsto \left|\frac{\mathsf{fma}\left(z, x, \color{blue}{\left(\mathsf{neg}\left(4\right)\right) - x}\right)}{y}\right| \]
      18. lower--.f64N/A

        \[\leadsto \left|\frac{\mathsf{fma}\left(z, x, \color{blue}{\left(\mathsf{neg}\left(4\right)\right) - x}\right)}{y}\right| \]
      19. metadata-eval98.4

        \[\leadsto \left|\frac{\mathsf{fma}\left(z, x, \color{blue}{-4} - x\right)}{y}\right| \]
    4. Applied rewrites98.4%

      \[\leadsto \color{blue}{\left|\frac{\mathsf{fma}\left(z, x, -4 - x\right)}{y}\right|} \]

    if 1.38000000000000006e51 < y

    1. Initial program 98.3%

      \[\left|\frac{x + 4}{y} - \frac{x}{y} \cdot z\right| \]
    2. Add Preprocessing
    3. Step-by-step derivation
      1. lift--.f64N/A

        \[\leadsto \left|\color{blue}{\frac{x + 4}{y} - \frac{x}{y} \cdot z}\right| \]
      2. sub-negN/A

        \[\leadsto \left|\color{blue}{\frac{x + 4}{y} + \left(\mathsf{neg}\left(\frac{x}{y} \cdot z\right)\right)}\right| \]
      3. +-commutativeN/A

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

        \[\leadsto \left|\left(\mathsf{neg}\left(\color{blue}{\frac{x}{y} \cdot z}\right)\right) + \frac{x + 4}{y}\right| \]
      5. lift-/.f64N/A

        \[\leadsto \left|\left(\mathsf{neg}\left(\color{blue}{\frac{x}{y}} \cdot z\right)\right) + \frac{x + 4}{y}\right| \]
      6. associate-*l/N/A

        \[\leadsto \left|\left(\mathsf{neg}\left(\color{blue}{\frac{x \cdot z}{y}}\right)\right) + \frac{x + 4}{y}\right| \]
      7. associate-/l*N/A

        \[\leadsto \left|\left(\mathsf{neg}\left(\color{blue}{x \cdot \frac{z}{y}}\right)\right) + \frac{x + 4}{y}\right| \]
      8. distribute-lft-neg-inN/A

        \[\leadsto \left|\color{blue}{\left(\mathsf{neg}\left(x\right)\right) \cdot \frac{z}{y}} + \frac{x + 4}{y}\right| \]
      9. lower-fma.f64N/A

        \[\leadsto \left|\color{blue}{\mathsf{fma}\left(\mathsf{neg}\left(x\right), \frac{z}{y}, \frac{x + 4}{y}\right)}\right| \]
      10. lower-neg.f64N/A

        \[\leadsto \left|\mathsf{fma}\left(\color{blue}{-x}, \frac{z}{y}, \frac{x + 4}{y}\right)\right| \]
      11. lower-/.f6499.9

        \[\leadsto \left|\mathsf{fma}\left(-x, \color{blue}{\frac{z}{y}}, \frac{x + 4}{y}\right)\right| \]
      12. lift-+.f64N/A

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

        \[\leadsto \left|\mathsf{fma}\left(-x, \frac{z}{y}, \frac{\color{blue}{4 + x}}{y}\right)\right| \]
      14. lower-+.f6499.9

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

      \[\leadsto \left|\color{blue}{\mathsf{fma}\left(-x, \frac{z}{y}, \frac{4 + x}{y}\right)}\right| \]
  3. Recombined 2 regimes into one program.
  4. Add Preprocessing

Alternative 2: 98.8% accurate, 1.1× speedup?

\[\begin{array}{l} y_m = \left|y\right| \\ \begin{array}{l} \mathbf{if}\;x \leq -500 \lor \neg \left(x \leq 4.2\right):\\ \;\;\;\;\left|\left(1 - z\right) \cdot \frac{x}{y\_m}\right|\\ \mathbf{else}:\\ \;\;\;\;\left|\frac{4 - z \cdot x}{y\_m}\right|\\ \end{array} \end{array} \]
y_m = (fabs.f64 y)
(FPCore (x y_m z)
 :precision binary64
 (if (or (<= x -500.0) (not (<= x 4.2)))
   (fabs (* (- 1.0 z) (/ x y_m)))
   (fabs (/ (- 4.0 (* z x)) y_m))))
y_m = fabs(y);
double code(double x, double y_m, double z) {
	double tmp;
	if ((x <= -500.0) || !(x <= 4.2)) {
		tmp = fabs(((1.0 - z) * (x / y_m)));
	} else {
		tmp = fabs(((4.0 - (z * x)) / y_m));
	}
	return tmp;
}
y_m = abs(y)
real(8) function code(x, y_m, z)
    real(8), intent (in) :: x
    real(8), intent (in) :: y_m
    real(8), intent (in) :: z
    real(8) :: tmp
    if ((x <= (-500.0d0)) .or. (.not. (x <= 4.2d0))) then
        tmp = abs(((1.0d0 - z) * (x / y_m)))
    else
        tmp = abs(((4.0d0 - (z * x)) / y_m))
    end if
    code = tmp
end function
y_m = Math.abs(y);
public static double code(double x, double y_m, double z) {
	double tmp;
	if ((x <= -500.0) || !(x <= 4.2)) {
		tmp = Math.abs(((1.0 - z) * (x / y_m)));
	} else {
		tmp = Math.abs(((4.0 - (z * x)) / y_m));
	}
	return tmp;
}
y_m = math.fabs(y)
def code(x, y_m, z):
	tmp = 0
	if (x <= -500.0) or not (x <= 4.2):
		tmp = math.fabs(((1.0 - z) * (x / y_m)))
	else:
		tmp = math.fabs(((4.0 - (z * x)) / y_m))
	return tmp
y_m = abs(y)
function code(x, y_m, z)
	tmp = 0.0
	if ((x <= -500.0) || !(x <= 4.2))
		tmp = abs(Float64(Float64(1.0 - z) * Float64(x / y_m)));
	else
		tmp = abs(Float64(Float64(4.0 - Float64(z * x)) / y_m));
	end
	return tmp
end
y_m = abs(y);
function tmp_2 = code(x, y_m, z)
	tmp = 0.0;
	if ((x <= -500.0) || ~((x <= 4.2)))
		tmp = abs(((1.0 - z) * (x / y_m)));
	else
		tmp = abs(((4.0 - (z * x)) / y_m));
	end
	tmp_2 = tmp;
end
y_m = N[Abs[y], $MachinePrecision]
code[x_, y$95$m_, z_] := If[Or[LessEqual[x, -500.0], N[Not[LessEqual[x, 4.2]], $MachinePrecision]], N[Abs[N[(N[(1.0 - z), $MachinePrecision] * N[(x / y$95$m), $MachinePrecision]), $MachinePrecision]], $MachinePrecision], N[Abs[N[(N[(4.0 - N[(z * x), $MachinePrecision]), $MachinePrecision] / y$95$m), $MachinePrecision]], $MachinePrecision]]
\begin{array}{l}
y_m = \left|y\right|

