Quotient of products

Percentage Accurate: 86.3% → 97.8%
Time: 4.5s
Alternatives: 4
Speedup: 1.0×

Specification

?
\[\begin{array}{l} \\ \frac{a1 \cdot a2}{b1 \cdot b2} \end{array} \]
(FPCore (a1 a2 b1 b2) :precision binary64 (/ (* a1 a2) (* b1 b2)))
double code(double a1, double a2, double b1, double b2) {
	return (a1 * a2) / (b1 * b2);
}
real(8) function code(a1, a2, b1, b2)
    real(8), intent (in) :: a1
    real(8), intent (in) :: a2
    real(8), intent (in) :: b1
    real(8), intent (in) :: b2
    code = (a1 * a2) / (b1 * b2)
end function
public static double code(double a1, double a2, double b1, double b2) {
	return (a1 * a2) / (b1 * b2);
}
def code(a1, a2, b1, b2):
	return (a1 * a2) / (b1 * b2)
function code(a1, a2, b1, b2)
	return Float64(Float64(a1 * a2) / Float64(b1 * b2))
end
function tmp = code(a1, a2, b1, b2)
	tmp = (a1 * a2) / (b1 * b2);
end
code[a1_, a2_, b1_, b2_] := N[(N[(a1 * a2), $MachinePrecision] / N[(b1 * b2), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{a1 \cdot a2}{b1 \cdot b2}
\end{array}

Sampling outcomes in binary64 precision:

Local Percentage Accuracy vs ?

The average percentage accuracy by input value. Horizontal axis shows value of an input variable; the variable is choosen in the title. Vertical axis is accuracy; higher is better. Red represent the original program, while blue represents Herbie's suggestion. These can be toggled with buttons below the plot. The line is an average while dots represent individual samples.

Accuracy vs Speed?

Herbie found 4 alternatives:

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

Initial Program: 86.3% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \frac{a1 \cdot a2}{b1 \cdot b2} \end{array} \]
(FPCore (a1 a2 b1 b2) :precision binary64 (/ (* a1 a2) (* b1 b2)))
double code(double a1, double a2, double b1, double b2) {
	return (a1 * a2) / (b1 * b2);
}
real(8) function code(a1, a2, b1, b2)
    real(8), intent (in) :: a1
    real(8), intent (in) :: a2
    real(8), intent (in) :: b1
    real(8), intent (in) :: b2
    code = (a1 * a2) / (b1 * b2)
end function
public static double code(double a1, double a2, double b1, double b2) {
	return (a1 * a2) / (b1 * b2);
}
def code(a1, a2, b1, b2):
	return (a1 * a2) / (b1 * b2)
function code(a1, a2, b1, b2)
	return Float64(Float64(a1 * a2) / Float64(b1 * b2))
end
function tmp = code(a1, a2, b1, b2)
	tmp = (a1 * a2) / (b1 * b2);
end
code[a1_, a2_, b1_, b2_] := N[(N[(a1 * a2), $MachinePrecision] / N[(b1 * b2), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{a1 \cdot a2}{b1 \cdot b2}
\end{array}

Alternative 1: 97.8% accurate, 0.3× speedup?

