
(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:
Herbie found 9 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(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}
y-scale_m = (fabs.f64 y-scale)
x-scale_m = (fabs.f64 x-scale)
b_m = (fabs.f64 b)
a_m = (fabs.f64 a)
(FPCore (a_m b_m angle x-scale_m y-scale_m)
:precision binary64
(*
-4.0
(exp
(-
(fma 2.0 (log b_m) (* 2.0 (log a_m)))
(* 2.0 (log (* x-scale_m y-scale_m)))))))y-scale_m = fabs(y_45_scale);
x-scale_m = fabs(x_45_scale);
b_m = fabs(b);
a_m = fabs(a);
double code(double a_m, double b_m, double angle, double x_45_scale_m, double y_45_scale_m) {
return -4.0 * exp((fma(2.0, log(b_m), (2.0 * log(a_m))) - (2.0 * log((x_45_scale_m * y_45_scale_m)))));
}
y-scale_m = abs(y_45_scale) x-scale_m = abs(x_45_scale) b_m = abs(b) a_m = abs(a) function code(a_m, b_m, angle, x_45_scale_m, y_45_scale_m) return Float64(-4.0 * exp(Float64(fma(2.0, log(b_m), Float64(2.0 * log(a_m))) - Float64(2.0 * log(Float64(x_45_scale_m * y_45_scale_m)))))) end
y-scale_m = N[Abs[y$45$scale], $MachinePrecision] x-scale_m = N[Abs[x$45$scale], $MachinePrecision] b_m = N[Abs[b], $MachinePrecision] a_m = N[Abs[a], $MachinePrecision] code[a$95$m_, b$95$m_, angle_, x$45$scale$95$m_, y$45$scale$95$m_] := N[(-4.0 * N[Exp[N[(N[(2.0 * N[Log[b$95$m], $MachinePrecision] + N[(2.0 * N[Log[a$95$m], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(2.0 * N[Log[N[(x$45$scale$95$m * y$45$scale$95$m), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
y-scale_m = \left|y-scale\right|
\\
x-scale_m = \left|x-scale\right|
\\
b_m = \left|b\right|
\\
a_m = \left|a\right|
\\
-4 \cdot e^{\mathsf{fma}\left(2, \log b\_m, 2 \cdot \log a\_m\right) - 2 \cdot \log \left(x-scale\_m \cdot y-scale\_m\right)}
\end{array}
Initial program 23.6%
Taylor expanded in angle around 0
associate-*r/N/A
lower-/.f64N/A
*-commutativeN/A
associate-*r*N/A
lower-*.f64N/A
lower-*.f64N/A
unpow2N/A
lower-*.f64N/A
unpow2N/A
lower-*.f64N/A
unpow2N/A
associate-*l*N/A
lower-*.f64N/A
lower-*.f64N/A
unpow2N/A
lower-*.f6451.7
Applied rewrites51.7%
Applied rewrites51.1%
Applied rewrites63.2%
Applied rewrites91.9%
Final simplification91.9%
y-scale_m = (fabs.f64 y-scale)
x-scale_m = (fabs.f64 x-scale)
b_m = (fabs.f64 b)
a_m = (fabs.f64 a)
(FPCore (a_m b_m angle x-scale_m y-scale_m)
:precision binary64
(let* ((t_0 (* x-scale_m (* y-scale_m (* x-scale_m y-scale_m))))
(t_1 (* b_m (/ (* a_m (* a_m (* b_m -4.0))) t_0))))
(if (<= b_m 3e-150)
t_1
(if (<= b_m 7.2e+169) (* (* a_m -4.0) (* (* b_m b_m) (/ a_m t_0))) t_1))))y-scale_m = fabs(y_45_scale);
x-scale_m = fabs(x_45_scale);
b_m = fabs(b);
