Complex division, imag part

Percentage Accurate: 61.4% → 79.4%
Time: 6.5s
Alternatives: 7
Speedup: 1.5×

Specification

?
\[\begin{array}{l} \\ \frac{b \cdot c - a \cdot d}{c \cdot c + d \cdot d} \end{array} \]
(FPCore (a b c d)
 :precision binary64
 (/ (- (* b c) (* a d)) (+ (* c c) (* d d))))
double code(double a, double b, double c, double d) {
	return ((b * c) - (a * d)) / ((c * c) + (d * d));
}
real(8) function code(a, b, c, d)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    real(8), intent (in) :: c
    real(8), intent (in) :: d
    code = ((b * c) - (a * d)) / ((c * c) + (d * d))
end function
public static double code(double a, double b, double c, double d) {
	return ((b * c) - (a * d)) / ((c * c) + (d * d));
}
def code(a, b, c, d):
	return ((b * c) - (a * d)) / ((c * c) + (d * d))
function code(a, b, c, d)
	return Float64(Float64(Float64(b * c) - Float64(a * d)) / Float64(Float64(c * c) + Float64(d * d)))
end
function tmp = code(a, b, c, d)
	tmp = ((b * c) - (a * d)) / ((c * c) + (d * d));
end
code[a_, b_, c_, d_] := N[(N[(N[(b * c), $MachinePrecision] - N[(a * d), $MachinePrecision]), $MachinePrecision] / N[(N[(c * c), $MachinePrecision] + N[(d * d), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{b \cdot c - a \cdot d}{c \cdot c + d \cdot d}
\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: 61.4% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \frac{b \cdot c - a \cdot d}{c \cdot c + d \cdot d} \end{array} \]
(FPCore (a b c d)
 :precision binary64
 (/ (- (* b c) (* a d)) (+ (* c c) (* d d))))
double code(double a, double b, double c, double d) {
	return ((b * c) - (a * d)) / ((c * c) + (d * d));
}
real(8) function code(a, b, c, d)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    real(8), intent (in) :: c
    real(8), intent (in) :: d
    code = ((b * c) - (a * d)) / ((c * c) + (d * d))
end function
public static double code(double a, double b, double c, double d) {
	return ((b * c) - (a * d)) / ((c * c) + (d * d));
}
def code(a, b, c, d):
	return ((b * c) - (a * d)) / ((c * c) + (d * d))
function code(a, b, c, d)
	return Float64(Float64(Float64(b * c) - Float64(a * d)) / Float64(Float64(c * c) + Float64(d * d)))
end
function tmp = code(a, b, c, d)
	tmp = ((b * c) - (a * d)) / ((c * c) + (d * d));
end
code[a_, b_, c_, d_] := N[(N[(N[(b * c), $MachinePrecision] - N[(a * d), $MachinePrecision]), $MachinePrecision] / N[(N[(c * c), $MachinePrecision] + N[(d * d), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{b \cdot c - a \cdot d}{c \cdot c + d \cdot d}
\end{array}

Alternative 1: 79.4% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \mathsf{fma}\left(d, d, c \cdot c\right)\\ t_1 := \mathsf{fma}\left(\frac{c}{t\_0}, b, \frac{a}{t\_0} \cdot \left(-d\right)\right)\\ \mathbf{if}\;c \leq -4 \cdot 10^{+150}:\\ \;\;\;\;\frac{b - \frac{d \cdot a}{c}}{c}\\ \mathbf{elif}\;c \leq -9 \cdot 10^{+19}:\\ \;\;\;\;t\_1\\ \mathbf{elif}\;c \leq 6.8 \cdot 10^{-10}:\\ \;\;\;\;\frac{\frac{b \cdot c}{d} - a}{d}\\ \mathbf{elif}\;c \leq 2.5 \cdot 10^{+132}:\\ \;\;\;\;t\_1\\ \mathbf{else}:\\ \;\;\;\;\frac{b}{c}\\ \end{array} \end{array} \]
(FPCore (a b c d)
 :precision binary64
 (let* ((t_0 (fma d d (* c c))) (t_1 (fma (/ c t_0) b (* (/ a t_0) (- d)))))
   (if (<= c -4e+150)
     (/ (- b (/ (* d a) c)) c)
     (if (<= c -9e+19)
       t_1
       (if (<= c 6.8e-10)
         (/ (- (/ (* b c) d) a) d)
         (if (<= c 2.5e+132) t_1 (/ b c)))))))
double code(double a, double b, double c, double d) {
	double t_0 = fma(d, d, (c * c));
	double t_1 = fma((c / t_0), b, ((a / t_0) * -d));
	double tmp;
	if (c <= -4e+150) {
		tmp = (b - ((d * a) / c)) / c;
	} else if (c <= -9e+19) {
		tmp = t_1;
	} else if (c <= 6.8e-10) {
		tmp = (((b * c) / d) - a) / d;
	} else if (c <= 2.5e+132) {
		tmp = t_1;
	} else {
		tmp = b / c;
	}
	return tmp;
}
function code(a, b, c, d)
	t_0 = fma(d, d, Float64(c * c))
	t_1 = fma(Float64(c / t_0), b, Float64(Float64(a / t_0) * Float64(-d)))
	tmp = 0.0
	if (c <= -4e+150)
		tmp = Float64(Float64(b - Float64(Float64(d * a) / c)) / c);
	elseif (c <= -9e+19)
		tmp = t_1;
	elseif (c <= 6.8e-10)
		tmp = Float64(Float64(Float64(Float64(b * c) / d) - a) / d);
	elseif (c <= 2.5e+132)
		tmp = t_1;
	else
		tmp = Float64(b / c);
	end
	return tmp
end
code[a_, b_, c_, d_] := Block[{t$95$0 = N[(d * d + N[(c * c), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[(N[(c / t$95$0), $MachinePrecision] * b + N[(N[(a / t$95$0), $MachinePrecision] * (-d)), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[c, -4e+150], N[(N[(b - N[(N[(d * a), $MachinePrecision] / c), $MachinePrecision]), $MachinePrecision] / c), $MachinePrecision], If[LessEqual[c, -9e+19], t$95$1, If[LessEqual[c, 6.8e-10], N[(N[(N[(N[(b * c), $MachinePrecision] / d), $MachinePrecision] - a), $MachinePrecision] / d), $MachinePrecision], If[LessEqual[c, 2.5e+132], t$95$1, N[(b / c), $MachinePrecision]]]]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \mathsf{fma}\left(d, d, c \cdot c\right)\\
t_1 := \mathsf{fma}\left(\frac{c}{t\_0}, b, \frac{a}{t\_0} \cdot \left(-d\right)\right)\\
\mathbf{if}\;c \leq -4 \cdot 10^{+150}:\\
\;\;\;\;\frac{b - \frac{d \cdot a}{c}}{c}\\

\mathbf{elif}\;c \leq -9 \cdot 10^{+19}:\\
\;\;\;\;t\_1\\

\mathbf{elif}\;c \leq 6.8 \cdot 10^{-10}:\\
\;\;\;\;\frac{\frac{b \cdot c}{d} - a}{d}\\

\mathbf{elif}\;c \leq 2.5 \cdot 10^{+132}:\\
\;\;\;\;t\_1\\

\mathbf{else}:\\
\;\;\;\;\frac{b}{c}\\


\end{array}
\end{array}
Derivation
  1. Split input into 4 regimes
  2. if c < -3.99999999999999992e150

