Simplification of discriminant from scale-rotated-ellipse

Percentage Accurate: 24.8% → 95.0%
Time: 1.3min
Alternatives: 4
Speedup: 2485.0×

Specification

?
\[\begin{array}{l} \\ \begin{array}{l} t_0 := \frac{angle}{180} \cdot \pi\\ t_1 := \sin t_0\\ t_2 := \cos t_0\\ t_3 := \frac{\frac{\left(\left(2 \cdot \left({b}^{2} - {a}^{2}\right)\right) \cdot t_1\right) \cdot t_2}{x-scale}}{y-scale}\\ t_3 \cdot t_3 - \left(4 \cdot \frac{\frac{{\left(a \cdot t_1\right)}^{2} + {\left(b \cdot t_2\right)}^{2}}{x-scale}}{x-scale}\right) \cdot \frac{\frac{{\left(a \cdot t_2\right)}^{2} + {\left(b \cdot t_1\right)}^{2}}{y-scale}}{y-scale} \end{array} \end{array} \]
(FPCore (a b angle x-scale y-scale)
 :precision binary64
 (let* ((t_0 (* (/ angle 180.0) PI))
        (t_1 (sin t_0))
        (t_2 (cos t_0))
        (t_3
         (/
          (/ (* (* (* 2.0 (- (pow b 2.0) (pow a 2.0))) t_1) t_2) x-scale)
          y-scale)))
   (-
    (* t_3 t_3)
    (*
     (*
      4.0
      (/ (/ (+ (pow (* a t_1) 2.0) (pow (* b t_2) 2.0)) x-scale) x-scale))
     (/ (/ (+ (pow (* a t_2) 2.0) (pow (* b t_1) 2.0)) y-scale) y-scale)))))
double code(double a, double b, double angle, double x_45_scale, double y_45_scale) {
	double t_0 = (angle / 180.0) * ((double) M_PI);
	double t_1 = sin(t_0);
	double t_2 = cos(t_0);
	double t_3 = ((((2.0 * (pow(b, 2.0) - pow(a, 2.0))) * t_1) * t_2) / x_45_scale) / y_45_scale;
	return (t_3 * t_3) - ((4.0 * (((pow((a * t_1), 2.0) + pow((b * t_2), 2.0)) / x_45_scale) / x_45_scale)) * (((pow((a * t_2), 2.0) + pow((b * t_1), 2.0)) / y_45_scale) / y_45_scale));
}
public static double code(double a, double b, double angle, double x_45_scale, double y_45_scale) {
	double t_0 = (angle / 180.0) * Math.PI;
	double t_1 = Math.sin(t_0);
	double t_2 = Math.cos(t_0);
	double t_3 = ((((2.0 * (Math.pow(b, 2.0) - Math.pow(a, 2.0))) * t_1) * t_2) / x_45_scale) / y_45_scale;
	return (t_3 * t_3) - ((4.0 * (((Math.pow((a * t_1), 2.0) + Math.pow((b * t_2), 2.0)) / x_45_scale) / x_45_scale)) * (((Math.pow((a * t_2), 2.0) + Math.pow((b * t_1), 2.0)) / y_45_scale) / y_45_scale));
}
def code(a, b, angle, x_45_scale, y_45_scale):
	t_0 = (angle / 180.0) * math.pi
	t_1 = math.sin(t_0)
	t_2 = math.cos(t_0)
	t_3 = ((((2.0 * (math.pow(b, 2.0) - math.pow(a, 2.0))) * t_1) * t_2) / x_45_scale) / y_45_scale
	return (t_3 * t_3) - ((4.0 * (((math.pow((a * t_1), 2.0) + math.pow((b * t_2), 2.0)) / x_45_scale) / x_45_scale)) * (((math.pow((a * t_2), 2.0) + math.pow((b * t_1), 2.0)) / y_45_scale) / y_45_scale))
function code(a, b, angle, x_45_scale, y_45_scale)
	t_0 = Float64(Float64(angle / 180.0) * pi)
	t_1 = sin(t_0)
	t_2 = cos(t_0)
	t_3 = Float64(Float64(Float64(Float64(Float64(2.0 * Float64((b ^ 2.0) - (a ^ 2.0))) * t_1) * t_2) / x_45_scale) / y_45_scale)
	return Float64(Float64(t_3 * t_3) - Float64(Float64(4.0 * Float64(Float64(Float64((Float64(a * t_1) ^ 2.0) + (Float64(b * t_2) ^ 2.0)) / x_45_scale) / x_45_scale)) * Float64(Float64(Float64((Float64(a * t_2) ^ 2.0) + (Float64(b * t_1) ^ 2.0)) / y_45_scale) / y_45_scale)))
end
function tmp = code(a, b, angle, x_45_scale, y_45_scale)
	t_0 = (angle / 180.0) * pi;
	t_1 = sin(t_0);
	t_2 = cos(t_0);
	t_3 = ((((2.0 * ((b ^ 2.0) - (a ^ 2.0))) * t_1) * t_2) / x_45_scale) / y_45_scale;
	tmp = (t_3 * t_3) - ((4.0 * (((((a * t_1) ^ 2.0) + ((b * t_2) ^ 2.0)) / x_45_scale) / x_45_scale)) * (((((a * t_2) ^ 2.0) + ((b * t_1) ^ 2.0)) / y_45_scale) / y_45_scale));
end
code[a_, b_, angle_, x$45$scale_, y$45$scale_] := Block[{t$95$0 = N[(N[(angle / 180.0), $MachinePrecision] * Pi), $MachinePrecision]}, Block[{t$95$1 = N[Sin[t$95$0], $MachinePrecision]}, Block[{t$95$2 = N[Cos[t$95$0], $MachinePrecision]}, Block[{t$95$3 = N[(N[(N[(N[(N[(2.0 * N[(N[Power[b, 2.0], $MachinePrecision] - N[Power[a, 2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * t$95$1), $MachinePrecision] * t$95$2), $MachinePrecision] / x$45$scale), $MachinePrecision] / y$45$scale), $MachinePrecision]}, N[(N[(t$95$3 * t$95$3), $MachinePrecision] - N[(N[(4.0 * N[(N[(N[(N[Power[N[(a * t$95$1), $MachinePrecision], 2.0], $MachinePrecision] + N[Power[N[(b * t$95$2), $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision] / x$45$scale), $MachinePrecision] / x$45$scale), $MachinePrecision]), $MachinePrecision] * N[(N[(N[(N[Power[N[(a * t$95$2), $MachinePrecision], 2.0], $MachinePrecision] + N[Power[N[(b * t$95$1), $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision] / y$45$scale), $MachinePrecision] / y$45$scale), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \frac{angle}{180} \cdot \pi\\
t_1 := \sin t_0\\
t_2 := \cos t_0\\
t_3 := \frac{\frac{\left(\left(2 \cdot \left({b}^{2} - {a}^{2}\right)\right) \cdot t_1\right) \cdot t_2}{x-scale}}{y-scale}\\
t_3 \cdot t_3 - \left(4 \cdot \frac{\frac{{\left(a \cdot t_1\right)}^{2} + {\left(b \cdot t_2\right)}^{2}}{x-scale}}{x-scale}\right) \cdot \frac{\frac{{\left(a \cdot t_2\right)}^{2} + {\left(b \cdot t_1\right)}^{2}}{y-scale}}{y-scale}