\[\begin{array}{l} b2\_m = \left|b2\right| \\ b2\_s = \mathsf{copysign}\left(1, b2\right) \\ b1\_m = \left|b1\right| \\ b1\_s = \mathsf{copysign}\left(1, b1\right) \\ a2\_m = \left|a2\right| \\ a2\_s = \mathsf{copysign}\left(1, a2\right) \\ a1\_m = \left|a1\right| \\ a1\_s = \mathsf{copysign}\left(1, a1\right) \\ \begin{array}{l} t_0 := \frac{a2\_m \cdot a1\_m}{b2\_m \cdot b1\_m}\\ t_1 := \frac{a2\_m}{b1\_m} \cdot \frac{a1\_m}{b2\_m}\\ a1\_s \cdot \left(a2\_s \cdot \left(b1\_s \cdot \left(b2\_s \cdot \begin{array}{l} \mathbf{if}\;t\_0 \leq 0:\\ \;\;\;\;t\_1\\ \mathbf{elif}\;t\_0 \leq 10^{+308}:\\ \;\;\;\;t\_0\\ \mathbf{else}:\\ \;\;\;\;t\_1\\ \end{array}\right)\right)\right) \end{array} \end{array} \]
b2\_m = (fabs.f64 b2)
b2\_s = (copysign.f64 #s(literal 1 binary64) b2)
b1\_m = (fabs.f64 b1)
b1\_s = (copysign.f64 #s(literal 1 binary64) b1)
a2\_m = (fabs.f64 a2)
a2\_s = (copysign.f64 #s(literal 1 binary64) a2)
a1\_m = (fabs.f64 a1)
a1\_s = (copysign.f64 #s(literal 1 binary64) a1)
(FPCore (a1_s a2_s b1_s b2_s a1_m a2_m b1_m b2_m)
 :precision binary64
 (let* ((t_0 (/ (* a2_m a1_m) (* b2_m b1_m)))
        (t_1 (* (/ a2_m b1_m) (/ a1_m b2_m))))
   (*
    a1_s
    (*
     a2_s
     (* b1_s (* b2_s (if (<= t_0 0.0) t_1 (if (<= t_0 1e+308) t_0 t_1))))))))
b2\_m = fabs(b2);
b2\_s = copysign(1.0, b2);
b1\_m = fabs(b1);
b1\_s = copysign(1.0, b1);
a2\_m = fabs(a2);
a2\_s = copysign(1.0, a2);
a1\_m = fabs(a1);
a1\_s = copysign(1.0, a1);
double code(double a1_s, double a2_s, double b1_s, double b2_s, double a1_m, double a2_m, double b1_m, double b2_m) {
	double t_0 = (a2_m * a1_m) / (b2_m * b1_m);
	double t_1 = (a2_m / b1_m) * (a1_m / b2_m);
	double tmp;
	if (t_0 <= 0.0) {
		tmp = t_1;
	} else if (t_0 <= 1e+308) {
		tmp = t_0;
	} else {
		tmp = t_1;
	}
	return a1_s * (a2_s * (b1_s * (b2_s * tmp)));
}
b2\_m = abs(b2)
b2\_s = copysign(1.0d0, b2)
b1\_m = abs(b1)
b1\_s = copysign(1.0d0, b1)
a2\_m = abs(a2)
a2\_s = copysign(1.0d0, a2)
a1\_m = abs(a1)
a1\_s = copysign(1.0d0, a1)
real(8) function code(a1_s, a2_s, b1_s, b2_s, a1_m, a2_m, b1_m, b2_m)
    real(8), intent (in) :: a1_s
    real(8), intent (in) :: a2_s
    real(8), intent (in) :: b1_s
    real(8), intent (in) :: b2_s
    real(8), intent (in) :: a1_m
    real(8), intent (in) :: a2_m
    real(8), intent (in) :: b1_m
    real(8), intent (in) :: b2_m
    real(8) :: t_0
    real(8) :: t_1
    real(8) :: tmp
    t_0 = (a2_m * a1_m) / (b2_m * b1_m)
    t_1 = (a2_m / b1_m) * (a1_m / b2_m)
    if (t_0 <= 0.0d0) then
        tmp = t_1
    else if (t_0 <= 1d+308) then
        tmp = t_0
    else
        tmp = t_1
    end if
    code = a1_s * (a2_s * (b1_s * (b2_s * tmp)))
end function
b2\_m = Math.abs(b2);
b2\_s = Math.copySign(1.0, b2);
b1\_m = Math.abs(b1);
b1\_s = Math.copySign(1.0, b1);
a2\_m = Math.abs(a2);
a2\_s = Math.copySign(1.0, a2);
a1\_m = Math.abs(a1);
a1\_s = Math.copySign(1.0, a1);
public static double code(double a1_s, double a2_s, double b1_s, double b2_s, double a1_m, double a2_m, double b1_m, double b2_m) {
	double t_0 = (a2_m * a1_m) / (b2_m * b1_m);
	double t_1 = (a2_m / b1_m) * (a1_m / b2_m);
	double tmp;
	if (t_0 <= 0.0) {
		tmp = t_1;
	} else if (t_0 <= 1e+308) {
		tmp = t_0;
	} else {
		tmp = t_1;
	}
	return a1_s * (a2_s * (b1_s * (b2_s * tmp)));
}
b2\_m = math.fabs(b2)
b2\_s = math.copysign(1.0, b2)
b1\_m = math.fabs(b1)
b1\_s = math.copysign(1.0, b1)
a2\_m = math.fabs(a2)
a2\_s = math.copysign(1.0, a2)
a1\_m = math.fabs(a1)
a1\_s = math.copysign(1.0, a1)
def code(a1_s, a2_s, b1_s, b2_s, a1_m, a2_m, b1_m, b2_m):
	t_0 = (a2_m * a1_m) / (b2_m * b1_m)
	t_1 = (a2_m / b1_m) * (a1_m / b2_m)
	tmp = 0
	if t_0 <= 0.0:
		tmp = t_1
	elif t_0 <= 1e+308:
		tmp = t_0
	else:
		tmp = t_1
	return a1_s * (a2_s * (b1_s * (b2_s * tmp)))
b2\_m = abs(b2)
b2\_s = copysign(1.0, b2)
b1\_m = abs(b1)
b1\_s = copysign(1.0, b1)
a2\_m = abs(a2)
a2\_s = copysign(1.0, a2)
a1\_m = abs(a1)
a1\_s = copysign(1.0, a1)
function code(a1_s, a2_s, b1_s, b2_s, a1_m, a2_m, b1_m, b2_m)
	t_0 = Float64(Float64(a2_m * a1_m) / Float64(b2_m * b1_m))
	t_1 = Float64(Float64(a2_m / b1_m) * Float64(a1_m / b2_m))
	tmp = 0.0
	if (t_0 <= 0.0)
		tmp = t_1;
	elseif (t_0 <= 1e+308)
		tmp = t_0;
	else
		tmp = t_1;
	end
	return Float64(a1_s * Float64(a2_s * Float64(b1_s * Float64(b2_s * tmp))))
end
b2\_m = abs(b2);
b2\_s = sign(b2) * abs(1.0);
b1\_m = abs(b1);
b1\_s = sign(b1) * abs(1.0);
a2\_m = abs(a2);
a2\_s = sign(a2) * abs(1.0);
a1\_m = abs(a1);
a1\_s = sign(a1) * abs(1.0);
function tmp_2 = code(a1_s, a2_s, b1_s, b2_s, a1_m, a2_m, b1_m, b2_m)
	t_0 = (a2_m * a1_m) / (b2_m * b1_m);
	t_1 = (a2_m / b1_m) * (a1_m / b2_m);
	tmp = 0.0;
	if (t_0 <= 0.0)
		tmp = t_1;
	elseif (t_0 <= 1e+308)
		tmp = t_0;
	else
		tmp = t_1;
	end
	tmp_2 = a1_s * (a2_s * (b1_s * (b2_s * tmp)));
end
b2\_m = N[Abs[b2], $MachinePrecision]
b2\_s = N[With[{TMP1 = Abs[1.0], TMP2 = Sign[b2]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
b1\_m = N[Abs[b1], $MachinePrecision]
b1\_s = N[With[{TMP1 = Abs[1.0], TMP2 = Sign[b1]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
a2\_m = N[Abs[a2], $MachinePrecision]
a2\_s = N[With[{TMP1 = Abs[1.0], TMP2 = Sign[a2]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
a1\_m = N[Abs[a1], $MachinePrecision]
a1\_s = N[With[{TMP1 = Abs[1.0], TMP2 = Sign[a1]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
code[a1$95$s_, a2$95$s_, b1$95$s_, b2$95$s_, a1$95$m_, a2$95$m_, b1$95$m_, b2$95$m_] := Block[{t$95$0 = N[(N[(a2$95$m * a1$95$m), $MachinePrecision] / N[(b2$95$m * b1$95$m), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[(N[(a2$95$m / b1$95$m), $MachinePrecision] * N[(a1$95$m / b2$95$m), $MachinePrecision]), $MachinePrecision]}, N[(a1$95$s * N[(a2$95$s * N[(b1$95$s * N[(b2$95$s * If[LessEqual[t$95$0, 0.0], t$95$1, If[LessEqual[t$95$0, 1e+308], t$95$0, t$95$1]]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
b2\_m = \left|b2\right|
\\
b2\_s = \mathsf{copysign}\left(1, b2\right)
\\
b1\_m = \left|b1\right|
\\
b1\_s = \mathsf{copysign}\left(1, b1\right)
\\
a2\_m = \left|a2\right|
\\
a2\_s = \mathsf{copysign}\left(1, a2\right)
\\
a1\_m = \left|a1\right|
\\
a1\_s = \mathsf{copysign}\left(1, a1\right)