\\
\begin{array}{l}
\mathbf{if}\;x \leq -500 \lor \neg \left(x \leq 4.2\right):\\
\;\;\;\;\left|\left(1 - z\right) \cdot \frac{x}{y\_m}\right|\\

\mathbf{else}:\\
\;\;\;\;\left|\frac{4 - z \cdot x}{y\_m}\right|\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if x < -500 or 4.20000000000000018 < x

    1. Initial program 91.8%

      \[\left|\frac{x + 4}{y} - \frac{x}{y} \cdot z\right| \]
    2. Add Preprocessing
    3. Taylor expanded in x around inf

      \[\leadsto \left|\color{blue}{x \cdot \left(\frac{1}{y} - \frac{z}{y}\right)}\right| \]
    4. Step-by-step derivation
      1. distribute-lft-out--N/A

        \[\leadsto \left|\color{blue}{x \cdot \frac{1}{y} - x \cdot \frac{z}{y}}\right| \]
      2. associate-*r/N/A

        \[\leadsto \left|\color{blue}{\frac{x \cdot 1}{y}} - x \cdot \frac{z}{y}\right| \]
      3. *-rgt-identityN/A

        \[\leadsto \left|\frac{\color{blue}{x}}{y} - x \cdot \frac{z}{y}\right| \]
      4. associate-/l*N/A

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

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

        \[\leadsto \left|\frac{x}{y} - \color{blue}{z \cdot \frac{x}{y}}\right| \]
      7. cancel-sign-sub-invN/A

        \[\leadsto \left|\color{blue}{\frac{x}{y} + \left(\mathsf{neg}\left(z\right)\right) \cdot \frac{x}{y}}\right| \]
      8. mul-1-negN/A

        \[\leadsto \left|\frac{x}{y} + \color{blue}{\left(-1 \cdot z\right)} \cdot \frac{x}{y}\right| \]
      9. distribute-rgt1-inN/A

        \[\leadsto \left|\color{blue}{\left(-1 \cdot z + 1\right) \cdot \frac{x}{y}}\right| \]
      10. lower-*.f64N/A

        \[\leadsto \left|\color{blue}{\left(-1 \cdot z + 1\right) \cdot \frac{x}{y}}\right| \]
      11. +-commutativeN/A

        \[\leadsto \left|\color{blue}{\left(1 + -1 \cdot z\right)} \cdot \frac{x}{y}\right| \]
      12. mul-1-negN/A

        \[\leadsto \left|\left(1 + \color{blue}{\left(\mathsf{neg}\left(z\right)\right)}\right) \cdot \frac{x}{y}\right| \]
      13. sub-negN/A

        \[\leadsto \left|\color{blue}{\left(1 - z\right)} \cdot \frac{x}{y}\right| \]
      14. lower--.f64N/A

        \[\leadsto \left|\color{blue}{\left(1 - z\right)} \cdot \frac{x}{y}\right| \]
      15. lower-/.f6499.0

        \[\leadsto \left|\left(1 - z\right) \cdot \color{blue}{\frac{x}{y}}\right| \]
    5. Applied rewrites99.0%

      \[\leadsto \left|\color{blue}{\left(1 - z\right) \cdot \frac{x}{y}}\right| \]

    if -500 < x < 4.20000000000000018

    1. Initial program 97.0%

      \[\left|\frac{x + 4}{y} - \frac{x}{y} \cdot z\right| \]
    2. Add Preprocessing
    3. Taylor expanded in x around 0

      \[\leadsto \left|\frac{\color{blue}{4}}{y} - \frac{x}{y} \cdot z\right| \]
    4. Step-by-step derivation
      1. Applied rewrites95.4%

        \[\leadsto \left|\frac{\color{blue}{4}}{y} - \frac{x}{y} \cdot z\right| \]
      2. Step-by-step derivation
        1. lift-fabs.f64N/A

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

          \[\leadsto \left|\color{blue}{\frac{4}{y} - \frac{x}{y} \cdot z}\right| \]
        3. fabs-subN/A

          \[\leadsto \color{blue}{\left|\frac{x}{y} \cdot z - \frac{4}{y}\right|} \]
        4. lower-fabs.f64N/A

          \[\leadsto \color{blue}{\left|\frac{x}{y} \cdot z - \frac{4}{y}\right|} \]
        5. lift-*.f64N/A

          \[\leadsto \left|\color{blue}{\frac{x}{y} \cdot z} - \frac{4}{y}\right| \]
        6. lift-/.f64N/A

          \[\leadsto \left|\color{blue}{\frac{x}{y}} \cdot z - \frac{4}{y}\right| \]
        7. associate-*l/N/A

          \[\leadsto \left|\color{blue}{\frac{x \cdot z}{y}} - \frac{4}{y}\right| \]
        8. *-commutativeN/A

          \[\leadsto \left|\frac{\color{blue}{z \cdot x}}{y} - \frac{4}{y}\right| \]
        9. lift-/.f64N/A

          \[\leadsto \left|\frac{z \cdot x}{y} - \color{blue}{\frac{4}{y}}\right| \]
        10. sub-divN/A

          \[\leadsto \left|\color{blue}{\frac{z \cdot x - 4}{y}}\right| \]
        11. lower-/.f64N/A

          \[\leadsto \left|\color{blue}{\frac{z \cdot x - 4}{y}}\right| \]
        12. lower--.f64N/A

          \[\leadsto \left|\frac{\color{blue}{z \cdot x - 4}}{y}\right| \]
        13. lower-*.f6498.3

          \[\leadsto \left|\frac{\color{blue}{z \cdot x} - 4}{y}\right| \]
      3. Applied rewrites98.3%

        \[\leadsto \color{blue}{\left|\frac{z \cdot x - 4}{y}\right|} \]
    5. Recombined 2 regimes into one program.
    6. Final simplification98.6%

      \[\leadsto \begin{array}{l} \mathbf{if}\;x \leq -500 \lor \neg \left(x \leq 4.2\right):\\ \;\;\;\;\left|\left(1 - z\right) \cdot \frac{x}{y}\right|\\ \mathbf{else}:\\ \;\;\;\;\left|\frac{4 - z \cdot x}{y}\right|\\ \end{array} \]
    7. Add Preprocessing

