
(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 8 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 (* b (* b b))))
(fma
(fma
c
(fma
(/
(* (* a (* a (* a a))) (* c 6.328125))
(* (* (* b b) (* b t_0)) (* a b)))
-0.16666666666666666
(/ (* (* a a) -0.5625) (* (* b b) t_0)))
(/ (* a -0.375) t_0))
(* c c)
(/ c (* b -2.0)))))
double code(double a, double b, double c) {
double t_0 = b * (b * b);
return fma(fma(c, fma((((a * (a * (a * a))) * (c * 6.328125)) / (((b * b) * (b * t_0)) * (a * b))), -0.16666666666666666, (((a * a) * -0.5625) / ((b * b) * t_0))), ((a * -0.375) / t_0)), (c * c), (c / (b * -2.0)));
}
function code(a, b, c) t_0 = Float64(b * Float64(b * b)) return fma(fma(c, fma(Float64(Float64(Float64(a * Float64(a * Float64(a * a))) * Float64(c * 6.328125)) / Float64(Float64(Float64(b * b) * Float64(b * t_0)) * Float64(a * b))), -0.16666666666666666, Float64(Float64(Float64(a * a) * -0.5625) / Float64(Float64(b * b) * t_0))), Float64(Float64(a * -0.375) / t_0)), Float64(c * c), Float64(c / Float64(b * -2.0))) end
code[a_, b_, c_] := Block[{t$95$0 = N[(b * N[(b * b), $MachinePrecision]), $MachinePrecision]}, N[(N[(c * N[(N[(N[(N[(a * N[(a * N[(a * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[(c * 6.328125), $MachinePrecision]), $MachinePrecision] / N[(N[(N[(b * b), $MachinePrecision] * N[(b * t$95$0), $MachinePrecision]), $MachinePrecision] * N[(a * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * -0.16666666666666666 + N[(N[(N[(a * a), $MachinePrecision] * -0.5625), $MachinePrecision] / N[(N[(b * b), $MachinePrecision] * t$95$0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(N[(a * -0.375), $MachinePrecision] / t$95$0), $MachinePrecision]), $MachinePrecision] * N[(c * c), $MachinePrecision] + N[(c / N[(b * -2.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := b \cdot \left(b \cdot b\right)\\
\mathsf{fma}\left(\mathsf{fma}\left(c, \mathsf{fma}\left(\frac{\left(a \cdot \left(a \cdot \left(a \cdot a\right)\right)\right) \cdot \left(c \cdot 6.328125\right)}{\left(\left(b \cdot b\right) \cdot \left(b \cdot t\_0\right)\right) \cdot \left(a \cdot b\right)}, -0.16666666666666666, \frac{\left(a \cdot a\right) \cdot -0.5625}{\left(b \cdot b\right) \cdot t\_0}\right), \frac{a \cdot -0.375}{t\_0}\right), c \cdot c, \frac{c}{b \cdot -2}\right)
\end{array}
\end{array}
Initial program 18.1%
Taylor expanded in c around 0
Applied rewrites96.9%
Applied rewrites97.3%
Final simplification97.3%
(FPCore (a b c)
:precision binary64
(let* ((t_0 (* b (* b b))))
(fma
(/ -0.5 b)
c
(*
(fma
c
(fma
(/
(* (* a (* a (* a a))) (* c 6.328125))
(* (* (* b b) (* b t_0)) (* a b)))
-0.16666666666666666
(/ (* (* a a) -0.5625) (* (* b b) t_0)))
(/ (* a -0.375) t_0))
(* c c)))))
double code(double a, double b, double c) {
double t_0 = b * (b * b);
return fma((-0.5 / b), c, (fma(c, fma((((a * (a * (a * a))) * (c * 6.328125)) / (((b * b) * (b * t_0)) * (a * b))), -0.16666666666666666, (((a * a) * -0.5625) / ((b * b) * t_0))), ((a * -0.375) / t_0)) * (c * c)));
}
function code(a, b, c) t_0 = Float64(b * Float64(b * b)) return fma(Float64(-0.5 / b), c, Float64(fma(c, fma(Float64(Float64(Float64(a * Float64(a * Float64(a * a))) * Float64(c * 6.328125)) / Float64(Float64(Float64(b * b) * Float64(b * t_0)) * Float64(a * b))), -0.16666666666666666, Float64(Float64(Float64(a * a) * -0.5625) / Float64(Float64(b * b) * t_0))), Float64(Float64(a * -0.375) / t_0)) * Float64(c * c))) end
code[a_, b_, c_] := Block[{t$95$0 = N[(b * N[(b * b), $MachinePrecision]), $MachinePrecision]}, N[(N[(-0.5 / b), $MachinePrecision] * c + N[(N[(c * N[(N[(N[(N[(a * N[(a * N[(a * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[(c * 6.328125), $MachinePrecision]), $MachinePrecision] / N[(N[(N[(b * b), $MachinePrecision] * N[(b * t$95$0), $MachinePrecision]), $MachinePrecision] * N[(a * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * -0.16666666666666666 + N[(N[(N[(a * a), $MachinePrecision] * -0.5625), $MachinePrecision] / N[(N[(b * b), $MachinePrecision] * t$95$0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(N[(a * -0.375), $MachinePrecision] / t$95$0), $MachinePrecision]), $MachinePrecision] * N[(c * c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := b \cdot \left(b \cdot b\right)\\