\\
\begin{array}{l}
t_0 := \frac{a2\_m \cdot a1\_m}{b2\_m \cdot b1\_m}\\
t_1 := \frac{a2\_m}{b1\_m} \cdot \frac{a1\_m}{b2\_m}\\
a1\_s \cdot \left(a2\_s \cdot \left(b1\_s \cdot \left(b2\_s \cdot \begin{array}{l}
\mathbf{if}\;t\_0 \leq 0:\\
\;\;\;\;t\_1\\

\mathbf{elif}\;t\_0 \leq 10^{+308}:\\
\;\;\;\;t\_0\\

\mathbf{else}:\\
\;\;\;\;t\_1\\


\end{array}\right)\right)\right)
\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (/.f64 (*.f64 a1 a2) (*.f64 b1 b2)) < 0.0 or 1e308 < (/.f64 (*.f64 a1 a2) (*.f64 b1 b2))

    1. Initial program 83.1%

      \[\frac{a1 \cdot a2}{b1 \cdot b2} \]
    2. Add Preprocessing
    3. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \frac{\color{blue}{a2 \cdot a1}}{b1 \cdot b2} \]
      2. times-fracN/A

        \[\leadsto \color{blue}{\frac{a2}{b1} \cdot \frac{a1}{b2}} \]
      3. lower-*.f64N/A

        \[\leadsto \color{blue}{\frac{a2}{b1} \cdot \frac{a1}{b2}} \]
      4. lower-/.f64N/A

        \[\leadsto \color{blue}{\frac{a2}{b1}} \cdot \frac{a1}{b2} \]
      5. lower-/.f6492.2

        \[\leadsto \frac{a2}{b1} \cdot \color{blue}{\frac{a1}{b2}} \]
    4. Applied egg-rr92.2%

      \[\leadsto \color{blue}{\frac{a2}{b1} \cdot \frac{a1}{b2}} \]

    if 0.0 < (/.f64 (*.f64 a1 a2) (*.f64 b1 b2)) < 1e308

    1. Initial program 99.1%

      \[\frac{a1 \cdot a2}{b1 \cdot b2} \]
    2. Add Preprocessing
  3. Recombined 2 regimes into one program.
  4. Final simplification93.8%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{a2 \cdot a1}{b2 \cdot b1} \leq 0:\\ \;\;\;\;\frac{a2}{b1} \cdot \frac{a1}{b2}\\ \mathbf{elif}\;\frac{a2 \cdot a1}{b2 \cdot b1} \leq 10^{+308}:\\ \;\;\;\;\frac{a2 \cdot a1}{b2 \cdot b1}\\ \mathbf{else}:\\ \;\;\;\;\frac{a2}{b1} \cdot \frac{a1}{b2}\\ \end{array} \]
  5. Add Preprocessing

Alternative 2: 86.7% accurate, 0.7× speedup?