    Alternative 3: 85.0% accurate, 1.2× speedup?

    \[\begin{array}{l} y_m = \left|y\right| \\ \begin{array}{l} \mathbf{if}\;z \leq -2.15 \cdot 10^{+21} \lor \neg \left(z \leq 5.1 \cdot 10^{+20}\right):\\ \;\;\;\;\left|\frac{x}{y\_m} \cdot z\right|\\ \mathbf{else}:\\ \;\;\;\;\left|\frac{-4 - x}{y\_m}\right|\\ \end{array} \end{array} \]
    y_m = (fabs.f64 y)
    (FPCore (x y_m z)
     :precision binary64
     (if (or (<= z -2.15e+21) (not (<= z 5.1e+20)))
       (fabs (* (/ x y_m) z))
       (fabs (/ (- -4.0 x) y_m))))
    y_m = fabs(y);
    double code(double x, double y_m, double z) {
    	double tmp;
    	if ((z <= -2.15e+21) || !(z <= 5.1e+20)) {
    		tmp = fabs(((x / y_m) * z));
    	} else {
    		tmp = fabs(((-4.0 - x) / y_m));
    	}
    	return tmp;
    }
    
    y_m = abs(y)
    real(8) function code(x, y_m, z)
        real(8), intent (in) :: x
        real(8), intent (in) :: y_m
        real(8), intent (in) :: z
        real(8) :: tmp
        if ((z <= (-2.15d+21)) .or. (.not. (z <= 5.1d+20))) then
            tmp = abs(((x / y_m) * z))
        else
            tmp = abs((((-4.0d0) - x) / y_m))
        end if
        code = tmp
    end function
    
    y_m = Math.abs(y);
    public static double code(double x, double y_m, double z) {
    	double tmp;
    	if ((z <= -2.15e+21) || !(z <= 5.1e+20)) {
    		tmp = Math.abs(((x / y_m) * z));
    	} else {
    		tmp = Math.abs(((-4.0 - x) / y_m));
    	}
    	return tmp;
    }
    
    y_m = math.fabs(y)
    def code(x, y_m, z):
    	tmp = 0
    	if (z <= -2.15e+21) or not (z <= 5.1e+20):
    		tmp = math.fabs(((x / y_m) * z))
    	else:
    		tmp = math.fabs(((-4.0 - x) / y_m))
    	return tmp
    
    y_m = abs(y)
    function code(x, y_m, z)
    	tmp = 0.0
    	if ((z <= -2.15e+21) || !(z <= 5.1e+20))
    		tmp = abs(Float64(Float64(x / y_m) * z));
    	else
    		tmp = abs(Float64(Float64(-4.0 - x) / y_m));
    	end
    	return tmp
    end
    
    y_m = abs(y);
    function tmp_2 = code(x, y_m, z)
    	tmp = 0.0;
    	if ((z <= -2.15e+21) || ~((z <= 5.1e+20)))
    		tmp = abs(((x / y_m) * z));
    	else
    		tmp = abs(((-4.0 - x) / y_m));
    	end
    	tmp_2 = tmp;
    end
    
    y_m = N[Abs[y], $MachinePrecision]
    code[x_, y$95$m_, z_] := If[Or[LessEqual[z, -2.15e+21], N[Not[LessEqual[z, 5.1e+20]], $MachinePrecision]], N[Abs[N[(N[(x / y$95$m), $MachinePrecision] * z), $MachinePrecision]], $MachinePrecision], N[Abs[N[(N[(-4.0 - x), $MachinePrecision] / y$95$m), $MachinePrecision]], $MachinePrecision]]
    
    \begin{array}{l}
    y_m = \left|y\right|
    
    \\
    \begin{array}{l}
    \mathbf{if}\;z \leq -2.15 \cdot 10^{+21} \lor \neg \left(z \leq 5.1 \cdot 10^{+20}\right):\\
    \;\;\;\;\left|\frac{x}{y\_m} \cdot z\right|\\
    
    \mathbf{else}:\\
    \;\;\;\;\left|\frac{-4 - x}{y\_m}\right|\\
    
    
    \end{array}
    \end{array}
    
    Derivation
    1. Split input into 2 regimes
    2. if z < -2.15e21 or 5.1e20 < z

      1. Initial program 91.9%

        \[\left|\frac{x + 4}{y} - \frac{x}{y} \cdot z\right| \]
      2. Add Preprocessing
      3. Step-by-step derivation
        1. lift-fabs.f64N/A

          \[\leadsto \color{blue}{\left|\frac{x + 4}{y} - \frac{x}{y} \cdot z\right|} \]
        2. lift--.f64N/A

          \[\leadsto \left|\color{blue}{\frac{x + 4}{y} - \frac{x}{y} \cdot z}\right| \]
        3. fabs-subN/A

          \[\leadsto \color{blue}{\left|\frac{x}{y} \cdot z - \frac{x + 4}{y}\right|} \]
        4. lower-fabs.f64N/A

          \[\leadsto \color{blue}{\left|\frac{x}{y} \cdot z - \frac{x + 4}{y}\right|} \]
        5. lift-*.f64N/A

          \[\leadsto \left|\color{blue}{\frac{x}{y} \cdot z} - \frac{x + 4}{y}\right| \]
        6. lift-/.f64N/A

          \[\leadsto \left|\color{blue}{\frac{x}{y}} \cdot z - \frac{x + 4}{y}\right| \]
        7. associate-*l/N/A

          \[\leadsto \left|\color{blue}{\frac{x \cdot z}{y}} - \frac{x + 4}{y}\right| \]
        8. lift-/.f64N/A

          \[\leadsto \left|\frac{x \cdot z}{y} - \color{blue}{\frac{x + 4}{y}}\right| \]
        9. sub-divN/A

          \[\leadsto \left|\color{blue}{\frac{x \cdot z - \left(x + 4\right)}{y}}\right| \]
        10. lower-/.f64N/A

          \[\leadsto \left|\color{blue}{\frac{x \cdot z - \left(x + 4\right)}{y}}\right| \]
        11. sub-negN/A

          \[\leadsto \left|\frac{\color{blue}{x \cdot z + \left(\mathsf{neg}\left(\left(x + 4\right)\right)\right)}}{y}\right| \]
        12. *-commutativeN/A

          \[\leadsto \left|\frac{\color{blue}{z \cdot x} + \left(\mathsf{neg}\left(\left(x + 4\right)\right)\right)}{y}\right| \]
        13. lower-fma.f64N/A

