
(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 11 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
(/
(fma
(* (pow c 4.0) -1.0546875)
(* a a)
(* (* (fma -0.375 (* b b) (* (* c a) -0.5625)) (* c c)) (* b b)))
(pow b 7.0))
a
(* (/ c b) -0.5)))
double code(double a, double b, double c) {
return fma((fma((pow(c, 4.0) * -1.0546875), (a * a), ((fma(-0.375, (b * b), ((c * a) * -0.5625)) * (c * c)) * (b * b))) / pow(b, 7.0)), a, ((c / b) * -0.5));
}
function code(a, b, c) return fma(Float64(fma(Float64((c ^ 4.0) * -1.0546875), Float64(a * a), Float64(Float64(fma(-0.375, Float64(b * b), Float64(Float64(c * a) * -0.5625)) * Float64(c * c)) * Float64(b * b))) / (b ^ 7.0)), a, Float64(Float64(c / b) * -0.5)) end
code[a_, b_, c_] := N[(N[(N[(N[(N[Power[c, 4.0], $MachinePrecision] * -1.0546875), $MachinePrecision] * N[(a * a), $MachinePrecision] + N[(N[(N[(-0.375 * N[(b * b), $MachinePrecision] + N[(N[(c * a), $MachinePrecision] * -0.5625), $MachinePrecision]), $MachinePrecision] * N[(c * c), $MachinePrecision]), $MachinePrecision] * N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[Power[b, 7.0], $MachinePrecision]), $MachinePrecision] * a + N[(N[(c / b), $MachinePrecision] * -0.5), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(\frac{\mathsf{fma}\left({c}^{4} \cdot -1.0546875, a \cdot a, \left(\mathsf{fma}\left(-0.375, b \cdot b, \left(c \cdot a\right) \cdot -0.5625\right) \cdot \left(c \cdot c\right)\right) \cdot \left(b \cdot b\right)\right)}{{b}^{7}}, a, \frac{c}{b} \cdot -0.5\right)
\end{array}
Initial program 34.2%
Taylor expanded in a around 0
+-commutativeN/A
*-commutativeN/A
lower-fma.f64N/A
Applied rewrites94.3%
Taylor expanded in b around 0
Applied rewrites94.3%
Taylor expanded in c around 0
Applied rewrites94.3%
Final simplification94.3%
(FPCore (a b c)
:precision binary64
(fma
(/ c b)
-0.5
(*
(*
(fma
(* (* (fma (* b b) -0.375 (* (* c a) -0.5625)) c) c)
(* b b)
(* (* (* a a) -1.0546875) (pow c 4.0)))
(pow b -7.0))
a)))
double code(double a, double b, double c) {
return fma((c / b), -0.5, ((fma(((fma((b * b), -0.375, ((c * a) * -0.5625)) * c) * c), (b * b), (((a * a) * -1.0546875) * pow(c, 4.0))) * pow(b, -7.0)) * a));
}
function code(a, b, c) return fma(Float64(c / b), -0.5, Float64(Float64(fma(Float64(Float64(fma(Float64(b * b), -0.375, Float64(Float64(c * a) * -0.5625)) * c) * c), Float64(b * b), Float64(Float64(Float64(a * a) * -1.0546875) * (c ^ 4.0))) * (b ^ -7.0)) * a)) end
code[a_, b_, c_] := N[(N[(c / b), $MachinePrecision] * -0.5 + N[(N[(N[(N[(N[(N[(N[(b * b), $MachinePrecision] * -0.375 + N[(N[(c * a), $MachinePrecision] * -0.5625), $MachinePrecision]), $MachinePrecision] * c), $MachinePrecision] * c), $MachinePrecision] * N[(b * b), $MachinePrecision] + N[(N[(N[(a * a), $MachinePrecision] * -1.0546875), $MachinePrecision] * N[Power[c, 4.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[Power[b, -7.0], $MachinePrecision]), $MachinePrecision] * a), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(\frac{c}{b}, -0.5, \left(\mathsf{fma}\left(\left(\mathsf{fma}\left(b \cdot b, -0.375, \left(c \cdot a\right) \cdot -0.5625\right) \cdot c\right) \cdot c, b \cdot b, \left(\left(a \cdot a\right) \cdot -1.0546875\right) \cdot {c}^{4}\right) \cdot {b}^{-7}\right) \cdot a\right)