\[\begin{array}{l} b2\_m = \left|b2\right| \\ b2\_s = \mathsf{copysign}\left(1, b2\right) \\ b1\_m = \left|b1\right| \\ b1\_s = \mathsf{copysign}\left(1, b1\right) \\ a2\_m = \left|a2\right| \\ a2\_s = \mathsf{copysign}\left(1, a2\right) \\ a1\_m = \left|a1\right| \\ a1\_s = \mathsf{copysign}\left(1, a1\right) \\ a1\_s \cdot \left(a2\_s \cdot \left(b1\_s \cdot \left(b2\_s \cdot \begin{array}{l} \mathbf{if}\;b2\_m \cdot b1\_m \leq 5 \cdot 10^{-45}:\\ \;\;\;\;a2\_m \cdot \frac{a1\_m}{b2\_m \cdot b1\_m}\\ \mathbf{else}:\\ \;\;\;\;a1\_m \cdot \frac{a2\_m}{b2\_m \cdot b1\_m}\\ \end{array}\right)\right)\right) \end{array} \]
b2\_m = (fabs.f64 b2)
b2\_s = (copysign.f64 #s(literal 1 binary64) b2)
b1\_m = (fabs.f64 b1)
b1\_s = (copysign.f64 #s(literal 1 binary64) b1)
a2\_m = (fabs.f64 a2)
a2\_s = (copysign.f64 #s(literal 1 binary64) a2)
a1\_m = (fabs.f64 a1)
a1\_s = (copysign.f64 #s(literal 1 binary64) a1)
(FPCore (a1_s a2_s b1_s b2_s a1_m a2_m b1_m b2_m)
 :precision binary64
 (*
  a1_s
  (*
   a2_s
   (*
    b1_s
    (*
     b2_s
     (if (<= (* b2_m b1_m) 5e-45)
       (* a2_m (/ a1_m (* b2_m b1_m)))
       (* a1_m (/ a2_m (* b2_m b1_m)))))))))
b2\_m = fabs(b2);
b2\_s = copysign(1.0, b2);
b1\_m = fabs(b1);
b1\_s = copysign(1.0, b1);
a2\_m = fabs(a2);
a2\_s = copysign(1.0, a2);
a1\_m = fabs(a1);
a1\_s = copysign(1.0, a1);
double code(double a1_s, double a2_s, double b1_s, double b2_s, double a1_m, double a2_m, double b1_m, double b2_m) {
	double tmp;
	if ((b2_m * b1_m) <= 5e-45) {
		tmp = a2_m * (a1_m / (b2_m * b1_m));
	} else {
		tmp = a1_m * (a2_m / (b2_m * b1_m));
	}
	return a1_s * (a2_s * (b1_s * (b2_s * tmp)));
}
b2\_m = abs(b2)
b2\_s = copysign(1.0d0, b2)
b1\_m = abs(b1)
b1\_s = copysign(1.0d0, b1)
a2\_m = abs(a2)
a2\_s = copysign(1.0d0, a2)
a1\_m = abs(a1)
a1\_s = copysign(1.0d0, a1)
real(8) function code(a1_s, a2_s, b1_s, b2_s, a1_m, a2_m, b1_m, b2_m)
    real(8), intent (in) :: a1_s
    real(8), intent (in) :: a2_s
    real(8), intent (in) :: b1_s
    real(8), intent (in) :: b2_s
    real(8), intent (in) :: a1_m
    real(8), intent (in) :: a2_m
    real(8), intent (in) :: b1_m
    real(8), intent (in) :: b2_m
    real(8) :: tmp
    if ((b2_m * b1_m) <= 5d-45) then
        tmp = a2_m * (a1_m / (b2_m * b1_m))
    else
        tmp = a1_m * (a2_m / (b2_m * b1_m))
    end if
    code = a1_s * (a2_s * (b1_s * (b2_s * tmp)))
end function
b2\_m = Math.abs(b2);
b2\_s = Math.copySign(1.0, b2);
b1\_m = Math.abs(b1);
b1\_s = Math.copySign(1.0, b1);
a2\_m = Math.abs(a2);
a2\_s = Math.copySign(1.0, a2);
a1\_m = Math.abs(a1);
a1\_s = Math.copySign(1.0, a1);
public static double code(double a1_s, double a2_s, double b1_s, double b2_s, double a1_m, double a2_m, double b1_m, double b2_m) {
	double tmp;
	if ((b2_m * b1_m) <= 5e-45) {
		tmp = a2_m * (a1_m / (b2_m * b1_m));
	} else {
		tmp = a1_m * (a2_m / (b2_m * b1_m));
	}
	return a1_s * (a2_s * (b1_s * (b2_s * tmp)));
}
b2\_m = math.fabs(b2)
b2\_s = math.copysign(1.0, b2)
b1\_m = math.fabs(b1)
b1\_s = math.copysign(1.0, b1)
a2\_m = math.fabs(a2)
a2\_s = math.copysign(1.0, a2)
a1\_m = math.fabs(a1)
a1\_s = math.copysign(1.0, a1)
def code(a1_s, a2_s, b1_s, b2_s, a1_m, a2_m, b1_m, b2_m):
	tmp = 0
	if (b2_m * b1_m) <= 5e-45:
		tmp = a2_m * (a1_m / (b2_m * b1_m))
	else:
		tmp = a1_m * (a2_m / (b2_m * b1_m))
	return a1_s * (a2_s * (b1_s * (b2_s * tmp)))
b2\_m = abs(b2)
b2\_s = copysign(1.0, b2)
b1\_m = abs(b1)
b1\_s = copysign(1.0, b1)
a2\_m = abs(a2)
a2\_s = copysign(1.0, a2)
a1\_m = abs(a1)
a1\_s = copysign(1.0, a1)
function code(a1_s, a2_s, b1_s, b2_s, a1_m, a2_m, b1_m, b2_m)
	tmp = 0.0
	if (Float64(b2_m * b1_m) <= 5e-45)
		tmp = Float64(a2_m * Float64(a1_m / Float64(b2_m * b1_m)));
	else
		tmp = Float64(a1_m * Float64(a2_m / Float64(b2_m * b1_m)));
	end
	return Float64(a1_s * Float64(a2_s * Float64(b1_s * Float64(b2_s * tmp))))
end
b2\_m = abs(b2);
b2\_s = sign(b2) * abs(1.0);
b1\_m = abs(b1);
b1\_s = sign(b1) * abs(1.0);
a2\_m = abs(a2);
a2\_s = sign(a2) * abs(1.0);
a1\_m = abs(a1);
a1\_s = sign(a1) * abs(1.0);
function tmp_2 = code(a1_s, a2_s, b1_s, b2_s, a1_m, a2_m, b1_m, b2_m)
	tmp = 0.0;
	if ((b2_m * b1_m) <= 5e-45)
		tmp = a2_m * (a1_m / (b2_m * b1_m));
	else
		tmp = a1_m * (a2_m / (b2_m * b1_m));
	end
	tmp_2 = a1_s * (a2_s * (b1_s * (b2_s * tmp)));
end
b2\_m = N[Abs[b2], $MachinePrecision]
b2\_s = N[With[{TMP1 = Abs[1.0], TMP2 = Sign[b2]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
b1\_m = N[Abs[b1], $MachinePrecision]
b1\_s = N[With[{TMP1 = Abs[1.0], TMP2 = Sign[b1]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
a2\_m = N[Abs[a2], $MachinePrecision]
a2\_s = N[With[{TMP1 = Abs[1.0], TMP2 = Sign[a2]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
a1\_m = N[Abs[a1], $MachinePrecision]
a1\_s = N[With[{TMP1 = Abs[1.0], TMP2 = Sign[a1]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
code[a1$95$s_, a2$95$s_, b1$95$s_, b2$95$s_, a1$95$m_, a2$95$m_, b1$95$m_, b2$95$m_] := N[(a1$95$s * N[(a2$95$s * N[(b1$95$s * N[(b2$95$s * If[LessEqual[N[(b2$95$m * b1$95$m), $MachinePrecision], 5e-45], N[(a2$95$m * N[(a1$95$m / N[(b2$95$m * b1$95$m), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(a1$95$m * N[(a2$95$m / N[(b2$95$m * b1$95$m), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
b2\_m = \left|b2\right|
\\
b2\_s = \mathsf{copysign}\left(1, b2\right)
\\
b1\_m = \left|b1\right|
\\
b1\_s = \mathsf{copysign}\left(1, b1\right)
\\
a2\_m = \left|a2\right|
\\
a2\_s = \mathsf{copysign}\left(1, a2\right)
\\
a1\_m = \left|a1\right|
\\
a1\_s = \mathsf{copysign}\left(1, a1\right)