a_m = fabs(a);
double code(double a_m, double b_m, double angle, double x_45_scale_m, double y_45_scale_m) {
double t_0 = x_45_scale_m * (y_45_scale_m * (x_45_scale_m * y_45_scale_m));
double t_1 = b_m * ((a_m * (a_m * (b_m * -4.0))) / t_0);
double tmp;
if (b_m <= 3e-150) {
tmp = t_1;
} else if (b_m <= 7.2e+169) {
tmp = (a_m * -4.0) * ((b_m * b_m) * (a_m / t_0));
} else {
tmp = t_1;
}
return tmp;
}
y-scale_m = abs(y_45scale)
x-scale_m = abs(x_45scale)
b_m = abs(b)
a_m = abs(a)
real(8) function code(a_m, b_m, angle, x_45scale_m, y_45scale_m)
real(8), intent (in) :: a_m
real(8), intent (in) :: b_m
real(8), intent (in) :: angle
real(8), intent (in) :: x_45scale_m
real(8), intent (in) :: y_45scale_m
real(8) :: t_0
real(8) :: t_1
real(8) :: tmp
t_0 = x_45scale_m * (y_45scale_m * (x_45scale_m * y_45scale_m))
t_1 = b_m * ((a_m * (a_m * (b_m * (-4.0d0)))) / t_0)
if (b_m <= 3d-150) then
tmp = t_1
else if (b_m <= 7.2d+169) then
tmp = (a_m * (-4.0d0)) * ((b_m * b_m) * (a_m / t_0))
else
tmp = t_1
end if
code = tmp
end function
y-scale_m = Math.abs(y_45_scale);
x-scale_m = Math.abs(x_45_scale);
b_m = Math.abs(b);
a_m = Math.abs(a);
public static double code(double a_m, double b_m, double angle, double x_45_scale_m, double y_45_scale_m) {
double t_0 = x_45_scale_m * (y_45_scale_m * (x_45_scale_m * y_45_scale_m));
double t_1 = b_m * ((a_m * (a_m * (b_m * -4.0))) / t_0);
double tmp;
if (b_m <= 3e-150) {
tmp = t_1;
} else if (b_m <= 7.2e+169) {
tmp = (a_m * -4.0) * ((b_m * b_m) * (a_m / t_0));
} else {
tmp = t_1;
}
return tmp;
}
y-scale_m = math.fabs(y_45_scale) x-scale_m = math.fabs(x_45_scale) b_m = math.fabs(b) a_m = math.fabs(a) def code(a_m, b_m, angle, x_45_scale_m, y_45_scale_m): t_0 = x_45_scale_m * (y_45_scale_m * (x_45_scale_m * y_45_scale_m)) t_1 = b_m * ((a_m * (a_m * (b_m * -4.0))) / t_0) tmp = 0 if b_m <= 3e-150: tmp = t_1 elif b_m <= 7.2e+169: tmp = (a_m * -4.0) * ((b_m * b_m) * (a_m / t_0)) else: tmp = t_1 return tmp
y-scale_m = abs(y_45_scale) x-scale_m = abs(x_45_scale) b_m = abs(b) a_m = abs(a) function code(a_m, b_m, angle, x_45_scale_m, y_45_scale_m) t_0 = Float64(x_45_scale_m * Float64(y_45_scale_m * Float64(x_45_scale_m * y_45_scale_m))) t_1 = Float64(b_m * Float64(Float64(a_m * Float64(a_m * Float64(b_m * -4.0))) / t_0)) tmp = 0.0 if (b_m <= 3e-150) tmp = t_1; elseif (b_m <= 7.2e+169) tmp = Float64(Float64(a_m * -4.0) * Float64(Float64(b_m * b_m) * Float64(a_m / t_0))); else tmp = t_1; end return tmp end