\end{array}
\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: 24.8% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \frac{angle}{180} \cdot \pi\\ t_1 := \sin t_0\\ t_2 := \cos t_0\\ t_3 := \frac{\frac{\left(\left(2 \cdot \left({b}^{2} - {a}^{2}\right)\right) \cdot t_1\right) \cdot t_2}{x-scale}}{y-scale}\\ t_3 \cdot t_3 - \left(4 \cdot \frac{\frac{{\left(a \cdot t_1\right)}^{2} + {\left(b \cdot t_2\right)}^{2}}{x-scale}}{x-scale}\right) \cdot \frac{\frac{{\left(a \cdot t_2\right)}^{2} + {\left(b \cdot t_1\right)}^{2}}{y-scale}}{y-scale} \end{array} \end{array} \]
(FPCore (a b angle x-scale y-scale)
 :precision binary64
 (let* ((t_0 (* (/ angle 180.0) PI))
        (t_1 (sin t_0))
        (t_2 (cos t_0))
        (t_3
         (/
          (/ (* (* (* 2.0 (- (pow b 2.0) (pow a 2.0))) t_1) t_2) x-scale)
          y-scale)))
   (-
    (* t_3 t_3)
    (*
     (*
      4.0
      (/ (/ (+ (pow (* a t_1) 2.0) (pow (* b t_2) 2.0)) x-scale) x-scale))
     (/ (/ (+ (pow (* a t_2) 2.0) (pow (* b t_1) 2.0)) y-scale) y-scale)))))
double code(double a, double b, double angle, double x_45_scale, double y_45_scale) {
	double t_0 = (angle / 180.0) * ((double) M_PI);
	double t_1 = sin(t_0);
	double t_2 = cos(t_0);
	double t_3 = ((((2.0 * (pow(b, 2.0) - pow(a, 2.0))) * t_1) * t_2) / x_45_scale) / y_45_scale;
	return (t_3 * t_3) - ((4.0 * (((pow((a * t_1), 2.0) + pow((b * t_2), 2.0)) / x_45_scale) / x_45_scale)) * (((pow((a * t_2), 2.0) + pow((b * t_1), 2.0)) / y_45_scale) / y_45_scale));
}
public static double code(double a, double b, double angle, double x_45_scale, double y_45_scale) {
	double t_0 = (angle / 180.0) * Math.PI;
	double t_1 = Math.sin(t_0);
	double t_2 = Math.cos(t_0);
	double t_3 = ((((2.0 * (Math.pow(b, 2.0) - Math.pow(a, 2.0))) * t_1) * t_2) / x_45_scale) / y_45_scale;
	return (t_3 * t_3) - ((4.0 * (((Math.pow((a * t_1), 2.0) + Math.pow((b * t_2), 2.0)) / x_45_scale) / x_45_scale)) * (((Math.pow((a * t_2), 2.0) + Math.pow((b * t_1), 2.0)) / y_45_scale) / y_45_scale));
}
def code(a, b, angle, x_45_scale, y_45_scale):
	t_0 = (angle / 180.0) * math.pi
	t_1 = math.sin(t_0)
	t_2 = math.cos(t_0)
	t_3 = ((((2.0 * (math.pow(b, 2.0) - math.pow(a, 2.0))) * t_1) * t_2) / x_45_scale) / y_45_scale
	return (t_3 * t_3) - ((4.0 * (((math.pow((a * t_1), 2.0) + math.pow((b * t_2), 2.0)) / x_45_scale) / x_45_scale)) * (((math.pow((a * t_2), 2.0) + math.pow((b * t_1), 2.0)) / y_45_scale) / y_45_scale))
function code(a, b, angle, x_45_scale, y_45_scale)
	t_0 = Float64(Float64(angle / 180.0) * pi)
	t_1 = sin(t_0)
	t_2 = cos(t_0)
	t_3 = Float64(Float64(Float64(Float64(Float64(2.0 * Float64((b ^ 2.0) - (a ^ 2.0))) * t_1) * t_2) / x_45_scale) / y_45_scale)
	return Float64(Float64(t_3 * t_3) - Float64(Float64(4.0 * Float64(Float64(Float64((Float64(a * t_1) ^ 2.0) + (Float64(b * t_2) ^ 2.0)) / x_45_scale) / x_45_scale)) * Float64(Float64(Float64((Float64(a * t_2) ^ 2.0) + (Float64(b * t_1) ^ 2.0)) / y_45_scale) / y_45_scale)))
end
function tmp = code(a, b, angle, x_45_scale, y_45_scale)
	t_0 = (angle / 180.0) * pi;
	t_1 = sin(t_0);
	t_2 = cos(t_0);
	t_3 = ((((2.0 * ((b ^ 2.0) - (a ^ 2.0))) * t_1) * t_2) / x_45_scale) / y_45_scale;
	tmp = (t_3 * t_3) - ((4.0 * (((((a * t_1) ^ 2.0) + ((b * t_2) ^ 2.0)) / x_45_scale) / x_45_scale)) * (((((a * t_2) ^ 2.0) + ((b * t_1) ^ 2.0)) / y_45_scale) / y_45_scale));
end
code[a_, b_, angle_, x$45$scale_, y$45$scale_] := Block[{t$95$0 = N[(N[(angle / 180.0), $MachinePrecision] * Pi), $MachinePrecision]}, Block[{t$95$1 = N[Sin[t$95$0], $MachinePrecision]}, Block[{t$95$2 = N[Cos[t$95$0], $MachinePrecision]}, Block[{t$95$3 = N[(N[(N[(N[(N[(2.0 * N[(N[Power[b, 2.0], $MachinePrecision] - N[Power[a, 2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * t$95$1), $MachinePrecision] * t$95$2), $MachinePrecision] / x$45$scale), $MachinePrecision] / y$45$scale), $MachinePrecision]}, N[(N[(t$95$3 * t$95$3), $MachinePrecision] - N[(N[(4.0 * N[(N[(N[(N[Power[N[(a * t$95$1), $MachinePrecision], 2.0], $MachinePrecision] + N[Power[N[(b * t$95$2), $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision] / x$45$scale), $MachinePrecision] / x$45$scale), $MachinePrecision]), $MachinePrecision] * N[(N[(N[(N[Power[N[(a * t$95$2), $MachinePrecision], 2.0], $MachinePrecision] + N[Power[N[(b * t$95$1), $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision] / y$45$scale), $MachinePrecision] / y$45$scale), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \frac{angle}{180} \cdot \pi\\
t_1 := \sin t_0\\
t_2 := \cos t_0\\
t_3 := \frac{\frac{\left(\left(2 \cdot \left({b}^{2} - {a}^{2}\right)\right) \cdot t_1\right) \cdot t_2}{x-scale}}{y-scale}\\
t_3 \cdot t_3 - \left(4 \cdot \frac{\frac{{\left(a \cdot t_1\right)}^{2} + {\left(b \cdot t_2\right)}^{2}}{x-scale}}{x-scale}\right) \cdot \frac{\frac{{\left(a \cdot t_2\right)}^{2} + {\left(b \cdot t_1\right)}^{2}}{y-scale}}{y-scale}
\end{array}
\end{array}