\\
a1\_s \cdot \left(a2\_s \cdot \left(b1\_s \cdot \left(b2\_s \cdot \begin{array}{l}
\mathbf{if}\;b2\_m \cdot b1\_m \leq 5 \cdot 10^{-45}:\\
\;\;\;\;a2\_m \cdot \frac{a1\_m}{b2\_m \cdot b1\_m}\\

\mathbf{else}:\\
\;\;\;\;a1\_m \cdot \frac{a2\_m}{b2\_m \cdot b1\_m}\\


\end{array}\right)\right)\right)
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (*.f64 b1 b2) < 4.99999999999999976e-45

    1. Initial program 87.3%

      \[\frac{a1 \cdot a2}{b1 \cdot b2} \]
    2. Add Preprocessing
    3. Step-by-step derivation
      1. lift-*.f64N/A

        \[\leadsto \frac{a1 \cdot a2}{\color{blue}{b1 \cdot b2}} \]
      2. associate-*l/N/A

        \[\leadsto \color{blue}{\frac{a1}{b1 \cdot b2} \cdot a2} \]
      3. lower-*.f64N/A

        \[\leadsto \color{blue}{\frac{a1}{b1 \cdot b2} \cdot a2} \]
      4. lower-/.f6486.9

        \[\leadsto \color{blue}{\frac{a1}{b1 \cdot b2}} \cdot a2 \]
    4. Applied egg-rr86.9%

      \[\leadsto \color{blue}{\frac{a1}{b1 \cdot b2} \cdot a2} \]

    if 4.99999999999999976e-45 < (*.f64 b1 b2)

    1. Initial program 86.3%

      \[\frac{a1 \cdot a2}{b1 \cdot b2} \]
    2. Add Preprocessing
    3. Step-by-step derivation
      1. lift-*.f64N/A

        \[\leadsto \frac{a1 \cdot a2}{\color{blue}{b1 \cdot b2}} \]
      2. associate-/l*N/A

        \[\leadsto \color{blue}{a1 \cdot \frac{a2}{b1 \cdot b2}} \]
      3. *-commutativeN/A

        \[\leadsto \color{blue}{\frac{a2}{b1 \cdot b2} \cdot a1} \]
      4. lower-*.f64N/A

        \[\leadsto \color{blue}{\frac{a2}{b1 \cdot b2} \cdot a1} \]
      5. lower-/.f6489.6

        \[\leadsto \color{blue}{\frac{a2}{b1 \cdot b2}} \cdot a1 \]
    4. Applied egg-rr89.6%

      \[\leadsto \color{blue}{\frac{a2}{b1 \cdot b2} \cdot a1} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification87.8%

    \[\leadsto \begin{array}{l} \mathbf{if}\;b2 \cdot b1 \leq 5 \cdot 10^{-45}:\\ \;\;\;\;a2 \cdot \frac{a1}{b2 \cdot b1}\\ \mathbf{else}:\\ \;\;\;\;a1 \cdot \frac{a2}{b2 \cdot b1}\\ \end{array} \]
  5. Add Preprocessing

Alternative 3: 85.7% accurate, 0.8× speedup?