          \[\leadsto \left|\frac{\color{blue}{\mathsf{fma}\left(z, x, \mathsf{neg}\left(\left(x + 4\right)\right)\right)}}{y}\right| \]
        14. lift-+.f64N/A

          \[\leadsto \left|\frac{\mathsf{fma}\left(z, x, \mathsf{neg}\left(\color{blue}{\left(x + 4\right)}\right)\right)}{y}\right| \]
        15. +-commutativeN/A

          \[\leadsto \left|\frac{\mathsf{fma}\left(z, x, \mathsf{neg}\left(\color{blue}{\left(4 + x\right)}\right)\right)}{y}\right| \]
        16. distribute-neg-inN/A

          \[\leadsto \left|\frac{\mathsf{fma}\left(z, x, \color{blue}{\left(\mathsf{neg}\left(4\right)\right) + \left(\mathsf{neg}\left(x\right)\right)}\right)}{y}\right| \]
        17. unsub-negN/A

          \[\leadsto \left|\frac{\mathsf{fma}\left(z, x, \color{blue}{\left(\mathsf{neg}\left(4\right)\right) - x}\right)}{y}\right| \]
        18. lower--.f64N/A

          \[\leadsto \left|\frac{\mathsf{fma}\left(z, x, \color{blue}{\left(\mathsf{neg}\left(4\right)\right) - x}\right)}{y}\right| \]
        19. metadata-eval93.7

          \[\leadsto \left|\frac{\mathsf{fma}\left(z, x, \color{blue}{-4} - x\right)}{y}\right| \]
      4. Applied rewrites93.7%

        \[\leadsto \color{blue}{\left|\frac{\mathsf{fma}\left(z, x, -4 - x\right)}{y}\right|} \]
      5. Taylor expanded in z around inf

        \[\leadsto \left|\color{blue}{\frac{x \cdot z}{y}}\right| \]
      6. Step-by-step derivation
        1. associate-/l*N/A

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

          \[\leadsto \left|\color{blue}{\frac{z}{y} \cdot x}\right| \]
        3. lower-*.f64N/A

          \[\leadsto \left|\color{blue}{\frac{z}{y} \cdot x}\right| \]
        4. lower-/.f6474.7

          \[\leadsto \left|\color{blue}{\frac{z}{y}} \cdot x\right| \]
      7. Applied rewrites74.7%

        \[\leadsto \left|\color{blue}{\frac{z}{y} \cdot x}\right| \]
      8. Step-by-step derivation
        1. Applied rewrites78.9%

          \[\leadsto \left|\frac{x}{y} \cdot \color{blue}{z}\right| \]

        if -2.15e21 < z < 5.1e20

        1. Initial program 96.9%

          \[\left|\frac{x + 4}{y} - \frac{x}{y} \cdot z\right| \]
        2. Add Preprocessing
        3. Step-by-step derivation
          1. lift-fabs.f64N/A

            \[\leadsto \color{blue}{\left|\frac{x + 4}{y} - \frac{x}{y} \cdot z\right|} \]
          2. lift--.f64N/A

            \[\leadsto \left|\color{blue}{\frac{x + 4}{y} - \frac{x}{y} \cdot z}\right| \]
          3. fabs-subN/A

            \[\leadsto \color{blue}{\left|\frac{x}{y} \cdot z - \frac{x + 4}{y}\right|} \]
          4. lower-fabs.f64N/A

            \[\leadsto \color{blue}{\left|\frac{x}{y} \cdot z - \frac{x + 4}{y}\right|} \]
          5. lift-*.f64N/A

            \[\leadsto \left|\color{blue}{\frac{x}{y} \cdot z} - \frac{x + 4}{y}\right| \]
          6. lift-/.f64N/A

            \[\leadsto \left|\color{blue}{\frac{x}{y}} \cdot z - \frac{x + 4}{y}\right| \]
          7. associate-*l/N/A

            \[\leadsto \left|\color{blue}{\frac{x \cdot z}{y}} - \frac{x + 4}{y}\right| \]
          8. lift-/.f64N/A

            \[\leadsto \left|\frac{x \cdot z}{y} - \color{blue}{\frac{x + 4}{y}}\right| \]
          9. sub-divN/A

            \[\leadsto \left|\color{blue}{\frac{x \cdot z - \left(x + 4\right)}{y}}\right| \]
          10. lower-/.f64N/A

            \[\leadsto \left|\color{blue}{\frac{x \cdot z - \left(x + 4\right)}{y}}\right| \]
          11. sub-negN/A

            \[\leadsto \left|\frac{\color{blue}{x \cdot z + \left(\mathsf{neg}\left(\left(x + 4\right)\right)\right)}}{y}\right| \]
          12. *-commutativeN/A

            \[\leadsto \left|\frac{\color{blue}{z \cdot x} + \left(\mathsf{neg}\left(\left(x + 4\right)\right)\right)}{y}\right| \]
          13. lower-fma.f64N/A

            \[\leadsto \left|\frac{\color{blue}{\mathsf{fma}\left(z, x, \mathsf{neg}\left(\left(x + 4\right)\right)\right)}}{y}\right| \]
          14. lift-+.f64N/A

            \[\leadsto \left|\frac{\mathsf{fma}\left(z, x, \mathsf{neg}\left(\color{blue}{\left(x + 4\right)}\right)\right)}{y}\right| \]
          15. +-commutativeN/A

            \[\leadsto \left|\frac{\mathsf{fma}\left(z, x, \mathsf{neg}\left(\color{blue}{\left(4 + x\right)}\right)\right)}{y}\right| \]
          16. distribute-neg-inN/A

            \[\leadsto \left|\frac{\mathsf{fma}\left(z, x, \color{blue}{\left(\mathsf{neg}\left(4\right)\right) + \left(\mathsf{neg}\left(x\right)\right)}\right)}{y}\right| \]
          17. unsub-negN/A

            \[\leadsto \left|\frac{\mathsf{fma}\left(z, x, \color{blue}{\left(\mathsf{neg}\left(4\right)\right) - x}\right)}{y}\right| \]
          18. lower--.f64N/A

            \[\leadsto \left|\frac{\mathsf{fma}\left(z, x, \color{blue}{\left(\mathsf{neg}\left(4\right)\right) - x}\right)}{y}\right| \]
          19. metadata-eval100.0

            \[\leadsto \left|\frac{\mathsf{fma}\left(z, x, \color{blue}{-4} - x\right)}{y}\right| \]
        4. Applied rewrites100.0%

