
(FPCore (a b angle x-scale y-scale)
:precision binary64
(let* ((t_0 (* (/ angle 180.0) (PI)))
(t_1 (cos t_0))
(t_2 (sin t_0))
(t_3
(/
(/ (* (* (* 2.0 (- (pow b 2.0) (pow a 2.0))) t_2) t_1) x-scale)
y-scale))
(t_4
(/ (/ (+ (pow (* a t_1) 2.0) (pow (* b t_2) 2.0)) y-scale) y-scale))
(t_5
(/ (/ (+ (pow (* a t_2) 2.0) (pow (* b t_1) 2.0)) x-scale) x-scale)))
(*
180.0
(/
(atan
(/ (- (- t_4 t_5) (sqrt (+ (pow (- t_5 t_4) 2.0) (pow t_3 2.0)))) t_3))
(PI)))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{angle}{180} \cdot \mathsf{PI}\left(\right)\\
t_1 := \cos t\_0\\
t_2 := \sin t\_0\\
t_3 := \frac{\frac{\left(\left(2 \cdot \left({b}^{2} - {a}^{2}\right)\right) \cdot t\_2\right) \cdot t\_1}{x-scale}}{y-scale}\\
t_4 := \frac{\frac{{\left(a \cdot t\_1\right)}^{2} + {\left(b \cdot t\_2\right)}^{2}}{y-scale}}{y-scale}\\
t_5 := \frac{\frac{{\left(a \cdot t\_2\right)}^{2} + {\left(b \cdot t\_1\right)}^{2}}{x-scale}}{x-scale}\\
180 \cdot \frac{\tan^{-1} \left(\frac{\left(t\_4 - t\_5\right) - \sqrt{{\left(t\_5 - t\_4\right)}^{2} + {t\_3}^{2}}}{t\_3}\right)}{\mathsf{PI}\left(\right)}
\end{array}
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 8 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (a b angle x-scale y-scale)
:precision binary64
(let* ((t_0 (* (/ angle 180.0) (PI)))
(t_1 (cos t_0))
(t_2 (sin t_0))
(t_3
(/
(/ (* (* (* 2.0 (- (pow b 2.0) (pow a 2.0))) t_2) t_1) x-scale)
y-scale))
(t_4
(/ (/ (+ (pow (* a t_1) 2.0) (pow (* b t_2) 2.0)) y-scale) y-scale))
(t_5
(/ (/ (+ (pow (* a t_2) 2.0) (pow (* b t_1) 2.0)) x-scale) x-scale)))
(*
180.0
(/
(atan
(/ (- (- t_4 t_5) (sqrt (+ (pow (- t_5 t_4) 2.0) (pow t_3 2.0)))) t_3))
(PI)))))\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{angle}{180} \cdot \mathsf{PI}\left(\right)\\
t_1 := \cos t\_0\\
t_2 := \sin t\_0\\
t_3 := \frac{\frac{\left(\left(2 \cdot \left({b}^{2} - {a}^{2}\right)\right) \cdot t\_2\right) \cdot t\_1}{x-scale}}{y-scale}\\
t_4 := \frac{\frac{{\left(a \cdot t\_1\right)}^{2} + {\left(b \cdot t\_2\right)}^{2}}{y-scale}}{y-scale}\\
t_5 := \frac{\frac{{\left(a \cdot t\_2\right)}^{2} + {\left(b \cdot t\_1\right)}^{2}}{x-scale}}{x-scale}\\
180 \cdot \frac{\tan^{-1} \left(\frac{\left(t\_4 - t\_5\right) - \sqrt{{\left(t\_5 - t\_4\right)}^{2} + {t\_3}^{2}}}{t\_3}\right)}{\mathsf{PI}\left(\right)}
\end{array}
\end{array}
a_m = (fabs.f64 a)
(FPCore (a_m b angle x-scale y-scale)
:precision binary64
(let* ((t_0 (* angle (PI)))
(t_1 (* 0.005555555555555556 t_0))
(t_2 (sin t_1))
(t_3 (/ (- y-scale) x-scale)))
(if (<= a_m 4.4e-157)
(*
180.0
(/
(atan (* t_3 (/ (sin (fma 0.005555555555555556 t_0 (/ (PI) 2.0))) t_2)))
