
(FPCore (a b c) :precision binary64 (/ (+ (- b) (sqrt (- (* b b) (* (* 3.0 a) c)))) (* 3.0 a)))
double code(double a, double b, double c) {
return (-b + sqrt(((b * b) - ((3.0 * a) * c)))) / (3.0 * a);
}
real(8) function code(a, b, c)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: c
code = (-b + sqrt(((b * b) - ((3.0d0 * a) * c)))) / (3.0d0 * a)
end function
public static double code(double a, double b, double c) {
return (-b + Math.sqrt(((b * b) - ((3.0 * a) * c)))) / (3.0 * a);
}
def code(a, b, c): return (-b + math.sqrt(((b * b) - ((3.0 * a) * c)))) / (3.0 * a)
function code(a, b, c) return Float64(Float64(Float64(-b) + sqrt(Float64(Float64(b * b) - Float64(Float64(3.0 * a) * c)))) / Float64(3.0 * a)) end
function tmp = code(a, b, c) tmp = (-b + sqrt(((b * b) - ((3.0 * a) * c)))) / (3.0 * a); end
code[a_, b_, c_] := N[(N[((-b) + N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(N[(3.0 * a), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / N[(3.0 * a), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\left(-b\right) + \sqrt{b \cdot b - \left(3 \cdot a\right) \cdot c}}{3 \cdot a}
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 5 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (a b c) :precision binary64 (/ (+ (- b) (sqrt (- (* b b) (* (* 3.0 a) c)))) (* 3.0 a)))
double code(double a, double b, double c) {
return (-b + sqrt(((b * b) - ((3.0 * a) * c)))) / (3.0 * a);
}
real(8) function code(a, b, c)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: c
code = (-b + sqrt(((b * b) - ((3.0d0 * a) * c)))) / (3.0d0 * a)
end function
public static double code(double a, double b, double c) {
return (-b + Math.sqrt(((b * b) - ((3.0 * a) * c)))) / (3.0 * a);
}
def code(a, b, c): return (-b + math.sqrt(((b * b) - ((3.0 * a) * c)))) / (3.0 * a)
function code(a, b, c) return Float64(Float64(Float64(-b) + sqrt(Float64(Float64(b * b) - Float64(Float64(3.0 * a) * c)))) / Float64(3.0 * a)) end
function tmp = code(a, b, c) tmp = (-b + sqrt(((b * b) - ((3.0 * a) * c)))) / (3.0 * a); end
code[a_, b_, c_] := N[(N[((-b) + N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(N[(3.0 * a), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / N[(3.0 * a), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\left(-b\right) + \sqrt{b \cdot b - \left(3 \cdot a\right) \cdot c}}{3 \cdot a}
\end{array}
(FPCore (a b c)
:precision binary64
(fma
-0.16666666666666666
(* (/ (pow c 4.0) a) (/ (* (/ (pow a 4.0) (pow b 6.0)) 6.328125) b))
(fma
-0.5
(/ c b)
(fma
-0.375
(/ c (/ (/ (pow b 3.0) a) c))
(/ -0.5625 (/ (pow b 5.0) (* c (pow (* c a) 2.0))))))))
double code(double a, double b, double c) {
return fma(-0.16666666666666666, ((pow(c, 4.0) / a) * (((pow(a, 4.0) / pow(b, 6.0)) * 6.328125) / b)), fma(-0.5, (c / b), fma(-0.375, (c / ((pow(b, 3.0) / a) / c)), (-0.5625 / (pow(b, 5.0) / (c * pow((c * a), 2.0)))))));
}
function code(a, b, c) return fma(-0.16666666666666666, Float64(Float64((c ^ 4.0) / a) * Float64(Float64(Float64((a ^ 4.0) / (b ^ 6.0)) * 6.328125) / b)), fma(-0.5, Float64(c / b), fma(-0.375, Float64(c / Float64(Float64((b ^ 3.0) / a) / c)), Float64(-0.5625 / Float64((b ^ 5.0) / Float64(c * (Float64(c * a) ^ 2.0))))))) end