\[\begin{array}{l} b2\_m = \left|b2\right| \\ b2\_s = \mathsf{copysign}\left(1, b2\right) \\ b1\_m = \left|b1\right| \\ b1\_s = \mathsf{copysign}\left(1, b1\right) \\ a2\_m = \left|a2\right| \\ a2\_s = \mathsf{copysign}\left(1, a2\right) \\ a1\_m = \left|a1\right| \\ a1\_s = \mathsf{copysign}\left(1, a1\right) \\ a1\_s \cdot \left(a2\_s \cdot \left(b1\_s \cdot \left(b2\_s \cdot \left(\frac{a2\_m}{b2\_m} \cdot \frac{a1\_m}{b1\_m}\right)\right)\right)\right) \end{array} \]
b2\_m = (fabs.f64 b2)
b2\_s = (copysign.f64 #s(literal 1 binary64) b2)
b1\_m = (fabs.f64 b1)
b1\_s = (copysign.f64 #s(literal 1 binary64) b1)
a2\_m = (fabs.f64 a2)
a2\_s = (copysign.f64 #s(literal 1 binary64) a2)
a1\_m = (fabs.f64 a1)
a1\_s = (copysign.f64 #s(literal 1 binary64) a1)
(FPCore (a1_s a2_s b1_s b2_s a1_m a2_m b1_m b2_m)
 :precision binary64
 (* a1_s (* a2_s (* b1_s (* b2_s (* (/ a2_m b2_m) (/ a1_m b1_m)))))))
b2\_m = fabs(b2);
b2\_s = copysign(1.0, b2);
b1\_m = fabs(b1);
b1\_s = copysign(1.0, b1);
a2\_m = fabs(a2);
a2\_s = copysign(1.0, a2);
a1\_m = fabs(a1);
a1\_s = copysign(1.0, a1);
double code(double a1_s, double a2_s, double b1_s, double b2_s, double a1_m, double a2_m, double b1_m, double b2_m) {
	return a1_s * (a2_s * (b1_s * (b2_s * ((a2_m / b2_m) * (a1_m / b1_m)))));
}
b2\_m = abs(b2)
b2\_s = copysign(1.0d0, b2)
b1\_m = abs(b1)
b1\_s = copysign(1.0d0, b1)
a2\_m = abs(a2)
a2\_s = copysign(1.0d0, a2)
a1\_m = abs(a1)
a1\_s = copysign(1.0d0, a1)
real(8) function code(a1_s, a2_s, b1_s, b2_s, a1_m, a2_m, b1_m, b2_m)
    real(8), intent (in) :: a1_s
    real(8), intent (in) :: a2_s
    real(8), intent (in) :: b1_s
    real(8), intent (in) :: b2_s
    real(8), intent (in) :: a1_m
    real(8), intent (in) :: a2_m
    real(8), intent (in) :: b1_m
    real(8), intent (in) :: b2_m
    code = a1_s * (a2_s * (b1_s * (b2_s * ((a2_m / b2_m) * (a1_m / b1_m)))))
end function
b2\_m = Math.abs(b2);
b2\_s = Math.copySign(1.0, b2);
b1\_m = Math.abs(b1);
b1\_s = Math.copySign(1.0, b1);
a2\_m = Math.abs(a2);
a2\_s = Math.copySign(1.0, a2);
a1\_m = Math.abs(a1);
a1\_s = Math.copySign(1.0, a1);
public static double code(double a1_s, double a2_s, double b1_s, double b2_s, double a1_m, double a2_m, double b1_m, double b2_m) {
	return a1_s * (a2_s * (b1_s * (b2_s * ((a2_m / b2_m) * (a1_m / b1_m)))));
}
b2\_m = math.fabs(b2)
b2\_s = math.copysign(1.0, b2)
b1\_m = math.fabs(b1)
b1\_s = math.copysign(1.0, b1)
a2\_m = math.fabs(a2)
a2\_s = math.copysign(1.0, a2)
a1\_m = math.fabs(a1)
a1\_s = math.copysign(1.0, a1)
def code(a1_s, a2_s, b1_s, b2_s, a1_m, a2_m, b1_m, b2_m):
	return a1_s * (a2_s * (b1_s * (b2_s * ((a2_m / b2_m) * (a1_m / b1_m)))))
b2\_m = abs(b2)
b2\_s = copysign(1.0, b2)
b1\_m = abs(b1)
b1\_s = copysign(1.0, b1)
a2\_m = abs(a2)
a2\_s = copysign(1.0, a2)
a1\_m = abs(a1)
a1\_s = copysign(1.0, a1)
function code(a1_s, a2_s, b1_s, b2_s, a1_m, a2_m, b1_m, b2_m)
	return Float64(a1_s * Float64(a2_s * Float64(b1_s * Float64(b2_s * Float64(Float64(a2_m / b2_m) * Float64(a1_m / b1_m))))))
end
b2\_m = abs(b2);
b2\_s = sign(b2) * abs(1.0);
b1\_m = abs(b1);
b1\_s = sign(b1) * abs(1.0);
a2\_m = abs(a2);
a2\_s = sign(a2) * abs(1.0);
a1\_m = abs(a1);
a1\_s = sign(a1) * abs(1.0);
function tmp = code(a1_s, a2_s, b1_s, b2_s, a1_m, a2_m, b1_m, b2_m)
	tmp = a1_s * (a2_s * (b1_s * (b2_s * ((a2_m / b2_m) * (a1_m / b1_m)))));
end
b2\_m = N[Abs[b2], $MachinePrecision]
b2\_s = N[With[{TMP1 = Abs[1.0], TMP2 = Sign[b2]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
b1\_m = N[Abs[b1], $MachinePrecision]
b1\_s = N[With[{TMP1 = Abs[1.0], TMP2 = Sign[b1]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
a2\_m = N[Abs[a2], $MachinePrecision]
a2\_s = N[With[{TMP1 = Abs[1.0], TMP2 = Sign[a2]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
a1\_m = N[Abs[a1], $MachinePrecision]
a1\_s = N[With[{TMP1 = Abs[1.0], TMP2 = Sign[a1]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
code[a1$95$s_, a2$95$s_, b1$95$s_, b2$95$s_, a1$95$m_, a2$95$m_, b1$95$m_, b2$95$m_] := N[(a1$95$s * N[(a2$95$s * N[(b1$95$s * N[(b2$95$s * N[(N[(a2$95$m / b2$95$m), $MachinePrecision] * N[(a1$95$m / b1$95$m), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
b2\_m = \left|b2\right|
\\
b2\_s = \mathsf{copysign}\left(1, b2\right)
\\
b1\_m = \left|b1\right|
\\
b1\_s = \mathsf{copysign}\left(1, b1\right)
\\
a2\_m = \left|a2\right|
\\
a2\_s = \mathsf{copysign}\left(1, a2\right)
\\
a1\_m = \left|a1\right|
\\
a1\_s = \mathsf{copysign}\left(1, a1\right)