    1. Initial program 35.7%

      \[\frac{b \cdot c - a \cdot d}{c \cdot c + d \cdot d} \]
    2. Add Preprocessing
    3. Taylor expanded in c around inf

      \[\leadsto \color{blue}{\frac{b + -1 \cdot \frac{a \cdot d}{c}}{c}} \]
    4. Step-by-step derivation
      1. lower-/.f64N/A

        \[\leadsto \color{blue}{\frac{b + -1 \cdot \frac{a \cdot d}{c}}{c}} \]
      2. mul-1-negN/A

        \[\leadsto \frac{b + \color{blue}{\left(\mathsf{neg}\left(\frac{a \cdot d}{c}\right)\right)}}{c} \]
      3. unsub-negN/A

        \[\leadsto \frac{\color{blue}{b - \frac{a \cdot d}{c}}}{c} \]
      4. lower--.f64N/A

        \[\leadsto \frac{\color{blue}{b - \frac{a \cdot d}{c}}}{c} \]
      5. lower-/.f64N/A

        \[\leadsto \frac{b - \color{blue}{\frac{a \cdot d}{c}}}{c} \]
      6. lower-*.f6495.5

        \[\leadsto \frac{b - \frac{\color{blue}{a \cdot d}}{c}}{c} \]
    5. Applied rewrites95.5%

      \[\leadsto \color{blue}{\frac{b - \frac{a \cdot d}{c}}{c}} \]

    if -3.99999999999999992e150 < c < -9e19 or 6.8000000000000003e-10 < c < 2.5000000000000001e132

    1. Initial program 79.9%

      \[\frac{b \cdot c - a \cdot d}{c \cdot c + d \cdot d} \]
    2. Add Preprocessing
    3. Step-by-step derivation
      1. lift-/.f64N/A

        \[\leadsto \color{blue}{\frac{b \cdot c - a \cdot d}{c \cdot c + d \cdot d}} \]
      2. lift--.f64N/A

        \[\leadsto \frac{\color{blue}{b \cdot c - a \cdot d}}{c \cdot c + d \cdot d} \]
      3. div-subN/A

        \[\leadsto \color{blue}{\frac{b \cdot c}{c \cdot c + d \cdot d} - \frac{a \cdot d}{c \cdot c + d \cdot d}} \]
      4. sub-negN/A

        \[\leadsto \color{blue}{\frac{b \cdot c}{c \cdot c + d \cdot d} + \left(\mathsf{neg}\left(\frac{a \cdot d}{c \cdot c + d \cdot d}\right)\right)} \]
      5. lift-*.f64N/A

        \[\leadsto \frac{\color{blue}{b \cdot c}}{c \cdot c + d \cdot d} + \left(\mathsf{neg}\left(\frac{a \cdot d}{c \cdot c + d \cdot d}\right)\right) \]
      6. associate-/l*N/A

        \[\leadsto \color{blue}{b \cdot \frac{c}{c \cdot c + d \cdot d}} + \left(\mathsf{neg}\left(\frac{a \cdot d}{c \cdot c + d \cdot d}\right)\right) \]
      7. *-commutativeN/A

        \[\leadsto \color{blue}{\frac{c}{c \cdot c + d \cdot d} \cdot b} + \left(\mathsf{neg}\left(\frac{a \cdot d}{c \cdot c + d \cdot d}\right)\right) \]
      8. lower-fma.f64N/A

        \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{c}{c \cdot c + d \cdot d}, b, \mathsf{neg}\left(\frac{a \cdot d}{c \cdot c + d \cdot d}\right)\right)} \]
      9. lower-/.f64N/A

        \[\leadsto \mathsf{fma}\left(\color{blue}{\frac{c}{c \cdot c + d \cdot d}}, b, \mathsf{neg}\left(\frac{a \cdot d}{c \cdot c + d \cdot d}\right)\right) \]
      10. lift-+.f64N/A

        \[\leadsto \mathsf{fma}\left(\frac{c}{\color{blue}{c \cdot c + d \cdot d}}, b, \mathsf{neg}\left(\frac{a \cdot d}{c \cdot c + d \cdot d}\right)\right) \]
      11. +-commutativeN/A

        \[\leadsto \mathsf{fma}\left(\frac{c}{\color{blue}{d \cdot d + c \cdot c}}, b, \mathsf{neg}\left(\frac{a \cdot d}{c \cdot c + d \cdot d}\right)\right) \]
      12. lift-*.f64N/A

        \[\leadsto \mathsf{fma}\left(\frac{c}{\color{blue}{d \cdot d} + c \cdot c}, b, \mathsf{neg}\left(\frac{a \cdot d}{c \cdot c + d \cdot d}\right)\right) \]
      13. lower-fma.f64N/A

        \[\leadsto \mathsf{fma}\left(\frac{c}{\color{blue}{\mathsf{fma}\left(d, d, c \cdot c\right)}}, b, \mathsf{neg}\left(\frac{a \cdot d}{c \cdot c + d \cdot d}\right)\right) \]
      14. lift-*.f64N/A

        \[\leadsto \mathsf{fma}\left(\frac{c}{\mathsf{fma}\left(d, d, c \cdot c\right)}, b, \mathsf{neg}\left(\frac{\color{blue}{a \cdot d}}{c \cdot c + d \cdot d}\right)\right) \]
      15. *-commutativeN/A

        \[\leadsto \mathsf{fma}\left(\frac{c}{\mathsf{fma}\left(d, d, c \cdot c\right)}, b, \mathsf{neg}\left(\frac{\color{blue}{d \cdot a}}{c \cdot c + d \cdot d}\right)\right) \]
      16. associate-/l*N/A

        \[\leadsto \mathsf{fma}\left(\frac{c}{\mathsf{fma}\left(d, d, c \cdot c\right)}, b, \mathsf{neg}\left(\color{blue}{d \cdot \frac{a}{c \cdot c + d \cdot d}}\right)\right) \]
    4. Applied rewrites84.9%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{c}{\mathsf{fma}\left(d, d, c \cdot c\right)}, b, \left(-d\right) \cdot \frac{a}{\mathsf{fma}\left(d, d, c \cdot c\right)}\right)} \]

    if -9e19 < c < 6.8000000000000003e-10

    1. Initial program 70.6%

      \[\frac{b \cdot c - a \cdot d}{c \cdot c + d \cdot d} \]
    2. Add Preprocessing
    3. Taylor expanded in c around 0

      \[\leadsto \color{blue}{-1 \cdot \frac{a}{d} + \frac{b \cdot c}{{d}^{2}}} \]
    4. Step-by-step derivation
      1. +-commutativeN/A

        \[\leadsto \color{blue}{\frac{b \cdot c}{{d}^{2}} + -1 \cdot \frac{a}{d}} \]
      2. mul-1-negN/A

        \[\leadsto \frac{b \cdot c}{{d}^{2}} + \color{blue}{\left(\mathsf{neg}\left(\frac{a}{d}\right)\right)} \]
      3. unsub-negN/A

        \[\leadsto \color{blue}{\frac{b \cdot c}{{d}^{2}} - \frac{a}{d}} \]
      4. unpow2N/A

        \[\leadsto \frac{b \cdot c}{\color{blue}{d \cdot d}} - \frac{a}{d} \]
      5. associate-/r*N/A

        \[\leadsto \color{blue}{\frac{\frac{b \cdot c}{d}}{d}} - \frac{a}{d} \]
      6. div-subN/A

        \[\leadsto \color{blue}{\frac{\frac{b \cdot c}{d} - a}{d}} \]
      7. lower-/.f64N/A

        \[\leadsto \color{blue}{\frac{\frac{b \cdot c}{d} - a}{d}} \]
      8. lower--.f64N/A