(PI)))
(if (<= a_m 1.25e-49)
(* 180.0 (/ (atan (* t_3 (/ 1.0 t_2))) (PI)))
(* 180.0 (/ (atan (* (/ y-scale x-scale) (tan t_1))) (PI)))))))\begin{array}{l}
a_m = \left|a\right|
\\
\begin{array}{l}
t_0 := angle \cdot \mathsf{PI}\left(\right)\\
t_1 := 0.005555555555555556 \cdot t\_0\\
t_2 := \sin t\_1\\
t_3 := \frac{-y-scale}{x-scale}\\
\mathbf{if}\;a\_m \leq 4.4 \cdot 10^{-157}:\\
\;\;\;\;180 \cdot \frac{\tan^{-1} \left(t\_3 \cdot \frac{\sin \left(\mathsf{fma}\left(0.005555555555555556, t\_0, \frac{\mathsf{PI}\left(\right)}{2}\right)\right)}{t\_2}\right)}{\mathsf{PI}\left(\right)}\\
\mathbf{elif}\;a\_m \leq 1.25 \cdot 10^{-49}:\\
\;\;\;\;180 \cdot \frac{\tan^{-1} \left(t\_3 \cdot \frac{1}{t\_2}\right)}{\mathsf{PI}\left(\right)}\\
\mathbf{else}:\\
\;\;\;\;180 \cdot \frac{\tan^{-1} \left(\frac{y-scale}{x-scale} \cdot \tan t\_1\right)}{\mathsf{PI}\left(\right)}\\
\end{array}
\end{array}
if a < 4.4000000000000002e-157Initial program 12.8%
Taylor expanded in b around inf
Applied rewrites26.2%
Taylor expanded in angle around 0
lower-*.f64N/A
lower-/.f64N/A
lower-*.f64N/A
lower-*.f64N/A
pow2N/A
lift-*.f64N/A
lift-PI.f6439.9
Applied rewrites39.9%
Taylor expanded in x-scale around 0
lower-*.f64N/A
times-fracN/A
lower-*.f64N/A
Applied rewrites44.7%
lift-cos.f64N/A
lift-*.f64N/A
lift-PI.f64N/A
lift-*.f64N/A
sin-+PI/2-revN/A
lower-sin.f64N/A
lower-fma.f64N/A
lift-*.f64N/A
lift-PI.f64N/A
lower-/.f64N/A
lift-PI.f6445.4
Applied rewrites45.4%
if 4.4000000000000002e-157 < a < 1.25e-49Initial program 21.0%
Taylor expanded in b around inf
Applied rewrites27.0%
Taylor expanded in angle around 0
lower-*.f64N/A
lower-/.f64N/A
lower-*.f64N/A
lower-*.f64N/A
pow2N/A
lift-*.f64N/A
lift-PI.f6456.4
Applied rewrites56.4%
Taylor expanded in x-scale around 0
lower-*.f64N/A
times-fracN/A
lower-*.f64N/A
Applied rewrites59.6%
Taylor expanded in angle around 0
Applied rewrites67.7%
if 1.25e-49 < a Initial program 9.1%
Taylor expanded in x-scale around 0
Applied rewrites26.4%
Taylor expanded in a around inf
lower-*.f64N/A
quot-tanN/A
lower-tan.f64N/A
lift-*.f64N/A
lift-PI.f64N/A
lift-*.f6458.2
Applied rewrites58.2%
Taylor expanded in a around inf
times-fracN/A
tan-quotN/A
lower-*.f64N/A
lift-/.f64N/A
lift-*.f64N/A
lift-PI.f64N/A
lift-*.f64N/A
lift-tan.f6458.2
Applied rewrites58.2%
Final simplification52.1%
a_m = (fabs.f64 a)
(FPCore (a_m b angle x-scale y-scale)
:precision binary64
(let* ((t_0 (* 0.005555555555555556 (* angle (PI)))))
(if (<= a_m 7.2e-8)
(*
180.0
(/ (atan (* (/ (- y-scale) x-scale) (/ (cos t_0) (sin t_0)))) (PI)))
(* 180.0 (/ (atan (* (/ y-scale x-scale) (tan t_0))) (PI))))))\begin{array}{l}
