
(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 (* (* 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
(/ (* -0.375 (* c c)) t_0))
a
(* -0.5 (/ c b)))))
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, ((-0.375 * (c * c)) / t_0)), a, (-0.5 * (c / b)));
}
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(-0.5625 * Float64(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(-0.375 * Float64(c * c)) / t_0)), a, Float64(-0.5 * Float64(c / b))) 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[(-0.5625 * N[(c * c), $MachinePrecision]), $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[(-0.375 * N[(c * c), $MachinePrecision]), $MachinePrecision] / t$95$0), $MachinePrecision]), $MachinePrecision] * a + N[(-0.5 * N[(c / b), $MachinePrecision]), $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)}, -0.5625 \cdot \left(c \cdot c\right), \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{-0.375 \cdot \left(c \cdot c\right)}{t\_0}\right), a, -0.5 \cdot \frac{c}{b}\right)
\end{array}
\end{array}
Initial program 14.6%
Taylor expanded in a around 0
Applied rewrites98.7%
Applied rewrites98.7%
Final simplification98.7%
(FPCore (a b c) :precision binary64 (fma (/ (fma (/ (* (* (* c a) c) c) (* b b)) -0.5625 (* (* -0.375 c) c)) (* (* b b) b)) a (* -0.5 (/ c b))))
double code(double a, double b, double c) {
return fma((fma(((((c * a) * c) * c) / (b * b)), -0.5625, ((-0.375 * c) * c)) / ((b * b) * b)), a, (-0.5 * (c / b)));
}
function code(a, b, c) return fma(Float64(fma(Float64(Float64(Float64(Float64(c * a) * c) * c) / Float64(b * b)), -0.5625, Float64(Float64(-0.375 * c) * c)) / Float64(Float64(b * b) * b)), a, Float64(-0.5 * Float64(c / b))) end
code[a_, b_, c_] := N[(N[(N[(N[(N[(N[(N[(c * a), $MachinePrecision] * c), $MachinePrecision] * c), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision] * -0.5625 + N[(N[(-0.375 * c), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision] / N[(N[(b * b), $MachinePrecision] * b), $MachinePrecision]), $MachinePrecision] * a + N[(-0.5 * N[(c / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(\frac{\mathsf{fma}\left(\frac{\left(\left(c \cdot a\right) \cdot c\right) \cdot c}{b \cdot b}, -0.5625, \left(-0.375 \cdot c\right) \cdot c\right)}{\left(b \cdot b\right) \cdot b}, a, -0.5 \cdot \frac{c}{b}\right)
\end{array}
Initial program 14.6%
Taylor expanded in a around 0
Applied rewrites98.7%
Taylor expanded in b around inf
Applied rewrites98.4%
Final simplification98.4%
(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 14.6%
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-*.f6497.4
Applied rewrites97.4%
Final simplification97.4%
(FPCore (a b c) :precision binary64 (/ (* (fma (* -0.375 a) (/ c (* b b)) -0.5) c) b))
double code(double a, double b, double c) {
return (fma((-0.375 * a), (c / (b * b)), -0.5) * c) / b;
}
function code(a, b, c) return Float64(Float64(fma(Float64(-0.375 * a), Float64(c / Float64(b * b)), -0.5) * c) / b) end
code[a_, b_, c_] := N[(N[(N[(N[(-0.375 * a), $MachinePrecision] * N[(c / N[(b * b), $MachinePrecision]), $MachinePrecision] + -0.5), $MachinePrecision] * c), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(-0.375 \cdot a, \frac{c}{b \cdot b}, -0.5\right) \cdot c}{b}
\end{array}
Initial program 14.6%
lift-/.f64N/A
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
div-subN/A
lower--.f64N/A
Applied rewrites14.5%
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 rewrites14.4%
Taylor expanded in b around inf
lower-/.f64N/A
+-commutativeN/A
*-commutativeN/A
lower-fma.f64N/A
lower-/.f64N/A
*-commutativeN/A
lower-*.f64N/A
unpow2N/A
lower-*.f64N/A
unpow2N/A
lower-*.f64N/A
lower-*.f6497.4
Applied rewrites97.4%
Taylor expanded in c around 0
Applied rewrites97.4%
(FPCore (a b c) :precision binary64 (* (/ (fma (* -0.375 a) (/ c (* b b)) -0.5) b) c))
double code(double a, double b, double c) {
return (fma((-0.375 * a), (c / (b * b)), -0.5) / b) * c;
}
function code(a, b, c) return Float64(Float64(fma(Float64(-0.375 * a), Float64(c / Float64(b * b)), -0.5) / b) * c) end
code[a_, b_, c_] := N[(N[(N[(N[(-0.375 * a), $MachinePrecision] * N[(c / N[(b * b), $MachinePrecision]), $MachinePrecision] + -0.5), $MachinePrecision] / b), $MachinePrecision] * c), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(-0.375 \cdot a, \frac{c}{b \cdot b}, -0.5\right)}{b} \cdot c
\end{array}
Initial program 14.6%
Taylor expanded in a around 0
Applied rewrites98.7%
Taylor expanded in c around 0
*-commutativeN/A
associate-*r/N/A
associate-*r*N/A
associate-*l/N/A
associate-*r/N/A
lower-*.f64N/A
Applied rewrites97.0%
(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 14.6%
Taylor expanded in c around 0
*-commutativeN/A
lower-*.f64N/A
lower-/.f6492.9
Applied rewrites92.9%
Final simplification92.9%
(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 14.6%
Taylor expanded in c around 0
*-commutativeN/A
sub-negN/A
associate-*r/N/A
associate-*r*N/A
associate-*l/N/A
associate-*r/N/A
lower-*.f64N/A
Applied rewrites97.1%
Taylor expanded in c around 0
Applied rewrites92.6%
herbie shell --seed 2024235
(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)))