Alternative 1: 95.0% accurate, 7.9× speedup?

\[\begin{array}{l} a = |a|\\ b = |b|\\ \\ \begin{array}{l} t_0 := \sqrt{a \cdot b}\\ \mathbf{if}\;x-scale \leq 4.6 \cdot 10^{-158}:\\ \;\;\;\;-4 \cdot \left(\frac{a}{\frac{y-scale}{\frac{b}{x-scale}}} \cdot \frac{a}{y-scale \cdot \frac{x-scale}{b}}\right)\\ \mathbf{else}:\\ \;\;\;\;-4 \cdot {\left(\frac{t_0}{x-scale} \cdot \frac{t_0}{y-scale}\right)}^{2}\\ \end{array} \end{array} \]
NOTE: a should be positive before calling this function
NOTE: b should be positive before calling this function
(FPCore (a b angle x-scale y-scale)
 :precision binary64
 (let* ((t_0 (sqrt (* a b))))
   (if (<= x-scale 4.6e-158)
     (*
      -4.0
      (* (/ a (/ y-scale (/ b x-scale))) (/ a (* y-scale (/ x-scale b)))))
     (* -4.0 (pow (* (/ t_0 x-scale) (/ t_0 y-scale)) 2.0)))))
a = abs(a);
b = abs(b);
double code(double a, double b, double angle, double x_45_scale, double y_45_scale) {
	double t_0 = sqrt((a * b));
	double tmp;
	if (x_45_scale <= 4.6e-158) {
		tmp = -4.0 * ((a / (y_45_scale / (b / x_45_scale))) * (a / (y_45_scale * (x_45_scale / b))));
	} else {
		tmp = -4.0 * pow(((t_0 / x_45_scale) * (t_0 / y_45_scale)), 2.0);
	}
	return tmp;
}
NOTE: a should be positive before calling this function
NOTE: b should be positive before calling this function
real(8) function code(a, b, angle, x_45scale, y_45scale)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    real(8), intent (in) :: angle
    real(8), intent (in) :: x_45scale
    real(8), intent (in) :: y_45scale
    real(8) :: t_0
    real(8) :: tmp
    t_0 = sqrt((a * b))
    if (x_45scale <= 4.6d-158) then
        tmp = (-4.0d0) * ((a / (y_45scale / (b / x_45scale))) * (a / (y_45scale * (x_45scale / b))))
    else
        tmp = (-4.0d0) * (((t_0 / x_45scale) * (t_0 / y_45scale)) ** 2.0d0)
    end if
    code = tmp
end function
a = Math.abs(a);
b = Math.abs(b);
public static double code(double a, double b, double angle, double x_45_scale, double y_45_scale) {
	double t_0 = Math.sqrt((a * b));
	double tmp;
	if (x_45_scale <= 4.6e-158) {
		tmp = -4.0 * ((a / (y_45_scale / (b / x_45_scale))) * (a / (y_45_scale * (x_45_scale / b))));
	} else {
		tmp = -4.0 * Math.pow(((t_0 / x_45_scale) * (t_0 / y_45_scale)), 2.0);
	}
	return tmp;
}
a = abs(a)
b = abs(b)
def code(a, b, angle, x_45_scale, y_45_scale):
	t_0 = math.sqrt((a * b))
	tmp = 0
	if x_45_scale <= 4.6e-158:
		tmp = -4.0 * ((a / (y_45_scale / (b / x_45_scale))) * (a / (y_45_scale * (x_45_scale / b))))
	else:
		tmp = -4.0 * math.pow(((t_0 / x_45_scale) * (t_0 / y_45_scale)), 2.0)
	return tmp
a = abs(a)
b = abs(b)
function code(a, b, angle, x_45_scale, y_45_scale)
	t_0 = sqrt(Float64(a * b))
	tmp = 0.0
	if (x_45_scale <= 4.6e-158)
		tmp = Float64(-4.0 * Float64(Float64(a / Float64(y_45_scale / Float64(b / x_45_scale))) * Float64(a / Float64(y_45_scale * Float64(x_45_scale / b)))));
	else
		tmp = Float64(-4.0 * (Float64(Float64(t_0 / x_45_scale) * Float64(t_0 / y_45_scale)) ^ 2.0));
	end
	return tmp
end
a = abs(a)
b = abs(b)
function tmp_2 = code(a, b, angle, x_45_scale, y_45_scale)
	t_0 = sqrt((a * b));
	tmp = 0.0;
	if (x_45_scale <= 4.6e-158)
		tmp = -4.0 * ((a / (y_45_scale / (b / x_45_scale))) * (a / (y_45_scale * (x_45_scale / b))));
	else
		tmp = -4.0 * (((t_0 / x_45_scale) * (t_0 / y_45_scale)) ^ 2.0);
	end
	tmp_2 = tmp;
end
NOTE: a should be positive before calling this function
NOTE: b should be positive before calling this function
code[a_, b_, angle_, x$45$scale_, y$45$scale_] := Block[{t$95$0 = N[Sqrt[N[(a * b), $MachinePrecision]], $MachinePrecision]}, If[LessEqual[x$45$scale, 4.6e-158], N[(-4.0 * N[(N[(a / N[(y$45$scale / N[(b / x$45$scale), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[(a / N[(y$45$scale * N[(x$45$scale / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(-4.0 * N[Power[N[(N[(t$95$0 / x$45$scale), $MachinePrecision] * N[(t$95$0 / y$45$scale), $MachinePrecision]), $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
a = |a|\\
b = |b|\\
\\
\begin{array}{l}
t_0 := \sqrt{a \cdot b}\\
\mathbf{if}\;x-scale \leq 4.6 \cdot 10^{-158}:\\
\;\;\;\;-4 \cdot \left(\frac{a}{\frac{y-scale}{\frac{b}{x-scale}}} \cdot \frac{a}{y-scale \cdot \frac{x-scale}{b}}\right)\\

\mathbf{else}:\\
\;\;\;\;-4 \cdot {\left(\frac{t_0}{x-scale} \cdot \frac{t_0}{y-scale}\right)}^{2}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if x-scale < 4.5999999999999998e-158

    1. Initial program 21.1%

      \[\frac{\frac{\left(\left(2 \cdot \left({b}^{2} - {a}^{2}\right)\right) \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right) \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)}{x-scale}}{y-scale} \cdot \frac{\frac{\left(\left(2 \cdot \left({b}^{2} - {a}^{2}\right)\right) \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right) \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)}{x-scale}}{y-scale} - \left(4 \cdot \frac{\frac{{\left(a \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2} + {\left(b \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2}}{x-scale}}{x-scale}\right) \cdot \frac{\frac{{\left(a \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2} + {\left(b \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2}}{y-scale}}{y-scale} \]
    2. Taylor expanded in angle around 0 40.3%

      \[\leadsto \color{blue}{-4 \cdot \frac{{a}^{2} \cdot {b}^{2}}{{y-scale}^{2} \cdot {x-scale}^{2}}} \]
    3. Step-by-step derivation
      1. associate-/l*42.6%

        \[\leadsto -4 \cdot \color{blue}{\frac{{a}^{2}}{\frac{{y-scale}^{2} \cdot {x-scale}^{2}}{{b}^{2}}}} \]
      2. unpow242.6%

        \[\leadsto -4 \cdot \frac{\color{blue}{a \cdot a}}{\frac{{y-scale}^{2} \cdot {x-scale}^{2}}{{b}^{2}}} \]
      3. unpow242.6%

        \[\leadsto -4 \cdot \frac{a \cdot a}{\frac{\color{blue}{\left(y-scale \cdot y-scale\right)} \cdot {x-scale}^{2}}{{b}^{2}}} \]
      4. unpow242.6%

        \[\leadsto -4 \cdot \frac{a \cdot a}{\frac{\left(y-scale \cdot y-scale\right) \cdot \color{blue}{\left(x-scale \cdot x-scale\right)}}{{b}^{2}}} \]
      5. unswap-sqr58.2%

        \[\leadsto -4 \cdot \frac{a \cdot a}{\frac{\color{blue}{\left(y-scale \cdot x-scale\right) \cdot \left(y-scale \cdot x-scale\right)}}{{b}^{2}}} \]
      6. unpow258.2%

        \[\leadsto -4 \cdot \frac{a \cdot a}{\frac{\left(y-scale \cdot x-scale\right) \cdot \left(y-scale \cdot x-scale\right)}{\color{blue}{b \cdot b}}} \]
    4. Simplified58.2%