\\
a1\_s \cdot \left(a2\_s \cdot \left(b1\_s \cdot \left(b2\_s \cdot \left(\frac{a2\_m}{b2\_m} \cdot \frac{a1\_m}{b1\_m}\right)\right)\right)\right)
\end{array}
Derivation
  1. Initial program 87.0%

    \[\frac{a1 \cdot a2}{b1 \cdot b2} \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. times-fracN/A

      \[\leadsto \color{blue}{\frac{a1}{b1} \cdot \frac{a2}{b2}} \]
    2. *-commutativeN/A

      \[\leadsto \color{blue}{\frac{a2}{b2} \cdot \frac{a1}{b1}} \]
    3. lower-*.f64N/A

      \[\leadsto \color{blue}{\frac{a2}{b2} \cdot \frac{a1}{b1}} \]
    4. lower-/.f64N/A

      \[\leadsto \color{blue}{\frac{a2}{b2}} \cdot \frac{a1}{b1} \]
    5. lower-/.f6488.7

      \[\leadsto \frac{a2}{b2} \cdot \color{blue}{\frac{a1}{b1}} \]
  4. Applied egg-rr88.7%

    \[\leadsto \color{blue}{\frac{a2}{b2} \cdot \frac{a1}{b1}} \]
  5. Add Preprocessing

Alternative 4: 86.5% accurate, 1.0× speedup?

\[\begin{array}{l} b2\_m = \left|b2\right| \\ b2\_s = \mathsf{copysign}\left(1, b2\right) \\ b1\_m = \left|b1\right| \\ b1\_s = \mathsf{copysign}\left(1, b1\right) \\ a2\_m = \left|a2\right| \\ a2\_s = \mathsf{copysign}\left(1, a2\right) \\ a1\_m = \left|a1\right| \\ a1\_s = \mathsf{copysign}\left(1, a1\right) \\ a1\_s \cdot \left(a2\_s \cdot \left(b1\_s \cdot \left(b2\_s \cdot \left(a2\_m \cdot \frac{a1\_m}{b2\_m \cdot b1\_m}\right)\right)\right)\right) \end{array} \]
b2\_m = (fabs.f64 b2)
b2\_s = (copysign.f64 #s(literal 1 binary64) b2)
b1\_m = (fabs.f64 b1)
b1\_s = (copysign.f64 #s(literal 1 binary64) b1)
a2\_m = (fabs.f64 a2)
a2\_s = (copysign.f64 #s(literal 1 binary64) a2)
a1\_m = (fabs.f64 a1)
a1\_s = (copysign.f64 #s(literal 1 binary64) a1)
(FPCore (a1_s a2_s b1_s b2_s a1_m a2_m b1_m b2_m)
 :precision binary64
 (* a1_s (* a2_s (* b1_s (* b2_s (* a2_m (/ a1_m (* b2_m b1_m))))))))
b2\_m = fabs(b2);
b2\_s = copysign(1.0, b2);
b1\_m = fabs(b1);
b1\_s = copysign(1.0, b1);
a2\_m = fabs(a2);
a2\_s = copysign(1.0, a2);
a1\_m = fabs(a1);
a1\_s = copysign(1.0, a1);
double code(double a1_s, double a2_s, double b1_s, double b2_s, double a1_m, double a2_m, double b1_m, double b2_m) {
	return a1_s * (a2_s * (b1_s * (b2_s * (a2_m * (a1_m / (b2_m * b1_m))))));
}
b2\_m = abs(b2)
b2\_s = copysign(1.0d0, b2)
b1\_m = abs(b1)
b1\_s = copysign(1.0d0, b1)
a2\_m = abs(a2)
a2\_s = copysign(1.0d0, a2)
a1\_m = abs(a1)
a1\_s = copysign(1.0d0, a1)
real(8) function code(a1_s, a2_s, b1_s, b2_s, a1_m, a2_m, b1_m, b2_m)
    real(8), intent (in) :: a1_s
    real(8), intent (in) :: a2_s
    real(8), intent (in) :: b1_s
    real(8), intent (in) :: b2_s
    real(8), intent (in) :: a1_m
    real(8), intent (in) :: a2_m
    real(8), intent (in) :: b1_m
    real(8), intent (in) :: b2_m
    code = a1_s * (a2_s * (b1_s * (b2_s * (a2_m * (a1_m / (b2_m * b1_m))))))
end function
b2\_m = Math.abs(b2);
b2\_s = Math.copySign(1.0, b2);
b1\_m = Math.abs(b1);
b1\_s = Math.copySign(1.0, b1);
a2\_m = Math.abs(a2);
a2\_s = Math.copySign(1.0, a2);
a1\_m = Math.abs(a1);
a1\_s = Math.copySign(1.0, a1);
public static double code(double a1_s, double a2_s, double b1_s, double b2_s, double a1_m, double a2_m, double b1_m, double b2_m) {
	return a1_s * (a2_s * (b1_s * (b2_s * (a2_m * (a1_m / (b2_m * b1_m))))));
}
b2\_m = math.fabs(b2)
b2\_s = math.copysign(1.0, b2)
b1\_m = math.fabs(b1)
b1\_s = math.copysign(1.0, b1)
a2\_m = math.fabs(a2)
a2\_s = math.copysign(1.0, a2)
a1\_m = math.fabs(a1)
a1\_s = math.copysign(1.0, a1)
def code(a1_s, a2_s, b1_s, b2_s, a1_m, a2_m, b1_m, b2_m):
	return a1_s * (a2_s * (b1_s * (b2_s * (a2_m * (a1_m / (b2_m * b1_m))))))
b2\_m = abs(b2)
b2\_s = copysign(1.0, b2)
b1\_m = abs(b1)
b1\_s = copysign(1.0, b1)
a2\_m = abs(a2)
a2\_s = copysign(1.0, a2)
a1\_m = abs(a1)
a1\_s = copysign(1.0, a1)
function code(a1_s, a2_s, b1_s, b2_s, a1_m, a2_m, b1_m, b2_m)
	return Float64(a1_s * Float64(a2_s * Float64(b1_s * Float64(b2_s * Float64(a2_m * Float64(a1_m / Float64(b2_m * b1_m)))))))
end
b2\_m = abs(b2);
b2\_s = sign(b2) * abs(1.0);
b1\_m = abs(b1);
b1\_s = sign(b1) * abs(1.0);
a2\_m = abs(a2);
a2\_s = sign(a2) * abs(1.0);
a1\_m = abs(a1);
a1\_s = sign(a1) * abs(1.0);
function tmp = code(a1_s, a2_s, b1_s, b2_s, a1_m, a2_m, b1_m, b2_m)
	tmp = a1_s * (a2_s * (b1_s * (b2_s * (a2_m * (a1_m / (b2_m * b1_m))))));
end
b2\_m = N[Abs[b2], $MachinePrecision]
b2\_s = N[With[{TMP1 = Abs[1.0], TMP2 = Sign[b2]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
b1\_m = N[Abs[b1], $MachinePrecision]
b1\_s = N[With[{TMP1 = Abs[1.0], TMP2 = Sign[b1]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
a2\_m = N[Abs[a2], $MachinePrecision]
a2\_s = N[With[{TMP1 = Abs[1.0], TMP2 = Sign[a2]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
a1\_m = N[Abs[a1], $MachinePrecision]
a1\_s = N[With[{TMP1 = Abs[1.0], TMP2 = Sign[a1]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision]
code[a1$95$s_, a2$95$s_, b1$95$s_, b2$95$s_, a1$95$m_, a2$95$m_, b1$95$m_, b2$95$m_] := N[(a1$95$s * N[(a2$95$s * N[(b1$95$s * N[(b2$95$s * N[(a2$95$m * N[(a1$95$m / N[(b2$95$m * b1$95$m), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
b2\_m = \left|b2\right|
\\
b2\_s = \mathsf{copysign}\left(1, b2\right)
\\
b1\_m = \left|b1\right|
\\
b1\_s = \mathsf{copysign}\left(1, b1\right)
\\
a2\_m = \left|a2\right|
\\
a2\_s = \mathsf{copysign}\left(1, a2\right)
\\
a1\_m = \left|a1\right|
\\
a1\_s = \mathsf{copysign}\left(1, a1\right)