        \[\leadsto \frac{\color{blue}{\frac{b \cdot c}{d} - a}}{d} \]
      9. lower-/.f64N/A

        \[\leadsto \frac{\color{blue}{\frac{b \cdot c}{d}} - a}{d} \]
      10. lower-*.f6489.9

        \[\leadsto \frac{\frac{\color{blue}{b \cdot c}}{d} - a}{d} \]
    5. Applied rewrites89.9%

      \[\leadsto \color{blue}{\frac{\frac{b \cdot c}{d} - a}{d}} \]

    if 2.5000000000000001e132 < c

    1. Initial program 35.7%

      \[\frac{b \cdot c - a \cdot d}{c \cdot c + d \cdot d} \]
    2. Add Preprocessing
    3. Taylor expanded in c around inf

      \[\leadsto \color{blue}{\frac{b}{c}} \]
    4. Step-by-step derivation
      1. lower-/.f6493.8

        \[\leadsto \color{blue}{\frac{b}{c}} \]
    5. Applied rewrites93.8%

      \[\leadsto \color{blue}{\frac{b}{c}} \]
  3. Recombined 4 regimes into one program.
  4. Final simplification89.5%

    \[\leadsto \begin{array}{l} \mathbf{if}\;c \leq -4 \cdot 10^{+150}:\\ \;\;\;\;\frac{b - \frac{d \cdot a}{c}}{c}\\ \mathbf{elif}\;c \leq -9 \cdot 10^{+19}:\\ \;\;\;\;\mathsf{fma}\left(\frac{c}{\mathsf{fma}\left(d, d, c \cdot c\right)}, b, \frac{a}{\mathsf{fma}\left(d, d, c \cdot c\right)} \cdot \left(-d\right)\right)\\ \mathbf{elif}\;c \leq 6.8 \cdot 10^{-10}:\\ \;\;\;\;\frac{\frac{b \cdot c}{d} - a}{d}\\ \mathbf{elif}\;c \leq 2.5 \cdot 10^{+132}:\\ \;\;\;\;\mathsf{fma}\left(\frac{c}{\mathsf{fma}\left(d, d, c \cdot c\right)}, b, \frac{a}{\mathsf{fma}\left(d, d, c \cdot c\right)} \cdot \left(-d\right)\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{b}{c}\\ \end{array} \]
  5. Add Preprocessing

Alternative 2: 77.8% accurate, 0.7× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;c \leq -1.38 \cdot 10^{+20}:\\ \;\;\;\;\frac{b - \frac{d \cdot a}{c}}{c}\\ \mathbf{elif}\;c \leq 7.2 \cdot 10^{-59}:\\ \;\;\;\;\frac{\frac{b \cdot c}{d} - a}{d}\\ \mathbf{elif}\;c \leq 1.9 \cdot 10^{+132}:\\ \;\;\;\;\frac{b \cdot c - d \cdot a}{d \cdot d + c \cdot c}\\ \mathbf{else}:\\ \;\;\;\;\frac{b}{c}\\ \end{array} \end{array} \]
(FPCore (a b c d)
 :precision binary64
 (if (<= c -1.38e+20)
   (/ (- b (/ (* d a) c)) c)
   (if (<= c 7.2e-59)
     (/ (- (/ (* b c) d) a) d)
     (if (<= c 1.9e+132)
       (/ (- (* b c) (* d a)) (+ (* d d) (* c c)))
       (/ b c)))))
double code(double a, double b, double c, double d) {
	double tmp;
	if (c <= -1.38e+20) {
		tmp = (b - ((d * a) / c)) / c;
	} else if (c <= 7.2e-59) {
		tmp = (((b * c) / d) - a) / d;
	} else if (c <= 1.9e+132) {
		tmp = ((b * c) - (d * a)) / ((d * d) + (c * c));
	} else {
		tmp = b / c;
	}
	return tmp;
}
real(8) function code(a, b, c, d)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    real(8), intent (in) :: c
    real(8), intent (in) :: d
    real(8) :: tmp
    if (c <= (-1.38d+20)) then
        tmp = (b - ((d * a) / c)) / c
    else if (c <= 7.2d-59) then
        tmp = (((b * c) / d) - a) / d
    else if (c <= 1.9d+132) then
        tmp = ((b * c) - (d * a)) / ((d * d) + (c * c))
    else
        tmp = b / c
    end if
    code = tmp
end function
public static double code(double a, double b, double c, double d) {
	double tmp;
	if (c <= -1.38e+20) {
		tmp = (b - ((d * a) / c)) / c;
	} else if (c <= 7.2e-59) {
		tmp = (((b * c) / d) - a) / d;
	} else if (c <= 1.9e+132) {
		tmp = ((b * c) - (d * a)) / ((d * d) + (c * c));
	} else {
		tmp = b / c;
	}
	return tmp;
}
def code(a, b, c, d):
	tmp = 0
	if c <= -1.38e+20:
		tmp = (b - ((d * a) / c)) / c
	elif c <= 7.2e-59:
		tmp = (((b * c) / d) - a) / d
	elif c <= 1.9e+132:
		tmp = ((b * c) - (d * a)) / ((d * d) + (c * c))
	else:
		tmp = b / c
	return tmp
function code(a, b, c, d)
	tmp = 0.0
	if (c <= -1.38e+20)
		tmp = Float64(Float64(b - Float64(Float64(d * a) / c)) / c);
	elseif (c <= 7.2e-59)
		tmp = Float64(Float64(Float64(Float64(b * c) / d) - a) / d);
	elseif (c <= 1.9e+132)
		tmp = Float64(Float64(Float64(b * c) - Float64(d * a)) / Float64(Float64(d * d) + Float64(c * c)));
	else
		tmp = Float64(b / c);
	end
	return tmp
end
function tmp_2 = code(a, b, c, d)
	tmp = 0.0;
	if (c <= -1.38e+20)
		tmp = (b - ((d * a) / c)) / c;
	elseif (c <= 7.2e-59)
		tmp = (((b * c) / d) - a) / d;
	elseif (c <= 1.9e+132)
		tmp = ((b * c) - (d * a)) / ((d * d) + (c * c));
	else
		tmp = b / c;
	end
	tmp_2 = tmp;
end
code[a_, b_, c_, d_] := If[LessEqual[c, -1.38e+20], N[(N[(b - N[(N[(d * a), $MachinePrecision] / c), $MachinePrecision]), $MachinePrecision] / c), $MachinePrecision], If[LessEqual[c, 7.2e-59], N[(N[(N[(N[(b * c), $MachinePrecision] / d), $MachinePrecision] - a), $MachinePrecision] / d), $MachinePrecision], If[LessEqual[c, 1.9e+132], N[(N[(N[(b * c), $MachinePrecision] - N[(d * a), $MachinePrecision]), $MachinePrecision] / N[(N[(d * d), $MachinePrecision] + N[(c * c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(b / c), $MachinePrecision]]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;c \leq -1.38 \cdot 10^{+20}:\\
\;\;\;\;\frac{b - \frac{d \cdot a}{c}}{c}\\

\mathbf{elif}\;c \leq 7.2 \cdot 10^{-59}:\\
\;\;\;\;\frac{\frac{b \cdot c}{d} - a}{d}\\

\mathbf{elif}\;c \leq 1.9 \cdot 10^{+132}:\\
\;\;\;\;\frac{b \cdot c - d \cdot a}{d \cdot d + c \cdot c}\\

\mathbf{else}:\\
\;\;\;\;\frac{b}{c}\\


\end{array}
\end{array}
Derivation
  1. Split input into 4 regimes
  2. if c < -1.38e20

