Simplification of discriminant from scale-rotated-ellipse

Average Error: 41.0 → 5.8

Time: 1.1min

Precision: binary64

Math

\[\frac{\frac{\left(\left(2 \cdot \left({b}^{2} - {a}^{2}\right)\right) \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right) \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)}{x-scale}}{y-scale} \cdot \frac{\frac{\left(\left(2 \cdot \left({b}^{2} - {a}^{2}\right)\right) \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right) \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)}{x-scale}}{y-scale} - \left(4 \cdot \frac{\frac{{\left(a \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2} + {\left(b \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2}}{x-scale}}{x-scale}\right) \cdot \frac{\frac{{\left(a \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2} + {\left(b \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2}}{y-scale}}{y-scale} \]

↓

\[\begin{array}{l} t_0 := -4 \cdot {\left(\frac{b \cdot a}{x-scale \cdot y-scale}\right)}^{2}\\ t_1 := -4 \cdot {\left(\frac{b}{x-scale \cdot \frac{y-scale}{a}}\right)}^{2}\\ \mathbf{if}\;\frac{angle}{180} \leq -7.083147212391496 \cdot 10^{-105}:\\ \;\;\;\;t_1\\ \mathbf{elif}\;\frac{angle}{180} \leq -3.365480426795039 \cdot 10^{-296}:\\ \;\;\;\;t_0\\ \mathbf{elif}\;\frac{angle}{180} \leq 1.0042822233950538 \cdot 10^{-168}:\\ \;\;\;\;-4 \cdot {\left(\frac{\frac{b}{\frac{x-scale}{a}}}{y-scale}\right)}^{2}\\ \mathbf{elif}\;\frac{angle}{180} \leq 3.512556767822914 \cdot 10^{+195}:\\ \;\;\;\;t_0\\ \mathbf{else}:\\ \;\;\;\;t_1\\ \end{array} \]

FPCore

(FPCore (a b angle x-scale y-scale)
 :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))))

↓

(FPCore (a b angle x-scale y-scale)
 :precision binary64
 (let* ((t_0 (* -4.0 (pow (/ (* b a) (* x-scale y-scale)) 2.0)))
        (t_1 (* -4.0 (pow (/ b (* x-scale (/ y-scale a))) 2.0))))
   (if (<= (/ angle 180.0) -7.083147212391496e-105)
     t_1
     (if (<= (/ angle 180.0) -3.365480426795039e-296)
       t_0
       (if (<= (/ angle 180.0) 1.0042822233950538e-168)
         (* -4.0 (pow (/ (/ b (/ x-scale a)) y-scale) 2.0))
         (if (<= (/ angle 180.0) 3.512556767822914e+195) t_0 t_1))))))

C

double code(double a, double b, double angle, double x_45_scale, double y_45_scale) {
	return ((((((2.0 * (pow(b, 2.0) - pow(a, 2.0))) * sin(((angle / 180.0) * ((double) M_PI)))) * cos(((angle / 180.0) * ((double) M_PI)))) / x_45_scale) / y_45_scale) * (((((2.0 * (pow(b, 2.0) - pow(a, 2.0))) * sin(((angle / 180.0) * ((double) M_PI)))) * cos(((angle / 180.0) * ((double) M_PI)))) / x_45_scale) / y_45_scale)) - ((4.0 * (((pow((a * sin(((angle / 180.0) * ((double) M_PI)))), 2.0) + pow((b * cos(((angle / 180.0) * ((double) M_PI)))), 2.0)) / x_45_scale) / x_45_scale)) * (((pow((a * cos(((angle / 180.0) * ((double) M_PI)))), 2.0) + pow((b * sin(((angle / 180.0) * ((double) M_PI)))), 2.0)) / y_45_scale) / y_45_scale));
}

