(cos (* (atan (* (tan (- (* z0 (+ PI PI)) (* -1/2 PI))) (/ z1 z2))) -2))

Percentage Accurate: 82.3% → 99.9%
Time: 16.0s
Alternatives: 2
Speedup: 1.0×

Specification

?
\[\cos \left(\tan^{-1} \left(\tan \left(z0 \cdot \left(\pi + \pi\right) - \frac{-1}{2} \cdot \pi\right) \cdot \frac{z1}{z2}\right) \cdot -2\right) \]
(FPCore (z0 z1 z2)
  :precision binary64
  (cos
 (* (atan (* (tan (- (* z0 (+ PI PI)) (* -1/2 PI))) (/ z1 z2))) -2)))
double code(double z0, double z1, double z2) {
	return cos((atan((tan(((z0 * (((double) M_PI) + ((double) M_PI))) - (-0.5 * ((double) M_PI)))) * (z1 / z2))) * -2.0));
}
public static double code(double z0, double z1, double z2) {
	return Math.cos((Math.atan((Math.tan(((z0 * (Math.PI + Math.PI)) - (-0.5 * Math.PI))) * (z1 / z2))) * -2.0));
}
def code(z0, z1, z2):
	return math.cos((math.atan((math.tan(((z0 * (math.pi + math.pi)) - (-0.5 * math.pi))) * (z1 / z2))) * -2.0))
function code(z0, z1, z2)
	return cos(Float64(atan(Float64(tan(Float64(Float64(z0 * Float64(pi + pi)) - Float64(-0.5 * pi))) * Float64(z1 / z2))) * -2.0))
end
function tmp = code(z0, z1, z2)
	tmp = cos((atan((tan(((z0 * (pi + pi)) - (-0.5 * pi))) * (z1 / z2))) * -2.0));
end
code[z0_, z1_, z2_] := N[Cos[N[(N[ArcTan[N[(N[Tan[N[(N[(z0 * N[(Pi + Pi), $MachinePrecision]), $MachinePrecision] - N[(-1/2 * Pi), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * N[(z1 / z2), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * -2), $MachinePrecision]], $MachinePrecision]
\cos \left(\tan^{-1} \left(\tan \left(z0 \cdot \left(\pi + \pi\right) - \frac{-1}{2} \cdot \pi\right) \cdot \frac{z1}{z2}\right) \cdot -2\right)

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 2 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: 82.3% accurate, 1.0× speedup?

\[\cos \left(\tan^{-1} \left(\tan \left(z0 \cdot \left(\pi + \pi\right) - \frac{-1}{2} \cdot \pi\right) \cdot \frac{z1}{z2}\right) \cdot -2\right) \]
(FPCore (z0 z1 z2)
  :precision binary64
  (cos
 (* (atan (* (tan (- (* z0 (+ PI PI)) (* -1/2 PI))) (/ z1 z2))) -2)))
double code(double z0, double z1, double z2) {
	return cos((atan((tan(((z0 * (((double) M_PI) + ((double) M_PI))) - (-0.5 * ((double) M_PI)))) * (z1 / z2))) * -2.0));
}
public static double code(double z0, double z1, double z2) {
	return Math.cos((Math.atan((Math.tan(((z0 * (Math.PI + Math.PI)) - (-0.5 * Math.PI))) * (z1 / z2))) * -2.0));
}
def code(z0, z1, z2):
	return math.cos((math.atan((math.tan(((z0 * (math.pi + math.pi)) - (-0.5 * math.pi))) * (z1 / z2))) * -2.0))
function code(z0, z1, z2)
	return cos(Float64(atan(Float64(tan(Float64(Float64(z0 * Float64(pi + pi)) - Float64(-0.5 * pi))) * Float64(z1 / z2))) * -2.0))
end
function tmp = code(z0, z1, z2)
	tmp = cos((atan((tan(((z0 * (pi + pi)) - (-0.5 * pi))) * (z1 / z2))) * -2.0));
end
code[z0_, z1_, z2_] := N[Cos[N[(N[ArcTan[N[(N[Tan[N[(N[(z0 * N[(Pi + Pi), $MachinePrecision]), $MachinePrecision] - N[(-1/2 * Pi), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * N[(z1 / z2), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * -2), $MachinePrecision]], $MachinePrecision]
\cos \left(\tan^{-1} \left(\tan \left(z0 \cdot \left(\pi + \pi\right) - \frac{-1}{2} \cdot \pi\right) \cdot \frac{z1}{z2}\right) \cdot -2\right)

Alternative 1: 99.9% accurate, 0.8× speedup?