code[a_, b_, c_] := N[(-0.16666666666666666 * N[(N[(N[Power[c, 4.0], $MachinePrecision] / a), $MachinePrecision] * N[(N[(N[(N[Power[a, 4.0], $MachinePrecision] / N[Power[b, 6.0], $MachinePrecision]), $MachinePrecision] * 6.328125), $MachinePrecision] / b), $MachinePrecision]), $MachinePrecision] + N[(-0.5 * N[(c / b), $MachinePrecision] + N[(-0.375 * N[(c / N[(N[(N[Power[b, 3.0], $MachinePrecision] / a), $MachinePrecision] / c), $MachinePrecision]), $MachinePrecision] + N[(-0.5625 / N[(N[Power[b, 5.0], $MachinePrecision] / N[(c * N[Power[N[(c * a), $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(-0.16666666666666666, \frac{{c}^{4}}{a} \cdot \frac{\frac{{a}^{4}}{{b}^{6}} \cdot 6.328125}{b}, \mathsf{fma}\left(-0.5, \frac{c}{b}, \mathsf{fma}\left(-0.375, \frac{c}{\frac{\frac{{b}^{3}}{a}}{c}}, \frac{-0.5625}{\frac{{b}^{5}}{c \cdot {\left(c \cdot a\right)}^{2}}}\right)\right)\right)
\end{array}
Initial program 18.6%
/-rgt-identity18.6%
metadata-eval18.6%
associate-/r/18.6%
metadata-eval18.6%
metadata-eval18.6%
times-frac18.6%
*-commutative18.6%
times-frac18.6%
associate-/r*18.7%
Simplified18.7%
div-inv18.7%
Applied egg-rr18.7%
Taylor expanded in c around 0 97.3%
Simplified97.3%
Final simplification97.3%
(FPCore (a b c)
:precision binary64
(fma
-0.5625
(/ (pow c 3.0) (/ (pow b 5.0) (* a a)))
(fma
-0.375
(/ c (/ (/ (pow b 3.0) a) c))
(fma
-0.16666666666666666
(/ (* 6.328125 (pow (* c a) 4.0)) (* a (pow b 7.0)))
(* -0.5 (/ c b))))))
double code(double a, double b, double c) {
return fma(-0.5625, (pow(c, 3.0) / (pow(b, 5.0) / (a * a))), fma(-0.375, (c / ((pow(b, 3.0) / a) / c)), fma(-0.16666666666666666, ((6.328125 * pow((c * a), 4.0)) / (a * pow(b, 7.0))), (-0.5 * (c / b)))));
}
function code(a, b, c) return fma(-0.5625, Float64((c ^ 3.0) / Float64((b ^ 5.0) / Float64(a * a))), fma(-0.375, Float64(c / Float64(Float64((b ^ 3.0) / a) / c)), fma(-0.16666666666666666, Float64(Float64(6.328125 * (Float64(c * a) ^ 4.0)) / Float64(a * (b ^ 7.0))), Float64(-0.5 * Float64(c / b))))) end
code[a_, b_, c_] := N[(-0.5625 * N[(N[Power[c, 3.0], $MachinePrecision] / N[(N[Power[b, 5.0], $MachinePrecision] / N[(a * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(-0.375 * N[(c / N[(N[(N[Power[b, 3.0], $MachinePrecision] / a), $MachinePrecision] / c), $MachinePrecision]), $MachinePrecision] + N[(-0.16666666666666666 * N[(N[(6.328125 * N[Power[N[(c * a), $MachinePrecision], 4.0], $MachinePrecision]), $MachinePrecision] / N[(a * N[Power[b, 7.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(-0.5 * N[(c / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(-0.5625, \frac{{c}^{3}}{\frac{{b}^{5}}{a \cdot a}}, \mathsf{fma}\left(-0.375, \frac{c}{\frac{\frac{{b}^{3}}{a}}{c}}, \mathsf{fma}\left(-0.16666666666666666, \frac{6.328125 \cdot {\left(c \cdot a\right)}^{4}}{a \cdot {b}^{7}}, -0.5 \cdot \frac{c}{b}\right)\right)\right)
\end{array}
Initial program 18.6%
/-rgt-identity18.6%
metadata-eval18.6%
associate-/r/18.6%
metadata-eval18.6%
metadata-eval18.6%
times-frac18.6%
*-commutative18.6%
times-frac18.6%
associate-/r*18.7%
Simplified18.7%
div-inv18.7%
Applied egg-rr18.7%
Taylor expanded in b around inf 97.3%
Simplified97.3%
Final simplification97.3%
(FPCore (a b c) :precision binary64 (fma -0.5625 (/ (pow c 3.0) (/ (pow b 5.0) (* a a))) (fma -0.5 (/ c b) (/ (* -0.375 (* c c)) (/ (pow b 3.0) a)))))
double code(double a, double b, double c) {
return fma(-0.5625, (pow(c, 3.0) / (pow(b, 5.0) / (a * a))), fma(-0.5, (c / b), ((-0.375 * (c * c)) / (pow(b, 3.0) / a))));
}
function code(a, b, c) return fma(-0.5625, Float64((c ^ 3.0) / Float64((b ^ 5.0) / Float64(a * a))), fma(-0.5, Float64(c / b), Float64(Float64(-0.375 * Float64(c * c)) / Float64((b ^ 3.0) / a)))) end