↓

double code(double a, double b, double angle, double x_45_scale, double y_45_scale) {
	double t_0 = -4.0 * pow(((b * a) / (x_45_scale * y_45_scale)), 2.0);
	double t_1 = -4.0 * pow((b / (x_45_scale * (y_45_scale / a))), 2.0);
	double tmp;
	if ((angle / 180.0) <= -7.083147212391496e-105) {
		tmp = t_1;
	} else if ((angle / 180.0) <= -3.365480426795039e-296) {
		tmp = t_0;
	} else if ((angle / 180.0) <= 1.0042822233950538e-168) {
		tmp = -4.0 * pow(((b / (x_45_scale / a)) / y_45_scale), 2.0);
	} else if ((angle / 180.0) <= 3.512556767822914e+195) {
		tmp = t_0;
	} else {
		tmp = t_1;
	}
	return tmp;
}

Java

public static double code(double a, double b, double angle, double x_45_scale, double y_45_scale) {
	return ((((((2.0 * (Math.pow(b, 2.0) - Math.pow(a, 2.0))) * Math.sin(((angle / 180.0) * Math.PI))) * Math.cos(((angle / 180.0) * Math.PI))) / x_45_scale) / y_45_scale) * (((((2.0 * (Math.pow(b, 2.0) - Math.pow(a, 2.0))) * Math.sin(((angle / 180.0) * Math.PI))) * Math.cos(((angle / 180.0) * Math.PI))) / x_45_scale) / y_45_scale)) - ((4.0 * (((Math.pow((a * Math.sin(((angle / 180.0) * Math.PI))), 2.0) + Math.pow((b * Math.cos(((angle / 180.0) * Math.PI))), 2.0)) / x_45_scale) / x_45_scale)) * (((Math.pow((a * Math.cos(((angle / 180.0) * Math.PI))), 2.0) + Math.pow((b * Math.sin(((angle / 180.0) * Math.PI))), 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 = -4.0 * Math.pow(((b * a) / (x_45_scale * y_45_scale)), 2.0);
	double t_1 = -4.0 * Math.pow((b / (x_45_scale * (y_45_scale / a))), 2.0);
	double tmp;
	if ((angle / 180.0) <= -7.083147212391496e-105) {
		tmp = t_1;
	} else if ((angle / 180.0) <= -3.365480426795039e-296) {
		tmp = t_0;
	} else if ((angle / 180.0) <= 1.0042822233950538e-168) {
		tmp = -4.0 * Math.pow(((b / (x_45_scale / a)) / y_45_scale), 2.0);
	} else if ((angle / 180.0) <= 3.512556767822914e+195) {
		tmp = t_0;
	} else {
		tmp = t_1;
	}
	return tmp;
}

Python

def code(a, b, angle, x_45_scale, y_45_scale):
	return ((((((2.0 * (math.pow(b, 2.0) - math.pow(a, 2.0))) * math.sin(((angle / 180.0) * math.pi))) * math.cos(((angle / 180.0) * math.pi))) / x_45_scale) / y_45_scale) * (((((2.0 * (math.pow(b, 2.0) - math.pow(a, 2.0))) * math.sin(((angle / 180.0) * math.pi))) * math.cos(((angle / 180.0) * math.pi))) / x_45_scale) / y_45_scale)) - ((4.0 * (((math.pow((a * math.sin(((angle / 180.0) * math.pi))), 2.0) + math.pow((b * math.cos(((angle / 180.0) * math.pi))), 2.0)) / x_45_scale) / x_45_scale)) * (((math.pow((a * math.cos(((angle / 180.0) * math.pi))), 2.0) + math.pow((b * math.sin(((angle / 180.0) * math.pi))), 2.0)) / y_45_scale) / y_45_scale))

↓

def code(a, b, angle, x_45_scale, y_45_scale):
	t_0 = -4.0 * math.pow(((b * a) / (x_45_scale * y_45_scale)), 2.0)
	t_1 = -4.0 * math.pow((b / (x_45_scale * (y_45_scale / a))), 2.0)
	tmp = 0
	if (angle / 180.0) <= -7.083147212391496e-105:
		tmp = t_1
	elif (angle / 180.0) <= -3.365480426795039e-296:
		tmp = t_0
	elif (angle / 180.0) <= 1.0042822233950538e-168:
		tmp = -4.0 * math.pow(((b / (x_45_scale / a)) / y_45_scale), 2.0)
	elif (angle / 180.0) <= 3.512556767822914e+195:
		tmp = t_0
	else:
		tmp = t_1
	return tmp