a_m = \left|a\right|
\\
\begin{array}{l}
t_0 := 0.005555555555555556 \cdot \left(angle \cdot \mathsf{PI}\left(\right)\right)\\
\mathbf{if}\;a\_m \leq 7.2 \cdot 10^{-8}:\\
\;\;\;\;180 \cdot \frac{\tan^{-1} \left(\frac{-y-scale}{x-scale} \cdot \frac{\cos t\_0}{\sin t\_0}\right)}{\mathsf{PI}\left(\right)}\\
\mathbf{else}:\\
\;\;\;\;180 \cdot \frac{\tan^{-1} \left(\frac{y-scale}{x-scale} \cdot \tan t\_0\right)}{\mathsf{PI}\left(\right)}\\
\end{array}
\end{array}
if a < 7.19999999999999962e-8Initial program 14.4%
Taylor expanded in b around inf
Applied rewrites27.3%
Taylor expanded in angle around 0
lower-*.f64N/A
lower-/.f64N/A
lower-*.f64N/A
lower-*.f64N/A
pow2N/A
lift-*.f64N/A
lift-PI.f6442.2
Applied rewrites42.2%
Taylor expanded in x-scale around 0
lower-*.f64N/A
times-fracN/A
lower-*.f64N/A
Applied rewrites48.4%
if 7.19999999999999962e-8 < a Initial program 8.3%
Taylor expanded in x-scale around 0
Applied rewrites26.6%
Taylor expanded in a around inf
lower-*.f64N/A
quot-tanN/A
lower-tan.f64N/A
lift-*.f64N/A
lift-PI.f64N/A
lift-*.f6462.6
Applied rewrites62.6%
Taylor expanded in a around inf
times-fracN/A
tan-quotN/A
lower-*.f64N/A
lift-/.f64N/A
lift-*.f64N/A
lift-PI.f64N/A
lift-*.f64N/A
lift-tan.f6462.6
Applied rewrites62.6%
Final simplification51.9%
a_m = (fabs.f64 a)
(FPCore (a_m b angle x-scale y-scale)
:precision binary64
(let* ((t_0 (* 0.005555555555555556 (* angle (PI)))))
(if (<= a_m 1.1e-53)
(* 180.0 (/ (atan (* (/ (- y-scale) x-scale) (/ 1.0 (sin t_0)))) (PI)))
(* 180.0 (/ (atan (* (/ y-scale x-scale) (tan t_0))) (PI))))))\begin{array}{l}
a_m = \left|a\right|
\\
\begin{array}{l}
t_0 := 0.005555555555555556 \cdot \left(angle \cdot \mathsf{PI}\left(\right)\right)\\
\mathbf{if}\;a\_m \leq 1.1 \cdot 10^{-53}:\\
\;\;\;\;180 \cdot \frac{\tan^{-1} \left(\frac{-y-scale}{x-scale} \cdot \frac{1}{\sin t\_0}\right)}{\mathsf{PI}\left(\right)}\\
\mathbf{else}:\\
\;\;\;\;180 \cdot \frac{\tan^{-1} \left(\frac{y-scale}{x-scale} \cdot \tan t\_0\right)}{\mathsf{PI}\left(\right)}\\
\end{array}
\end{array}
if a < 1.10000000000000009e-53Initial program 14.3%
Taylor expanded in b around inf
Applied rewrites26.4%
Taylor expanded in angle around 0
lower-*.f64N/A
lower-/.f64N/A
lower-*.f64N/A
lower-*.f64N/A
pow2N/A
lift-*.f64N/A
lift-PI.f6443.0
Applied rewrites43.0%
Taylor expanded in x-scale around 0
lower-*.f64N/A
times-fracN/A
lower-*.f64N/A
Applied rewrites47.5%
Taylor expanded in angle around 0
Applied rewrites48.9%
if 1.10000000000000009e-53 < a Initial program 9.1%
Taylor expanded in x-scale around 0
Applied rewrites26.4%