\end{array}
Initial program 34.2%
Taylor expanded in a around 0
+-commutativeN/A
*-commutativeN/A
lower-fma.f64N/A
Applied rewrites94.3%
Taylor expanded in b around 0
Applied rewrites94.3%
Taylor expanded in c around 0
Applied rewrites94.3%
Applied rewrites94.3%
Final simplification94.3%
(FPCore (a b c)
:precision binary64
(fma
(/ -0.5 b)
c
(*
(*
(fma
(* (* (fma (* b b) -0.375 (* (* c a) -0.5625)) c) c)
(* b b)
(* (* (* a a) -1.0546875) (pow c 4.0)))
(pow b -7.0))
a)))
double code(double a, double b, double c) {
return fma((-0.5 / b), c, ((fma(((fma((b * b), -0.375, ((c * a) * -0.5625)) * c) * c), (b * b), (((a * a) * -1.0546875) * pow(c, 4.0))) * pow(b, -7.0)) * a));
}
function code(a, b, c) return fma(Float64(-0.5 / b), c, Float64(Float64(fma(Float64(Float64(fma(Float64(b * b), -0.375, Float64(Float64(c * a) * -0.5625)) * c) * c), Float64(b * b), Float64(Float64(Float64(a * a) * -1.0546875) * (c ^ 4.0))) * (b ^ -7.0)) * a)) end
code[a_, b_, c_] := N[(N[(-0.5 / b), $MachinePrecision] * c + N[(N[(N[(N[(N[(N[(N[(b * b), $MachinePrecision] * -0.375 + N[(N[(c * a), $MachinePrecision] * -0.5625), $MachinePrecision]), $MachinePrecision] * c), $MachinePrecision] * c), $MachinePrecision] * N[(b * b), $MachinePrecision] + N[(N[(N[(a * a), $MachinePrecision] * -1.0546875), $MachinePrecision] * N[Power[c, 4.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[Power[b, -7.0], $MachinePrecision]), $MachinePrecision] * a), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(\frac{-0.5}{b}, c, \left(\mathsf{fma}\left(\left(\mathsf{fma}\left(b \cdot b, -0.375, \left(c \cdot a\right) \cdot -0.5625\right) \cdot c\right) \cdot c, b \cdot b, \left(\left(a \cdot a\right) \cdot -1.0546875\right) \cdot {c}^{4}\right) \cdot {b}^{-7}\right) \cdot a\right)
\end{array}
Initial program 34.2%
Taylor expanded in a around 0
+-commutativeN/A
*-commutativeN/A
lower-fma.f64N/A
Applied rewrites94.3%
Taylor expanded in b around 0
Applied rewrites94.3%
Taylor expanded in c around 0
Applied rewrites94.3%
Applied rewrites94.0%
Final simplification94.0%
(FPCore (a b c) :precision binary64 (fma (* (fma (* -0.5625 a) (/ c (pow b 5.0)) (/ -0.375 (pow b 3.0))) (* c c)) a (* (/ c b) -0.5)))
double code(double a, double b, double c) {
return fma((fma((-0.5625 * a), (c / pow(b, 5.0)), (-0.375 / pow(b, 3.0))) * (c * c)), a, ((c / b) * -0.5));
}
function code(a, b, c) return fma(Float64(fma(Float64(-0.5625 * a), Float64(c / (b ^ 5.0)), Float64(-0.375 / (b ^ 3.0))) * Float64(c * c)), a, Float64(Float64(c / b) * -0.5)) end
code[a_, b_, c_] := N[(N[(N[(N[(-0.5625 * a), $MachinePrecision] * N[(c / N[Power[b, 5.0], $MachinePrecision]), $MachinePrecision] + N[(-0.375 / N[Power[b, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[(c * c), $MachinePrecision]), $MachinePrecision] * a + N[(N[(c / b), $MachinePrecision] * -0.5), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(\mathsf{fma}\left(-0.5625 \cdot a, \frac{c}{{b}^{5}}, \frac{-0.375}{{b}^{3}}\right) \cdot \left(c \cdot c\right), a, \frac{c}{b} \cdot -0.5\right)
