
(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 6 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 -0.5625 (* a (/ (* a (pow c 3.0)) (pow b 5.0))) (fma -0.16666666666666666 (* (/ (pow (* a c) 4.0) a) (/ 6.328125 (pow b 7.0))) (fma -0.5 (/ c b) (* -0.375 (* a (/ c (/ (pow b 3.0) c))))))))
double code(double a, double b, double c) {
return fma(-0.5625, (a * ((a * pow(c, 3.0)) / pow(b, 5.0))), fma(-0.16666666666666666, ((pow((a * c), 4.0) / a) * (6.328125 / pow(b, 7.0))), fma(-0.5, (c / b), (-0.375 * (a * (c / (pow(b, 3.0) / c)))))));
}
function code(a, b, c) return fma(-0.5625, Float64(a * Float64(Float64(a * (c ^ 3.0)) / (b ^ 5.0))), fma(-0.16666666666666666, Float64(Float64((Float64(a * c) ^ 4.0) / a) * Float64(6.328125 / (b ^ 7.0))), fma(-0.5, Float64(c / b), Float64(-0.375 * Float64(a * Float64(c / Float64((b ^ 3.0) / c))))))) end
code[a_, b_, c_] := N[(-0.5625 * N[(a * N[(N[(a * N[Power[c, 3.0], $MachinePrecision]), $MachinePrecision] / N[Power[b, 5.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(-0.16666666666666666 * N[(N[(N[Power[N[(a * c), $MachinePrecision], 4.0], $MachinePrecision] / a), $MachinePrecision] * N[(6.328125 / N[Power[b, 7.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(-0.5 * N[(c / b), $MachinePrecision] + N[(-0.375 * N[(a * N[(c / N[(N[Power[b, 3.0], $MachinePrecision] / c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(-0.5625, a \cdot \frac{a \cdot {c}^{3}}{{b}^{5}}, \mathsf{fma}\left(-0.16666666666666666, \frac{{\left(a \cdot c\right)}^{4}}{a} \cdot \frac{6.328125}{{b}^{7}}, \mathsf{fma}\left(-0.5, \frac{c}{b}, -0.375 \cdot \left(a \cdot \frac{c}{\frac{{b}^{3}}{c}}\right)\right)\right)\right)
\end{array}
Initial program 18.0%
neg-sub018.0%
associate-+l-18.0%
sub0-neg18.0%
neg-mul-118.0%
associate-*r/18.0%
*-commutative18.0%
metadata-eval18.0%
metadata-eval18.0%
times-frac18.0%
*-commutative18.0%
times-frac18.0%
Simplified18.0%
div-inv18.0%
Applied egg-rr18.0%
Taylor expanded in b around inf 97.9%
fma-def97.9%
associate-*l/97.9%
unpow297.9%
associate-*r*97.9%
*-commutative97.9%
associate-*l/97.9%
fma-def97.9%
Simplified97.9%
Taylor expanded in c around 0 97.9%
+-commutative97.9%
distribute-rgt-out97.9%
associate-*r*97.9%
times-frac97.9%
Simplified97.9%
Final simplification97.9%
(FPCore (a b c) :precision binary64 (fma -0.5625 (* (* a a) (/ (pow c 3.0) (pow b 5.0))) (fma -0.375 (* (* a c) (/ c (pow b 3.0))) (* c (/ -0.5 b)))))
double code(double a, double b, double c) {
return fma(-0.5625, ((a * a) * (pow(c, 3.0) / pow(b, 5.0))), fma(-0.375, ((a * c) * (c / pow(b, 3.0))), (c * (-0.5 / b))));
}
function code(a, b, c) return fma(-0.5625, Float64(Float64(a * a) * Float64((c ^ 3.0) / (b ^ 5.0))), fma(-0.375, Float64(Float64(a * c) * Float64(c / (b ^ 3.0))), Float64(c * Float64(-0.5 / b)))) end
code[a_, b_, c_] := N[(-0.5625 * N[(N[(a * a), $MachinePrecision] * N[(N[Power[c, 3.0], $MachinePrecision] / N[Power[b, 5.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(-0.375 * N[(N[(a * c), $MachinePrecision] * N[(c / N[Power[b, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(c * N[(-0.5 / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(-0.5625, \left(a \cdot a\right) \cdot \frac{{c}^{3}}{{b}^{5}}, \mathsf{fma}\left(-0.375, \left(a \cdot c\right) \cdot \frac{c}{{b}^{3}}, c \cdot \frac{-0.5}{b}\right)\right)
\end{array}
Initial program 18.0%
neg-sub018.0%
associate-+l-18.0%
sub0-neg18.0%
neg-mul-118.0%
associate-*r/18.0%
*-commutative18.0%
metadata-eval18.0%
metadata-eval18.0%
times-frac18.0%
*-commutative18.0%
times-frac18.0%
Simplified18.0%
add-log-exp5.4%
Applied egg-rr5.4%
Taylor expanded in b around inf 97.0%
fma-def97.0%
associate-/l*97.0%
associate-/r/97.0%
unpow297.0%
associate-*r/97.0%
+-commutative97.0%
fma-def97.0%
associate-/l*97.0%
associate-/r/97.0%
unpow297.0%
associate-*l/97.0%
associate-*l*97.0%
associate-/l*96.7%
associate-/r/96.7%
Simplified96.7%
Final simplification96.7%
(FPCore (a b c) :precision binary64 (fma -0.5625 (* (* a a) (/ (pow c 3.0) (pow b 5.0))) (fma c (/ -0.5 b) (* -0.375 (* a (/ c (/ (pow b 3.0) c)))))))
double code(double a, double b, double c) {
return fma(-0.5625, ((a * a) * (pow(c, 3.0) / pow(b, 5.0))), fma(c, (-0.5 / b), (-0.375 * (a * (c / (pow(b, 3.0) / c))))));
}