\mathsf{fma}\left(\frac{-0.5}{b}, c, \mathsf{fma}\left(c, \mathsf{fma}\left(\frac{\left(a \cdot \left(a \cdot \left(a \cdot a\right)\right)\right) \cdot \left(c \cdot 6.328125\right)}{\left(\left(b \cdot b\right) \cdot \left(b \cdot t\_0\right)\right) \cdot \left(a \cdot b\right)}, -0.16666666666666666, \frac{\left(a \cdot a\right) \cdot -0.5625}{\left(b \cdot b\right) \cdot t\_0}\right), \frac{a \cdot -0.375}{t\_0}\right) \cdot \left(c \cdot c\right)\right)
\end{array}
\end{array}
Initial program 18.1%
Taylor expanded in c around 0
Applied rewrites96.9%
Applied rewrites97.0%
Final simplification97.0%
(FPCore (a b c)
:precision binary64
(let* ((t_0 (* b (* b b))))
(*
c
(fma
c
(fma
c
(fma
(/
(* (* a (* a (* a a))) (* c 6.328125))
(* (* (* b b) (* b t_0)) (* a b)))
-0.16666666666666666
(/ (* (* a a) -0.5625) (* (* b b) t_0)))
(/ (* a -0.375) t_0))
(/ -0.5 b)))))
double code(double a, double b, double c) {
double t_0 = b * (b * b);
return c * fma(c, fma(c, fma((((a * (a * (a * a))) * (c * 6.328125)) / (((b * b) * (b * t_0)) * (a * b))), -0.16666666666666666, (((a * a) * -0.5625) / ((b * b) * t_0))), ((a * -0.375) / t_0)), (-0.5 / b));
}
function code(a, b, c) t_0 = Float64(b * Float64(b * b)) return Float64(c * fma(c, fma(c, fma(Float64(Float64(Float64(a * Float64(a * Float64(a * a))) * Float64(c * 6.328125)) / Float64(Float64(Float64(b * b) * Float64(b * t_0)) * Float64(a * b))), -0.16666666666666666, Float64(Float64(Float64(a * a) * -0.5625) / Float64(Float64(b * b) * t_0))), Float64(Float64(a * -0.375) / t_0)), Float64(-0.5 / b))) end
code[a_, b_, c_] := Block[{t$95$0 = N[(b * N[(b * b), $MachinePrecision]), $MachinePrecision]}, N[(c * N[(c * N[(c * N[(N[(N[(N[(a * N[(a * N[(a * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[(c * 6.328125), $MachinePrecision]), $MachinePrecision] / N[(N[(N[(b * b), $MachinePrecision] * N[(b * t$95$0), $MachinePrecision]), $MachinePrecision] * N[(a * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * -0.16666666666666666 + N[(N[(N[(a * a), $MachinePrecision] * -0.5625), $MachinePrecision] / N[(N[(b * b), $MachinePrecision] * t$95$0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(N[(a * -0.375), $MachinePrecision] / t$95$0), $MachinePrecision]), $MachinePrecision] + N[(-0.5 / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := b \cdot \left(b \cdot b\right)\\
c \cdot \mathsf{fma}\left(c, \mathsf{fma}\left(c, \mathsf{fma}\left(\frac{\left(a \cdot \left(a \cdot \left(a \cdot a\right)\right)\right) \cdot \left(c \cdot 6.328125\right)}{\left(\left(b \cdot b\right) \cdot \left(b \cdot t\_0\right)\right) \cdot \left(a \cdot b\right)}, -0.16666666666666666, \frac{\left(a \cdot a\right) \cdot -0.5625}{\left(b \cdot b\right) \cdot t\_0}\right), \frac{a \cdot -0.375}{t\_0}\right), \frac{-0.5}{b}\right)
\end{array}
\end{array}
Initial program 18.1%
Taylor expanded in c around 0
Applied rewrites96.9%
Applied rewrites96.9%
Final simplification96.9%
(FPCore (a b c) :precision binary64 (fma (/ (fma -0.5625 (/ (* c (* a a)) (* b b)) (* a -0.375)) (* b (* b b))) (* c c) (/ c (* b -2.0))))
double code(double a, double b, double c) {
return fma((fma(-0.5625, ((c * (a * a)) / (b * b)), (a * -0.375)) / (b * (b * b))), (c * c), (c / (b * -2.0)));
}
function code(a, b, c) return fma(Float64(fma(-0.5625, Float64(Float64(c * Float64(a * a)) / Float64(b * b)), Float64(a * -0.375)) / Float64(b * Float64(b * b))), Float64(c * c), Float64(c / Float64(b * -2.0))) end