          \[\leadsto \color{blue}{\left|\frac{\mathsf{fma}\left(z, x, -4 - x\right)}{y}\right|} \]
        5. Taylor expanded in z around 0

          \[\leadsto \left|\frac{\color{blue}{-1 \cdot \left(4 + x\right)}}{y}\right| \]
        6. Step-by-step derivation
          1. distribute-lft-inN/A

            \[\leadsto \left|\frac{\color{blue}{-1 \cdot 4 + -1 \cdot x}}{y}\right| \]
          2. metadata-evalN/A

            \[\leadsto \left|\frac{\color{blue}{-4} + -1 \cdot x}{y}\right| \]
          3. mul-1-negN/A

            \[\leadsto \left|\frac{-4 + \color{blue}{\left(\mathsf{neg}\left(x\right)\right)}}{y}\right| \]
          4. unsub-negN/A

            \[\leadsto \left|\frac{\color{blue}{-4 - x}}{y}\right| \]
          5. lower--.f6497.0

            \[\leadsto \left|\frac{\color{blue}{-4 - x}}{y}\right| \]
        7. Applied rewrites97.0%

          \[\leadsto \left|\frac{\color{blue}{-4 - x}}{y}\right| \]
      9. Recombined 2 regimes into one program.
      10. Final simplification88.2%

        \[\leadsto \begin{array}{l} \mathbf{if}\;z \leq -2.15 \cdot 10^{+21} \lor \neg \left(z \leq 5.1 \cdot 10^{+20}\right):\\ \;\;\;\;\left|\frac{x}{y} \cdot z\right|\\ \mathbf{else}:\\ \;\;\;\;\left|\frac{-4 - x}{y}\right|\\ \end{array} \]
      11. Add Preprocessing

      Alternative 4: 69.5% accurate, 1.4× speedup?

      \[\begin{array}{l} y_m = \left|y\right| \\ \begin{array}{l} \mathbf{if}\;x \leq -1.5 \lor \neg \left(x \leq 4\right):\\ \;\;\;\;\left|\frac{x}{y\_m}\right|\\ \mathbf{else}:\\ \;\;\;\;\left|\frac{4}{y\_m}\right|\\ \end{array} \end{array} \]
      y_m = (fabs.f64 y)
      (FPCore (x y_m z)
       :precision binary64
       (if (or (<= x -1.5) (not (<= x 4.0))) (fabs (/ x y_m)) (fabs (/ 4.0 y_m))))
      y_m = fabs(y);
      double code(double x, double y_m, double z) {
      	double tmp;
      	if ((x <= -1.5) || !(x <= 4.0)) {
      		tmp = fabs((x / y_m));
      	} else {
      		tmp = fabs((4.0 / y_m));
      	}
      	return tmp;
      }
      
      y_m = abs(y)
      real(8) function code(x, y_m, z)
          real(8), intent (in) :: x
          real(8), intent (in) :: y_m
          real(8), intent (in) :: z
          real(8) :: tmp
          if ((x <= (-1.5d0)) .or. (.not. (x <= 4.0d0))) then
              tmp = abs((x / y_m))
          else
              tmp = abs((4.0d0 / y_m))
          end if
          code = tmp
      end function
      
      y_m = Math.abs(y);
      public static double code(double x, double y_m, double z) {
      	double tmp;
      	if ((x <= -1.5) || !(x <= 4.0)) {
      		tmp = Math.abs((x / y_m));
      	} else {
      		tmp = Math.abs((4.0 / y_m));
      	}
      	return tmp;
      }
      
      y_m = math.fabs(y)
      def code(x, y_m, z):
      	tmp = 0
      	if (x <= -1.5) or not (x <= 4.0):
      		tmp = math.fabs((x / y_m))
      	else:
      		tmp = math.fabs((4.0 / y_m))
      	return tmp
      
      y_m = abs(y)
      function code(x, y_m, z)
      	tmp = 0.0
      	if ((x <= -1.5) || !(x <= 4.0))
      		tmp = abs(Float64(x / y_m));
      	else
      		tmp = abs(Float64(4.0 / y_m));
      	end
      	return tmp
      end
      
      y_m = abs(y);
      function tmp_2 = code(x, y_m, z)
      	tmp = 0.0;
      	if ((x <= -1.5) || ~((x <= 4.0)))
      		tmp = abs((x / y_m));
      	else
      		tmp = abs((4.0 / y_m));
      	end
      	tmp_2 = tmp;
      end
      
      y_m = N[Abs[y], $MachinePrecision]
      code[x_, y$95$m_, z_] := If[Or[LessEqual[x, -1.5], N[Not[LessEqual[x, 4.0]], $MachinePrecision]], N[Abs[N[(x / y$95$m), $MachinePrecision]], $MachinePrecision], N[Abs[N[(4.0 / y$95$m), $MachinePrecision]], $MachinePrecision]]
      
      \begin{array}{l}
      y_m = \left|y\right|
      
      \\
      \begin{array}{l}
      \mathbf{if}\;x \leq -1.5 \lor \neg \left(x \leq 4\right):\\
      \;\;\;\;\left|\frac{x}{y\_m}\right|\\
      
      \mathbf{else}:\\
      \;\;\;\;\left|\frac{4}{y\_m}\right|\\
      
      
      \end{array}
      \end{array}
      
      Derivation
      1. Split input into 2 regimes
      2. if x < -1.5 or 4 < x

        1. Initial program 91.9%

          \[\left|\frac{x + 4}{y} - \frac{x}{y} \cdot z\right| \]
        2. Add Preprocessing
        3. Taylor expanded in x around inf

          \[\leadsto \left|\color{blue}{x \cdot \left(\frac{1}{y} - \frac{z}{y}\right)}\right| \]
        4. Step-by-step derivation
          1. distribute-lft-out--N/A

            \[\leadsto \left|\color{blue}{x \cdot \frac{1}{y} - x \cdot \frac{z}{y}}\right| \]
          2. associate-*r/N/A

            \[\leadsto \left|\color{blue}{\frac{x \cdot 1}{y}} - x \cdot \frac{z}{y}\right| \]
          3. *-rgt-identityN/A

            \[\leadsto \left|\frac{\color{blue}{x}}{y} - x \cdot \frac{z}{y}\right| \]
          4. associate-/l*N/A