    1. Initial program 64.7%

      \[\frac{b \cdot c - a \cdot d}{c \cdot c + d \cdot d} \]
    2. Add Preprocessing
    3. Taylor expanded in c around inf

      \[\leadsto \color{blue}{\frac{b + -1 \cdot \frac{a \cdot d}{c}}{c}} \]
    4. Step-by-step derivation
      1. lower-/.f64N/A

        \[\leadsto \color{blue}{\frac{b + -1 \cdot \frac{a \cdot d}{c}}{c}} \]
      2. mul-1-negN/A

        \[\leadsto \frac{b + \color{blue}{\left(\mathsf{neg}\left(\frac{a \cdot d}{c}\right)\right)}}{c} \]
      3. unsub-negN/A

        \[\leadsto \frac{\color{blue}{b - \frac{a \cdot d}{c}}}{c} \]
      4. lower--.f64N/A

        \[\leadsto \frac{\color{blue}{b - \frac{a \cdot d}{c}}}{c} \]
      5. lower-/.f64N/A

        \[\leadsto \frac{b - \color{blue}{\frac{a \cdot d}{c}}}{c} \]
      6. lower-*.f6484.0

        \[\leadsto \frac{b - \frac{\color{blue}{a \cdot d}}{c}}{c} \]
    5. Applied rewrites84.0%

      \[\leadsto \color{blue}{\frac{b - \frac{a \cdot d}{c}}{c}} \]

    if -1.38e20 < c < 7.20000000000000001e-59

    1. Initial program 69.9%

      \[\frac{b \cdot c - a \cdot d}{c \cdot c + d \cdot d} \]
    2. Add Preprocessing
    3. Taylor expanded in c around 0

      \[\leadsto \color{blue}{-1 \cdot \frac{a}{d} + \frac{b \cdot c}{{d}^{2}}} \]
    4. Step-by-step derivation
      1. +-commutativeN/A

        \[\leadsto \color{blue}{\frac{b \cdot c}{{d}^{2}} + -1 \cdot \frac{a}{d}} \]
      2. mul-1-negN/A

        \[\leadsto \frac{b \cdot c}{{d}^{2}} + \color{blue}{\left(\mathsf{neg}\left(\frac{a}{d}\right)\right)} \]
      3. unsub-negN/A

        \[\leadsto \color{blue}{\frac{b \cdot c}{{d}^{2}} - \frac{a}{d}} \]
      4. unpow2N/A

        \[\leadsto \frac{b \cdot c}{\color{blue}{d \cdot d}} - \frac{a}{d} \]
      5. associate-/r*N/A

        \[\leadsto \color{blue}{\frac{\frac{b \cdot c}{d}}{d}} - \frac{a}{d} \]
      6. div-subN/A

        \[\leadsto \color{blue}{\frac{\frac{b \cdot c}{d} - a}{d}} \]
      7. lower-/.f64N/A

        \[\leadsto \color{blue}{\frac{\frac{b \cdot c}{d} - a}{d}} \]
      8. lower--.f64N/A

        \[\leadsto \frac{\color{blue}{\frac{b \cdot c}{d} - a}}{d} \]
      9. lower-/.f64N/A

        \[\leadsto \frac{\color{blue}{\frac{b \cdot c}{d}} - a}{d} \]
      10. lower-*.f6491.8

        \[\leadsto \frac{\frac{\color{blue}{b \cdot c}}{d} - a}{d} \]
    5. Applied rewrites91.8%

      \[\leadsto \color{blue}{\frac{\frac{b \cdot c}{d} - a}{d}} \]

    if 7.20000000000000001e-59 < c < 1.90000000000000003e132

    1. Initial program 77.1%

      \[\frac{b \cdot c - a \cdot d}{c \cdot c + d \cdot d} \]
    2. Add Preprocessing

    if 1.90000000000000003e132 < c

    1. Initial program 35.7%

      \[\frac{b \cdot c - a \cdot d}{c \cdot c + d \cdot d} \]
    2. Add Preprocessing
    3. Taylor expanded in c around inf

      \[\leadsto \color{blue}{\frac{b}{c}} \]
    4. Step-by-step derivation
      1. lower-/.f6493.8

        \[\leadsto \color{blue}{\frac{b}{c}} \]
    5. Applied rewrites93.8%

      \[\leadsto \color{blue}{\frac{b}{c}} \]
  3. Recombined 4 regimes into one program.
  4. Final simplification87.9%

    \[\leadsto \begin{array}{l} \mathbf{if}\;c \leq -1.38 \cdot 10^{+20}:\\ \;\;\;\;\frac{b - \frac{d \cdot a}{c}}{c}\\ \mathbf{elif}\;c \leq 7.2 \cdot 10^{-59}:\\ \;\;\;\;\frac{\frac{b \cdot c}{d} - a}{d}\\ \mathbf{elif}\;c \leq 1.9 \cdot 10^{+132}:\\ \;\;\;\;\frac{b \cdot c - d \cdot a}{d \cdot d + c \cdot c}\\ \mathbf{else}:\\ \;\;\;\;\frac{b}{c}\\ \end{array} \]
  5. Add Preprocessing

Alternative 3: 63.7% accurate, 0.7× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \frac{b \cdot c - d \cdot a}{c \cdot c}\\ \mathbf{if}\;c \leq -1.22 \cdot 10^{+178}:\\ \;\;\;\;\frac{b}{c}\\ \mathbf{elif}\;c \leq -9.8 \cdot 10^{+19}:\\ \;\;\;\;t\_0\\ \mathbf{elif}\;c \leq 1.05 \cdot 10^{-8}:\\ \;\;\;\;\frac{a}{-d}\\ \mathbf{elif}\;c \leq 10^{+130}:\\ \;\;\;\;t\_0\\ \mathbf{else}:\\ \;\;\;\;\frac{b}{c}\\ \end{array} \end{array} \]
(FPCore (a b c d)
 :precision binary64
 (let* ((t_0 (/ (- (* b c) (* d a)) (* c c))))
   (if (<= c -1.22e+178)
     (/ b c)
     (if (<= c -9.8e+19)
       t_0
       (if (<= c 1.05e-8) (/ a (- d)) (if (<= c 1e+130) t_0 (/ b c)))))))
double code(double a, double b, double c, double d) {
	double t_0 = ((b * c) - (d * a)) / (c * c);
	double tmp;
	if (c <= -1.22e+178) {
		tmp = b / c;
	} else if (c <= -9.8e+19) {
		tmp = t_0;
	} else if (c <= 1.05e-8) {
		tmp = a / -d;
	} else if (c <= 1e+130) {
		tmp = t_0;
	} else {
		tmp = b / c;
	}
	return tmp;
}
real(8) function code(a, b, c, d)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    real(8), intent (in) :: c
    real(8), intent (in) :: d
    real(8) :: t_0
    real(8) :: tmp
    t_0 = ((b * c) - (d * a)) / (c * c)
    if (c <= (-1.22d+178)) then
        tmp = b / c
    else if (c <= (-9.8d+19)) then
        tmp = t_0
    else if (c <= 1.05d-8) then
        tmp = a / -d
    else if (c <= 1d+130) then
        tmp = t_0
    else
        tmp = b / c
    end if
    code = tmp
end function
public static double code(double a, double b, double c, double d) {
	double t_0 = ((b * c) - (d * a)) / (c * c);
	double tmp;
	if (c <= -1.22e+178) {
		tmp = b / c;
	} else if (c <= -9.8e+19) {
		tmp = t_0;
	} else if (c <= 1.05e-8) {
		tmp = a / -d;
	} else if (c <= 1e+130) {
		tmp = t_0;
	} else {
		tmp = b / c;
	}
	return tmp;
}
def code(a, b, c, d):
	t_0 = ((b * c) - (d * a)) / (c * c)
	tmp = 0
	if c <= -1.22e+178:
		tmp = b / c
	elif c <= -9.8e+19:
		tmp = t_0
	elif c <= 1.05e-8:
		tmp = a / -d
	elif c <= 1e+130:
		tmp = t_0
	else:
		tmp = b / c
	return tmp
function code(a, b, c, d)
	t_0 = Float64(Float64(Float64(b * c) - Float64(d * a)) / Float64(c * c))
	tmp = 0.0
	if (c <= -1.22e+178)
		tmp = Float64(b / c);
	elseif (c <= -9.8e+19)
		tmp = t_0;
	elseif (c <= 1.05e-8)
		tmp = Float64(a / Float64(-d));
	elseif (c <= 1e+130)
		tmp = t_0;
	else
		tmp = Float64(b / c);
	end
	return tmp
end
function tmp_2 = code(a, b, c, d)
	t_0 = ((b * c) - (d * a)) / (c * c);
	tmp = 0.0;
	if (c <= -1.22e+178)
		tmp = b / c;
	elseif (c <= -9.8e+19)
		tmp = t_0;
	elseif (c <= 1.05e-8)
		tmp = a / -d;
	elseif (c <= 1e+130)
		tmp = t_0;
	else
		tmp = b / c;
	end
	tmp_2 = tmp;
end
code[a_, b_, c_, d_] := Block[{t$95$0 = N[(N[(N[(b * c), $MachinePrecision] - N[(d * a), $MachinePrecision]), $MachinePrecision] / N[(c * c), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[c, -1.22e+178], N[(b / c), $MachinePrecision], If[LessEqual[c, -9.8e+19], t$95$0, If[LessEqual[c, 1.05e-8], N[(a / (-d)), $MachinePrecision], If[LessEqual[c, 1e+130], t$95$0, N[(b / c), $MachinePrecision]]]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \frac{b \cdot c - d \cdot a}{c \cdot c}\\
\mathbf{if}\;c \leq -1.22 \cdot 10^{+178}:\\
\;\;\;\;\frac{b}{c}\\