      \[\leadsto \color{blue}{-4 \cdot \frac{a \cdot a}{\frac{\left(y-scale \cdot x-scale\right) \cdot \left(y-scale \cdot x-scale\right)}{b \cdot b}}} \]
    5. Step-by-step derivation
      1. times-frac74.2%

        \[\leadsto -4 \cdot \frac{a \cdot a}{\color{blue}{\frac{y-scale \cdot x-scale}{b} \cdot \frac{y-scale \cdot x-scale}{b}}} \]
    6. Applied egg-rr74.2%

      \[\leadsto -4 \cdot \frac{a \cdot a}{\color{blue}{\frac{y-scale \cdot x-scale}{b} \cdot \frac{y-scale \cdot x-scale}{b}}} \]
    7. Step-by-step derivation
      1. times-frac92.2%

        \[\leadsto -4 \cdot \color{blue}{\left(\frac{a}{\frac{y-scale \cdot x-scale}{b}} \cdot \frac{a}{\frac{y-scale \cdot x-scale}{b}}\right)} \]
      2. associate-/l*90.5%

        \[\leadsto -4 \cdot \left(\frac{a}{\color{blue}{\frac{y-scale}{\frac{b}{x-scale}}}} \cdot \frac{a}{\frac{y-scale \cdot x-scale}{b}}\right) \]
      3. associate-/l*96.1%

        \[\leadsto -4 \cdot \left(\frac{a}{\frac{y-scale}{\frac{b}{x-scale}}} \cdot \frac{a}{\color{blue}{\frac{y-scale}{\frac{b}{x-scale}}}}\right) \]
    8. Applied egg-rr96.1%

      \[\leadsto -4 \cdot \color{blue}{\left(\frac{a}{\frac{y-scale}{\frac{b}{x-scale}}} \cdot \frac{a}{\frac{y-scale}{\frac{b}{x-scale}}}\right)} \]
    9. Step-by-step derivation
      1. div-inv96.1%

        \[\leadsto -4 \cdot \left(\frac{a}{\frac{y-scale}{\frac{b}{x-scale}}} \cdot \frac{a}{\color{blue}{y-scale \cdot \frac{1}{\frac{b}{x-scale}}}}\right) \]
      2. clear-num96.2%

        \[\leadsto -4 \cdot \left(\frac{a}{\frac{y-scale}{\frac{b}{x-scale}}} \cdot \frac{a}{y-scale \cdot \color{blue}{\frac{x-scale}{b}}}\right) \]
    10. Applied egg-rr96.2%

      \[\leadsto -4 \cdot \left(\frac{a}{\frac{y-scale}{\frac{b}{x-scale}}} \cdot \frac{a}{\color{blue}{y-scale \cdot \frac{x-scale}{b}}}\right) \]

    if 4.5999999999999998e-158 < x-scale

    1. Initial program 24.7%

      \[\frac{\frac{\left(\left(2 \cdot \left({b}^{2} - {a}^{2}\right)\right) \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right) \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)}{x-scale}}{y-scale} \cdot \frac{\frac{\left(\left(2 \cdot \left({b}^{2} - {a}^{2}\right)\right) \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right) \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)}{x-scale}}{y-scale} - \left(4 \cdot \frac{\frac{{\left(a \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2} + {\left(b \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2}}{x-scale}}{x-scale}\right) \cdot \frac{\frac{{\left(a \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2} + {\left(b \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2}}{y-scale}}{y-scale} \]
    2. Taylor expanded in angle around 0 49.4%

      \[\leadsto \color{blue}{-4 \cdot \frac{{a}^{2} \cdot {b}^{2}}{{y-scale}^{2} \cdot {x-scale}^{2}}} \]
    3. Step-by-step derivation
      1. associate-/l*51.4%

        \[\leadsto -4 \cdot \color{blue}{\frac{{a}^{2}}{\frac{{y-scale}^{2} \cdot {x-scale}^{2}}{{b}^{2}}}} \]
      2. unpow251.4%

        \[\leadsto -4 \cdot \frac{\color{blue}{a \cdot a}}{\frac{{y-scale}^{2} \cdot {x-scale}^{2}}{{b}^{2}}} \]
      3. unpow251.4%

        \[\leadsto -4 \cdot \frac{a \cdot a}{\frac{\color{blue}{\left(y-scale \cdot y-scale\right)} \cdot {x-scale}^{2}}{{b}^{2}}} \]
      4. unpow251.4%

        \[\leadsto -4 \cdot \frac{a \cdot a}{\frac{\left(y-scale \cdot y-scale\right) \cdot \color{blue}{\left(x-scale \cdot x-scale\right)}}{{b}^{2}}} \]
      5. unswap-sqr61.0%

        \[\leadsto -4 \cdot \frac{a \cdot a}{\frac{\color{blue}{\left(y-scale \cdot x-scale\right) \cdot \left(y-scale \cdot x-scale\right)}}{{b}^{2}}} \]
      6. unpow261.0%

        \[\leadsto -4 \cdot \frac{a \cdot a}{\frac{\left(y-scale \cdot x-scale\right) \cdot \left(y-scale \cdot x-scale\right)}{\color{blue}{b \cdot b}}} \]
    4. Simplified61.0%

      \[\leadsto \color{blue}{-4 \cdot \frac{a \cdot a}{\frac{\left(y-scale \cdot x-scale\right) \cdot \left(y-scale \cdot x-scale\right)}{b \cdot b}}} \]
    5. Step-by-step derivation
      1. times-frac74.3%

        \[\leadsto -4 \cdot \frac{a \cdot a}{\color{blue}{\frac{y-scale \cdot x-scale}{b} \cdot \frac{y-scale \cdot x-scale}{b}}} \]
    6. Applied egg-rr74.3%

      \[\leadsto -4 \cdot \frac{a \cdot a}{\color{blue}{\frac{y-scale \cdot x-scale}{b} \cdot \frac{y-scale \cdot x-scale}{b}}} \]
    7. Step-by-step derivation
      1. frac-times61.0%

        \[\leadsto -4 \cdot \frac{a \cdot a}{\color{blue}{\frac{\left(y-scale \cdot x-scale\right) \cdot \left(y-scale \cdot x-scale\right)}{b \cdot b}}} \]
      2. unpow261.0%

        \[\leadsto -4 \cdot \frac{a \cdot a}{\frac{\color{blue}{{\left(y-scale \cdot x-scale\right)}^{2}}}{b \cdot b}} \]
      3. unpow-prod-down51.4%

        \[\leadsto -4 \cdot \frac{a \cdot a}{\frac{\color{blue}{{y-scale}^{2} \cdot {x-scale}^{2}}}{b \cdot b}} \]
      4. pow251.4%

        \[\leadsto -4 \cdot \frac{a \cdot a}{\frac{\color{blue}{\left(y-scale \cdot y-scale\right)} \cdot {x-scale}^{2}}{b \cdot b}} \]
      5. pow251.4%

        \[\leadsto -4 \cdot \frac{a \cdot a}{\frac{\left(y-scale \cdot y-scale\right) \cdot \color{blue}{\left(x-scale \cdot x-scale\right)}}{b \cdot b}} \]
      6. frac-times58.7%

        \[\leadsto -4 \cdot \frac{a \cdot a}{\color{blue}{\frac{y-scale \cdot y-scale}{b} \cdot \frac{x-scale \cdot x-scale}{b}}} \]
      7. times-frac66.2%