Taylor expanded in a around inf
lower-*.f64N/A
quot-tanN/A
lower-tan.f64N/A
lift-*.f64N/A
lift-PI.f64N/A
lift-*.f6458.2
Applied rewrites58.2%
Taylor expanded in a around inf
times-fracN/A
tan-quotN/A
lower-*.f64N/A
lift-/.f64N/A
lift-*.f64N/A
lift-PI.f64N/A
lift-*.f64N/A
lift-tan.f6458.2
Applied rewrites58.2%
Final simplification51.5%
a_m = (fabs.f64 a)
(FPCore (a_m b angle x-scale y-scale)
:precision binary64
(let* ((t_0 (* angle (PI))))
(if (<= a_m 3.9e-50)
(* 180.0 (/ (atan (* (/ (- y-scale) x-scale) (/ 180.0 t_0))) (PI)))
(*
180.0
(/
(atan (* (/ y-scale x-scale) (tan (* 0.005555555555555556 t_0))))
(PI))))))\begin{array}{l}
a_m = \left|a\right|
\\
\begin{array}{l}
t_0 := angle \cdot \mathsf{PI}\left(\right)\\
\mathbf{if}\;a\_m \leq 3.9 \cdot 10^{-50}:\\
\;\;\;\;180 \cdot \frac{\tan^{-1} \left(\frac{-y-scale}{x-scale} \cdot \frac{180}{t\_0}\right)}{\mathsf{PI}\left(\right)}\\
\mathbf{else}:\\
\;\;\;\;180 \cdot \frac{\tan^{-1} \left(\frac{y-scale}{x-scale} \cdot \tan \left(0.005555555555555556 \cdot t\_0\right)\right)}{\mathsf{PI}\left(\right)}\\
\end{array}
\end{array}
if a < 3.90000000000000021e-50Initial program 14.3%
Taylor expanded in b around inf
Applied rewrites26.4%
Taylor expanded in angle around 0
lower-*.f64N/A
lower-/.f64N/A
lower-*.f64N/A
lower-*.f64N/A
pow2N/A
lift-*.f64N/A
lift-PI.f6443.0
Applied rewrites43.0%
Taylor expanded in x-scale around 0
lower-*.f64N/A
times-fracN/A
lower-*.f64N/A
Applied rewrites47.5%
Taylor expanded in angle around 0
lower-/.f64N/A
lift-*.f64N/A
lift-PI.f6442.5
Applied rewrites42.5%
if 3.90000000000000021e-50 < a Initial program 9.1%
Taylor expanded in x-scale around 0
Applied rewrites26.4%
Taylor expanded in a around inf
lower-*.f64N/A
quot-tanN/A
lower-tan.f64N/A
lift-*.f64N/A
lift-PI.f64N/A
lift-*.f6458.2
Applied rewrites58.2%
Taylor expanded in a around inf
times-fracN/A
tan-quotN/A
lower-*.f64N/A
lift-/.f64N/A
lift-*.f64N/A
lift-PI.f64N/A
lift-*.f64N/A
lift-tan.f6458.2
Applied rewrites58.2%
Final simplification46.9%
a_m = (fabs.f64 a)
(FPCore (a_m b angle x-scale y-scale)
:precision binary64
(let* ((t_0 (* angle (PI))))
(if (<= a_m 1.1e-53)
(* 180.0 (/ (atan (* (/ (- y-scale) x-scale) (/ 180.0 t_0))) (PI)))
(*
180.0
(/ (atan (* (/ y-scale x-scale) (* 0.005555555555555556 t_0))) (PI))))))\begin{array}{l}
a_m = \left|a\right|
\\
\begin{array}{l}
t_0 := angle \cdot \mathsf{PI}\left(\right)\\
\mathbf{if}\;a\_m \leq 1.1 \cdot 10^{-53}:\\
\;\;\;\;180 \cdot \frac{\tan^{-1} \left(\frac{-y-scale}{x-scale} \cdot \frac{180}{t\_0}\right)}{\mathsf{PI}\left(\right)}\\
\mathbf{else}:\\