\mathbf{elif}\;c \leq -9.8 \cdot 10^{+19}:\\
\;\;\;\;t\_0\\

\mathbf{elif}\;c \leq 1.05 \cdot 10^{-8}:\\
\;\;\;\;\frac{a}{-d}\\

\mathbf{elif}\;c \leq 10^{+130}:\\
\;\;\;\;t\_0\\

\mathbf{else}:\\
\;\;\;\;\frac{b}{c}\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if c < -1.2199999999999999e178 or 1.0000000000000001e130 < c

    1. Initial program 31.7%

      \[\frac{b \cdot c - a \cdot d}{c \cdot c + d \cdot d} \]
    2. Add Preprocessing
    3. Taylor expanded in c around inf

      \[\leadsto \color{blue}{\frac{b}{c}} \]
    4. Step-by-step derivation
      1. lower-/.f6492.2

        \[\leadsto \color{blue}{\frac{b}{c}} \]
    5. Applied rewrites92.2%

      \[\leadsto \color{blue}{\frac{b}{c}} \]

    if -1.2199999999999999e178 < c < -9.8e19 or 1.04999999999999997e-8 < c < 1.0000000000000001e130

    1. Initial program 80.8%

      \[\frac{b \cdot c - a \cdot d}{c \cdot c + d \cdot d} \]
    2. Add Preprocessing
    3. Taylor expanded in c around inf

      \[\leadsto \frac{b \cdot c - a \cdot d}{\color{blue}{{c}^{2}}} \]
    4. Step-by-step derivation
      1. unpow2N/A

        \[\leadsto \frac{b \cdot c - a \cdot d}{\color{blue}{c \cdot c}} \]
      2. lower-*.f6470.8

        \[\leadsto \frac{b \cdot c - a \cdot d}{\color{blue}{c \cdot c}} \]
    5. Applied rewrites70.8%

      \[\leadsto \frac{b \cdot c - a \cdot d}{\color{blue}{c \cdot c}} \]

    if -9.8e19 < c < 1.04999999999999997e-8

    1. Initial program 70.6%

      \[\frac{b \cdot c - a \cdot d}{c \cdot c + d \cdot d} \]
    2. Add Preprocessing
    3. Taylor expanded in c around 0

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

        \[\leadsto \color{blue}{\mathsf{neg}\left(\frac{a}{d}\right)} \]
      2. distribute-neg-frac2N/A

        \[\leadsto \color{blue}{\frac{a}{\mathsf{neg}\left(d\right)}} \]
      3. mul-1-negN/A

        \[\leadsto \frac{a}{\color{blue}{-1 \cdot d}} \]
      4. lower-/.f64N/A

        \[\leadsto \color{blue}{\frac{a}{-1 \cdot d}} \]
      5. mul-1-negN/A

        \[\leadsto \frac{a}{\color{blue}{\mathsf{neg}\left(d\right)}} \]
      6. lower-neg.f6474.1

        \[\leadsto \frac{a}{\color{blue}{-d}} \]
    5. Applied rewrites74.1%

      \[\leadsto \color{blue}{\frac{a}{-d}} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification76.6%

    \[\leadsto \begin{array}{l} \mathbf{if}\;c \leq -1.22 \cdot 10^{+178}:\\ \;\;\;\;\frac{b}{c}\\ \mathbf{elif}\;c \leq -9.8 \cdot 10^{+19}:\\ \;\;\;\;\frac{b \cdot c - d \cdot a}{c \cdot c}\\ \mathbf{elif}\;c \leq 1.05 \cdot 10^{-8}:\\ \;\;\;\;\frac{a}{-d}\\ \mathbf{elif}\;c \leq 10^{+130}:\\ \;\;\;\;\frac{b \cdot c - d \cdot a}{c \cdot c}\\ \mathbf{else}:\\ \;\;\;\;\frac{b}{c}\\ \end{array} \]
  5. Add Preprocessing