code[a_, b_, c_] := N[(N[(N[(-0.5625 * N[(N[(c * N[(a * a), $MachinePrecision]), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision] + N[(a * -0.375), $MachinePrecision]), $MachinePrecision] / N[(b * N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[(c * c), $MachinePrecision] + N[(c / N[(b * -2.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(\frac{\mathsf{fma}\left(-0.5625, \frac{c \cdot \left(a \cdot a\right)}{b \cdot b}, a \cdot -0.375\right)}{b \cdot \left(b \cdot b\right)}, c \cdot c, \frac{c}{b \cdot -2}\right)
\end{array}
Initial program 18.1%
Taylor expanded in c around 0
Applied rewrites96.9%
Applied rewrites97.3%
Taylor expanded in b around inf
lower-/.f64N/A
lower-fma.f64N/A
lower-/.f64N/A
lower-*.f64N/A
unpow2N/A
lower-*.f64N/A
unpow2N/A
lower-*.f64N/A
lower-*.f64N/A
cube-multN/A
unpow2N/A
lower-*.f64N/A
unpow2N/A
lower-*.f6496.2
Applied rewrites96.2%
Final simplification96.2%
(FPCore (a b c) :precision binary64 (/ (fma a (/ (* -0.375 (* c c)) (* b b)) (* c -0.5)) b))
double code(double a, double b, double c) {
return fma(a, ((-0.375 * (c * c)) / (b * b)), (c * -0.5)) / b;
}
function code(a, b, c) return Float64(fma(a, Float64(Float64(-0.375 * Float64(c * c)) / Float64(b * b)), Float64(c * -0.5)) / b) end
code[a_, b_, c_] := N[(N[(a * N[(N[(-0.375 * N[(c * c), $MachinePrecision]), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision] + N[(c * -0.5), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(a, \frac{-0.375 \cdot \left(c \cdot c\right)}{b \cdot b}, c \cdot -0.5\right)}{b}
\end{array}
Initial program 18.1%
Taylor expanded in b around inf
lower-/.f64N/A
Applied rewrites94.5%
Final simplification94.5%
(FPCore (a b c) :precision binary64 (* c (/ (fma -0.375 (/ (* c a) (* b b)) -0.5) b)))
double code(double a, double b, double c) {
return c * (fma(-0.375, ((c * a) / (b * b)), -0.5) / b);
}
function code(a, b, c) return Float64(c * Float64(fma(-0.375, Float64(Float64(c * a) / Float64(b * b)), -0.5) / b)) end
code[a_, b_, c_] := N[(c * N[(N[(-0.375 * N[(N[(c * a), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision] + -0.5), $MachinePrecision] / b), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
c \cdot \frac{\mathsf{fma}\left(-0.375, \frac{c \cdot a}{b \cdot b}, -0.5\right)}{b}
\end{array}
Initial program 18.1%
Taylor expanded in c around 0
sub-negN/A
distribute-lft-inN/A
associate-*r/N/A
associate-*r*N/A
associate-*l/N/A
associate-*r/N/A
distribute-lft-inN/A
lower-*.f64N/A
associate-*r/N/A
associate-*l/N/A
associate-*r*N/A
associate-*r/N/A
*-commutativeN/A
Applied rewrites94.2%
Taylor expanded in b around inf
lower-/.f64N/A
sub-negN/A
metadata-evalN/A
lower-fma.f64N/A
lower-/.f64N/A
lower-*.f64N/A
unpow2N/A
lower-*.f6494.2
Applied rewrites94.2%
Final simplification94.2%
(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 18.1%
Taylor expanded in b around inf
lower-*.f64N/A
lower-/.f6490.0
Applied rewrites90.0%
(FPCore (a b c) :precision binary64 0.0)
double code(double a, double b, double c) {
return 0.0;
}
real(8) function code(a, b, c)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: c
code = 0.0d0
end function
public static double code(double a, double b, double c) {
return 0.0;
}
def code(a, b, c): return 0.0
function code(a, b, c) return 0.0 end
function tmp = code(a, b, c) tmp = 0.0; end
code[a_, b_, c_] := 0.0
\begin{array}{l}
\\
0
\end{array}
Initial program 18.1%
lift-neg.f64N/A
lift-*.f64N/A
lift-*.f64N/A
lift-*.f64N/A
lift--.f64N/A
lift-sqrt.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
lift-*.f64N/A
div-subN/A
lower--.f64N/A
Applied rewrites17.8%
Applied rewrites19.3%
Taylor expanded in a around 0
associate-*r/N/A
distribute-rgt-outN/A
metadata-evalN/A
mul0-rgtN/A
metadata-evalN/A
lower-/.f643.3
Applied rewrites3.3%
div03.3
Applied rewrites3.3%
herbie shell --seed 2024214
(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)))