\end{array}
Initial program 34.2%
Taylor expanded in a around 0
+-commutativeN/A
*-commutativeN/A
lower-fma.f64N/A
Applied rewrites94.3%
Taylor expanded in c around 0
Applied rewrites92.6%
Final simplification92.6%
(FPCore (a b c) :precision binary64 (/ (fma (/ (* (* (pow c 3.0) a) a) (* b b)) (/ -0.5625 (* b b)) (fma -0.5 c (* (/ a b) (* (* (/ c b) c) -0.375)))) b))
double code(double a, double b, double c) {
return fma((((pow(c, 3.0) * a) * a) / (b * b)), (-0.5625 / (b * b)), fma(-0.5, c, ((a / b) * (((c / b) * c) * -0.375)))) / b;
}
function code(a, b, c) return Float64(fma(Float64(Float64(Float64((c ^ 3.0) * a) * a) / Float64(b * b)), Float64(-0.5625 / Float64(b * b)), fma(-0.5, c, Float64(Float64(a / b) * Float64(Float64(Float64(c / b) * c) * -0.375)))) / b) end
code[a_, b_, c_] := N[(N[(N[(N[(N[(N[Power[c, 3.0], $MachinePrecision] * a), $MachinePrecision] * a), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision] * N[(-0.5625 / N[(b * b), $MachinePrecision]), $MachinePrecision] + N[(-0.5 * c + N[(N[(a / b), $MachinePrecision] * N[(N[(N[(c / b), $MachinePrecision] * c), $MachinePrecision] * -0.375), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\frac{\left({c}^{3} \cdot a\right) \cdot a}{b \cdot b}, \frac{-0.5625}{b \cdot b}, \mathsf{fma}\left(-0.5, c, \frac{a}{b} \cdot \left(\left(\frac{c}{b} \cdot c\right) \cdot -0.375\right)\right)\right)}{b}
\end{array}
Initial program 34.2%
Taylor expanded in b around inf
lower-/.f64N/A
Applied rewrites92.5%
Applied rewrites92.5%
Final simplification92.5%
(FPCore (a b c) :precision binary64 (/ (fma (/ (* -0.375 a) b) (/ (* c c) b) (* (fma (* (* -0.5625 a) a) (/ (* c c) (pow b 4.0)) -0.5) c)) b))
double code(double a, double b, double c) {
return fma(((-0.375 * a) / b), ((c * c) / b), (fma(((-0.5625 * a) * a), ((c * c) / pow(b, 4.0)), -0.5) * c)) / b;
}
function code(a, b, c) return Float64(fma(Float64(Float64(-0.375 * a) / b), Float64(Float64(c * c) / b), Float64(fma(Float64(Float64(-0.5625 * a) * a), Float64(Float64(c * c) / (b ^ 4.0)), -0.5) * c)) / b) end
code[a_, b_, c_] := N[(N[(N[(N[(-0.375 * a), $MachinePrecision] / b), $MachinePrecision] * N[(N[(c * c), $MachinePrecision] / b), $MachinePrecision] + N[(N[(N[(N[(-0.5625 * a), $MachinePrecision] * a), $MachinePrecision] * N[(N[(c * c), $MachinePrecision] / N[Power[b, 4.0], $MachinePrecision]), $MachinePrecision] + -0.5), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\frac{-0.375 \cdot a}{b}, \frac{c \cdot c}{b}, \mathsf{fma}\left(\left(-0.5625 \cdot a\right) \cdot a, \frac{c \cdot c}{{b}^{4}}, -0.5\right) \cdot c\right)}{b}
\end{array}
Initial program 34.2%
Taylor expanded in b around inf
lower-/.f64N/A
Applied rewrites92.5%
Taylor expanded in c around 0
Applied rewrites92.5%
(FPCore (a b c)
:precision binary64
(/
(*
(fma
(fma (/ -0.375 b) (/ a b) (* (/ c (pow b 4.0)) (* (* -0.5625 a) a)))
c
-0.5)
c)
b))
double code(double a, double b, double c) {
return (fma(fma((-0.375 / b), (a / b), ((c / pow(b, 4.0)) * ((-0.5625 * a) * a))), c, -0.5) * c) / b;
}
