
(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 10 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
0.375
(/ (* (* c c) a) (* b b))
(fma
0.5
c
(fma
1.0546875
(* (/ (pow c 4.0) (pow b 6.0)) (* (* a a) a))
(* (/ (* (* (* c c) c) (* a a)) (pow b 4.0)) 0.5625))))
(- b)))
double code(double a, double b, double c) {
return fma(0.375, (((c * c) * a) / (b * b)), fma(0.5, c, fma(1.0546875, ((pow(c, 4.0) / pow(b, 6.0)) * ((a * a) * a)), (((((c * c) * c) * (a * a)) / pow(b, 4.0)) * 0.5625)))) / -b;
}
function code(a, b, c) return Float64(fma(0.375, Float64(Float64(Float64(c * c) * a) / Float64(b * b)), fma(0.5, c, fma(1.0546875, Float64(Float64((c ^ 4.0) / (b ^ 6.0)) * Float64(Float64(a * a) * a)), Float64(Float64(Float64(Float64(Float64(c * c) * c) * Float64(a * a)) / (b ^ 4.0)) * 0.5625)))) / Float64(-b)) end
code[a_, b_, c_] := N[(N[(0.375 * N[(N[(N[(c * c), $MachinePrecision] * a), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision] + N[(0.5 * c + N[(1.0546875 * N[(N[(N[Power[c, 4.0], $MachinePrecision] / N[Power[b, 6.0], $MachinePrecision]), $MachinePrecision] * N[(N[(a * a), $MachinePrecision] * a), $MachinePrecision]), $MachinePrecision] + N[(N[(N[(N[(N[(c * c), $MachinePrecision] * c), $MachinePrecision] * N[(a * a), $MachinePrecision]), $MachinePrecision] / N[Power[b, 4.0], $MachinePrecision]), $MachinePrecision] * 0.5625), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / (-b)), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(0.375, \frac{\left(c \cdot c\right) \cdot a}{b \cdot b}, \mathsf{fma}\left(0.5, c, \mathsf{fma}\left(1.0546875, \frac{{c}^{4}}{{b}^{6}} \cdot \left(\left(a \cdot a\right) \cdot a\right), \frac{\left(\left(c \cdot c\right) \cdot c\right) \cdot \left(a \cdot a\right)}{{b}^{4}} \cdot 0.5625\right)\right)\right)}{-b}
\end{array}
Initial program 30.3%
lift-/.f64N/A
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
div-subN/A
lower--.f64N/A
Applied rewrites29.7%
lift--.f64N/A
lift-/.f64N/A
lift-*.f64N/A
*-commutativeN/A
associate-/r*N/A
lift-/.f64N/A
lift-*.f64N/A
*-commutativeN/A
associate-/r*N/A
sub-divN/A
lower-/.f64N/A
Applied rewrites29.9%
Taylor expanded in c around 0
Applied rewrites95.1%
Taylor expanded in b around -inf
Applied rewrites95.3%
Final simplification95.3%
(FPCore (a b c)
:precision binary64
(let* ((t_0 (* (* b b) b)))
(fma
(fma
(fma
(/ c (* t_0 (* b b)))
(* (* -0.5625 c) c)
(*
(* (/ 6.328125 (* (* t_0 b) t_0)) (* (* (* c c) c) c))
(* -0.16666666666666666 a)))
a
(/ (* (* c c) -0.375) t_0))
a
(* (/ c b) -0.5))))
double code(double a, double b, double c) {
double t_0 = (b * b) * b;
return fma(fma(fma((c / (t_0 * (b * b))), ((-0.5625 * c) * c), (((6.328125 / ((t_0 * b) * t_0)) * (((c * c) * c) * c)) * (-0.16666666666666666 * a))), a, (((c * c) * -0.375) / t_0)), a, ((c / b) * -0.5));
}
function code(a, b, c) t_0 = Float64(Float64(b * b) * b) return fma(fma(fma(Float64(c / Float64(t_0 * Float64(b * b))), Float64(Float64(-0.5625 * c) * c), Float64(Float64(Float64(6.328125 / Float64(Float64(t_0 * b) * t_0)) * Float64(Float64(Float64(c * c) * c) * c)) * Float64(-0.16666666666666666 * a))), a, Float64(Float64(Float64(c * c) * -0.375) / t_0)), a, Float64(Float64(c / b) * -0.5)) end