\;\;\;\;180 \cdot \frac{\tan^{-1} \left(\frac{y-scale}{x-scale} \cdot \left(0.005555555555555556 \cdot t\_0\right)\right)}{\mathsf{PI}\left(\right)}\\
\end{array}
\end{array}
if a < 1.10000000000000009e-53Initial program 14.3%
Taylor expanded in b around inf
Applied rewrites26.4%
Taylor expanded in angle around 0
lower-*.f64N/A
lower-/.f64N/A
lower-*.f64N/A
lower-*.f64N/A
pow2N/A
lift-*.f64N/A
lift-PI.f6443.0
Applied rewrites43.0%
Taylor expanded in x-scale around 0
lower-*.f64N/A
times-fracN/A
lower-*.f64N/A
Applied rewrites47.5%
Taylor expanded in angle around 0
lower-/.f64N/A
lift-*.f64N/A
lift-PI.f6442.5
Applied rewrites42.5%
if 1.10000000000000009e-53 < a Initial program 9.1%
Taylor expanded in x-scale around 0
Applied rewrites26.4%
Taylor expanded in a around inf
lower-*.f64N/A
quot-tanN/A
lower-tan.f64N/A
lift-*.f64N/A
lift-PI.f64N/A
lift-*.f6458.2
Applied rewrites58.2%
Taylor expanded in a around inf
times-fracN/A
tan-quotN/A
lower-*.f64N/A
lift-/.f64N/A
lift-*.f64N/A
lift-PI.f64N/A
lift-*.f64N/A
lift-tan.f6458.2
Applied rewrites58.2%
Taylor expanded in angle around 0
lift-*.f64N/A
lift-PI.f64N/A
lift-*.f6455.9
Applied rewrites55.9%
Final simplification46.3%
a_m = (fabs.f64 a)
(FPCore (a_m b angle x-scale y-scale)
:precision binary64
(if (<= a_m 1.1e-53)
(* 180.0 (/ (atan (* -180.0 (/ y-scale (* angle (* x-scale (PI)))))) (PI)))
(*
180.0
(/
(atan (* (/ y-scale x-scale) (* 0.005555555555555556 (* angle (PI)))))
(PI)))))\begin{array}{l}
a_m = \left|a\right|
\\
\begin{array}{l}
\mathbf{if}\;a\_m \leq 1.1 \cdot 10^{-53}:\\
\;\;\;\;180 \cdot \frac{\tan^{-1} \left(-180 \cdot \frac{y-scale}{angle \cdot \left(x-scale \cdot \mathsf{PI}\left(\right)\right)}\right)}{\mathsf{PI}\left(\right)}\\
\mathbf{else}:\\
\;\;\;\;180 \cdot \frac{\tan^{-1} \left(\frac{y-scale}{x-scale} \cdot \left(0.005555555555555556 \cdot \left(angle \cdot \mathsf{PI}\left(\right)\right)\right)\right)}{\mathsf{PI}\left(\right)}\\
\end{array}
\end{array}
if a < 1.10000000000000009e-53Initial program 14.3%
Taylor expanded in angle around 0
Applied rewrites10.9%
Taylor expanded in a around 0
lower-*.f64N/A
lower-/.f64N/A
lower-*.f64N/A
lower-*.f64N/A
lift-PI.f6441.5
Applied rewrites41.5%
if 1.10000000000000009e-53 < a Initial program 9.1%
Taylor expanded in x-scale around 0
Applied rewrites26.4%
Taylor expanded in a around inf
lower-*.f64N/A
quot-tanN/A
lower-tan.f64N/A
lift-*.f64N/A
lift-PI.f64N/A
lift-*.f6458.2
Applied rewrites58.2%
Taylor expanded in a around inf
times-fracN/A
tan-quotN/A
lower-*.f64N/A
lift-/.f64N/A
lift-*.f64N/A
lift-PI.f64N/A
lift-*.f64N/A
lift-tan.f6458.2
Applied rewrites58.2%
Taylor expanded in angle around 0