function code(a, b, c) return Float64(Float64(fma(fma(Float64(-0.375 / b), Float64(a / b), Float64(Float64(c / (b ^ 4.0)) * Float64(Float64(-0.5625 * a) * a))), c, -0.5) * c) / b) end
code[a_, b_, c_] := N[(N[(N[(N[(N[(-0.375 / b), $MachinePrecision] * N[(a / b), $MachinePrecision] + N[(N[(c / N[Power[b, 4.0], $MachinePrecision]), $MachinePrecision] * N[(N[(-0.5625 * a), $MachinePrecision] * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * c + -0.5), $MachinePrecision] * c), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\mathsf{fma}\left(\frac{-0.375}{b}, \frac{a}{b}, \frac{c}{{b}^{4}} \cdot \left(\left(-0.5625 \cdot a\right) \cdot a\right)\right), c, -0.5\right) \cdot c}{b}
\end{array}
Initial program 34.2%
Taylor expanded in b around inf
lower-/.f64N/A
Applied rewrites92.5%
Taylor expanded in c around 0
Applied rewrites92.5%
Final simplification92.5%
(FPCore (a b c) :precision binary64 (fma (* -0.375 a) (/ (/ (* c c) (* b b)) b) (* (/ c b) -0.5)))
double code(double a, double b, double c) {
return fma((-0.375 * a), (((c * c) / (b * b)) / b), ((c / b) * -0.5));
}
function code(a, b, c) return fma(Float64(-0.375 * a), Float64(Float64(Float64(c * c) / Float64(b * b)) / b), Float64(Float64(c / b) * -0.5)) end
code[a_, b_, c_] := N[(N[(-0.375 * a), $MachinePrecision] * N[(N[(N[(c * c), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision] + N[(N[(c / b), $MachinePrecision] * -0.5), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(-0.375 \cdot a, \frac{\frac{c \cdot c}{b \cdot b}}{b}, \frac{c}{b} \cdot -0.5\right)
\end{array}
Initial program 34.2%
Taylor expanded in a around 0
+-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
lower-pow.f64N/A
lower-*.f64N/A
lower-/.f6489.0
Applied rewrites89.0%
Applied rewrites89.0%
Final simplification89.0%
(FPCore (a b c) :precision binary64 (/ (fma (/ (* -0.375 a) b) (/ (* c c) b) (* -0.5 c)) b))
double code(double a, double b, double c) {
return fma(((-0.375 * a) / b), ((c * c) / b), (-0.5 * c)) / b;
}
function code(a, b, c) return Float64(fma(Float64(Float64(-0.375 * a) / b), Float64(Float64(c * c) / b), Float64(-0.5 * c)) / b) end
code[a_, b_, c_] := N[(N[(N[(N[(-0.375 * a), $MachinePrecision] / b), $MachinePrecision] * N[(N[(c * c), $MachinePrecision] / b), $MachinePrecision] + N[(-0.5 * c), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\frac{-0.375 \cdot a}{b}, \frac{c \cdot c}{b}, -0.5 \cdot c\right)}{b}
\end{array}
Initial program 34.2%
Taylor expanded in b around inf
lower-/.f64N/A
+-commutativeN/A
associate-*r/N/A
unpow2N/A
associate-*r*N/A
times-fracN/A
lower-fma.f64N/A
lower-/.f64N/A
lower-*.f64N/A
lower-/.f64N/A
unpow2N/A
lower-*.f64N/A
lower-*.f6489.0
Applied rewrites89.0%
(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 34.2%
Taylor expanded in b around inf
lower-/.f64N/A
Applied rewrites92.5%
Taylor expanded in c around 0
Applied rewrites88.9%
(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 34.2%
Taylor expanded in a around 0
lower-*.f64N/A
lower-/.f6479.1
Applied rewrites79.1%
Final simplification79.1%
herbie shell --seed 2024327
(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)))