code[a_, b_, c_] := Block[{t$95$0 = N[(N[(b * b), $MachinePrecision] * b), $MachinePrecision]}, N[(N[(N[(N[(c / N[(t$95$0 * N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[(N[(-0.5625 * c), $MachinePrecision] * c), $MachinePrecision] + N[(N[(N[(6.328125 / N[(N[(t$95$0 * b), $MachinePrecision] * t$95$0), $MachinePrecision]), $MachinePrecision] * N[(N[(N[(c * c), $MachinePrecision] * c), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision] * N[(-0.16666666666666666 * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * a + N[(N[(N[(c * c), $MachinePrecision] * -0.375), $MachinePrecision] / t$95$0), $MachinePrecision]), $MachinePrecision] * a + N[(N[(c / b), $MachinePrecision] * -0.5), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \left(b \cdot b\right) \cdot b\\
\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\frac{c}{t\_0 \cdot \left(b \cdot b\right)}, \left(-0.5625 \cdot c\right) \cdot c, \left(\frac{6.328125}{\left(t\_0 \cdot b\right) \cdot t\_0} \cdot \left(\left(\left(c \cdot c\right) \cdot c\right) \cdot c\right)\right) \cdot \left(-0.16666666666666666 \cdot a\right)\right), a, \frac{\left(c \cdot c\right) \cdot -0.375}{t\_0}\right), a, \frac{c}{b} \cdot -0.5\right)
\end{array}
\end{array}
Initial program 30.3%
Taylor expanded in a around 0
Applied rewrites95.3%
Applied rewrites95.3%
Final simplification95.3%
(FPCore (a b c)
:precision binary64
(let* ((t_0 (* (* b b) b)))
(*
(fma
c
(fma
c
(fma
(/ (* (* (* a a) 6.328125) (* a a)) (* (* (* t_0 b) (* b b)) (* b a)))
(* -0.16666666666666666 c)
(/ (* (* a a) -0.5625) (* t_0 (* b b))))
(* (/ a t_0) -0.375))
(/ -0.5 b))
c)))
double code(double a, double b, double c) {
double t_0 = (b * b) * b;
return fma(c, fma(c, fma(((((a * a) * 6.328125) * (a * a)) / (((t_0 * b) * (b * b)) * (b * a))), (-0.16666666666666666 * c), (((a * a) * -0.5625) / (t_0 * (b * b)))), ((a / t_0) * -0.375)), (-0.5 / b)) * c;
}
function code(a, b, c) t_0 = Float64(Float64(b * b) * b) return Float64(fma(c, fma(c, fma(Float64(Float64(Float64(Float64(a * a) * 6.328125) * Float64(a * a)) / Float64(Float64(Float64(t_0 * b) * Float64(b * b)) * Float64(b * a))), Float64(-0.16666666666666666 * c), Float64(Float64(Float64(a * a) * -0.5625) / Float64(t_0 * Float64(b * b)))), Float64(Float64(a / t_0) * -0.375)), Float64(-0.5 / b)) * c) end
code[a_, b_, c_] := Block[{t$95$0 = N[(N[(b * b), $MachinePrecision] * b), $MachinePrecision]}, N[(N[(c * N[(c * N[(N[(N[(N[(N[(a * a), $MachinePrecision] * 6.328125), $MachinePrecision] * N[(a * a), $MachinePrecision]), $MachinePrecision] / N[(N[(N[(t$95$0 * b), $MachinePrecision] * N[(b * b), $MachinePrecision]), $MachinePrecision] * N[(b * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[(-0.16666666666666666 * c), $MachinePrecision] + N[(N[(N[(a * a), $MachinePrecision] * -0.5625), $MachinePrecision] / N[(t$95$0 * N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(N[(a / t$95$0), $MachinePrecision] * -0.375), $MachinePrecision]), $MachinePrecision] + N[(-0.5 / b), $MachinePrecision]), $MachinePrecision] * c), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \left(b \cdot b\right) \cdot b\\
\mathsf{fma}\left(c, \mathsf{fma}\left(c, \mathsf{fma}\left(\frac{\left(\left(a \cdot a\right) \cdot 6.328125\right) \cdot \left(a \cdot a\right)}{\left(\left(t\_0 \cdot b\right) \cdot \left(b \cdot b\right)\right) \cdot \left(b \cdot a\right)}, -0.16666666666666666 \cdot c, \frac{\left(a \cdot a\right) \cdot -0.5625}{t\_0 \cdot \left(b \cdot b\right)}\right), \frac{a}{t\_0} \cdot -0.375\right), \frac{-0.5}{b}\right) \cdot c
\end{array}
\end{array}
Initial program 30.3%
lift-/.f64N/A
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
div-subN/A
lower--.f64N/A
Applied rewrites29.7%
lift--.f64N/A
lift-/.f64N/A
lift-*.f64N/A
*-commutativeN/A
associate-/r*N/A
lift-/.f64N/A