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

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

            \[\leadsto \left|\frac{x}{y} - \color{blue}{z \cdot \frac{x}{y}}\right| \]
          7. cancel-sign-sub-invN/A

            \[\leadsto \left|\color{blue}{\frac{x}{y} + \left(\mathsf{neg}\left(z\right)\right) \cdot \frac{x}{y}}\right| \]
          8. mul-1-negN/A

            \[\leadsto \left|\frac{x}{y} + \color{blue}{\left(-1 \cdot z\right)} \cdot \frac{x}{y}\right| \]
          9. distribute-rgt1-inN/A

            \[\leadsto \left|\color{blue}{\left(-1 \cdot z + 1\right) \cdot \frac{x}{y}}\right| \]
          10. lower-*.f64N/A

            \[\leadsto \left|\color{blue}{\left(-1 \cdot z + 1\right) \cdot \frac{x}{y}}\right| \]
          11. +-commutativeN/A

            \[\leadsto \left|\color{blue}{\left(1 + -1 \cdot z\right)} \cdot \frac{x}{y}\right| \]
          12. mul-1-negN/A

            \[\leadsto \left|\left(1 + \color{blue}{\left(\mathsf{neg}\left(z\right)\right)}\right) \cdot \frac{x}{y}\right| \]
          13. sub-negN/A

            \[\leadsto \left|\color{blue}{\left(1 - z\right)} \cdot \frac{x}{y}\right| \]
          14. lower--.f64N/A

            \[\leadsto \left|\color{blue}{\left(1 - z\right)} \cdot \frac{x}{y}\right| \]
          15. lower-/.f6499.0

            \[\leadsto \left|\left(1 - z\right) \cdot \color{blue}{\frac{x}{y}}\right| \]
        5. Applied rewrites99.0%

          \[\leadsto \left|\color{blue}{\left(1 - z\right) \cdot \frac{x}{y}}\right| \]
        6. Taylor expanded in z around 0

          \[\leadsto \left|\frac{x}{\color{blue}{y}}\right| \]
        7. Step-by-step derivation
          1. Applied rewrites54.6%

            \[\leadsto \left|\frac{x}{\color{blue}{y}}\right| \]

          if -1.5 < x < 4

          1. Initial program 97.0%

            \[\left|\frac{x + 4}{y} - \frac{x}{y} \cdot z\right| \]
          2. Add Preprocessing
          3. Taylor expanded in x around 0

            \[\leadsto \left|\color{blue}{\frac{4}{y}}\right| \]
          4. Step-by-step derivation
            1. lower-/.f6471.1

              \[\leadsto \left|\color{blue}{\frac{4}{y}}\right| \]
          5. Applied rewrites71.1%

            \[\leadsto \left|\color{blue}{\frac{4}{y}}\right| \]
        8. Recombined 2 regimes into one program.
        9. Final simplification63.1%

          \[\leadsto \begin{array}{l} \mathbf{if}\;x \leq -1.5 \lor \neg \left(x \leq 4\right):\\ \;\;\;\;\left|\frac{x}{y}\right|\\ \mathbf{else}:\\ \;\;\;\;\left|\frac{4}{y}\right|\\ \end{array} \]
        10. Add Preprocessing

        Alternative 5: 96.0% accurate, 1.6× speedup?

        \[\begin{array}{l} y_m = \left|y\right| \\ \left|\frac{\mathsf{fma}\left(z, x, -4 - x\right)}{y\_m}\right| \end{array} \]
        y_m = (fabs.f64 y)
        (FPCore (x y_m z) :precision binary64 (fabs (/ (fma z x (- -4.0 x)) y_m)))
        y_m = fabs(y);
        double code(double x, double y_m, double z) {
        	return fabs((fma(z, x, (-4.0 - x)) / y_m));
        }
        
        y_m = abs(y)
        function code(x, y_m, z)
        	return abs(Float64(fma(z, x, Float64(-4.0 - x)) / y_m))
        end
        
        y_m = N[Abs[y], $MachinePrecision]
        code[x_, y$95$m_, z_] := N[Abs[N[(N[(z * x + N[(-4.0 - x), $MachinePrecision]), $MachinePrecision] / y$95$m), $MachinePrecision]], $MachinePrecision]
        
        \begin{array}{l}
        y_m = \left|y\right|
        
        \\
        \left|\frac{\mathsf{fma}\left(z, x, -4 - x\right)}{y\_m}\right|
        \end{array}
        
        Derivation
        1. Initial program 94.5%

          \[\left|\frac{x + 4}{y} - \frac{x}{y} \cdot z\right| \]
        2. Add Preprocessing
        3. Step-by-step derivation
          1. lift-fabs.f64N/A

            \[\leadsto \color{blue}{\left|\frac{x + 4}{y} - \frac{x}{y} \cdot z\right|} \]
          2. lift--.f64N/A

            \[\leadsto \left|\color{blue}{\frac{x + 4}{y} - \frac{x}{y} \cdot z}\right| \]
          3. fabs-subN/A

            \[\leadsto \color{blue}{\left|\frac{x}{y} \cdot z - \frac{x + 4}{y}\right|} \]
          4. lower-fabs.f64N/A

            \[\leadsto \color{blue}{\left|\frac{x}{y} \cdot z - \frac{x + 4}{y}\right|} \]
          5. lift-*.f64N/A

            \[\leadsto \left|\color{blue}{\frac{x}{y} \cdot z} - \frac{x + 4}{y}\right| \]
          6. lift-/.f64N/A

            \[\leadsto \left|\color{blue}{\frac{x}{y}} \cdot z - \frac{x + 4}{y}\right| \]
          7. associate-*l/N/A

            \[\leadsto \left|\color{blue}{\frac{x \cdot z}{y}} - \frac{x + 4}{y}\right| \]
          8. lift-/.f64N/A

            \[\leadsto \left|\frac{x \cdot z}{y} - \color{blue}{\frac{x + 4}{y}}\right| \]
          9. sub-divN/A

            \[\leadsto \left|\color{blue}{\frac{x \cdot z - \left(x + 4\right)}{y}}\right| \]
          10. lower-/.f64N/A

            \[\leadsto \left|\color{blue}{\frac{x \cdot z - \left(x + 4\right)}{y}}\right| \]
          11. sub-negN/A

            \[\leadsto \left|\frac{\color{blue}{x \cdot z + \left(\mathsf{neg}\left(\left(x + 4\right)\right)\right)}}{y}\right| \]
          12. *-commutativeN/A

            \[\leadsto \left|\frac{\color{blue}{z \cdot x} + \left(\mathsf{neg}\left(\left(x + 4\right)\right)\right)}{y}\right| \]
          13. lower-fma.f64N/A

            \[\leadsto \left|\frac{\color{blue}{\mathsf{fma}\left(z, x, \mathsf{neg}\left(\left(x + 4\right)\right)\right)}}{y}\right| \]
          14. lift-+.f64N/A