\[\begin{array}{l} t_0 := \left(\pi + \pi\right) \cdot z0\\ \cos \left(\tan^{-1} \left(\frac{\cos t\_0 \cdot z1}{\left(-\sin t\_0\right) \cdot z2}\right) \cdot -2\right) \end{array} \]
(FPCore (z0 z1 z2)
  :precision binary64
  (let* ((t_0 (* (+ PI PI) z0)))
  (cos (* (atan (/ (* (cos t_0) z1) (* (- (sin t_0)) z2))) -2))))
double code(double z0, double z1, double z2) {
	double t_0 = (((double) M_PI) + ((double) M_PI)) * z0;
	return cos((atan(((cos(t_0) * z1) / (-sin(t_0) * z2))) * -2.0));
}
public static double code(double z0, double z1, double z2) {
	double t_0 = (Math.PI + Math.PI) * z0;
	return Math.cos((Math.atan(((Math.cos(t_0) * z1) / (-Math.sin(t_0) * z2))) * -2.0));
}
def code(z0, z1, z2):
	t_0 = (math.pi + math.pi) * z0
	return math.cos((math.atan(((math.cos(t_0) * z1) / (-math.sin(t_0) * z2))) * -2.0))
function code(z0, z1, z2)
	t_0 = Float64(Float64(pi + pi) * z0)
	return cos(Float64(atan(Float64(Float64(cos(t_0) * z1) / Float64(Float64(-sin(t_0)) * z2))) * -2.0))
end
function tmp = code(z0, z1, z2)
	t_0 = (pi + pi) * z0;
	tmp = cos((atan(((cos(t_0) * z1) / (-sin(t_0) * z2))) * -2.0));
end
code[z0_, z1_, z2_] := Block[{t$95$0 = N[(N[(Pi + Pi), $MachinePrecision] * z0), $MachinePrecision]}, N[Cos[N[(N[ArcTan[N[(N[(N[Cos[t$95$0], $MachinePrecision] * z1), $MachinePrecision] / N[((-N[Sin[t$95$0], $MachinePrecision]) * z2), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * -2), $MachinePrecision]], $MachinePrecision]]
\begin{array}{l}
t_0 := \left(\pi + \pi\right) \cdot z0\\
\cos \left(\tan^{-1} \left(\frac{\cos t\_0 \cdot z1}{\left(-\sin t\_0\right) \cdot z2}\right) \cdot -2\right)
\end{array}
Derivation
  1. Initial program 82.3%

    \[\cos \left(\tan^{-1} \left(\tan \left(z0 \cdot \left(\pi + \pi\right) - \frac{-1}{2} \cdot \pi\right) \cdot \frac{z1}{z2}\right) \cdot -2\right) \]
  2. Step-by-step derivation
    1. lift-*.f64N/A

      \[\leadsto \cos \left(\tan^{-1} \color{blue}{\left(\tan \left(z0 \cdot \left(\pi + \pi\right) - \frac{-1}{2} \cdot \pi\right) \cdot \frac{z1}{z2}\right)} \cdot -2\right) \]
    2. lift-tan.f64N/A

      \[\leadsto \cos \left(\tan^{-1} \left(\color{blue}{\tan \left(z0 \cdot \left(\pi + \pi\right) - \frac{-1}{2} \cdot \pi\right)} \cdot \frac{z1}{z2}\right) \cdot -2\right) \]
    3. tan-quotN/A

      \[\leadsto \cos \left(\tan^{-1} \left(\color{blue}{\frac{\sin \left(z0 \cdot \left(\pi + \pi\right) - \frac{-1}{2} \cdot \pi\right)}{\cos \left(z0 \cdot \left(\pi + \pi\right) - \frac{-1}{2} \cdot \pi\right)}} \cdot \frac{z1}{z2}\right) \cdot -2\right) \]
    4. lift-/.f64N/A

      \[\leadsto \cos \left(\tan^{-1} \left(\frac{\sin \left(z0 \cdot \left(\pi + \pi\right) - \frac{-1}{2} \cdot \pi\right)}{\cos \left(z0 \cdot \left(\pi + \pi\right) - \frac{-1}{2} \cdot \pi\right)} \cdot \color{blue}{\frac{z1}{z2}}\right) \cdot -2\right) \]
    5. frac-timesN/A

      \[\leadsto \cos \left(\tan^{-1} \color{blue}{\left(\frac{\sin \left(z0 \cdot \left(\pi + \pi\right) - \frac{-1}{2} \cdot \pi\right) \cdot z1}{\cos \left(z0 \cdot \left(\pi + \pi\right) - \frac{-1}{2} \cdot \pi\right) \cdot z2}\right)} \cdot -2\right) \]
    6. lower-/.f64N/A

      \[\leadsto \cos \left(\tan^{-1} \color{blue}{\left(\frac{\sin \left(z0 \cdot \left(\pi + \pi\right) - \frac{-1}{2} \cdot \pi\right) \cdot z1}{\cos \left(z0 \cdot \left(\pi + \pi\right) - \frac{-1}{2} \cdot \pi\right) \cdot z2}\right)} \cdot -2\right) \]
  3. Applied rewrites99.9%

    \[\leadsto \cos \left(\tan^{-1} \color{blue}{\left(\frac{\cos \left(\left(\pi + \pi\right) \cdot z0\right) \cdot z1}{\left(-\sin \left(\left(\pi + \pi\right) \cdot z0\right)\right) \cdot z2}\right)} \cdot -2\right) \]
  4. Add Preprocessing

