
(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 (/ (pow c 3.0) (/ (pow b 5.0) (* a a))) (fma -0.16666666666666666 (/ (/ (pow (* c a) 4.0) (/ a 6.328125)) (pow b 7.0)) (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 / 6.328125)) / pow(b, 7.0)), 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((Float64(c * a) ^ 4.0) / Float64(a / 6.328125)) / (b ^ 7.0)), 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[(N[Power[N[(c * a), $MachinePrecision], 4.0], $MachinePrecision] / N[(a / 6.328125), $MachinePrecision]), $MachinePrecision] / N[Power[b, 7.0], $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{\frac{{\left(c \cdot a\right)}^{4}}{\frac{a}{6.328125}}}{{b}^{7}}, \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 29.3%
neg-sub029.3%
associate-+l-29.3%
sub0-neg29.3%
neg-mul-129.3%
associate-*r/29.3%
*-commutative29.3%
metadata-eval29.3%
metadata-eval29.3%
times-frac29.3%
*-commutative29.3%
times-frac29.3%
Simplified29.4%
Taylor expanded in b around inf 95.7%
fma-def95.7%
associate-/l*95.7%
unpow295.7%
fma-def95.7%
Simplified95.7%
Taylor expanded in c around 0 95.7%
associate-/r*95.7%
Simplified95.7%
Final simplification95.7%
(FPCore (a b c) :precision binary64 (fma -0.5625 (/ (* a (* (pow c 3.0) a)) (pow b 5.0)) (fma -0.16666666666666666 (/ (/ (pow (* c a) 4.0) (/ a 6.328125)) (pow b 7.0)) (fma -0.375 (/ (* c (* c a)) (pow b 3.0)) (/ -0.5 (/ b c))))))
double code(double a, double b, double c) {
return fma(-0.5625, ((a * (pow(c, 3.0) * a)) / pow(b, 5.0)), fma(-0.16666666666666666, ((pow((c * a), 4.0) / (a / 6.328125)) / pow(b, 7.0)), fma(-0.375, ((c * (c * a)) / pow(b, 3.0)), (-0.5 / (b / c)))));
}
function code(a, b, c) return fma(-0.5625, Float64(Float64(a * Float64((c ^ 3.0) * a)) / (b ^ 5.0)), fma(-0.16666666666666666, Float64(Float64((Float64(c * a) ^ 4.0) / Float64(a / 6.328125)) / (b ^ 7.0)), fma(-0.375, Float64(Float64(c * Float64(c * a)) / (b ^ 3.0)), Float64(-0.5 / Float64(b / c))))) end
code[a_, b_, c_] := N[(-0.5625 * N[(N[(a * N[(N[Power[c, 3.0], $MachinePrecision] * a), $MachinePrecision]), $MachinePrecision] / N[Power[b, 5.0], $MachinePrecision]), $MachinePrecision] + N[(-0.16666666666666666 * N[(N[(N[Power[N[(c * a), $MachinePrecision], 4.0], $MachinePrecision] / N[(a / 6.328125), $MachinePrecision]), $MachinePrecision] / N[Power[b, 7.0], $MachinePrecision]), $MachinePrecision] + N[(-0.375 * N[(N[(c * N[(c * a), $MachinePrecision]), $MachinePrecision] / N[Power[b, 3.0], $MachinePrecision]), $MachinePrecision] + N[(-0.5 / N[(b / c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(-0.5625, \frac{a \cdot \left({c}^{3} \cdot a\right)}{{b}^{5}}, \mathsf{fma}\left(-0.16666666666666666, \frac{\frac{{\left(c \cdot a\right)}^{4}}{\frac{a}{6.328125}}}{{b}^{7}}, \mathsf{fma}\left(-0.375, \frac{c \cdot \left(c \cdot a\right)}{{b}^{3}}, \frac{-0.5}{\frac{b}{c}}\right)\right)\right)
\end{array}
Initial program 29.3%
neg-sub029.3%
associate-+l-29.3%
sub0-neg29.3%
neg-mul-129.3%
associate-*r/29.3%
*-commutative29.3%
metadata-eval29.3%
metadata-eval29.3%
times-frac29.3%
*-commutative29.3%
times-frac29.3%
Simplified29.4%
div-inv29.3%
Applied egg-rr29.3%
Taylor expanded in b around inf 95.7%
Simplified95.4%
Final simplification95.4%
(FPCore (a b c) :precision binary64 (fma -0.5625 (/ (pow c 3.0) (/ (pow b 5.0) (* a a))) (fma -0.5 (/ c b) (/ (* (* c c) (* a -0.375)) (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), (((c * c) * (a * -0.375)) / 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(Float64(c * c) * Float64(a * -0.375)) / (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[(N[(c * c), $MachinePrecision] * N[(a * -0.375), $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{\left(c \cdot c\right) \cdot \left(a \cdot -0.375\right)}{{b}^{3}}\right)\right)
\end{array}
Initial program 29.3%
neg-sub029.3%
associate-+l-29.3%
sub0-neg29.3%
neg-mul-129.3%
associate-*r/29.3%
*-commutative29.3%
metadata-eval29.3%
metadata-eval29.3%
times-frac29.3%
*-commutative29.3%
times-frac29.3%
Simplified29.4%
Taylor expanded in b around inf 94.3%
fma-def94.3%