        \[\leadsto -4 \cdot \color{blue}{\left(\frac{a}{\frac{y-scale \cdot y-scale}{b}} \cdot \frac{a}{\frac{x-scale \cdot x-scale}{b}}\right)} \]
      8. associate-/l*71.3%

        \[\leadsto -4 \cdot \left(\frac{a}{\color{blue}{\frac{y-scale}{\frac{b}{y-scale}}}} \cdot \frac{a}{\frac{x-scale \cdot x-scale}{b}}\right) \]
      9. associate-/l*73.5%

        \[\leadsto -4 \cdot \left(\frac{a}{\frac{y-scale}{\frac{b}{y-scale}}} \cdot \frac{a}{\color{blue}{\frac{x-scale}{\frac{b}{x-scale}}}}\right) \]
    8. Applied egg-rr73.5%

      \[\leadsto -4 \cdot \color{blue}{\left(\frac{a}{\frac{y-scale}{\frac{b}{y-scale}}} \cdot \frac{a}{\frac{x-scale}{\frac{b}{x-scale}}}\right)} \]
    9. Step-by-step derivation
      1. associate-/r/76.6%

        \[\leadsto -4 \cdot \left(\color{blue}{\left(\frac{a}{y-scale} \cdot \frac{b}{y-scale}\right)} \cdot \frac{a}{\frac{x-scale}{\frac{b}{x-scale}}}\right) \]
      2. associate-/r/81.7%

        \[\leadsto -4 \cdot \left(\left(\frac{a}{y-scale} \cdot \frac{b}{y-scale}\right) \cdot \color{blue}{\left(\frac{a}{x-scale} \cdot \frac{b}{x-scale}\right)}\right) \]
    10. Simplified81.7%

      \[\leadsto -4 \cdot \color{blue}{\left(\left(\frac{a}{y-scale} \cdot \frac{b}{y-scale}\right) \cdot \left(\frac{a}{x-scale} \cdot \frac{b}{x-scale}\right)\right)} \]
    11. Step-by-step derivation
      1. add-sqr-sqrt81.7%

        \[\leadsto -4 \cdot \color{blue}{\left(\sqrt{\left(\frac{a}{y-scale} \cdot \frac{b}{y-scale}\right) \cdot \left(\frac{a}{x-scale} \cdot \frac{b}{x-scale}\right)} \cdot \sqrt{\left(\frac{a}{y-scale} \cdot \frac{b}{y-scale}\right) \cdot \left(\frac{a}{x-scale} \cdot \frac{b}{x-scale}\right)}\right)} \]
      2. pow281.7%

        \[\leadsto -4 \cdot \color{blue}{{\left(\sqrt{\left(\frac{a}{y-scale} \cdot \frac{b}{y-scale}\right) \cdot \left(\frac{a}{x-scale} \cdot \frac{b}{x-scale}\right)}\right)}^{2}} \]
    12. Applied egg-rr54.9%

      \[\leadsto -4 \cdot \color{blue}{{\left(\frac{\sqrt{a \cdot b}}{x-scale} \cdot \frac{\sqrt{a \cdot b}}{y-scale}\right)}^{2}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification80.7%

    \[\leadsto \begin{array}{l} \mathbf{if}\;x-scale \leq 4.6 \cdot 10^{-158}:\\ \;\;\;\;-4 \cdot \left(\frac{a}{\frac{y-scale}{\frac{b}{x-scale}}} \cdot \frac{a}{y-scale \cdot \frac{x-scale}{b}}\right)\\ \mathbf{else}:\\ \;\;\;\;-4 \cdot {\left(\frac{\sqrt{a \cdot b}}{x-scale} \cdot \frac{\sqrt{a \cdot b}}{y-scale}\right)}^{2}\\ \end{array} \]

Alternative 2: 82.9% accurate, 146.2× speedup?

\[\begin{array}{l} a = |a|\\ b = |b|\\ \\ -4 \cdot \left(\left(\frac{a}{y-scale} \cdot \frac{b}{y-scale}\right) \cdot \left(\frac{b}{x-scale} \cdot \frac{a}{x-scale}\right)\right) \end{array} \]
NOTE: a should be positive before calling this function
NOTE: b should be positive before calling this function
(FPCore (a b angle x-scale y-scale)
 :precision binary64
 (* -4.0 (* (* (/ a y-scale) (/ b y-scale)) (* (/ b x-scale) (/ a x-scale)))))
a = abs(a);
b = abs(b);
double code(double a, double b, double angle, double x_45_scale, double y_45_scale) {
	return -4.0 * (((a / y_45_scale) * (b / y_45_scale)) * ((b / x_45_scale) * (a / x_45_scale)));
}
NOTE: a should be positive before calling this function
NOTE: b should be positive before calling this function
real(8) function code(a, b, angle, x_45scale, y_45scale)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    real(8), intent (in) :: angle
    real(8), intent (in) :: x_45scale
    real(8), intent (in) :: y_45scale
    code = (-4.0d0) * (((a / y_45scale) * (b / y_45scale)) * ((b / x_45scale) * (a / x_45scale)))
end function
a = Math.abs(a);
b = Math.abs(b);
public static double code(double a, double b, double angle, double x_45_scale, double y_45_scale) {
	return -4.0 * (((a / y_45_scale) * (b / y_45_scale)) * ((b / x_45_scale) * (a / x_45_scale)));
}
a = abs(a)
b = abs(b)
def code(a, b, angle, x_45_scale, y_45_scale):
	return -4.0 * (((a / y_45_scale) * (b / y_45_scale)) * ((b / x_45_scale) * (a / x_45_scale)))
a = abs(a)
b = abs(b)
function code(a, b, angle, x_45_scale, y_45_scale)
	return Float64(-4.0 * Float64(Float64(Float64(a / y_45_scale) * Float64(b / y_45_scale)) * Float64(Float64(b / x_45_scale) * Float64(a / x_45_scale))))
end
a = abs(a)
b = abs(b)
function tmp = code(a, b, angle, x_45_scale, y_45_scale)
	tmp = -4.0 * (((a / y_45_scale) * (b / y_45_scale)) * ((b / x_45_scale) * (a / x_45_scale)));
end
NOTE: a should be positive before calling this function
NOTE: b should be positive before calling this function
code[a_, b_, angle_, x$45$scale_, y$45$scale_] := N[(-4.0 * N[(N[(N[(a / y$45$scale), $MachinePrecision] * N[(b / y$45$scale), $MachinePrecision]), $MachinePrecision] * N[(N[(b / x$45$scale), $MachinePrecision] * N[(a / x$45$scale), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
a = |a|\\
b = |b|\\
\\
-4 \cdot \left(\left(\frac{a}{y-scale} \cdot \frac{b}{y-scale}\right) \cdot \left(\frac{b}{x-scale} \cdot \frac{a}{x-scale}\right)\right)
\end{array}
Derivation
  1. Initial program 22.4%

    \[\frac{\frac{\left(\left(2 \cdot \left({b}^{2} - {a}^{2}\right)\right) \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right) \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)}{x-scale}}{y-scale} \cdot \frac{\frac{\left(\left(2 \cdot \left({b}^{2} - {a}^{2}\right)\right) \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right) \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)}{x-scale}}{y-scale} - \left(4 \cdot \frac{\frac{{\left(a \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2} + {\left(b \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2}}{x-scale}}{x-scale}\right) \cdot \frac{\frac{{\left(a \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2} + {\left(b \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2}}{y-scale}}{y-scale} \]
  2. Taylor expanded in angle around 0 43.8%

    \[\leadsto \color{blue}{-4 \cdot \frac{{a}^{2} \cdot {b}^{2}}{{y-scale}^{2} \cdot {x-scale}^{2}}} \]
  3. Step-by-step derivation
    1. associate-/l*45.9%