Julia

function code(a, b, angle, x_45_scale, y_45_scale)
	return Float64(Float64(Float64(Float64(Float64(Float64(Float64(2.0 * Float64((b ^ 2.0) - (a ^ 2.0))) * sin(Float64(Float64(angle / 180.0) * pi))) * cos(Float64(Float64(angle / 180.0) * pi))) / x_45_scale) / y_45_scale) * Float64(Float64(Float64(Float64(Float64(2.0 * Float64((b ^ 2.0) - (a ^ 2.0))) * sin(Float64(Float64(angle / 180.0) * pi))) * cos(Float64(Float64(angle / 180.0) * pi))) / x_45_scale) / y_45_scale)) - Float64(Float64(4.0 * Float64(Float64(Float64((Float64(a * sin(Float64(Float64(angle / 180.0) * pi))) ^ 2.0) + (Float64(b * cos(Float64(Float64(angle / 180.0) * pi))) ^ 2.0)) / x_45_scale) / x_45_scale)) * Float64(Float64(Float64((Float64(a * cos(Float64(Float64(angle / 180.0) * pi))) ^ 2.0) + (Float64(b * sin(Float64(Float64(angle / 180.0) * pi))) ^ 2.0)) / y_45_scale) / y_45_scale)))
end

↓

function code(a, b, angle, x_45_scale, y_45_scale)
	t_0 = Float64(-4.0 * (Float64(Float64(b * a) / Float64(x_45_scale * y_45_scale)) ^ 2.0))
	t_1 = Float64(-4.0 * (Float64(b / Float64(x_45_scale * Float64(y_45_scale / a))) ^ 2.0))
	tmp = 0.0
	if (Float64(angle / 180.0) <= -7.083147212391496e-105)
		tmp = t_1;
	elseif (Float64(angle / 180.0) <= -3.365480426795039e-296)
		tmp = t_0;
	elseif (Float64(angle / 180.0) <= 1.0042822233950538e-168)
		tmp = Float64(-4.0 * (Float64(Float64(b / Float64(x_45_scale / a)) / y_45_scale) ^ 2.0));
	elseif (Float64(angle / 180.0) <= 3.512556767822914e+195)
		tmp = t_0;
	else
		tmp = t_1;
	end
	return tmp
end

MATLAB

function tmp = code(a, b, angle, x_45_scale, y_45_scale)
	tmp = ((((((2.0 * ((b ^ 2.0) - (a ^ 2.0))) * sin(((angle / 180.0) * pi))) * cos(((angle / 180.0) * pi))) / x_45_scale) / y_45_scale) * (((((2.0 * ((b ^ 2.0) - (a ^ 2.0))) * sin(((angle / 180.0) * pi))) * cos(((angle / 180.0) * pi))) / x_45_scale) / y_45_scale)) - ((4.0 * (((((a * sin(((angle / 180.0) * pi))) ^ 2.0) + ((b * cos(((angle / 180.0) * pi))) ^ 2.0)) / x_45_scale) / x_45_scale)) * (((((a * cos(((angle / 180.0) * pi))) ^ 2.0) + ((b * sin(((angle / 180.0) * pi))) ^ 2.0)) / y_45_scale) / y_45_scale));
end

