
(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 4 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 (/ (pow c 3.0) (/ (pow b 5.0) (* a a))) (fma -0.16666666666666666 (/ (pow (* c a) 4.0) (/ (* a (pow b 7.0)) 6.328125)) (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(-0.16666666666666666, (pow((c * a), 4.0) / ((a * pow(b, 7.0)) / 6.328125)), 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(-0.16666666666666666, Float64((Float64(c * a) ^ 4.0) / Float64(Float64(a * (b ^ 7.0)) / 6.328125)), fma(-0.5, Float64(c / b), Float64(-0.375 * Float64(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[(-0.16666666666666666 * N[(N[Power[N[(c * a), $MachinePrecision], 4.0], $MachinePrecision] / N[(N[(a * N[Power[b, 7.0], $MachinePrecision]), $MachinePrecision] / 6.328125), $MachinePrecision]), $MachinePrecision] + N[(-0.5 * N[(c / b), $MachinePrecision] + N[(-0.375 * N[(N[(c * c), $MachinePrecision] / N[(N[Power[b, 3.0], $MachinePrecision] / a), $MachinePrecision]), $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(-0.16666666666666666, \frac{{\left(c \cdot a\right)}^{4}}{\frac{a \cdot {b}^{7}}{6.328125}}, \mathsf{fma}\left(-0.5, \frac{c}{b}, -0.375 \cdot \frac{c \cdot c}{\frac{{b}^{3}}{a}}\right)\right)\right)
\end{array}
Initial program 29.0%
neg-sub029.0%
associate-+l-29.0%
sub0-neg29.0%
neg-mul-129.0%
associate-*r/29.0%
metadata-eval29.0%
metadata-eval29.0%
times-frac29.0%
*-commutative29.0%
times-frac29.0%
associate-*l/29.0%
Simplified29.1%
Taylor expanded in b around inf 96.0%
fma-def96.0%
associate-/l*96.0%
unpow296.0%
fma-def96.0%
Simplified96.0%
pow196.0%
pow-prod-down96.0%
Applied egg-rr96.0%
unpow196.0%
Simplified96.0%
unpow296.0%
associate-*l*96.0%
associate-*l*96.0%
Applied egg-rr96.0%
Taylor expanded in c around 0 96.0%
distribute-rgt-out96.0%
associate-*r*96.0%
associate-/l*96.0%
Simplified96.0%
Final simplification96.0%
(FPCore (a b c) :precision binary64 (fma -0.5625 (/ (pow c 3.0) (/ (pow b 5.0) (* a a))) (fma -0.375 (/ (* c c) (/ (pow b 3.0) a)) (* -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 * c) / (pow(b, 3.0) / a)), (-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(Float64(c * c) / Float64((b ^ 3.0) / a)), 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[(N[(c * c), $MachinePrecision] / N[(N[Power[b, 3.0], $MachinePrecision] / a), $MachinePrecision]), $MachinePrecision] + N[(-0.5 * N[(c / b), $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 \cdot c}{\frac{{b}^{3}}{a}}, -0.5 \cdot \frac{c}{b}\right)\right)
\end{array}
Initial program 29.0%
neg-sub029.0%
associate-+l-29.0%
sub0-neg29.0%
neg-mul-129.0%
associate-*r/29.0%
metadata-eval29.0%
metadata-eval29.0%
times-frac29.0%
*-commutative29.0%
times-frac29.0%
associate-*l/29.0%
Simplified29.1%
Taylor expanded in b around inf 94.7%
fma-def94.7%
associate-/l*94.7%
unpow294.7%
+-commutative94.7%
fma-def94.7%
associate-/l*94.7%
unpow294.7%
Simplified94.7%
Final simplification94.7%
(FPCore (a b c) :precision binary64 (+ (* -0.5 (/ c b)) (* -0.375 (* a (/ (* c c) (pow b 3.0))))))
double code(double a, double b, double c) {
return (-0.5 * (c / b)) + (-0.375 * (a * ((c * c) / pow(b, 3.0))));
}
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) * (a * ((c * c) / (b ** 3.0d0))))
end function
public static double code(double a, double b, double c) {
return (-0.5 * (c / b)) + (-0.375 * (a * ((c * c) / Math.pow(b, 3.0))));
}
def code(a, b, c): return (-0.5 * (c / b)) + (-0.375 * (a * ((c * c) / math.pow(b, 3.0))))
function code(a, b, c) return Float64(Float64(-0.5 * Float64(c / b)) + Float64(-0.375 * Float64(a * Float64(Float64(c * c) / (b ^ 3.0))))) end
function tmp = code(a, b, c) tmp = (-0.5 * (c / b)) + (-0.375 * (a * ((c * c) / (b ^ 3.0)))); end
code[a_, b_, c_] := N[(N[(-0.5 * N[(c / b), $MachinePrecision]), $MachinePrecision] + N[(-0.375 * N[(a * N[(N[(c * c), $MachinePrecision] / N[Power[b, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
-0.5 \cdot \frac{c}{b} + -0.375 \cdot \left(a \cdot \frac{c \cdot c}{{b}^{3}}\right)
\end{array}
Initial program 29.0%
neg-sub029.0%
associate-+l-29.0%
sub0-neg29.0%
neg-mul-129.0%
associate-*r/29.0%
metadata-eval29.0%
metadata-eval29.0%
times-frac29.0%
*-commutative29.0%
times-frac29.0%
associate-*l/29.0%
Simplified29.1%
Taylor expanded in b around inf 92.2%
+-commutative92.2%
fma-def92.2%
associate-/l*92.2%
unpow292.2%
Simplified92.2%
fma-udef92.2%
associate-/r/92.2%
Applied egg-rr92.2%
Final simplification92.2%
(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 29.0%
neg-sub029.0%
associate-+l-29.0%
sub0-neg29.0%
neg-mul-129.0%
associate-*r/29.0%
metadata-eval29.0%
metadata-eval29.0%
times-frac29.0%
*-commutative29.0%
times-frac29.0%
associate-*l/29.0%
Simplified29.1%
Taylor expanded in b around inf 83.5%
Final simplification83.5%
herbie shell --seed 2023181
(FPCore (a b c)
:name "Cubic critical, medium range"
:precision binary64
:pre (and (and (and (< 1.1102230246251565e-16 a) (< a 9007199254740992.0)) (and (< 1.1102230246251565e-16 b) (< b 9007199254740992.0))) (and (< 1.1102230246251565e-16 c) (< c 9007199254740992.0)))
(/ (+ (- b) (sqrt (- (* b b) (* (* 3.0 a) c)))) (* 3.0 a)))