      \[\leadsto -4 \cdot \color{blue}{\frac{{a}^{2}}{\frac{{y-scale}^{2} \cdot {x-scale}^{2}}{{b}^{2}}}} \]
    2. unpow245.9%

      \[\leadsto -4 \cdot \frac{\color{blue}{a \cdot a}}{\frac{{y-scale}^{2} \cdot {x-scale}^{2}}{{b}^{2}}} \]
    3. unpow245.9%

      \[\leadsto -4 \cdot \frac{a \cdot a}{\frac{\color{blue}{\left(y-scale \cdot y-scale\right)} \cdot {x-scale}^{2}}{{b}^{2}}} \]
    4. unpow245.9%

      \[\leadsto -4 \cdot \frac{a \cdot a}{\frac{\left(y-scale \cdot y-scale\right) \cdot \color{blue}{\left(x-scale \cdot x-scale\right)}}{{b}^{2}}} \]
    5. unswap-sqr59.3%

      \[\leadsto -4 \cdot \frac{a \cdot a}{\frac{\color{blue}{\left(y-scale \cdot x-scale\right) \cdot \left(y-scale \cdot x-scale\right)}}{{b}^{2}}} \]
    6. unpow259.3%

      \[\leadsto -4 \cdot \frac{a \cdot a}{\frac{\left(y-scale \cdot x-scale\right) \cdot \left(y-scale \cdot x-scale\right)}{\color{blue}{b \cdot b}}} \]
  4. Simplified59.3%

    \[\leadsto \color{blue}{-4 \cdot \frac{a \cdot a}{\frac{\left(y-scale \cdot x-scale\right) \cdot \left(y-scale \cdot x-scale\right)}{b \cdot b}}} \]
  5. Step-by-step derivation
    1. times-frac74.3%

      \[\leadsto -4 \cdot \frac{a \cdot a}{\color{blue}{\frac{y-scale \cdot x-scale}{b} \cdot \frac{y-scale \cdot x-scale}{b}}} \]
  6. Applied egg-rr74.3%

    \[\leadsto -4 \cdot \frac{a \cdot a}{\color{blue}{\frac{y-scale \cdot x-scale}{b} \cdot \frac{y-scale \cdot x-scale}{b}}} \]
  7. Step-by-step derivation
    1. frac-times59.3%

      \[\leadsto -4 \cdot \frac{a \cdot a}{\color{blue}{\frac{\left(y-scale \cdot x-scale\right) \cdot \left(y-scale \cdot x-scale\right)}{b \cdot b}}} \]
    2. unpow259.3%

      \[\leadsto -4 \cdot \frac{a \cdot a}{\frac{\color{blue}{{\left(y-scale \cdot x-scale\right)}^{2}}}{b \cdot b}} \]
    3. unpow-prod-down45.9%

      \[\leadsto -4 \cdot \frac{a \cdot a}{\frac{\color{blue}{{y-scale}^{2} \cdot {x-scale}^{2}}}{b \cdot b}} \]
    4. pow245.9%

      \[\leadsto -4 \cdot \frac{a \cdot a}{\frac{\color{blue}{\left(y-scale \cdot y-scale\right)} \cdot {x-scale}^{2}}{b \cdot b}} \]
    5. pow245.9%

      \[\leadsto -4 \cdot \frac{a \cdot a}{\frac{\left(y-scale \cdot y-scale\right) \cdot \color{blue}{\left(x-scale \cdot x-scale\right)}}{b \cdot b}} \]
    6. frac-times52.5%

      \[\leadsto -4 \cdot \frac{a \cdot a}{\color{blue}{\frac{y-scale \cdot y-scale}{b} \cdot \frac{x-scale \cdot x-scale}{b}}} \]
    7. times-frac61.8%

      \[\leadsto -4 \cdot \color{blue}{\left(\frac{a}{\frac{y-scale \cdot y-scale}{b}} \cdot \frac{a}{\frac{x-scale \cdot x-scale}{b}}\right)} \]
    8. associate-/l*66.8%

      \[\leadsto -4 \cdot \left(\frac{a}{\color{blue}{\frac{y-scale}{\frac{b}{y-scale}}}} \cdot \frac{a}{\frac{x-scale \cdot x-scale}{b}}\right) \]
    9. associate-/l*73.3%

      \[\leadsto -4 \cdot \left(\frac{a}{\frac{y-scale}{\frac{b}{y-scale}}} \cdot \frac{a}{\color{blue}{\frac{x-scale}{\frac{b}{x-scale}}}}\right) \]
  8. Applied egg-rr73.3%

    \[\leadsto -4 \cdot \color{blue}{\left(\frac{a}{\frac{y-scale}{\frac{b}{y-scale}}} \cdot \frac{a}{\frac{x-scale}{\frac{b}{x-scale}}}\right)} \]
  9. Step-by-step derivation
    1. associate-/r/75.9%

      \[\leadsto -4 \cdot \left(\color{blue}{\left(\frac{a}{y-scale} \cdot \frac{b}{y-scale}\right)} \cdot \frac{a}{\frac{x-scale}{\frac{b}{x-scale}}}\right) \]
    2. associate-/r/83.4%

      \[\leadsto -4 \cdot \left(\left(\frac{a}{y-scale} \cdot \frac{b}{y-scale}\right) \cdot \color{blue}{\left(\frac{a}{x-scale} \cdot \frac{b}{x-scale}\right)}\right) \]
  10. Simplified83.4%

    \[\leadsto -4 \cdot \color{blue}{\left(\left(\frac{a}{y-scale} \cdot \frac{b}{y-scale}\right) \cdot \left(\frac{a}{x-scale} \cdot \frac{b}{x-scale}\right)\right)} \]
  11. Final simplification83.4%

    \[\leadsto -4 \cdot \left(\left(\frac{a}{y-scale} \cdot \frac{b}{y-scale}\right) \cdot \left(\frac{b}{x-scale} \cdot \frac{a}{x-scale}\right)\right) \]

Alternative 3: 94.3% accurate, 146.2× speedup?

\[\begin{array}{l} a = |a|\\ b = |b|\\ \\ -4 \cdot \left(\frac{a}{\frac{y-scale}{\frac{b}{x-scale}}} \cdot \frac{a}{y-scale \cdot \frac{x-scale}{b}}\right) \end{array} \]
NOTE: a should be positive before calling this function
NOTE: b should be positive before calling this function
(FPCore (a b angle x-scale y-scale)
 :precision binary64
 (* -4.0 (* (/ a (/ y-scale (/ b x-scale))) (/ a (* y-scale (/ x-scale b))))))
a = abs(a);
b = abs(b);
double code(double a, double b, double angle, double x_45_scale, double y_45_scale) {
	return -4.0 * ((a / (y_45_scale / (b / x_45_scale))) * (a / (y_45_scale * (x_45_scale / b))));
}
NOTE: a should be positive before calling this function
NOTE: b should be positive before calling this function
real(8) function code(a, b, angle, x_45scale, y_45scale)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    real(8), intent (in) :: angle
    real(8), intent (in) :: x_45scale
    real(8), intent (in) :: y_45scale
    code = (-4.0d0) * ((a / (y_45scale / (b / x_45scale))) * (a / (y_45scale * (x_45scale / b))))
end function
a = Math.abs(a);
b = Math.abs(b);
public static double code(double a, double b, double angle, double x_45_scale, double y_45_scale) {
	return -4.0 * ((a / (y_45_scale / (b / x_45_scale))) * (a / (y_45_scale * (x_45_scale / b))));
}
a = abs(a)
b = abs(b)
def code(a, b, angle, x_45_scale, y_45_scale):
	return -4.0 * ((a / (y_45_scale / (b / x_45_scale))) * (a / (y_45_scale * (x_45_scale / b))))
a = abs(a)
b = abs(b)
function code(a, b, angle, x_45_scale, y_45_scale)
	return Float64(-4.0 * Float64(Float64(a / Float64(y_45_scale / Float64(b / x_45_scale))) * Float64(a / Float64(y_45_scale * Float64(x_45_scale / b)))))
end
a = abs(a)
b = abs(b)
function tmp = code(a, b, angle, x_45_scale, y_45_scale)
	tmp = -4.0 * ((a / (y_45_scale / (b / x_45_scale))) * (a / (y_45_scale * (x_45_scale / b))));
end
NOTE: a should be positive before calling this function
NOTE: b should be positive before calling this function
code[a_, b_, angle_, x$45$scale_, y$45$scale_] := N[(-4.0 * N[(N[(a / N[(y$45$scale / N[(b / x$45$scale), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[(a / N[(y$45$scale * N[(x$45$scale / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
a = |a|\\
b = |b|\\
\\
-4 \cdot \left(\frac{a}{\frac{y-scale}{\frac{b}{x-scale}}} \cdot \frac{a}{y-scale \cdot \frac{x-scale}{b}}\right)
\end{array}
Derivation
  1. Initial program 22.4%

