
(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
-0.5625
(/ (* a a) (/ (pow b 5.0) (pow c 3.0)))
(fma
-0.5
(/ c b)
(fma
-0.16666666666666666
(* (/ (pow (* a c) 4.0) a) (/ 6.328125 (pow b 7.0)))
(* (/ a (pow b 3.0)) (* (* c c) -0.375))))))
double code(double a, double b, double c) {
return fma(-0.5625, ((a * a) / (pow(b, 5.0) / pow(c, 3.0))), fma(-0.5, (c / b), fma(-0.16666666666666666, ((pow((a * c), 4.0) / a) * (6.328125 / pow(b, 7.0))), ((a / pow(b, 3.0)) * ((c * c) * -0.375)))));
}
function code(a, b, c) return fma(-0.5625, Float64(Float64(a * a) / Float64((b ^ 5.0) / (c ^ 3.0))), fma(-0.5, Float64(c / b), fma(-0.16666666666666666, Float64(Float64((Float64(a * c) ^ 4.0) / a) * Float64(6.328125 / (b ^ 7.0))), Float64(Float64(a / (b ^ 3.0)) * Float64(Float64(c * c) * -0.375))))) end
code[a_, b_, c_] := N[(-0.5625 * N[(N[(a * a), $MachinePrecision] / N[(N[Power[b, 5.0], $MachinePrecision] / N[Power[c, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(-0.5 * N[(c / b), $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[(N[(a / N[Power[b, 3.0], $MachinePrecision]), $MachinePrecision] * N[(N[(c * c), $MachinePrecision] * -0.375), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(-0.5625, \frac{a \cdot a}{\frac{{b}^{5}}{{c}^{3}}}, \mathsf{fma}\left(-0.5, \frac{c}{b}, \mathsf{fma}\left(-0.16666666666666666, \frac{{\left(a \cdot c\right)}^{4}}{a} \cdot \frac{6.328125}{{b}^{7}}, \frac{a}{{b}^{3}} \cdot \left(\left(c \cdot c\right) \cdot -0.375\right)\right)\right)\right)
\end{array}
Initial program 18.2%
neg-sub018.2%
sqr-neg18.2%
associate-+l-18.2%
sub0-neg18.2%
neg-mul-118.2%
Simplified18.3%
div-inv18.3%
metadata-eval18.3%
*-commutative18.3%
expm1-log1p-u18.2%
Applied egg-rr18.2%
Taylor expanded in b around inf 97.1%
Simplified97.1%
Final simplification97.1%
(FPCore (a b c) :precision binary64 (fma -0.5625 (/ (* a a) (/ (pow b 5.0) (pow c 3.0))) (fma -0.5 (/ c b) (* -0.375 (/ a (/ (pow b 3.0) (* c c)))))))
double code(double a, double b, double c) {
return fma(-0.5625, ((a * a) / (pow(b, 5.0) / pow(c, 3.0))), fma(-0.5, (c / b), (-0.375 * (a / (pow(b, 3.0) / (c * c))))));
}
function code(a, b, c) return fma(-0.5625, Float64(Float64(a * a) / Float64((b ^ 5.0) / (c ^ 3.0))), fma(-0.5, Float64(c / b), Float64(-0.375 * Float64(a / Float64((b ^ 3.0) / Float64(c * c)))))) end
code[a_, b_, c_] := N[(-0.5625 * N[(N[(a * a), $MachinePrecision] / N[(N[Power[b, 5.0], $MachinePrecision] / N[Power[c, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(-0.5 * N[(c / b), $MachinePrecision] + N[(-0.375 * N[(a / N[(N[Power[b, 3.0], $MachinePrecision] / N[(c * c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(-0.5625, \frac{a \cdot a}{\frac{{b}^{5}}{{c}^{3}}}, \mathsf{fma}\left(-0.5, \frac{c}{b}, -0.375 \cdot \frac{a}{\frac{{b}^{3}}{c \cdot c}}\right)\right)
\end{array}
Initial program 18.2%
sqr-neg18.2%
sqr-neg18.2%
associate-*l*18.2%
Simplified18.2%
Taylor expanded in b around inf 96.2%
fma-def96.2%
associate-/l*96.2%
unpow296.2%
fma-def96.2%
associate-/l*96.2%
unpow296.2%
Simplified96.2%
Final simplification96.2%
(FPCore (a b c)
:precision binary64
(let* ((t_0 (* 2.25 (/ (* a a) (* b b)))))
(/
(fma
-0.5
(+
(/ (* c c) (/ b t_0))
(/
(pow c 3.0)
(/ b (fma 1.5 (* (/ a b) (/ t_0 b)) (/ (* -3.0 (* a 0.0)) (* b b))))))
(/ (* a (* c -1.5)) b))
(* a 3.0))))
double code(double a, double b, double c) {
double t_0 = 2.25 * ((a * a) / (b * b));
return fma(-0.5, (((c * c) / (b / t_0)) + (pow(c, 3.0) / (b / fma(1.5, ((a / b) * (t_0 / b)), ((-3.0 * (a * 0.0)) / (b * b)))))), ((a * (c * -1.5)) / b)) / (a * 3.0);