            \[\leadsto \left|\frac{\mathsf{fma}\left(z, x, \mathsf{neg}\left(\color{blue}{\left(x + 4\right)}\right)\right)}{y}\right| \]
          15. +-commutativeN/A

            \[\leadsto \left|\frac{\mathsf{fma}\left(z, x, \mathsf{neg}\left(\color{blue}{\left(4 + x\right)}\right)\right)}{y}\right| \]
          16. distribute-neg-inN/A

            \[\leadsto \left|\frac{\mathsf{fma}\left(z, x, \color{blue}{\left(\mathsf{neg}\left(4\right)\right) + \left(\mathsf{neg}\left(x\right)\right)}\right)}{y}\right| \]
          17. unsub-negN/A

            \[\leadsto \left|\frac{\mathsf{fma}\left(z, x, \color{blue}{\left(\mathsf{neg}\left(4\right)\right) - x}\right)}{y}\right| \]
          18. lower--.f64N/A

            \[\leadsto \left|\frac{\mathsf{fma}\left(z, x, \color{blue}{\left(\mathsf{neg}\left(4\right)\right) - x}\right)}{y}\right| \]
          19. metadata-eval96.9

            \[\leadsto \left|\frac{\mathsf{fma}\left(z, x, \color{blue}{-4} - x\right)}{y}\right| \]
        4. Applied rewrites96.9%

          \[\leadsto \color{blue}{\left|\frac{\mathsf{fma}\left(z, x, -4 - x\right)}{y}\right|} \]
        5. Add Preprocessing

        Alternative 6: 70.6% accurate, 2.1× speedup?

        \[\begin{array}{l} y_m = \left|y\right| \\ \left|\frac{-4 - x}{y\_m}\right| \end{array} \]
        y_m = (fabs.f64 y)
        (FPCore (x y_m z) :precision binary64 (fabs (/ (- -4.0 x) y_m)))
        y_m = fabs(y);
        double code(double x, double y_m, double z) {
        	return fabs(((-4.0 - x) / y_m));
        }
        
        y_m = abs(y)
        real(8) function code(x, y_m, z)
            real(8), intent (in) :: x
            real(8), intent (in) :: y_m
            real(8), intent (in) :: z
            code = abs((((-4.0d0) - x) / y_m))
        end function
        
        y_m = Math.abs(y);
        public static double code(double x, double y_m, double z) {
        	return Math.abs(((-4.0 - x) / y_m));
        }
        
        y_m = math.fabs(y)
        def code(x, y_m, z):
        	return math.fabs(((-4.0 - x) / y_m))
        
        y_m = abs(y)
        function code(x, y_m, z)
        	return abs(Float64(Float64(-4.0 - x) / y_m))
        end
        
        y_m = abs(y);
        function tmp = code(x, y_m, z)
        	tmp = abs(((-4.0 - x) / y_m));
        end
        
        y_m = N[Abs[y], $MachinePrecision]
        code[x_, y$95$m_, z_] := N[Abs[N[(N[(-4.0 - x), $MachinePrecision] / y$95$m), $MachinePrecision]], $MachinePrecision]
        
        \begin{array}{l}
        y_m = \left|y\right|
        
        \\
        \left|\frac{-4 - x}{y\_m}\right|
        \end{array}
        
        Derivation
        1. Initial program 94.5%

          \[\left|\frac{x + 4}{y} - \frac{x}{y} \cdot z\right| \]
        2. Add Preprocessing
        3. Step-by-step derivation
          1. lift-fabs.f64N/A

            \[\leadsto \color{blue}{\left|\frac{x + 4}{y} - \frac{x}{y} \cdot z\right|} \]
          2. lift--.f64N/A

            \[\leadsto \left|\color{blue}{\frac{x + 4}{y} - \frac{x}{y} \cdot z}\right| \]
          3. fabs-subN/A

            \[\leadsto \color{blue}{\left|\frac{x}{y} \cdot z - \frac{x + 4}{y}\right|} \]
          4. lower-fabs.f64N/A

            \[\leadsto \color{blue}{\left|\frac{x}{y} \cdot z - \frac{x + 4}{y}\right|} \]
          5. lift-*.f64N/A

            \[\leadsto \left|\color{blue}{\frac{x}{y} \cdot z} - \frac{x + 4}{y}\right| \]
          6. lift-/.f64N/A

            \[\leadsto \left|\color{blue}{\frac{x}{y}} \cdot z - \frac{x + 4}{y}\right| \]
          7. associate-*l/N/A

            \[\leadsto \left|\color{blue}{\frac{x \cdot z}{y}} - \frac{x + 4}{y}\right| \]
          8. lift-/.f64N/A

            \[\leadsto \left|\frac{x \cdot z}{y} - \color{blue}{\frac{x + 4}{y}}\right| \]
          9. sub-divN/A

            \[\leadsto \left|\color{blue}{\frac{x \cdot z - \left(x + 4\right)}{y}}\right| \]
          10. lower-/.f64N/A

            \[\leadsto \left|\color{blue}{\frac{x \cdot z - \left(x + 4\right)}{y}}\right| \]
          11. sub-negN/A

            \[\leadsto \left|\frac{\color{blue}{x \cdot z + \left(\mathsf{neg}\left(\left(x + 4\right)\right)\right)}}{y}\right| \]
          12. *-commutativeN/A

            \[\leadsto \left|\frac{\color{blue}{z \cdot x} + \left(\mathsf{neg}\left(\left(x + 4\right)\right)\right)}{y}\right| \]
          13. lower-fma.f64N/A

            \[\leadsto \left|\frac{\color{blue}{\mathsf{fma}\left(z, x, \mathsf{neg}\left(\left(x + 4\right)\right)\right)}}{y}\right| \]
          14. lift-+.f64N/A

            \[\leadsto \left|\frac{\mathsf{fma}\left(z, x, \mathsf{neg}\left(\color{blue}{\left(x + 4\right)}\right)\right)}{y}\right| \]
          15. +-commutativeN/A

            \[\leadsto \left|\frac{\mathsf{fma}\left(z, x, \mathsf{neg}\left(\color{blue}{\left(4 + x\right)}\right)\right)}{y}\right| \]
          16. distribute-neg-inN/A

            \[\leadsto \left|\frac{\mathsf{fma}\left(z, x, \color{blue}{\left(\mathsf{neg}\left(4\right)\right) + \left(\mathsf{neg}\left(x\right)\right)}\right)}{y}\right| \]
          17. unsub-negN/A

            \[\leadsto \left|\frac{\mathsf{fma}\left(z, x, \color{blue}{\left(\mathsf{neg}\left(4\right)\right) - x}\right)}{y}\right| \]
          18. lower--.f64N/A