↓

function tmp_2 = code(a, b, angle, x_45_scale, y_45_scale)
	t_0 = -4.0 * (((b * a) / (x_45_scale * y_45_scale)) ^ 2.0);
	t_1 = -4.0 * ((b / (x_45_scale * (y_45_scale / a))) ^ 2.0);
	tmp = 0.0;
	if ((angle / 180.0) <= -7.083147212391496e-105)
		tmp = t_1;
	elseif ((angle / 180.0) <= -3.365480426795039e-296)
		tmp = t_0;
	elseif ((angle / 180.0) <= 1.0042822233950538e-168)
		tmp = -4.0 * (((b / (x_45_scale / a)) / y_45_scale) ^ 2.0);
	elseif ((angle / 180.0) <= 3.512556767822914e+195)
		tmp = t_0;
	else
		tmp = t_1;
	end
	tmp_2 = tmp;
end

Wolfram

code[a_, b_, angle_, x$45$scale_, y$45$scale_] := N[(N[(N[(N[(N[(N[(N[(2.0 * N[(N[Power[b, 2.0], $MachinePrecision] - N[Power[a, 2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[Sin[N[(N[(angle / 180.0), $MachinePrecision] * Pi), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * N[Cos[N[(N[(angle / 180.0), $MachinePrecision] * Pi), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / x$45$scale), $MachinePrecision] / y$45$scale), $MachinePrecision] * N[(N[(N[(N[(N[(2.0 * N[(N[Power[b, 2.0], $MachinePrecision] - N[Power[a, 2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[Sin[N[(N[(angle / 180.0), $MachinePrecision] * Pi), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * N[Cos[N[(N[(angle / 180.0), $MachinePrecision] * Pi), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / x$45$scale), $MachinePrecision] / y$45$scale), $MachinePrecision]), $MachinePrecision] - N[(N[(4.0 * N[(N[(N[(N[Power[N[(a * N[Sin[N[(N[(angle / 180.0), $MachinePrecision] * Pi), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], 2.0], $MachinePrecision] + N[Power[N[(b * N[Cos[N[(N[(angle / 180.0), $MachinePrecision] * Pi), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision] / x$45$scale), $MachinePrecision] / x$45$scale), $MachinePrecision]), $MachinePrecision] * N[(N[(N[(N[Power[N[(a * N[Cos[N[(N[(angle / 180.0), $MachinePrecision] * Pi), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], 2.0], $MachinePrecision] + N[Power[N[(b * N[Sin[N[(N[(angle / 180.0), $MachinePrecision] * Pi), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision] / y$45$scale), $MachinePrecision] / y$45$scale), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]

↓

code[a_, b_, angle_, x$45$scale_, y$45$scale_] := Block[{t$95$0 = N[(-4.0 * N[Power[N[(N[(b * a), $MachinePrecision] / N[(x$45$scale * y$45$scale), $MachinePrecision]), $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[(-4.0 * N[Power[N[(b / N[(x$45$scale * N[(y$45$scale / a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision]}, If[LessEqual[N[(angle / 180.0), $MachinePrecision], -7.083147212391496e-105], t$95$1, If[LessEqual[N[(angle / 180.0), $MachinePrecision], -3.365480426795039e-296], t$95$0, If[LessEqual[N[(angle / 180.0), $MachinePrecision], 1.0042822233950538e-168], N[(-4.0 * N[Power[N[(N[(b / N[(x$45$scale / a), $MachinePrecision]), $MachinePrecision] / y$45$scale), $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision], If[LessEqual[N[(angle / 180.0), $MachinePrecision], 3.512556767822914e+195], t$95$0, t$95$1]]]]]]

Error

Bits error versus a

Bits error versus b

Bits error versus angle

Bits error versus x-scale

Bits error versus y-scale

Derivation

1. Split input into 3 regimes

2. if (/.f64 angle 180) < -7.0831472123914964e-105 or 3.5125567678229142e195 < (/.f64 angle 180)

   1. Initial program 43.7

      \[\frac{\frac{\left(\left(2 \cdot \left({b}^{2} - {a}^{2}\right)\right) \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right) \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)}{x-scale}}{y-scale} \cdot \frac{\frac{\left(\left(2 \cdot \left({b}^{2} - {a}^{2}\right)\right) \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right) \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)}{x-scale}}{y-scale} - \left(4 \cdot \frac{\frac{{\left(a \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2} + {\left(b \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2}}{x-scale}}{x-scale}\right) \cdot \frac{\frac{{\left(a \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2} + {\left(b \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2}}{y-scale}}{y-scale} \]

