
(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 7 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
(let* ((t_0 (* -1.125 (* c (* c (* a a))))))
(fma
-0.5625
(/ (pow c 3.0) (/ (pow b 5.0) (* a a)))
(fma
-0.16666666666666666
(/ (+ (* t_0 t_0) (* 5.0625 (pow (* c a) 4.0))) (* a (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) {
double t_0 = -1.125 * (c * (c * (a * a)));
return fma(-0.5625, (pow(c, 3.0) / (pow(b, 5.0) / (a * a))), fma(-0.16666666666666666, (((t_0 * t_0) + (5.0625 * pow((c * a), 4.0))) / (a * pow(b, 7.0))), fma(-0.5, (c / b), (-0.375 * ((c * c) / (pow(b, 3.0) / a))))));
}
function code(a, b, c) t_0 = Float64(-1.125 * Float64(c * Float64(c * Float64(a * a)))) return fma(-0.5625, Float64((c ^ 3.0) / Float64((b ^ 5.0) / Float64(a * a))), fma(-0.16666666666666666, Float64(Float64(Float64(t_0 * t_0) + Float64(5.0625 * (Float64(c * a) ^ 4.0))) / Float64(a * (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_] := Block[{t$95$0 = N[(-1.125 * N[(c * N[(c * N[(a * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, 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[(t$95$0 * t$95$0), $MachinePrecision] + N[(5.0625 * N[Power[N[(c * a), $MachinePrecision], 4.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(a * N[Power[b, 7.0], $MachinePrecision]), $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}
\\
\begin{array}{l}
t_0 := -1.125 \cdot \left(c \cdot \left(c \cdot \left(a \cdot a\right)\right)\right)\\
\mathsf{fma}\left(-0.5625, \frac{{c}^{3}}{\frac{{b}^{5}}{a \cdot a}}, \mathsf{fma}\left(-0.16666666666666666, \frac{t_0 \cdot t_0 + 5.0625 \cdot {\left(c \cdot a\right)}^{4}}{a \cdot {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}
\end{array}
Initial program 32.0%
Taylor expanded in b around inf 96.9%
fma-def96.9%
associate-/l*96.9%
unpow296.9%
fma-def96.9%
Simplified96.9%
pow196.9%
pow-prod-down96.9%
Applied egg-rr96.9%
unpow196.9%
Simplified96.9%
unpow296.9%
associate-*l*96.9%
associate-*l*96.9%
Applied egg-rr96.9%
Final simplification96.9%
(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 a))) (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 * (c * (c * a))) / 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(c * Float64(c * a))) / (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[(c * N[(c * a), $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(c \cdot \left(c \cdot a\right)\right)}{{b}^{3}}\right)\right)
\end{array}
Initial program 32.0%
Taylor expanded in b around inf 95.1%
fma-def95.1%
associate-/l*95.1%
unpow295.1%
fma-def95.1%
associate-*r/95.1%
unpow295.1%
associate-*l*95.1%
Simplified95.1%
Final simplification95.1%
(FPCore (a b c)
:precision binary64
(/
(fma
(/ c (/ b a))
-0.5
(fma
(/ (* c c) (/ (pow b 3.0) (* a a)))
-0.375
(* -0.5625 (/ (* (* c (* c (* a a))) (* c a)) (pow b 5.0)))))
a))
double code(double a, double b, double c) {
return fma((c / (b / a)), -0.5, fma(((c * c) / (pow(b, 3.0) / (a * a))), -0.375, (-0.5625 * (((c * (c * (a * 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(c * c) / Float64((b ^ 3.0) / Float64(a * a))), -0.375, Float64(-0.5625 * Float64(Float64(Float64(c * Float64(c * Float64(a * 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[(c * c), $MachinePrecision] / N[(N[Power[b, 3.0], $MachinePrecision] / N[(a * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * -0.375 + N[(-0.5625 * N[(N[(N[(c * N[(c * N[(a * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[(c * a), $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{c \cdot c}{\frac{{b}^{3}}{a \cdot a}}, -0.375, -0.5625 \cdot \frac{\left(c \cdot \left(c \cdot \left(a \cdot a\right)\right)\right) \cdot \left(c \cdot a\right)}{{b}^{5}}\right)\right)}{a}
\end{array}
Initial program 32.0%
/-rgt-identity32.0%
metadata-eval32.0%
associate-/r/32.0%
metadata-eval32.0%
metadata-eval32.0%
times-frac32.0%
*-commutative32.0%
times-frac32.0%
*-commutative32.0%
associate-/r*32.0%
associate-*l/32.0%
Simplified32.0%
Taylor expanded in b around inf 94.9%
*-commutative94.9%
fma-def94.9%
associate-/l*94.9%
*-commutative94.9%
fma-def94.9%
associate-/l*94.9%
unpow294.9%
unpow294.9%
*-commutative94.9%
cube-prod94.9%