y-scale_m = abs(y_45_scale); x-scale_m = abs(x_45_scale); b_m = abs(b); a_m = abs(a); function tmp_2 = code(a_m, b_m, angle, x_45_scale_m, y_45_scale_m) t_0 = x_45_scale_m * (y_45_scale_m * (x_45_scale_m * y_45_scale_m)); t_1 = b_m * ((a_m * (a_m * (b_m * -4.0))) / t_0); tmp = 0.0; if (b_m <= 3e-150) tmp = t_1; elseif (b_m <= 7.2e+169) tmp = (a_m * -4.0) * ((b_m * b_m) * (a_m / t_0)); else tmp = t_1; end tmp_2 = tmp; end
y-scale_m = N[Abs[y$45$scale], $MachinePrecision]
x-scale_m = N[Abs[x$45$scale], $MachinePrecision]
b_m = N[Abs[b], $MachinePrecision]
a_m = N[Abs[a], $MachinePrecision]
code[a$95$m_, b$95$m_, angle_, x$45$scale$95$m_, y$45$scale$95$m_] := Block[{t$95$0 = N[(x$45$scale$95$m * N[(y$45$scale$95$m * N[(x$45$scale$95$m * y$45$scale$95$m), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[(b$95$m * N[(N[(a$95$m * N[(a$95$m * N[(b$95$m * -4.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / t$95$0), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[b$95$m, 3e-150], t$95$1, If[LessEqual[b$95$m, 7.2e+169], N[(N[(a$95$m * -4.0), $MachinePrecision] * N[(N[(b$95$m * b$95$m), $MachinePrecision] * N[(a$95$m / t$95$0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], t$95$1]]]]
\begin{array}{l}
y-scale_m = \left|y-scale\right|
\\
x-scale_m = \left|x-scale\right|
\\
b_m = \left|b\right|
\\
a_m = \left|a\right|
\\
\begin{array}{l}
t_0 := x-scale\_m \cdot \left(y-scale\_m \cdot \left(x-scale\_m \cdot y-scale\_m\right)\right)\\
t_1 := b\_m \cdot \frac{a\_m \cdot \left(a\_m \cdot \left(b\_m \cdot -4\right)\right)}{t\_0}\\
\mathbf{if}\;b\_m \leq 3 \cdot 10^{-150}:\\
\;\;\;\;t\_1\\
\mathbf{elif}\;b\_m \leq 7.2 \cdot 10^{+169}:\\
\;\;\;\;\left(a\_m \cdot -4\right) \cdot \left(\left(b\_m \cdot b\_m\right) \cdot \frac{a\_m}{t\_0}\right)\\
\mathbf{else}:\\
\;\;\;\;t\_1\\
\end{array}
\end{array}
if b < 3.0000000000000002e-150 or 7.20000000000000019e169 < b Initial program 24.1%
Taylor expanded in angle around 0
associate-*r/N/A
lower-/.f64N/A
*-commutativeN/A
associate-*r*N/A
lower-*.f64N/A
lower-*.f64N/A
unpow2N/A
lower-*.f64N/A
unpow2N/A
lower-*.f64N/A
unpow2N/A
associate-*l*N/A
lower-*.f64N/A
lower-*.f64N/A
unpow2N/A
lower-*.f6444.4
Applied rewrites44.4%
Applied rewrites61.7%
Applied rewrites74.3%
Applied rewrites73.5%
if 3.0000000000000002e-150 < b < 7.20000000000000019e169Initial program 27.9%
Taylor expanded in angle around 0
associate-*r/N/A
lower-/.f64N/A
*-commutativeN/A
associate-*r*N/A
lower-*.f64N/A
lower-*.f64N/A
unpow2N/A
lower-*.f64N/A
unpow2N/A
lower-*.f64N/A
unpow2N/A
associate-*l*N/A
lower-*.f64N/A
lower-*.f64N/A
unpow2N/A
lower-*.f6463.0
Applied rewrites63.0%
Applied rewrites90.6%
Applied rewrites92.4%
Applied rewrites79.6%
herbie shell --seed 2024226
(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))))