   2. Taylor expanded in angle around 0 39.8

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

   3. Simplified 31.3

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

   4. Applied egg-rr 5.8

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

   5. Taylor expanded in a around 0 6.2

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

   6. Simplified 5.7

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

   if -7.0831472123914964e-105 < (/.f64 angle 180) < -3.36548042679503896e-296 or 1.0042822233950538e-168 < (/.f64 angle 180) < 3.5125567678229142e195

   1. Initial program 40.4

      \[\frac{\frac{\left(\left(2 \cdot \left({b}^{2} - {a}^{2}\right)\right) \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right) \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)}{x-scale}}{y-scale} \cdot \frac{\frac{\left(\left(2 \cdot \left({b}^{2} - {a}^{2}\right)\right) \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right) \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)}{x-scale}}{y-scale} - \left(4 \cdot \frac{\frac{{\left(a \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2} + {\left(b \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2}}{x-scale}}{x-scale}\right) \cdot \frac{\frac{{\left(a \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2} + {\left(b \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2}}{y-scale}}{y-scale} \]

   2. Taylor expanded in angle around 0 39.5

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

   3. Simplified 31.7

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

   4. Applied egg-rr 6.0

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

   5. Taylor expanded in a around 0 5.9

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

   if -3.36548042679503896e-296 < (/.f64 angle 180) < 1.0042822233950538e-168

   1. Initial program 34.3

      \[\frac{\frac{\left(\left(2 \cdot \left({b}^{2} - {a}^{2}\right)\right) \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right) \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)}{x-scale}}{y-scale} \cdot \frac{\frac{\left(\left(2 \cdot \left({b}^{2} - {a}^{2}\right)\right) \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right) \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)}{x-scale}}{y-scale} - \left(4 \cdot \frac{\frac{{\left(a \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2} + {\left(b \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2}}{x-scale}}{x-scale}\right) \cdot \frac{\frac{{\left(a \cdot \cos \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2} + {\left(b \cdot \sin \left(\frac{angle}{180} \cdot \pi\right)\right)}^{2}}{y-scale}}{y-scale} \]

   2. Taylor expanded in angle around 0 39.8

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

   3. Simplified 31.7

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

   4. Applied egg-rr 6.4

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

   5. Taylor expanded in a around 0 6.2

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

   6. Simplified 5.9

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

4. Final simplification 5.8

   \[\leadsto \begin{array}{l} \mathbf{if}\;\frac{angle}{180} \leq -7.083147212391496 \cdot 10^{-105}:\\ \;\;\;\;-4 \cdot {\left(\frac{b}{x-scale \cdot \frac{y-scale}{a}}\right)}^{2}\\ \mathbf{elif}\;\frac{angle}{180} \leq -3.365480426795039 \cdot 10^{-296}:\\ \;\;\;\;-4 \cdot {\left(\frac{b \cdot a}{x-scale \cdot y-scale}\right)}^{2}\\ \mathbf{elif}\;\frac{angle}{180} \leq 1.0042822233950538 \cdot 10^{-168}:\\ \;\;\;\;-4 \cdot {\left(\frac{\frac{b}{\frac{x-scale}{a}}}{y-scale}\right)}^{2}\\ \mathbf{elif}\;\frac{angle}{180} \leq 3.512556767822914 \cdot 10^{+195}:\\ \;\;\;\;-4 \cdot {\left(\frac{b \cdot a}{x-scale \cdot y-scale}\right)}^{2}\\ \mathbf{else}:\\ \;\;\;\;-4 \cdot {\left(\frac{b}{x-scale \cdot \frac{y-scale}{a}}\right)}^{2}\\ \end{array} \]

Reproduce

herbie shell --seed 2022152 
(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))))