function code(a, b, c) return fma(-0.5625, Float64(Float64(a * a) * Float64((c ^ 3.0) / (b ^ 5.0))), fma(c, Float64(-0.5 / b), Float64(-0.375 * Float64(a * Float64(c / Float64((b ^ 3.0) / c)))))) end
code[a_, b_, c_] := N[(-0.5625 * N[(N[(a * a), $MachinePrecision] * N[(N[Power[c, 3.0], $MachinePrecision] / N[Power[b, 5.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(c * N[(-0.5 / b), $MachinePrecision] + N[(-0.375 * N[(a * N[(c / N[(N[Power[b, 3.0], $MachinePrecision] / c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(-0.5625, \left(a \cdot a\right) \cdot \frac{{c}^{3}}{{b}^{5}}, \mathsf{fma}\left(c, \frac{-0.5}{b}, -0.375 \cdot \left(a \cdot \frac{c}{\frac{{b}^{3}}{c}}\right)\right)\right)
\end{array}
Initial program 18.0%
neg-sub018.0%
associate-+l-18.0%
sub0-neg18.0%
neg-mul-118.0%
associate-*r/18.0%
*-commutative18.0%
metadata-eval18.0%
metadata-eval18.0%
times-frac18.0%
*-commutative18.0%
times-frac18.0%
Simplified18.0%
add-log-exp5.4%
Applied egg-rr5.4%
add-log-exp18.0%
add-cbrt-cube18.0%
Applied egg-rr18.0%
Taylor expanded in b around inf 97.0%
fma-def97.0%
associate-/l*97.0%
associate-/r/97.0%
unpow297.0%
associate-*r/97.0%
associate-*l/96.7%
*-commutative96.7%
fma-def96.7%
associate-/l*96.7%
associate-/r/96.7%
unpow296.7%
associate-/l*96.7%
Simplified96.7%
Final simplification96.7%
(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 (* a (* c c))) (pow b 3.0)))))
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 * (a * (c * c))) / pow(b, 3.0))));
}
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(a * Float64(c * c))) / (b ^ 3.0)))) 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[(a * N[(c * c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[Power[b, 3.0], $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(a \cdot \left(c \cdot c\right)\right)}{{b}^{3}}\right)\right)
\end{array}
Initial program 18.0%
neg-sub018.0%
associate-+l-18.0%
sub0-neg18.0%
neg-mul-118.0%
associate-*r/18.0%
metadata-eval18.0%
metadata-eval18.0%
times-frac18.0%
*-commutative18.0%
times-frac18.0%
associate-*l/18.0%
Simplified18.0%
Taylor expanded in b around inf 97.0%
fma-def97.0%
associate-/l*97.0%
unpow297.0%
fma-def97.0%
associate-*r/97.0%
*-commutative97.0%
unpow297.0%
Simplified97.0%
Final simplification97.0%
(FPCore (a b c) :precision binary64 (fma -0.5 (/ c b) (/ (* -0.375 (* a (* c c))) (pow b 3.0))))
double code(double a, double b, double c) {
return fma(-0.5, (c / b), ((-0.375 * (a * (c * c))) / pow(b, 3.0)));
}
function code(a, b, c) return fma(-0.5, Float64(c / b), Float64(Float64(-0.375 * Float64(a * Float64(c * c))) / (b ^ 3.0))) end
code[a_, b_, c_] := N[(-0.5 * N[(c / b), $MachinePrecision] + N[(N[(-0.375 * N[(a * N[(c * c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[Power[b, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(-0.5, \frac{c}{b}, \frac{-0.375 \cdot \left(a \cdot \left(c \cdot c\right)\right)}{{b}^{3}}\right)
\end{array}
Initial program 18.0%
neg-sub018.0%
associate-+l-18.0%
sub0-neg18.0%
neg-mul-118.0%
associate-*r/18.0%
metadata-eval18.0%
metadata-eval18.0%
times-frac18.0%
*-commutative18.0%
times-frac18.0%
associate-*l/18.0%
Simplified18.0%
Taylor expanded in b around inf 95.5%
fma-def95.5%
associate-*r/95.5%
*-commutative95.5%
unpow295.5%
Simplified95.5%
Final simplification95.5%
(FPCore (a b c) :precision binary64 (* -0.5 (/ c b)))
double code(double a, double b, double c) {
return -0.5 * (c / b);
}
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)
end function
public static double code(double a, double b, double c) {
return -0.5 * (c / b);
}
def code(a, b, c): return -0.5 * (c / b)
function code(a, b, c) return Float64(-0.5 * Float64(c / b)) end
function tmp = code(a, b, c) tmp = -0.5 * (c / b); end
code[a_, b_, c_] := N[(-0.5 * N[(c / b), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
-0.5 \cdot \frac{c}{b}
\end{array}
Initial program 18.0%
neg-sub018.0%
associate-+l-18.0%
sub0-neg18.0%
neg-mul-118.0%
associate-*r/18.0%
metadata-eval18.0%
metadata-eval18.0%
times-frac18.0%
*-commutative18.0%
times-frac18.0%
associate-*l/18.0%
Simplified18.0%
Taylor expanded in b around inf 90.4%
Final simplification90.4%
herbie shell --seed 2023181
(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)))