lift-*.f64N/A
lift-PI.f64N/A
lift-*.f6455.9
Applied rewrites55.9%
a_m = (fabs.f64 a) (FPCore (a_m b angle x-scale y-scale) :precision binary64 (* 180.0 (/ (atan (* (/ y-scale x-scale) (* 0.005555555555555556 (* angle (PI))))) (PI))))
\begin{array}{l}
a_m = \left|a\right|
\\
180 \cdot \frac{\tan^{-1} \left(\frac{y-scale}{x-scale} \cdot \left(0.005555555555555556 \cdot \left(angle \cdot \mathsf{PI}\left(\right)\right)\right)\right)}{\mathsf{PI}\left(\right)}
\end{array}
Initial program 12.9%
Taylor expanded in x-scale around 0
Applied rewrites33.6%
Taylor expanded in a around inf
lower-*.f64N/A
quot-tanN/A
lower-tan.f64N/A
lift-*.f64N/A
lift-PI.f64N/A
lift-*.f6450.0
Applied rewrites50.0%
Taylor expanded in a around inf
times-fracN/A
tan-quotN/A
lower-*.f64N/A
lift-/.f64N/A
lift-*.f64N/A
lift-PI.f64N/A
lift-*.f64N/A
lift-tan.f6450.0
Applied rewrites50.0%
Taylor expanded in angle around 0
lift-*.f64N/A
lift-PI.f64N/A
lift-*.f6448.8
Applied rewrites48.8%
a_m = (fabs.f64 a) (FPCore (a_m b angle x-scale y-scale) :precision binary64 (* 180.0 (/ (atan (* 0.005555555555555556 (/ (* angle (* y-scale (PI))) x-scale))) (PI))))
\begin{array}{l}
a_m = \left|a\right|
\\
180 \cdot \frac{\tan^{-1} \left(0.005555555555555556 \cdot \frac{angle \cdot \left(y-scale \cdot \mathsf{PI}\left(\right)\right)}{x-scale}\right)}{\mathsf{PI}\left(\right)}
\end{array}
Initial program 12.9%
Taylor expanded in x-scale around 0
Applied rewrites33.6%
Taylor expanded in a around inf
lower-*.f64N/A
quot-tanN/A
lower-tan.f64N/A
lift-*.f64N/A
lift-PI.f64N/A
lift-*.f6450.0
Applied rewrites50.0%
Taylor expanded in a around inf
times-fracN/A
tan-quotN/A
lower-*.f64N/A
lift-/.f64N/A
lift-*.f64N/A
lift-PI.f64N/A
lift-*.f64N/A
lift-tan.f6450.0
Applied rewrites50.0%
Taylor expanded in angle around 0
lower-*.f64N/A
lower-/.f64N/A
lower-*.f64N/A
lower-*.f64N/A
lift-PI.f6440.2
Applied rewrites40.2%
herbie shell --seed 2025079
(FPCore (a b angle x-scale y-scale)
:name "raw-angle from scale-rotated-ellipse"
:precision binary64
(* 180.0 (/ (atan (/ (- (- (/ (/ (+ (pow (* a (cos (* (/ angle 180.0) (PI)))) 2.0) (pow (* b (sin (* (/ angle 180.0) (PI)))) 2.0)) y-scale) y-scale) (/ (/ (+ (pow (* a (sin (* (/ angle 180.0) (PI)))) 2.0) (pow (* b (cos (* (/ angle 180.0) (PI)))) 2.0)) x-scale) x-scale)) (sqrt (+ (pow (- (/ (/ (+ (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)) 2.0) (pow (/ (/ (* (* (* 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)))) (/ (/ (* (* (* 2.0 (- (pow b 2.0) (pow a 2.0))) (sin (* (/ angle 180.0) (PI)))) (cos (* (/ angle 180.0) (PI)))) x-scale) y-scale))) (PI))))