    \[\frac{\frac{\left(\left(2 \cdot \left({b}^{2} - {a}^{2}\right)\right) \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right) \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)}{x-scale}}{y-scale} \cdot \frac{\frac{\left(\left(2 \cdot \left({b}^{2} - {a}^{2}\right)\right) \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right) \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)}{x-scale}}{y-scale} - \left(4 \cdot \frac{\frac{{\left(a \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2} + {\left(b \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2}}{x-scale}}{x-scale}\right) \cdot \frac{\frac{{\left(a \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2} + {\left(b \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2}}{y-scale}}{y-scale} \]
  2. Taylor expanded in angle around 0 43.8%

    \[\leadsto \color{blue}{-4 \cdot \frac{{a}^{2} \cdot {b}^{2}}{{y-scale}^{2} \cdot {x-scale}^{2}}} \]
  3. Step-by-step derivation
    1. associate-/l*45.9%

      \[\leadsto -4 \cdot \color{blue}{\frac{{a}^{2}}{\frac{{y-scale}^{2} \cdot {x-scale}^{2}}{{b}^{2}}}} \]
    2. unpow245.9%

      \[\leadsto -4 \cdot \frac{\color{blue}{a \cdot a}}{\frac{{y-scale}^{2} \cdot {x-scale}^{2}}{{b}^{2}}} \]
    3. unpow245.9%

      \[\leadsto -4 \cdot \frac{a \cdot a}{\frac{\color{blue}{\left(y-scale \cdot y-scale\right)} \cdot {x-scale}^{2}}{{b}^{2}}} \]
    4. unpow245.9%

      \[\leadsto -4 \cdot \frac{a \cdot a}{\frac{\left(y-scale \cdot y-scale\right) \cdot \color{blue}{\left(x-scale \cdot x-scale\right)}}{{b}^{2}}} \]
    5. unswap-sqr59.3%

      \[\leadsto -4 \cdot \frac{a \cdot a}{\frac{\color{blue}{\left(y-scale \cdot x-scale\right) \cdot \left(y-scale \cdot x-scale\right)}}{{b}^{2}}} \]
    6. unpow259.3%

      \[\leadsto -4 \cdot \frac{a \cdot a}{\frac{\left(y-scale \cdot x-scale\right) \cdot \left(y-scale \cdot x-scale\right)}{\color{blue}{b \cdot b}}} \]
  4. Simplified59.3%

    \[\leadsto \color{blue}{-4 \cdot \frac{a \cdot a}{\frac{\left(y-scale \cdot x-scale\right) \cdot \left(y-scale \cdot x-scale\right)}{b \cdot b}}} \]
  5. Step-by-step derivation
    1. times-frac74.3%

      \[\leadsto -4 \cdot \frac{a \cdot a}{\color{blue}{\frac{y-scale \cdot x-scale}{b} \cdot \frac{y-scale \cdot x-scale}{b}}} \]
  6. Applied egg-rr74.3%

    \[\leadsto -4 \cdot \frac{a \cdot a}{\color{blue}{\frac{y-scale \cdot x-scale}{b} \cdot \frac{y-scale \cdot x-scale}{b}}} \]
  7. Step-by-step derivation
    1. times-frac92.0%

      \[\leadsto -4 \cdot \color{blue}{\left(\frac{a}{\frac{y-scale \cdot x-scale}{b}} \cdot \frac{a}{\frac{y-scale \cdot x-scale}{b}}\right)} \]
    2. associate-/l*89.9%

      \[\leadsto -4 \cdot \left(\frac{a}{\color{blue}{\frac{y-scale}{\frac{b}{x-scale}}}} \cdot \frac{a}{\frac{y-scale \cdot x-scale}{b}}\right) \]
    3. associate-/l*93.8%

      \[\leadsto -4 \cdot \left(\frac{a}{\frac{y-scale}{\frac{b}{x-scale}}} \cdot \frac{a}{\color{blue}{\frac{y-scale}{\frac{b}{x-scale}}}}\right) \]
  8. Applied egg-rr93.8%

    \[\leadsto -4 \cdot \color{blue}{\left(\frac{a}{\frac{y-scale}{\frac{b}{x-scale}}} \cdot \frac{a}{\frac{y-scale}{\frac{b}{x-scale}}}\right)} \]
  9. Step-by-step derivation
    1. div-inv93.8%

      \[\leadsto -4 \cdot \left(\frac{a}{\frac{y-scale}{\frac{b}{x-scale}}} \cdot \frac{a}{\color{blue}{y-scale \cdot \frac{1}{\frac{b}{x-scale}}}}\right) \]
    2. clear-num93.8%

      \[\leadsto -4 \cdot \left(\frac{a}{\frac{y-scale}{\frac{b}{x-scale}}} \cdot \frac{a}{y-scale \cdot \color{blue}{\frac{x-scale}{b}}}\right) \]
  10. Applied egg-rr93.8%

    \[\leadsto -4 \cdot \left(\frac{a}{\frac{y-scale}{\frac{b}{x-scale}}} \cdot \frac{a}{\color{blue}{y-scale \cdot \frac{x-scale}{b}}}\right) \]
  11. Final simplification93.8%

    \[\leadsto -4 \cdot \left(\frac{a}{\frac{y-scale}{\frac{b}{x-scale}}} \cdot \frac{a}{y-scale \cdot \frac{x-scale}{b}}\right) \]

Alternative 4: 35.3% accurate, 2485.0× speedup?