Alternative 4: 76.2% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \frac{b - \frac{d \cdot a}{c}}{c}\\ \mathbf{if}\;c \leq -1.38 \cdot 10^{+20}:\\ \;\;\;\;t\_0\\ \mathbf{elif}\;c \leq 4 \cdot 10^{+26}:\\ \;\;\;\;\frac{\frac{b \cdot c}{d} - a}{d}\\ \mathbf{else}:\\ \;\;\;\;t\_0\\ \end{array} \end{array} \]
(FPCore (a b c d)
 :precision binary64
 (let* ((t_0 (/ (- b (/ (* d a) c)) c)))
   (if (<= c -1.38e+20) t_0 (if (<= c 4e+26) (/ (- (/ (* b c) d) a) d) t_0))))
double code(double a, double b, double c, double d) {
	double t_0 = (b - ((d * a) / c)) / c;
	double tmp;
	if (c <= -1.38e+20) {
		tmp = t_0;
	} else if (c <= 4e+26) {
		tmp = (((b * c) / d) - a) / d;
	} else {
		tmp = t_0;
	}
	return tmp;
}
real(8) function code(a, b, c, d)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    real(8), intent (in) :: c
    real(8), intent (in) :: d
    real(8) :: t_0
    real(8) :: tmp
    t_0 = (b - ((d * a) / c)) / c
    if (c <= (-1.38d+20)) then
        tmp = t_0
    else if (c <= 4d+26) then
        tmp = (((b * c) / d) - a) / d
    else
        tmp = t_0
    end if
    code = tmp
end function
public static double code(double a, double b, double c, double d) {
	double t_0 = (b - ((d * a) / c)) / c;
	double tmp;
	if (c <= -1.38e+20) {
		tmp = t_0;
	} else if (c <= 4e+26) {
		tmp = (((b * c) / d) - a) / d;
	} else {
		tmp = t_0;
	}
	return tmp;
}
def code(a, b, c, d):
	t_0 = (b - ((d * a) / c)) / c
	tmp = 0
	if c <= -1.38e+20:
		tmp = t_0
	elif c <= 4e+26:
		tmp = (((b * c) / d) - a) / d
	else:
		tmp = t_0
	return tmp
function code(a, b, c, d)
	t_0 = Float64(Float64(b - Float64(Float64(d * a) / c)) / c)
	tmp = 0.0
	if (c <= -1.38e+20)
		tmp = t_0;
	elseif (c <= 4e+26)
		tmp = Float64(Float64(Float64(Float64(b * c) / d) - a) / d);
	else
		tmp = t_0;
	end
	return tmp
end
function tmp_2 = code(a, b, c, d)
	t_0 = (b - ((d * a) / c)) / c;
	tmp = 0.0;
	if (c <= -1.38e+20)
		tmp = t_0;
	elseif (c <= 4e+26)
		tmp = (((b * c) / d) - a) / d;
	else
		tmp = t_0;
	end
	tmp_2 = tmp;
end
code[a_, b_, c_, d_] := Block[{t$95$0 = N[(N[(b - N[(N[(d * a), $MachinePrecision] / c), $MachinePrecision]), $MachinePrecision] / c), $MachinePrecision]}, If[LessEqual[c, -1.38e+20], t$95$0, If[LessEqual[c, 4e+26], N[(N[(N[(N[(b * c), $MachinePrecision] / d), $MachinePrecision] - a), $MachinePrecision] / d), $MachinePrecision], t$95$0]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \frac{b - \frac{d \cdot a}{c}}{c}\\
\mathbf{if}\;c \leq -1.38 \cdot 10^{+20}:\\
\;\;\;\;t\_0\\

\mathbf{elif}\;c \leq 4 \cdot 10^{+26}:\\
\;\;\;\;\frac{\frac{b \cdot c}{d} - a}{d}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if c < -1.38e20 or 4.00000000000000019e26 < c

    1. Initial program 60.9%

      \[\frac{b \cdot c - a \cdot d}{c \cdot c + d \cdot d} \]
    2. Add Preprocessing
    3. Taylor expanded in c around inf

      \[\leadsto \color{blue}{\frac{b + -1 \cdot \frac{a \cdot d}{c}}{c}} \]
    4. Step-by-step derivation
      1. lower-/.f64N/A

        \[\leadsto \color{blue}{\frac{b + -1 \cdot \frac{a \cdot d}{c}}{c}} \]
      2. mul-1-negN/A

        \[\leadsto \frac{b + \color{blue}{\left(\mathsf{neg}\left(\frac{a \cdot d}{c}\right)\right)}}{c} \]
      3. unsub-negN/A

        \[\leadsto \frac{\color{blue}{b - \frac{a \cdot d}{c}}}{c} \]
      4. lower--.f64N/A

        \[\leadsto \frac{\color{blue}{b - \frac{a \cdot d}{c}}}{c} \]
      5. lower-/.f64N/A

        \[\leadsto \frac{b - \color{blue}{\frac{a \cdot d}{c}}}{c} \]
      6. lower-*.f6483.8

        \[\leadsto \frac{b - \frac{\color{blue}{a \cdot d}}{c}}{c} \]
    5. Applied rewrites83.8%

      \[\leadsto \color{blue}{\frac{b - \frac{a \cdot d}{c}}{c}} \]

    if -1.38e20 < c < 4.00000000000000019e26

    1. Initial program 69.6%

      \[\frac{b \cdot c - a \cdot d}{c \cdot c + d \cdot d} \]
    2. Add Preprocessing
    3. Taylor expanded in c around 0

      \[\leadsto \color{blue}{-1 \cdot \frac{a}{d} + \frac{b \cdot c}{{d}^{2}}} \]
    4. Step-by-step derivation
      1. +-commutativeN/A

        \[\leadsto \color{blue}{\frac{b \cdot c}{{d}^{2}} + -1 \cdot \frac{a}{d}} \]
      2. mul-1-negN/A

        \[\leadsto \frac{b \cdot c}{{d}^{2}} + \color{blue}{\left(\mathsf{neg}\left(\frac{a}{d}\right)\right)} \]
      3. unsub-negN/A

        \[\leadsto \color{blue}{\frac{b \cdot c}{{d}^{2}} - \frac{a}{d}} \]
      4. unpow2N/A

        \[\leadsto \frac{b \cdot c}{\color{blue}{d \cdot d}} - \frac{a}{d} \]
      5. associate-/r*N/A

        \[\leadsto \color{blue}{\frac{\frac{b \cdot c}{d}}{d}} - \frac{a}{d} \]
      6. div-subN/A

        \[\leadsto \color{blue}{\frac{\frac{b \cdot c}{d} - a}{d}} \]
      7. lower-/.f64N/A

        \[\leadsto \color{blue}{\frac{\frac{b \cdot c}{d} - a}{d}} \]
      8. lower--.f64N/A

        \[\leadsto \frac{\color{blue}{\frac{b \cdot c}{d} - a}}{d} \]
      9. lower-/.f64N/A

        \[\leadsto \frac{\color{blue}{\frac{b \cdot c}{d}} - a}{d} \]
      10. lower-*.f6487.9

        \[\leadsto \frac{\frac{\color{blue}{b \cdot c}}{d} - a}{d} \]
    5. Applied rewrites87.9%

      \[\leadsto \color{blue}{\frac{\frac{b \cdot c}{d} - a}{d}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification86.2%

    \[\leadsto \begin{array}{l} \mathbf{if}\;c \leq -1.38 \cdot 10^{+20}:\\ \;\;\;\;\frac{b - \frac{d \cdot a}{c}}{c}\\ \mathbf{elif}\;c \leq 4 \cdot 10^{+26}:\\ \;\;\;\;\frac{\frac{b \cdot c}{d} - a}{d}\\ \mathbf{else}:\\ \;\;\;\;\frac{b - \frac{d \cdot a}{c}}{c}\\ \end{array} \]
  5. Add Preprocessing