}
function code(a, b, c) t_0 = Float64(2.25 * Float64(Float64(a * a) / Float64(b * b))) return Float64(fma(-0.5, Float64(Float64(Float64(c * c) / Float64(b / t_0)) + Float64((c ^ 3.0) / Float64(b / fma(1.5, Float64(Float64(a / b) * Float64(t_0 / b)), Float64(Float64(-3.0 * Float64(a * 0.0)) / Float64(b * b)))))), Float64(Float64(a * Float64(c * -1.5)) / b)) / Float64(a * 3.0)) end
code[a_, b_, c_] := Block[{t$95$0 = N[(2.25 * N[(N[(a * a), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, N[(N[(-0.5 * N[(N[(N[(c * c), $MachinePrecision] / N[(b / t$95$0), $MachinePrecision]), $MachinePrecision] + N[(N[Power[c, 3.0], $MachinePrecision] / N[(b / N[(1.5 * N[(N[(a / b), $MachinePrecision] * N[(t$95$0 / b), $MachinePrecision]), $MachinePrecision] + N[(N[(-3.0 * N[(a * 0.0), $MachinePrecision]), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(N[(a * N[(c * -1.5), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]), $MachinePrecision] / N[(a * 3.0), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := 2.25 \cdot \frac{a \cdot a}{b \cdot b}\\
\frac{\mathsf{fma}\left(-0.5, \frac{c \cdot c}{\frac{b}{t_0}} + \frac{{c}^{3}}{\frac{b}{\mathsf{fma}\left(1.5, \frac{a}{b} \cdot \frac{t_0}{b}, \frac{-3 \cdot \left(a \cdot 0\right)}{b \cdot b}\right)}}, \frac{a \cdot \left(c \cdot -1.5\right)}{b}\right)}{a \cdot 3}
\end{array}
\end{array}
Initial program 18.2%
sqr-neg18.2%
sqr-neg18.2%
associate-*l*18.2%
Simplified18.2%
flip3--18.2%
div-inv18.3%
pow218.3%
pow-pow18.3%
metadata-eval18.3%
pow218.3%
pow218.3%
pow-prod-up18.3%
metadata-eval18.3%
distribute-rgt-out18.3%
Applied egg-rr18.3%
Taylor expanded in c around 0 95.5%
Simplified95.6%
Taylor expanded in a around 0 95.6%
unpow295.6%
unpow295.6%
Simplified95.6%
Taylor expanded in a around 0 95.6%
unpow295.6%
unpow295.6%
Simplified95.6%
Final simplification95.6%
(FPCore (a b c) :precision binary64 (+ (* -0.375 (* (/ a (pow b 3.0)) (* c c))) (* -0.5 (/ c b))))
double code(double a, double b, double c) {
return (-0.375 * ((a / pow(b, 3.0)) * (c * c))) + (-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 = ((-0.375d0) * ((a / (b ** 3.0d0)) * (c * c))) + ((-0.5d0) * (c / b))
end function
public static double code(double a, double b, double c) {
return (-0.375 * ((a / Math.pow(b, 3.0)) * (c * c))) + (-0.5 * (c / b));
}
def code(a, b, c): return (-0.375 * ((a / math.pow(b, 3.0)) * (c * c))) + (-0.5 * (c / b))
function code(a, b, c) return Float64(Float64(-0.375 * Float64(Float64(a / (b ^ 3.0)) * Float64(c * c))) + Float64(-0.5 * Float64(c / b))) end
function tmp = code(a, b, c) tmp = (-0.375 * ((a / (b ^ 3.0)) * (c * c))) + (-0.5 * (c / b)); end
code[a_, b_, c_] := N[(N[(-0.375 * N[(N[(a / N[Power[b, 3.0], $MachinePrecision]), $MachinePrecision] * N[(c * c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(-0.5 * N[(c / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
-0.375 \cdot \left(\frac{a}{{b}^{3}} \cdot \left(c \cdot c\right)\right) + -0.5 \cdot \frac{c}{b}
\end{array}
Initial program 18.2%
sqr-neg18.2%
sqr-neg18.2%
associate-*l*18.2%
Simplified18.2%
Taylor expanded in b around inf 94.5%
+-commutative94.5%
fma-def94.5%
associate-/l*94.5%
associate-/r/94.5%
unpow294.5%
Simplified94.5%
fma-udef94.5%
*-commutative94.5%
Applied egg-rr94.5%
Final simplification94.5%
(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 18.2%
sqr-neg18.2%
sqr-neg18.2%
associate-*l*18.2%
Simplified18.2%
Taylor expanded in b around inf 89.8%
Final simplification89.8%
herbie shell --seed 2023283
(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)))