            \[\leadsto \left|\frac{\mathsf{fma}\left(z, x, \color{blue}{\left(\mathsf{neg}\left(4\right)\right) - x}\right)}{y}\right| \]
          19. metadata-eval96.9

            \[\leadsto \left|\frac{\mathsf{fma}\left(z, x, \color{blue}{-4} - x\right)}{y}\right| \]
        4. Applied rewrites96.9%

          \[\leadsto \color{blue}{\left|\frac{\mathsf{fma}\left(z, x, -4 - x\right)}{y}\right|} \]
        5. Taylor expanded in z around 0

          \[\leadsto \left|\frac{\color{blue}{-1 \cdot \left(4 + x\right)}}{y}\right| \]
        6. Step-by-step derivation
          1. distribute-lft-inN/A

            \[\leadsto \left|\frac{\color{blue}{-1 \cdot 4 + -1 \cdot x}}{y}\right| \]
          2. metadata-evalN/A

            \[\leadsto \left|\frac{\color{blue}{-4} + -1 \cdot x}{y}\right| \]
          3. mul-1-negN/A

            \[\leadsto \left|\frac{-4 + \color{blue}{\left(\mathsf{neg}\left(x\right)\right)}}{y}\right| \]
          4. unsub-negN/A

            \[\leadsto \left|\frac{\color{blue}{-4 - x}}{y}\right| \]
          5. lower--.f6464.2

            \[\leadsto \left|\frac{\color{blue}{-4 - x}}{y}\right| \]
        7. Applied rewrites64.2%

          \[\leadsto \left|\frac{\color{blue}{-4 - x}}{y}\right| \]
        8. Add Preprocessing

        Alternative 7: 34.3% accurate, 2.6× speedup?

        \[\begin{array}{l} y_m = \left|y\right| \\ \left|\frac{x}{y\_m}\right| \end{array} \]
        y_m = (fabs.f64 y)
        (FPCore (x y_m z) :precision binary64 (fabs (/ x y_m)))
        y_m = fabs(y);
        double code(double x, double y_m, double z) {
        	return fabs((x / y_m));
        }
        
        y_m = abs(y)
        real(8) function code(x, y_m, z)
            real(8), intent (in) :: x
            real(8), intent (in) :: y_m
            real(8), intent (in) :: z
            code = abs((x / y_m))
        end function
        
        y_m = Math.abs(y);
        public static double code(double x, double y_m, double z) {
        	return Math.abs((x / y_m));
        }
        
        y_m = math.fabs(y)
        def code(x, y_m, z):
        	return math.fabs((x / y_m))
        
        y_m = abs(y)
        function code(x, y_m, z)
        	return abs(Float64(x / y_m))
        end
        
        y_m = abs(y);
        function tmp = code(x, y_m, z)
        	tmp = abs((x / y_m));
        end
        
        y_m = N[Abs[y], $MachinePrecision]
        code[x_, y$95$m_, z_] := N[Abs[N[(x / y$95$m), $MachinePrecision]], $MachinePrecision]
        
        \begin{array}{l}
        y_m = \left|y\right|
        
        \\
        \left|\frac{x}{y\_m}\right|
        \end{array}
        
        Derivation
        1. Initial program 94.5%

          \[\left|\frac{x + 4}{y} - \frac{x}{y} \cdot z\right| \]
        2. Add Preprocessing
        3. Taylor expanded in x around inf

          \[\leadsto \left|\color{blue}{x \cdot \left(\frac{1}{y} - \frac{z}{y}\right)}\right| \]
        4. Step-by-step derivation
          1. distribute-lft-out--N/A

            \[\leadsto \left|\color{blue}{x \cdot \frac{1}{y} - x \cdot \frac{z}{y}}\right| \]
          2. associate-*r/N/A

            \[\leadsto \left|\color{blue}{\frac{x \cdot 1}{y}} - x \cdot \frac{z}{y}\right| \]
          3. *-rgt-identityN/A

            \[\leadsto \left|\frac{\color{blue}{x}}{y} - x \cdot \frac{z}{y}\right| \]
          4. associate-/l*N/A

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

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

            \[\leadsto \left|\frac{x}{y} - \color{blue}{z \cdot \frac{x}{y}}\right| \]
          7. cancel-sign-sub-invN/A

            \[\leadsto \left|\color{blue}{\frac{x}{y} + \left(\mathsf{neg}\left(z\right)\right) \cdot \frac{x}{y}}\right| \]
          8. mul-1-negN/A

            \[\leadsto \left|\frac{x}{y} + \color{blue}{\left(-1 \cdot z\right)} \cdot \frac{x}{y}\right| \]
          9. distribute-rgt1-inN/A

            \[\leadsto \left|\color{blue}{\left(-1 \cdot z + 1\right) \cdot \frac{x}{y}}\right| \]
          10. lower-*.f64N/A

            \[\leadsto \left|\color{blue}{\left(-1 \cdot z + 1\right) \cdot \frac{x}{y}}\right| \]
          11. +-commutativeN/A

            \[\leadsto \left|\color{blue}{\left(1 + -1 \cdot z\right)} \cdot \frac{x}{y}\right| \]
          12. mul-1-negN/A

            \[\leadsto \left|\left(1 + \color{blue}{\left(\mathsf{neg}\left(z\right)\right)}\right) \cdot \frac{x}{y}\right| \]
          13. sub-negN/A

            \[\leadsto \left|\color{blue}{\left(1 - z\right)} \cdot \frac{x}{y}\right| \]
          14. lower--.f64N/A

            \[\leadsto \left|\color{blue}{\left(1 - z\right)} \cdot \frac{x}{y}\right| \]
          15. lower-/.f6462.8

            \[\leadsto \left|\left(1 - z\right) \cdot \color{blue}{\frac{x}{y}}\right| \]
        5. Applied rewrites62.8%

          \[\leadsto \left|\color{blue}{\left(1 - z\right) \cdot \frac{x}{y}}\right| \]
        6. Taylor expanded in z around 0

          \[\leadsto \left|\frac{x}{\color{blue}{y}}\right| \]
        7. Step-by-step derivation
          1. Applied rewrites29.5%

            \[\leadsto \left|\frac{x}{\color{blue}{y}}\right| \]
          2. Add Preprocessing

          Reproduce

          ?
          herbie shell --seed 2024299 
          (FPCore (x y z)
            :name "fabs fraction 1"
            :precision binary64
            (fabs (- (/ (+ x 4.0) y) (* (/ x y) z))))