Alternative 5: 67.3% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \frac{b - \frac{d \cdot a}{c}}{c}\\ \mathbf{if}\;c \leq -9.8 \cdot 10^{+19}:\\ \;\;\;\;t\_0\\ \mathbf{elif}\;c \leq 1.05 \cdot 10^{-8}:\\ \;\;\;\;\frac{a}{-d}\\ \mathbf{else}:\\ \;\;\;\;t\_0\\ \end{array} \end{array} \]
(FPCore (a b c d)
 :precision binary64
 (let* ((t_0 (/ (- b (/ (* d a) c)) c)))
   (if (<= c -9.8e+19) t_0 (if (<= c 1.05e-8) (/ a (- d)) t_0))))
double code(double a, double b, double c, double d) {
	double t_0 = (b - ((d * a) / c)) / c;
	double tmp;
	if (c <= -9.8e+19) {
		tmp = t_0;
	} else if (c <= 1.05e-8) {
		tmp = a / -d;
	} else {
		tmp = t_0;
	}
	return tmp;
}
real(8) function code(a, b, c, d)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    real(8), intent (in) :: c
    real(8), intent (in) :: d
    real(8) :: t_0
    real(8) :: tmp
    t_0 = (b - ((d * a) / c)) / c
    if (c <= (-9.8d+19)) then
        tmp = t_0
    else if (c <= 1.05d-8) then
        tmp = a / -d
    else
        tmp = t_0
    end if
    code = tmp
end function
public static double code(double a, double b, double c, double d) {
	double t_0 = (b - ((d * a) / c)) / c;
	double tmp;
	if (c <= -9.8e+19) {
		tmp = t_0;
	} else if (c <= 1.05e-8) {
		tmp = a / -d;
	} else {
		tmp = t_0;
	}
	return tmp;
}
def code(a, b, c, d):
	t_0 = (b - ((d * a) / c)) / c
	tmp = 0
	if c <= -9.8e+19:
		tmp = t_0
	elif c <= 1.05e-8:
		tmp = a / -d
	else:
		tmp = t_0
	return tmp
function code(a, b, c, d)
	t_0 = Float64(Float64(b - Float64(Float64(d * a) / c)) / c)
	tmp = 0.0
	if (c <= -9.8e+19)
		tmp = t_0;
	elseif (c <= 1.05e-8)
		tmp = Float64(a / Float64(-d));
	else
		tmp = t_0;
	end
	return tmp
end
function tmp_2 = code(a, b, c, d)
	t_0 = (b - ((d * a) / c)) / c;
	tmp = 0.0;
	if (c <= -9.8e+19)
		tmp = t_0;
	elseif (c <= 1.05e-8)
		tmp = a / -d;
	else
		tmp = t_0;
	end
	tmp_2 = tmp;
end
code[a_, b_, c_, d_] := Block[{t$95$0 = N[(N[(b - N[(N[(d * a), $MachinePrecision] / c), $MachinePrecision]), $MachinePrecision] / c), $MachinePrecision]}, If[LessEqual[c, -9.8e+19], t$95$0, If[LessEqual[c, 1.05e-8], N[(a / (-d)), $MachinePrecision], t$95$0]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \frac{b - \frac{d \cdot a}{c}}{c}\\
\mathbf{if}\;c \leq -9.8 \cdot 10^{+19}:\\
\;\;\;\;t\_0\\

\mathbf{elif}\;c \leq 1.05 \cdot 10^{-8}:\\
\;\;\;\;\frac{a}{-d}\\

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


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if c < -9.8e19 or 1.04999999999999997e-8 < c

    1. Initial program 60.3%

      \[\frac{b \cdot c - a \cdot d}{c \cdot c + d \cdot d} \]
    2. Add Preprocessing
    3. Taylor expanded in c around inf

      \[\leadsto \color{blue}{\frac{b + -1 \cdot \frac{a \cdot d}{c}}{c}} \]
    4. Step-by-step derivation
      1. lower-/.f64N/A

        \[\leadsto \color{blue}{\frac{b + -1 \cdot \frac{a \cdot d}{c}}{c}} \]
      2. mul-1-negN/A

        \[\leadsto \frac{b + \color{blue}{\left(\mathsf{neg}\left(\frac{a \cdot d}{c}\right)\right)}}{c} \]
      3. unsub-negN/A

        \[\leadsto \frac{\color{blue}{b - \frac{a \cdot d}{c}}}{c} \]
      4. lower--.f64N/A

        \[\leadsto \frac{\color{blue}{b - \frac{a \cdot d}{c}}}{c} \]
      5. lower-/.f64N/A

        \[\leadsto \frac{b - \color{blue}{\frac{a \cdot d}{c}}}{c} \]
      6. lower-*.f6481.5

        \[\leadsto \frac{b - \frac{\color{blue}{a \cdot d}}{c}}{c} \]
    5. Applied rewrites81.5%

      \[\leadsto \color{blue}{\frac{b - \frac{a \cdot d}{c}}{c}} \]

    if -9.8e19 < c < 1.04999999999999997e-8

    1. Initial program 70.6%

      \[\frac{b \cdot c - a \cdot d}{c \cdot c + d \cdot d} \]
    2. Add Preprocessing
    3. Taylor expanded in c around 0

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

        \[\leadsto \color{blue}{\mathsf{neg}\left(\frac{a}{d}\right)} \]
      2. distribute-neg-frac2N/A

        \[\leadsto \color{blue}{\frac{a}{\mathsf{neg}\left(d\right)}} \]
      3. mul-1-negN/A

        \[\leadsto \frac{a}{\color{blue}{-1 \cdot d}} \]
      4. lower-/.f64N/A

        \[\leadsto \color{blue}{\frac{a}{-1 \cdot d}} \]
      5. mul-1-negN/A

        \[\leadsto \frac{a}{\color{blue}{\mathsf{neg}\left(d\right)}} \]
      6. lower-neg.f6474.1

        \[\leadsto \frac{a}{\color{blue}{-d}} \]
    5. Applied rewrites74.1%

      \[\leadsto \color{blue}{\frac{a}{-d}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification77.4%

    \[\leadsto \begin{array}{l} \mathbf{if}\;c \leq -9.8 \cdot 10^{+19}:\\ \;\;\;\;\frac{b - \frac{d \cdot a}{c}}{c}\\ \mathbf{elif}\;c \leq 1.05 \cdot 10^{-8}:\\ \;\;\;\;\frac{a}{-d}\\ \mathbf{else}:\\ \;\;\;\;\frac{b - \frac{d \cdot a}{c}}{c}\\ \end{array} \]
  5. Add Preprocessing

Alternative 6: 63.5% accurate, 1.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;c \leq -1.38 \cdot 10^{+20}:\\ \;\;\;\;\frac{b}{c}\\ \mathbf{elif}\;c \leq 4 \cdot 10^{+26}:\\ \;\;\;\;\frac{a}{-d}\\ \mathbf{else}:\\ \;\;\;\;\frac{b}{c}\\ \end{array} \end{array} \]
(FPCore (a b c d)
 :precision binary64
 (if (<= c -1.38e+20) (/ b c) (if (<= c 4e+26) (/ a (- d)) (/ b c))))
double code(double a, double b, double c, double d) {
	double tmp;
	if (c <= -1.38e+20) {
		tmp = b / c;
	} else if (c <= 4e+26) {
		tmp = a / -d;
	} else {
		tmp = b / c;
	}
	return tmp;
}
real(8) function code(a, b, c, d)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    real(8), intent (in) :: c
    real(8), intent (in) :: d
    real(8) :: tmp
    if (c <= (-1.38d+20)) then
        tmp = b / c
    else if (c <= 4d+26) then
        tmp = a / -d
    else
        tmp = b / c
    end if
    code = tmp
end function
public static double code(double a, double b, double c, double d) {
	double tmp;
	if (c <= -1.38e+20) {
		tmp = b / c;
	} else if (c <= 4e+26) {
		tmp = a / -d;
	} else {
		tmp = b / c;
	}
	return tmp;
}
def code(a, b, c, d):
	tmp = 0
	if c <= -1.38e+20:
		tmp = b / c
	elif c <= 4e+26:
		tmp = a / -d
	else:
		tmp = b / c
	return tmp
function code(a, b, c, d)
	tmp = 0.0
	if (c <= -1.38e+20)
		tmp = Float64(b / c);
	elseif (c <= 4e+26)
		tmp = Float64(a / Float64(-d));
	else
		tmp = Float64(b / c);
	end
	return tmp
end
function tmp_2 = code(a, b, c, d)
	tmp = 0.0;
	if (c <= -1.38e+20)
		tmp = b / c;
	elseif (c <= 4e+26)
		tmp = a / -d;
	else
		tmp = b / c;
	end
	tmp_2 = tmp;
end
code[a_, b_, c_, d_] := If[LessEqual[c, -1.38e+20], N[(b / c), $MachinePrecision], If[LessEqual[c, 4e+26], N[(a / (-d)), $MachinePrecision], N[(b / c), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;c \leq -1.38 \cdot 10^{+20}:\\
\;\;\;\;\frac{b}{c}\\