associate-/l*94.3%
unpow294.3%
fma-def94.3%
associate-*r/94.3%
*-commutative94.3%
associate-*r*94.3%
unpow294.3%
Simplified94.3%
Final simplification94.3%
(FPCore (a b c)
:precision binary64
(/
(fma
(/ c (/ b a))
-0.5
(fma
(/ (* (* a a) (* c c)) (pow b 3.0))
-0.375
(* -0.5625 (/ (* (* c a) (* (* c a) (* c a))) (pow b 5.0)))))
a))
double code(double a, double b, double c) {
return fma((c / (b / a)), -0.5, fma((((a * a) * (c * c)) / pow(b, 3.0)), -0.375, (-0.5625 * (((c * a) * ((c * a) * (c * a))) / pow(b, 5.0))))) / a;
}
function code(a, b, c) return Float64(fma(Float64(c / Float64(b / a)), -0.5, fma(Float64(Float64(Float64(a * a) * Float64(c * c)) / (b ^ 3.0)), -0.375, Float64(-0.5625 * Float64(Float64(Float64(c * a) * Float64(Float64(c * a) * Float64(c * a))) / (b ^ 5.0))))) / a) end
code[a_, b_, c_] := N[(N[(N[(c / N[(b / a), $MachinePrecision]), $MachinePrecision] * -0.5 + N[(N[(N[(N[(a * a), $MachinePrecision] * N[(c * c), $MachinePrecision]), $MachinePrecision] / N[Power[b, 3.0], $MachinePrecision]), $MachinePrecision] * -0.375 + N[(-0.5625 * N[(N[(N[(c * a), $MachinePrecision] * N[(N[(c * a), $MachinePrecision] * N[(c * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[Power[b, 5.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / a), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\frac{c}{\frac{b}{a}}, -0.5, \mathsf{fma}\left(\frac{\left(a \cdot a\right) \cdot \left(c \cdot c\right)}{{b}^{3}}, -0.375, -0.5625 \cdot \frac{\left(c \cdot a\right) \cdot \left(\left(c \cdot a\right) \cdot \left(c \cdot a\right)\right)}{{b}^{5}}\right)\right)}{a}
\end{array}
Initial program 29.3%
/-rgt-identity29.3%
metadata-eval29.3%
associate-/r/29.3%
metadata-eval29.3%
metadata-eval29.3%
times-frac29.3%
*-commutative29.3%
times-frac29.3%
*-commutative29.3%
associate-/r*29.3%
associate-*l/29.3%
Simplified29.3%
Taylor expanded in b around inf 93.9%
*-commutative93.9%
fma-def93.9%
associate-/l*93.9%
*-commutative93.9%
fma-def93.9%
unpow293.9%
unpow293.9%
*-commutative93.9%
cube-prod93.9%
Simplified93.9%
unpow393.9%
Applied egg-rr93.9%
Final simplification93.9%
(FPCore (a b c) :precision binary64 (+ (* -0.5 (/ c b)) (/ (* a -0.375) (/ (pow b 3.0) (* c c)))))
double code(double a, double b, double c) {
return (-0.5 * (c / b)) + ((a * -0.375) / (pow(b, 3.0) / (c * c)));
}
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)) + ((a * (-0.375d0)) / ((b ** 3.0d0) / (c * c)))
end function
public static double code(double a, double b, double c) {
return (-0.5 * (c / b)) + ((a * -0.375) / (Math.pow(b, 3.0) / (c * c)));
}
def code(a, b, c): return (-0.5 * (c / b)) + ((a * -0.375) / (math.pow(b, 3.0) / (c * c)))
function code(a, b, c) return Float64(Float64(-0.5 * Float64(c / b)) + Float64(Float64(a * -0.375) / Float64((b ^ 3.0) / Float64(c * c)))) end
function tmp = code(a, b, c) tmp = (-0.5 * (c / b)) + ((a * -0.375) / ((b ^ 3.0) / (c * c))); end
code[a_, b_, c_] := N[(N[(-0.5 * N[(c / b), $MachinePrecision]), $MachinePrecision] + N[(N[(a * -0.375), $MachinePrecision] / N[(N[Power[b, 3.0], $MachinePrecision] / N[(c * c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
-0.5 \cdot \frac{c}{b} + \frac{a \cdot -0.375}{\frac{{b}^{3}}{c \cdot c}}
\end{array}
Initial program 29.3%
neg-sub029.3%
associate-+l-29.3%
sub0-neg29.3%
neg-mul-129.3%
associate-*r/29.3%
*-commutative29.3%
metadata-eval29.3%
metadata-eval29.3%
times-frac29.3%
*-commutative29.3%
times-frac29.3%
Simplified29.4%
Taylor expanded in b around inf 91.4%
fma-def91.4%
associate-*r/91.4%
*-commutative91.4%
associate-*r*91.4%
unpow291.4%
Simplified91.4%
fma-udef91.4%
associate-/l*91.4%
*-commutative91.4%
Applied egg-rr91.4%
Final simplification91.4%
(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 29.3%
neg-sub029.3%
associate-+l-29.3%
sub0-neg29.3%
neg-mul-129.3%
associate-*r/29.3%
*-commutative29.3%
metadata-eval29.3%
metadata-eval29.3%
times-frac29.3%
*-commutative29.3%
times-frac29.3%
Simplified29.4%
Taylor expanded in b around inf 82.8%
Final simplification82.8%
herbie shell --seed 2023200
(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)))