lift-*.f64N/A
*-commutativeN/A
associate-/r*N/A
sub-divN/A
lower-/.f64N/A
Applied rewrites29.9%
Taylor expanded in c around 0
Applied rewrites95.1%
Applied rewrites95.1%
Final simplification95.1%
(FPCore (a b c) :precision binary64 (fma (/ (fma (* -0.375 c) c (/ (* (* (* (* c c) c) a) -0.5625) (* b b))) (* (* b b) b)) a (* (/ c b) -0.5)))
double code(double a, double b, double c) {
return fma((fma((-0.375 * c), c, (((((c * c) * c) * a) * -0.5625) / (b * b))) / ((b * b) * b)), a, ((c / b) * -0.5));
}
function code(a, b, c) return fma(Float64(fma(Float64(-0.375 * c), c, Float64(Float64(Float64(Float64(Float64(c * c) * c) * a) * -0.5625) / Float64(b * b))) / Float64(Float64(b * b) * b)), a, Float64(Float64(c / b) * -0.5)) end
code[a_, b_, c_] := N[(N[(N[(N[(-0.375 * c), $MachinePrecision] * c + N[(N[(N[(N[(N[(c * c), $MachinePrecision] * c), $MachinePrecision] * a), $MachinePrecision] * -0.5625), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(N[(b * b), $MachinePrecision] * b), $MachinePrecision]), $MachinePrecision] * a + N[(N[(c / b), $MachinePrecision] * -0.5), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(\frac{\mathsf{fma}\left(-0.375 \cdot c, c, \frac{\left(\left(\left(c \cdot c\right) \cdot c\right) \cdot a\right) \cdot -0.5625}{b \cdot b}\right)}{\left(b \cdot b\right) \cdot b}, a, \frac{c}{b} \cdot -0.5\right)
\end{array}
Initial program 30.3%
Taylor expanded in a around 0
Applied rewrites95.3%
Taylor expanded in b around inf
Applied rewrites93.8%
(FPCore (a b c) :precision binary64 (* (fma (/ (fma (* (* (/ c (* b b)) a) a) -0.5625 (* -0.375 a)) (* (* b b) b)) c (/ -0.5 b)) c))
double code(double a, double b, double c) {
return fma((fma((((c / (b * b)) * a) * a), -0.5625, (-0.375 * a)) / ((b * b) * b)), c, (-0.5 / b)) * c;
}
function code(a, b, c) return Float64(fma(Float64(fma(Float64(Float64(Float64(c / Float64(b * b)) * a) * a), -0.5625, Float64(-0.375 * a)) / Float64(Float64(b * b) * b)), c, Float64(-0.5 / b)) * c) end
code[a_, b_, c_] := N[(N[(N[(N[(N[(N[(N[(c / N[(b * b), $MachinePrecision]), $MachinePrecision] * a), $MachinePrecision] * a), $MachinePrecision] * -0.5625 + N[(-0.375 * a), $MachinePrecision]), $MachinePrecision] / N[(N[(b * b), $MachinePrecision] * b), $MachinePrecision]), $MachinePrecision] * c + N[(-0.5 / b), $MachinePrecision]), $MachinePrecision] * c), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(\frac{\mathsf{fma}\left(\left(\frac{c}{b \cdot b} \cdot a\right) \cdot a, -0.5625, -0.375 \cdot a\right)}{\left(b \cdot b\right) \cdot b}, c, \frac{-0.5}{b}\right) \cdot c
\end{array}
Initial program 30.3%
Taylor expanded in c around 0
*-commutativeN/A
lower-*.f64N/A
Applied rewrites93.5%
Taylor expanded in b around inf
Applied rewrites93.5%
Final simplification93.5%
(FPCore (a b c) :precision binary64 (/ (fma (* -0.375 a) (* (/ c (* b b)) c) (* -0.5 c)) b))
double code(double a, double b, double c) {
return fma((-0.375 * a), ((c / (b * b)) * c), (-0.5 * c)) / b;
}
function code(a, b, c) return Float64(fma(Float64(-0.375 * a), Float64(Float64(c / Float64(b * b)) * c), Float64(-0.5 * c)) / b) end
code[a_, b_, c_] := N[(N[(N[(-0.375 * a), $MachinePrecision] * N[(N[(c / N[(b * b), $MachinePrecision]), $MachinePrecision] * c), $MachinePrecision] + N[(-0.5 * c), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(-0.375 \cdot a, \frac{c}{b \cdot b} \cdot c, -0.5 \cdot c\right)}{b}
\end{array}
Initial program 30.3%
Taylor expanded in b around inf
lower-/.f64N/A
+-commutativeN/A
associate-/l*N/A
associate-*r*N/A