\mathbf{elif}\;c \leq 4 \cdot 10^{+26}:\\
\;\;\;\;\frac{a}{-d}\\

\mathbf{else}:\\
\;\;\;\;\frac{b}{c}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if c < -1.38e20 or 4.00000000000000019e26 < c

    1. Initial program 60.9%

      \[\frac{b \cdot c - a \cdot d}{c \cdot c + d \cdot d} \]
    2. Add Preprocessing
    3. Taylor expanded in c around inf

      \[\leadsto \color{blue}{\frac{b}{c}} \]
    4. Step-by-step derivation
      1. lower-/.f6470.4

        \[\leadsto \color{blue}{\frac{b}{c}} \]
    5. Applied rewrites70.4%

      \[\leadsto \color{blue}{\frac{b}{c}} \]

    if -1.38e20 < c < 4.00000000000000019e26

    1. Initial program 69.6%

      \[\frac{b \cdot c - a \cdot d}{c \cdot c + d \cdot d} \]
    2. Add Preprocessing
    3. Taylor expanded in c around 0

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

        \[\leadsto \color{blue}{\mathsf{neg}\left(\frac{a}{d}\right)} \]
      2. distribute-neg-frac2N/A

        \[\leadsto \color{blue}{\frac{a}{\mathsf{neg}\left(d\right)}} \]
      3. mul-1-negN/A

        \[\leadsto \frac{a}{\color{blue}{-1 \cdot d}} \]
      4. lower-/.f64N/A

        \[\leadsto \color{blue}{\frac{a}{-1 \cdot d}} \]
      5. mul-1-negN/A

        \[\leadsto \frac{a}{\color{blue}{\mathsf{neg}\left(d\right)}} \]
      6. lower-neg.f6472.3

        \[\leadsto \frac{a}{\color{blue}{-d}} \]
    5. Applied rewrites72.3%

      \[\leadsto \color{blue}{\frac{a}{-d}} \]
  3. Recombined 2 regimes into one program.
  4. Add Preprocessing

Alternative 7: 42.3% accurate, 3.2× speedup?

\[\begin{array}{l} \\ \frac{b}{c} \end{array} \]
(FPCore (a b c d) :precision binary64 (/ b c))
double code(double a, double b, double c, double d) {
	return b / c;
}
real(8) function code(a, b, c, d)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    real(8), intent (in) :: c
    real(8), intent (in) :: d
    code = b / c
end function
public static double code(double a, double b, double c, double d) {
	return b / c;
}
def code(a, b, c, d):
	return b / c
function code(a, b, c, d)
	return Float64(b / c)
end
function tmp = code(a, b, c, d)
	tmp = b / c;
end
code[a_, b_, c_, d_] := N[(b / c), $MachinePrecision]
\begin{array}{l}

\\
\frac{b}{c}
\end{array}
Derivation
  1. Initial program 66.0%

    \[\frac{b \cdot c - a \cdot d}{c \cdot c + d \cdot d} \]
  2. Add Preprocessing
  3. Taylor expanded in c around inf

    \[\leadsto \color{blue}{\frac{b}{c}} \]
  4. Step-by-step derivation
    1. lower-/.f6437.6

      \[\leadsto \color{blue}{\frac{b}{c}} \]
  5. Applied rewrites37.6%

    \[\leadsto \color{blue}{\frac{b}{c}} \]
  6. Add Preprocessing

Developer Target 1: 99.3% accurate, 0.6× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;\left|d\right| < \left|c\right|:\\ \;\;\;\;\frac{b - a \cdot \frac{d}{c}}{c + d \cdot \frac{d}{c}}\\ \mathbf{else}:\\ \;\;\;\;\frac{\left(-a\right) + b \cdot \frac{c}{d}}{d + c \cdot \frac{c}{d}}\\ \end{array} \end{array} \]
(FPCore (a b c d)
 :precision binary64
 (if (< (fabs d) (fabs c))
   (/ (- b (* a (/ d c))) (+ c (* d (/ d c))))
   (/ (+ (- a) (* b (/ c d))) (+ d (* c (/ c d))))))
double code(double a, double b, double c, double d) {
	double tmp;
	if (fabs(d) < fabs(c)) {
		tmp = (b - (a * (d / c))) / (c + (d * (d / c)));
	} else {
		tmp = (-a + (b * (c / d))) / (d + (c * (c / d)));
	}
	return tmp;
}
real(8) function code(a, b, c, d)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    real(8), intent (in) :: c
    real(8), intent (in) :: d
    real(8) :: tmp
    if (abs(d) < abs(c)) then
        tmp = (b - (a * (d / c))) / (c + (d * (d / c)))
    else
        tmp = (-a + (b * (c / d))) / (d + (c * (c / d)))
    end if
    code = tmp
end function
public static double code(double a, double b, double c, double d) {
	double tmp;
	if (Math.abs(d) < Math.abs(c)) {
		tmp = (b - (a * (d / c))) / (c + (d * (d / c)));
	} else {
		tmp = (-a + (b * (c / d))) / (d + (c * (c / d)));
	}
	return tmp;
}
def code(a, b, c, d):
	tmp = 0
	if math.fabs(d) < math.fabs(c):
		tmp = (b - (a * (d / c))) / (c + (d * (d / c)))
	else:
		tmp = (-a + (b * (c / d))) / (d + (c * (c / d)))
	return tmp
function code(a, b, c, d)
	tmp = 0.0
	if (abs(d) < abs(c))
		tmp = Float64(Float64(b - Float64(a * Float64(d / c))) / Float64(c + Float64(d * Float64(d / c))));
	else
		tmp = Float64(Float64(Float64(-a) + Float64(b * Float64(c / d))) / Float64(d + Float64(c * Float64(c / d))));
	end
	return tmp
end
function tmp_2 = code(a, b, c, d)
	tmp = 0.0;
	if (abs(d) < abs(c))
		tmp = (b - (a * (d / c))) / (c + (d * (d / c)));
	else
		tmp = (-a + (b * (c / d))) / (d + (c * (c / d)));
	end
	tmp_2 = tmp;
end
code[a_, b_, c_, d_] := If[Less[N[Abs[d], $MachinePrecision], N[Abs[c], $MachinePrecision]], N[(N[(b - N[(a * N[(d / c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(c + N[(d * N[(d / c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[((-a) + N[(b * N[(c / d), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(d + N[(c * N[(c / d), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;\left|d\right| < \left|c\right|:\\
\;\;\;\;\frac{b - a \cdot \frac{d}{c}}{c + d \cdot \frac{d}{c}}\\

\mathbf{else}:\\
\;\;\;\;\frac{\left(-a\right) + b \cdot \frac{c}{d}}{d + c \cdot \frac{c}{d}}\\


\end{array}
\end{array}

Reproduce

?
herbie shell --seed 2024327 
(FPCore (a b c d)
  :name "Complex division, imag part"
  :precision binary64

  :alt
  (! :herbie-platform default (if (< (fabs d) (fabs c)) (/ (- b (* a (/ d c))) (+ c (* d (/ d c)))) (/ (+ (- a) (* b (/ c d))) (+ d (* c (/ c d))))))

  (/ (- (* b c) (* a d)) (+ (* c c) (* d d))))