code[a_, b_, c_] := N[(-0.5625 * N[(N[Power[c, 3.0], $MachinePrecision] / N[(N[Power[b, 5.0], $MachinePrecision] / N[(a * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(-0.5 * N[(c / b), $MachinePrecision] + N[(N[(-0.375 * N[(c * c), $MachinePrecision]), $MachinePrecision] / N[(N[Power[b, 3.0], $MachinePrecision] / a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(-0.5625, \frac{{c}^{3}}{\frac{{b}^{5}}{a \cdot a}}, \mathsf{fma}\left(-0.5, \frac{c}{b}, \frac{-0.375 \cdot \left(c \cdot c\right)}{\frac{{b}^{3}}{a}}\right)\right)
\end{array}
Initial program 18.6%
/-rgt-identity18.6%
metadata-eval18.6%
associate-/r/18.6%
metadata-eval18.6%
metadata-eval18.6%
times-frac18.6%
*-commutative18.6%
times-frac18.6%
associate-/r*18.7%
Simplified18.7%
Taylor expanded in b around inf 96.3%
fma-def96.3%
associate-/l*96.3%
unpow296.3%
fma-def96.3%
associate-/l*96.3%
associate-*r/96.3%
unpow296.3%
Simplified96.3%
Final simplification96.3%
(FPCore (a b c) :precision binary64 (+ (* -0.5 (/ c b)) (/ (* -0.375 (* c c)) (/ (pow b 3.0) a))))
double code(double a, double b, double c) {
return (-0.5 * (c / b)) + ((-0.375 * (c * c)) / (pow(b, 3.0) / a));
}
real(8) function code(a, b, c)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: c
code = ((-0.5d0) * (c / b)) + (((-0.375d0) * (c * c)) / ((b ** 3.0d0) / a))
end function
public static double code(double a, double b, double c) {
return (-0.5 * (c / b)) + ((-0.375 * (c * c)) / (Math.pow(b, 3.0) / a));
}
def code(a, b, c): return (-0.5 * (c / b)) + ((-0.375 * (c * c)) / (math.pow(b, 3.0) / a))
function code(a, b, c) return Float64(Float64(-0.5 * Float64(c / b)) + Float64(Float64(-0.375 * Float64(c * c)) / Float64((b ^ 3.0) / a))) end
function tmp = code(a, b, c) tmp = (-0.5 * (c / b)) + ((-0.375 * (c * c)) / ((b ^ 3.0) / a)); end
code[a_, b_, c_] := N[(N[(-0.5 * N[(c / b), $MachinePrecision]), $MachinePrecision] + N[(N[(-0.375 * N[(c * c), $MachinePrecision]), $MachinePrecision] / N[(N[Power[b, 3.0], $MachinePrecision] / a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
-0.5 \cdot \frac{c}{b} + \frac{-0.375 \cdot \left(c \cdot c\right)}{\frac{{b}^{3}}{a}}
\end{array}
Initial program 18.6%
/-rgt-identity18.6%
metadata-eval18.6%
associate-/r/18.6%
metadata-eval18.6%
metadata-eval18.6%
times-frac18.6%
*-commutative18.6%
times-frac18.6%
associate-/r*18.7%
Simplified18.7%
Taylor expanded in b around inf 94.6%
fma-def94.6%
associate-/l*94.6%
associate-*r/94.6%
unpow294.6%
Simplified94.6%
fma-udef94.6%
*-commutative94.6%
Applied egg-rr94.6%
Final simplification94.6%
(FPCore (a b c) :precision binary64 (/ (* c -0.5) b))
double code(double a, double b, double c) {
return (c * -0.5) / b;
}
real(8) function code(a, b, c)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: c
code = (c * (-0.5d0)) / b
end function
public static double code(double a, double b, double c) {
return (c * -0.5) / b;
}
def code(a, b, c): return (c * -0.5) / b
function code(a, b, c) return Float64(Float64(c * -0.5) / b) end
function tmp = code(a, b, c) tmp = (c * -0.5) / b; end
code[a_, b_, c_] := N[(N[(c * -0.5), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{c \cdot -0.5}{b}
\end{array}
Initial program 18.6%
/-rgt-identity18.6%
metadata-eval18.6%
associate-/r/18.6%
metadata-eval18.6%
metadata-eval18.6%
times-frac18.6%
*-commutative18.6%
times-frac18.6%
associate-/r*18.7%
Simplified18.7%
Taylor expanded in b around inf 89.8%
associate-*r/89.8%
Simplified89.8%
Final simplification89.8%
herbie shell --seed 2023222
(FPCore (a b c)
:name "Cubic critical, wide range"
:precision binary64
:pre (and (and (and (< 4.930380657631324e-32 a) (< a 2.028240960365167e+31)) (and (< 4.930380657631324e-32 b) (< b 2.028240960365167e+31))) (and (< 4.930380657631324e-32 c) (< c 2.028240960365167e+31)))
(/ (+ (- b) (sqrt (- (* b b) (* (* 3.0 a) c)))) (* 3.0 a)))