Alternative 2: 82.3% accurate, 1.0× speedup?

\[\cos \left(\tan^{-1} \left(\frac{z1 \cdot \tan \left(\pi \cdot \left(\frac{1}{2} + \left(z0 + z0\right)\right)\right)}{z2}\right) \cdot -2\right) \]
(FPCore (z0 z1 z2)
  :precision binary64
  (cos (* (atan (/ (* z1 (tan (* PI (+ 1/2 (+ z0 z0))))) z2)) -2)))
double code(double z0, double z1, double z2) {
	return cos((atan(((z1 * tan((((double) M_PI) * (0.5 + (z0 + z0))))) / z2)) * -2.0));
}
public static double code(double z0, double z1, double z2) {
	return Math.cos((Math.atan(((z1 * Math.tan((Math.PI * (0.5 + (z0 + z0))))) / z2)) * -2.0));
}
def code(z0, z1, z2):
	return math.cos((math.atan(((z1 * math.tan((math.pi * (0.5 + (z0 + z0))))) / z2)) * -2.0))
function code(z0, z1, z2)
	return cos(Float64(atan(Float64(Float64(z1 * tan(Float64(pi * Float64(0.5 + Float64(z0 + z0))))) / z2)) * -2.0))
end
function tmp = code(z0, z1, z2)
	tmp = cos((atan(((z1 * tan((pi * (0.5 + (z0 + z0))))) / z2)) * -2.0));
end
code[z0_, z1_, z2_] := N[Cos[N[(N[ArcTan[N[(N[(z1 * N[Tan[N[(Pi * N[(1/2 + N[(z0 + z0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / z2), $MachinePrecision]], $MachinePrecision] * -2), $MachinePrecision]], $MachinePrecision]
\cos \left(\tan^{-1} \left(\frac{z1 \cdot \tan \left(\pi \cdot \left(\frac{1}{2} + \left(z0 + z0\right)\right)\right)}{z2}\right) \cdot -2\right)
Derivation
  1. Initial program 82.3%

    \[\cos \left(\tan^{-1} \left(\tan \left(z0 \cdot \left(\pi + \pi\right) - \frac{-1}{2} \cdot \pi\right) \cdot \frac{z1}{z2}\right) \cdot -2\right) \]
  2. Step-by-step derivation
    1. lift-*.f64N/A

      \[\leadsto \cos \left(\tan^{-1} \color{blue}{\left(\tan \left(z0 \cdot \left(\pi + \pi\right) - \frac{-1}{2} \cdot \pi\right) \cdot \frac{z1}{z2}\right)} \cdot -2\right) \]
    2. lift-/.f64N/A

      \[\leadsto \cos \left(\tan^{-1} \left(\tan \left(z0 \cdot \left(\pi + \pi\right) - \frac{-1}{2} \cdot \pi\right) \cdot \color{blue}{\frac{z1}{z2}}\right) \cdot -2\right) \]
    3. associate-*r/N/A

      \[\leadsto \cos \left(\tan^{-1} \color{blue}{\left(\frac{\tan \left(z0 \cdot \left(\pi + \pi\right) - \frac{-1}{2} \cdot \pi\right) \cdot z1}{z2}\right)} \cdot -2\right) \]
    4. lower-/.f64N/A

      \[\leadsto \cos \left(\tan^{-1} \color{blue}{\left(\frac{\tan \left(z0 \cdot \left(\pi + \pi\right) - \frac{-1}{2} \cdot \pi\right) \cdot z1}{z2}\right)} \cdot -2\right) \]
  3. Applied rewrites82.3%

    \[\leadsto \cos \left(\tan^{-1} \color{blue}{\left(\frac{z1 \cdot \tan \left(\pi \cdot \left(\frac{1}{2} + \left(z0 + z0\right)\right)\right)}{z2}\right)} \cdot -2\right) \]
  4. Add Preprocessing

Reproduce

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herbie shell --seed 2025277 -o generate:taylor -o generate:evaluate
(FPCore (z0 z1 z2)
  :name "(cos (* (atan (* (tan (- (* z0 (+ PI PI)) (* -1/2 PI))) (/ z1 z2))) -2))"
  :precision binary64
  (cos (* (atan (* (tan (- (* z0 (+ PI PI)) (* -1/2 PI))) (/ z1 z2))) -2)))