lower-fma.f64N/A
lower-*.f64N/A
unpow2N/A
associate-/l*N/A
lower-*.f64N/A
lower-/.f64N/A
unpow2N/A
lower-*.f64N/A
lower-*.f6491.0
Applied rewrites91.0%
Final simplification91.0%
(FPCore (a b c) :precision binary64 (/ (* (fma (* (/ c (* b b)) a) -0.375 -0.5) c) b))
double code(double a, double b, double c) {
return (fma(((c / (b * b)) * a), -0.375, -0.5) * c) / b;
}
function code(a, b, c) return Float64(Float64(fma(Float64(Float64(c / Float64(b * b)) * a), -0.375, -0.5) * c) / b) end
code[a_, b_, c_] := N[(N[(N[(N[(N[(c / N[(b * b), $MachinePrecision]), $MachinePrecision] * a), $MachinePrecision] * -0.375 + -0.5), $MachinePrecision] * c), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\frac{c}{b \cdot b} \cdot a, -0.375, -0.5\right) \cdot c}{b}
\end{array}
Initial program 30.3%
Taylor expanded in b around inf
lower-/.f64N/A
+-commutativeN/A
associate-/l*N/A
associate-*r*N/A
lower-fma.f64N/A
lower-*.f64N/A
unpow2N/A
associate-/l*N/A
lower-*.f64N/A
lower-/.f64N/A
unpow2N/A
lower-*.f64N/A
lower-*.f6491.0
Applied rewrites91.0%
Taylor expanded in c around 0
Applied rewrites91.0%
Final simplification91.0%
(FPCore (a b c) :precision binary64 (* (/ (fma (* (/ c (* b b)) a) -0.375 -0.5) b) c))
double code(double a, double b, double c) {
return (fma(((c / (b * b)) * a), -0.375, -0.5) / b) * c;
}
function code(a, b, c) return Float64(Float64(fma(Float64(Float64(c / Float64(b * b)) * a), -0.375, -0.5) / b) * c) end
code[a_, b_, c_] := N[(N[(N[(N[(N[(c / N[(b * b), $MachinePrecision]), $MachinePrecision] * a), $MachinePrecision] * -0.375 + -0.5), $MachinePrecision] / b), $MachinePrecision] * c), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\frac{c}{b \cdot b} \cdot a, -0.375, -0.5\right)}{b} \cdot c
\end{array}
Initial program 30.3%
Taylor expanded in c around 0
*-commutativeN/A
lower-*.f64N/A
Applied rewrites93.5%
Taylor expanded in b around inf
Applied rewrites90.7%
Final simplification90.7%
(FPCore (a b c) :precision binary64 (* (/ c b) -0.5))
double code(double a, double b, double c) {
return (c / b) * -0.5;
}
real(8) function code(a, b, c)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: c
code = (c / b) * (-0.5d0)
end function
public static double code(double a, double b, double c) {
return (c / b) * -0.5;
}
def code(a, b, c): return (c / b) * -0.5
function code(a, b, c) return Float64(Float64(c / b) * -0.5) end
function tmp = code(a, b, c) tmp = (c / b) * -0.5; end
code[a_, b_, c_] := N[(N[(c / b), $MachinePrecision] * -0.5), $MachinePrecision]
\begin{array}{l}
\\
\frac{c}{b} \cdot -0.5
\end{array}
Initial program 30.3%
Taylor expanded in b around inf
*-commutativeN/A
lower-*.f64N/A
lower-/.f6482.2
Applied rewrites82.2%
(FPCore (a b c) :precision binary64 (* (/ -0.5 b) c))
double code(double a, double b, double c) {
return (-0.5 / b) * 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) / b) * c
end function
public static double code(double a, double b, double c) {
return (-0.5 / b) * c;
}
def code(a, b, c): return (-0.5 / b) * c
function code(a, b, c) return Float64(Float64(-0.5 / b) * c) end
function tmp = code(a, b, c) tmp = (-0.5 / b) * c; end
code[a_, b_, c_] := N[(N[(-0.5 / b), $MachinePrecision] * c), $MachinePrecision]
\begin{array}{l}
\\
\frac{-0.5}{b} \cdot c
\end{array}
Initial program 30.3%
Taylor expanded in c around 0
*-commutativeN/A
lower-*.f64N/A
Applied rewrites93.5%
Taylor expanded in c around 0
Applied rewrites82.0%
herbie shell --seed 2024235
(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)))