\\
a1\_s \cdot \left(a2\_s \cdot \left(b1\_s \cdot \left(b2\_s \cdot \left(a2\_m \cdot \frac{a1\_m}{b2\_m \cdot b1\_m}\right)\right)\right)\right)
\end{array}
Derivation
  1. Initial program 87.0%

    \[\frac{a1 \cdot a2}{b1 \cdot b2} \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. lift-*.f64N/A

      \[\leadsto \frac{a1 \cdot a2}{\color{blue}{b1 \cdot b2}} \]
    2. associate-*l/N/A

      \[\leadsto \color{blue}{\frac{a1}{b1 \cdot b2} \cdot a2} \]
    3. lower-*.f64N/A

      \[\leadsto \color{blue}{\frac{a1}{b1 \cdot b2} \cdot a2} \]
    4. lower-/.f6487.2

      \[\leadsto \color{blue}{\frac{a1}{b1 \cdot b2}} \cdot a2 \]
  4. Applied egg-rr87.2%

    \[\leadsto \color{blue}{\frac{a1}{b1 \cdot b2} \cdot a2} \]
  5. Final simplification87.2%

    \[\leadsto a2 \cdot \frac{a1}{b2 \cdot b1} \]
  6. Add Preprocessing

Developer Target 1: 85.7% accurate, 0.8× speedup?

\[\begin{array}{l} \\ \frac{a1}{b1} \cdot \frac{a2}{b2} \end{array} \]
(FPCore (a1 a2 b1 b2) :precision binary64 (* (/ a1 b1) (/ a2 b2)))
double code(double a1, double a2, double b1, double b2) {
	return (a1 / b1) * (a2 / b2);
}
real(8) function code(a1, a2, b1, b2)
    real(8), intent (in) :: a1
    real(8), intent (in) :: a2
    real(8), intent (in) :: b1
    real(8), intent (in) :: b2
    code = (a1 / b1) * (a2 / b2)
end function
public static double code(double a1, double a2, double b1, double b2) {
	return (a1 / b1) * (a2 / b2);
}
def code(a1, a2, b1, b2):
	return (a1 / b1) * (a2 / b2)
function code(a1, a2, b1, b2)
	return Float64(Float64(a1 / b1) * Float64(a2 / b2))
end
function tmp = code(a1, a2, b1, b2)
	tmp = (a1 / b1) * (a2 / b2);
end
code[a1_, a2_, b1_, b2_] := N[(N[(a1 / b1), $MachinePrecision] * N[(a2 / b2), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{a1}{b1} \cdot \frac{a2}{b2}
\end{array}

Reproduce

?
herbie shell --seed 2024215 
(FPCore (a1 a2 b1 b2)
  :name "Quotient of products"
  :precision binary64

  :alt
  (! :herbie-platform default (* (/ a1 b1) (/ a2 b2)))

  (/ (* a1 a2) (* b1 b2)))