Simplified94.9%
unpow394.9%
unswap-sqr94.9%
associate-*l*94.9%
Applied egg-rr94.9%
Final simplification94.9%
(FPCore (a b c) :precision binary64 (let* ((t_0 (/ (- (sqrt (- (* b b) (* c (* 3.0 a)))) b) (* 3.0 a)))) (if (<= t_0 -2e-7) t_0 (* -0.5 (/ c b)))))
double code(double a, double b, double c) {
double t_0 = (sqrt(((b * b) - (c * (3.0 * a)))) - b) / (3.0 * a);
double tmp;
if (t_0 <= -2e-7) {
tmp = t_0;
} else {
tmp = -0.5 * (c / b);
}
return tmp;
}
real(8) function code(a, b, c)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: c
real(8) :: t_0
real(8) :: tmp
t_0 = (sqrt(((b * b) - (c * (3.0d0 * a)))) - b) / (3.0d0 * a)
if (t_0 <= (-2d-7)) then
tmp = t_0
else
tmp = (-0.5d0) * (c / b)
end if
code = tmp
end function
public static double code(double a, double b, double c) {
double t_0 = (Math.sqrt(((b * b) - (c * (3.0 * a)))) - b) / (3.0 * a);
double tmp;
if (t_0 <= -2e-7) {
tmp = t_0;
} else {
tmp = -0.5 * (c / b);
}
return tmp;
}
def code(a, b, c): t_0 = (math.sqrt(((b * b) - (c * (3.0 * a)))) - b) / (3.0 * a) tmp = 0 if t_0 <= -2e-7: tmp = t_0 else: tmp = -0.5 * (c / b) return tmp
function code(a, b, c) t_0 = Float64(Float64(sqrt(Float64(Float64(b * b) - Float64(c * Float64(3.0 * a)))) - b) / Float64(3.0 * a)) tmp = 0.0 if (t_0 <= -2e-7) tmp = t_0; else tmp = Float64(-0.5 * Float64(c / b)); end return tmp end
function tmp_2 = code(a, b, c) t_0 = (sqrt(((b * b) - (c * (3.0 * a)))) - b) / (3.0 * a); tmp = 0.0; if (t_0 <= -2e-7) tmp = t_0; else tmp = -0.5 * (c / b); end tmp_2 = tmp; end
code[a_, b_, c_] := Block[{t$95$0 = N[(N[(N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(c * N[(3.0 * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] / N[(3.0 * a), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[t$95$0, -2e-7], t$95$0, N[(-0.5 * N[(c / b), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{\sqrt{b \cdot b - c \cdot \left(3 \cdot a\right)} - b}{3 \cdot a}\\
\mathbf{if}\;t_0 \leq -2 \cdot 10^{-7}:\\
\;\;\;\;t_0\\
\mathbf{else}:\\
\;\;\;\;-0.5 \cdot \frac{c}{b}\\
\end{array}
\end{array}
if (/.f64 (+.f64 (neg.f64 b) (sqrt.f64 (-.f64 (*.f64 b b) (*.f64 (*.f64 3 a) c)))) (*.f64 3 a)) < -1.9999999999999999e-7Initial program 67.5%
if -1.9999999999999999e-7 < (/.f64 (+.f64 (neg.f64 b) (sqrt.f64 (-.f64 (*.f64 b b) (*.f64 (*.f64 3 a) c)))) (*.f64 3 a)) Initial program 14.7%
Taylor expanded in b around inf 93.3%
Final simplification84.8%
(FPCore (a b c) :precision binary64 (fma -0.5 (/ c b) (/ (* -0.375 (* c (* c a))) (pow b 3.0))))
double code(double a, double b, double c) {
return fma(-0.5, (c / b), ((-0.375 * (c * (c * a))) / pow(b, 3.0)));
}
function code(a, b, c) return fma(-0.5, Float64(c / b), Float64(Float64(-0.375 * Float64(c * Float64(c * a))) / (b ^ 3.0))) end
code[a_, b_, c_] := N[(-0.5 * N[(c / b), $MachinePrecision] + N[(N[(-0.375 * N[(c * N[(c * a), $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(c \cdot \left(c \cdot a\right)\right)}{{b}^{3}}\right)
\end{array}
Initial program 32.0%
Taylor expanded in b around inf 91.4%
fma-def91.4%
associate-*r/91.4%
unpow291.4%
associate-*l*91.4%
Simplified91.4%
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 32.0%
Taylor expanded in b around inf 80.9%
Final simplification80.9%
(FPCore (a b c) :precision binary64 (/ 0.0 a))
double code(double a, double b, double c) {
return 0.0 / a;
}
real(8) function code(a, b, c)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: c
code = 0.0d0 / a
end function
public static double code(double a, double b, double c) {
return 0.0 / a;
}
def code(a, b, c): return 0.0 / a
function code(a, b, c) return Float64(0.0 / a) end
function tmp = code(a, b, c) tmp = 0.0 / a; end
code[a_, b_, c_] := N[(0.0 / a), $MachinePrecision]
\begin{array}{l}
\\
\frac{0}{a}
\end{array}
Initial program 32.0%
add-cube-cbrt32.0%
pow332.0%
neg-mul-132.0%
fma-def32.0%
associate-*l*32.0%
Applied egg-rr32.0%
Taylor expanded in c around 0 3.2%
pow-base-13.2%
*-rgt-identity3.2%
distribute-rgt1-in3.2%
metadata-eval3.2%
mul0-lft3.2%
associate-*r/3.2%
metadata-eval3.2%
Simplified3.2%
Final simplification3.2%
herbie shell --seed 2023224
(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)))