\[\begin{array}{l} a = |a|\\ b = |b|\\ \\ 0 \end{array} \]
NOTE: a should be positive before calling this function
NOTE: b should be positive before calling this function
(FPCore (a b angle x-scale y-scale) :precision binary64 0.0)
a = abs(a);
b = abs(b);
double code(double a, double b, double angle, double x_45_scale, double y_45_scale) {
	return 0.0;
}
NOTE: a should be positive before calling this function
NOTE: b should be positive before calling this function
real(8) function code(a, b, angle, x_45scale, y_45scale)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    real(8), intent (in) :: angle
    real(8), intent (in) :: x_45scale
    real(8), intent (in) :: y_45scale
    code = 0.0d0
end function
a = Math.abs(a);
b = Math.abs(b);
public static double code(double a, double b, double angle, double x_45_scale, double y_45_scale) {
	return 0.0;
}
a = abs(a)
b = abs(b)
def code(a, b, angle, x_45_scale, y_45_scale):
	return 0.0
a = abs(a)
b = abs(b)
function code(a, b, angle, x_45_scale, y_45_scale)
	return 0.0
end
a = abs(a)
b = abs(b)
function tmp = code(a, b, angle, x_45_scale, y_45_scale)
	tmp = 0.0;
end
NOTE: a should be positive before calling this function
NOTE: b should be positive before calling this function
code[a_, b_, angle_, x$45$scale_, y$45$scale_] := 0.0
\begin{array}{l}
a = |a|\\
b = |b|\\
\\
0
\end{array}
Derivation
  1. Initial program 22.4%

    \[\frac{\frac{\left(\left(2 \cdot \left({b}^{2} - {a}^{2}\right)\right) \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right) \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)}{x-scale}}{y-scale} \cdot \frac{\frac{\left(\left(2 \cdot \left({b}^{2} - {a}^{2}\right)\right) \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right) \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)}{x-scale}}{y-scale} - \left(4 \cdot \frac{\frac{{\left(a \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2} + {\left(b \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2}}{x-scale}}{x-scale}\right) \cdot \frac{\frac{{\left(a \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2} + {\left(b \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2}}{y-scale}}{y-scale} \]
  2. Step-by-step derivation
    1. fma-neg23.8%

      \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{\frac{\left(\left(2 \cdot \left({b}^{2} - {a}^{2}\right)\right) \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right) \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)}{x-scale}}{y-scale}, \frac{\frac{\left(\left(2 \cdot \left({b}^{2} - {a}^{2}\right)\right) \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right) \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)}{x-scale}}{y-scale}, -\left(4 \cdot \frac{\frac{{\left(a \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2} + {\left(b \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2}}{x-scale}}{x-scale}\right) \cdot \frac{\frac{{\left(a \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2} + {\left(b \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2}}{y-scale}}{y-scale}\right)} \]
  3. Simplified20.2%

    \[\leadsto \color{blue}{\mathsf{fma}\left(\frac{\left(2 \cdot \left(b \cdot b - a \cdot a\right)\right) \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)}{y-scale} \cdot \frac{\cos \left(\frac{angle}{180} \cdot \pi\right)}{x-scale}, \frac{\left(2 \cdot \left(b \cdot b - a \cdot a\right)\right) \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)}{y-scale} \cdot \frac{\cos \left(\frac{angle}{180} \cdot \pi\right)}{x-scale}, \frac{{\left(a \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2} + {\left(b \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2}}{y-scale \cdot y-scale} \cdot \left(\frac{{\left(a \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2} + {\left(b \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2}}{x-scale \cdot x-scale} \cdot -4\right)\right)} \]
  4. Taylor expanded in b around 0 21.3%

    \[\leadsto \color{blue}{4 \cdot \frac{{a}^{4} \cdot \left({\cos \left(0.005555555555555556 \cdot \left(angle \cdot \pi\right)\right)}^{2} \cdot {\sin \left(0.005555555555555556 \cdot \left(angle \cdot \pi\right)\right)}^{2}\right)}{{y-scale}^{2} \cdot {x-scale}^{2}} + -4 \cdot \frac{{a}^{4} \cdot \left({\cos \left(0.005555555555555556 \cdot \left(angle \cdot \pi\right)\right)}^{2} \cdot {\sin \left(0.005555555555555556 \cdot \left(angle \cdot \pi\right)\right)}^{2}\right)}{{x-scale}^{2} \cdot {y-scale}^{2}}} \]
  5. Step-by-step derivation
    1. *-commutative21.3%

      \[\leadsto \color{blue}{\frac{{a}^{4} \cdot \left({\cos \left(0.005555555555555556 \cdot \left(angle \cdot \pi\right)\right)}^{2} \cdot {\sin \left(0.005555555555555556 \cdot \left(angle \cdot \pi\right)\right)}^{2}\right)}{{y-scale}^{2} \cdot {x-scale}^{2}} \cdot 4} + -4 \cdot \frac{{a}^{4} \cdot \left({\cos \left(0.005555555555555556 \cdot \left(angle \cdot \pi\right)\right)}^{2} \cdot {\sin \left(0.005555555555555556 \cdot \left(angle \cdot \pi\right)\right)}^{2}\right)}{{x-scale}^{2} \cdot {y-scale}^{2}} \]
    2. *-commutative21.3%

      \[\leadsto \frac{{a}^{4} \cdot \left({\cos \left(0.005555555555555556 \cdot \left(angle \cdot \pi\right)\right)}^{2} \cdot {\sin \left(0.005555555555555556 \cdot \left(angle \cdot \pi\right)\right)}^{2}\right)}{{y-scale}^{2} \cdot {x-scale}^{2}} \cdot 4 + \color{blue}{\frac{{a}^{4} \cdot \left({\cos \left(0.005555555555555556 \cdot \left(angle \cdot \pi\right)\right)}^{2} \cdot {\sin \left(0.005555555555555556 \cdot \left(angle \cdot \pi\right)\right)}^{2}\right)}{{x-scale}^{2} \cdot {y-scale}^{2}} \cdot -4} \]
    3. *-commutative21.3%

      \[\leadsto \frac{{a}^{4} \cdot \left({\cos \left(0.005555555555555556 \cdot \left(angle \cdot \pi\right)\right)}^{2} \cdot {\sin \left(0.005555555555555556 \cdot \left(angle \cdot \pi\right)\right)}^{2}\right)}{{y-scale}^{2} \cdot {x-scale}^{2}} \cdot 4 + \frac{{a}^{4} \cdot \left({\cos \left(0.005555555555555556 \cdot \left(angle \cdot \pi\right)\right)}^{2} \cdot {\sin \left(0.005555555555555556 \cdot \left(angle \cdot \pi\right)\right)}^{2}\right)}{\color{blue}{{y-scale}^{2} \cdot {x-scale}^{2}}} \cdot -4 \]
    4. distribute-lft-out21.3%

      \[\leadsto \color{blue}{\frac{{a}^{4} \cdot \left({\cos \left(0.005555555555555556 \cdot \left(angle \cdot \pi\right)\right)}^{2} \cdot {\sin \left(0.005555555555555556 \cdot \left(angle \cdot \pi\right)\right)}^{2}\right)}{{y-scale}^{2} \cdot {x-scale}^{2}} \cdot \left(4 + -4\right)} \]
  6. Simplified31.9%

    \[\leadsto \color{blue}{0} \]
  7. Final simplification31.9%

    \[\leadsto 0 \]

Reproduce

?
herbie shell --seed 2023208 
(FPCore (a b angle x-scale y-scale)
  :name "Simplification of discriminant from scale-rotated-ellipse"
  :precision binary64
  (- (* (/ (/ (* (* (* 2.0 (- (pow b 2.0) (pow a 2.0))) (sin (* (/ angle 180.0) PI))) (cos (* (/ angle 180.0) PI))) x-scale) y-scale) (/ (/ (* (* (* 2.0 (- (pow b 2.0) (pow a 2.0))) (sin (* (/ angle 180.0) PI))) (cos (* (/ angle 180.0) PI))) x-scale) y-scale)) (* (* 4.0 (/ (/ (+ (pow (* a (sin (* (/ angle 180.0) PI))) 2.0) (pow (* b (cos (* (/ angle 180.0) PI))) 2.0)) x-scale) x-scale)) (/ (/ (+ (pow (* a (cos (* (/ angle 180.0) PI))) 2.0) (pow (* b (sin (* (/ angle 180.0) PI))) 2.0)) y-scale) y-scale))))