
(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 9 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
(* (* a a) -0.5625)
(/ (pow c 3.0) (pow b 4.0))
(fma
(/ -0.16666666666666666 a)
(* (/ 6.328125 (pow b 6.0)) (* (pow a 4.0) (pow c 4.0)))
(fma (/ (* -0.375 (* c c)) b) (/ a b) (* -0.5 c))))
b))
double code(double a, double b, double c) {
return fma(((a * a) * -0.5625), (pow(c, 3.0) / pow(b, 4.0)), fma((-0.16666666666666666 / a), ((6.328125 / pow(b, 6.0)) * (pow(a, 4.0) * pow(c, 4.0))), fma(((-0.375 * (c * c)) / b), (a / b), (-0.5 * c)))) / b;
}
function code(a, b, c) return Float64(fma(Float64(Float64(a * a) * -0.5625), Float64((c ^ 3.0) / (b ^ 4.0)), fma(Float64(-0.16666666666666666 / a), Float64(Float64(6.328125 / (b ^ 6.0)) * Float64((a ^ 4.0) * (c ^ 4.0))), fma(Float64(Float64(-0.375 * Float64(c * c)) / b), Float64(a / b), Float64(-0.5 * c)))) / b) end
code[a_, b_, c_] := N[(N[(N[(N[(a * a), $MachinePrecision] * -0.5625), $MachinePrecision] * N[(N[Power[c, 3.0], $MachinePrecision] / N[Power[b, 4.0], $MachinePrecision]), $MachinePrecision] + N[(N[(-0.16666666666666666 / a), $MachinePrecision] * N[(N[(6.328125 / N[Power[b, 6.0], $MachinePrecision]), $MachinePrecision] * N[(N[Power[a, 4.0], $MachinePrecision] * N[Power[c, 4.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(N[(N[(-0.375 * N[(c * c), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision] * N[(a / b), $MachinePrecision] + N[(-0.5 * c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\left(a \cdot a\right) \cdot -0.5625, \frac{{c}^{3}}{{b}^{4}}, \mathsf{fma}\left(\frac{-0.16666666666666666}{a}, \frac{6.328125}{{b}^{6}} \cdot \left({a}^{4} \cdot {c}^{4}\right), \mathsf{fma}\left(\frac{-0.375 \cdot \left(c \cdot c\right)}{b}, \frac{a}{b}, -0.5 \cdot c\right)\right)\right)}{b}
\end{array}
Initial program 19.1%
Taylor expanded in b around inf
Applied rewrites98.3%
Final simplification98.3%
(FPCore (a b c)
:precision binary64
(fma
(fma
(fma
(* -0.16666666666666666 a)
(* (/ 6.328125 b) (/ (pow c 4.0) (pow b 6.0)))
(/ (* (pow c 3.0) -0.5625) (pow b 5.0)))
a
(/ (* -0.375 (* c c)) (pow b 3.0)))
a
(* (/ c b) -0.5)))
double code(double a, double b, double c) {
return fma(fma(fma((-0.16666666666666666 * a), ((6.328125 / b) * (pow(c, 4.0) / pow(b, 6.0))), ((pow(c, 3.0) * -0.5625) / pow(b, 5.0))), a, ((-0.375 * (c * c)) / pow(b, 3.0))), a, ((c / b) * -0.5));
}
function code(a, b, c) return fma(fma(fma(Float64(-0.16666666666666666 * a), Float64(Float64(6.328125 / b) * Float64((c ^ 4.0) / (b ^ 6.0))), Float64(Float64((c ^ 3.0) * -0.5625) / (b ^ 5.0))), a, Float64(Float64(-0.375 * Float64(c * c)) / (b ^ 3.0))), a, Float64(Float64(c / b) * -0.5)) end
code[a_, b_, c_] := N[(N[(N[(N[(-0.16666666666666666 * a), $MachinePrecision] * N[(N[(6.328125 / b), $MachinePrecision] * N[(N[Power[c, 4.0], $MachinePrecision] / N[Power[b, 6.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(N[(N[Power[c, 3.0], $MachinePrecision] * -0.5625), $MachinePrecision] / N[Power[b, 5.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * a + N[(N[(-0.375 * N[(c * c), $MachinePrecision]), $MachinePrecision] / N[Power[b, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * a + N[(N[(c / b), $MachinePrecision] * -0.5), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(-0.16666666666666666 \cdot a, \frac{6.328125}{b} \cdot \frac{{c}^{4}}{{b}^{6}}, \frac{{c}^{3} \cdot -0.5625}{{b}^{5}}\right), a, \frac{-0.375 \cdot \left(c \cdot c\right)}{{b}^{3}}\right), a, \frac{c}{b} \cdot -0.5\right)
\end{array}
Initial program 19.1%
Taylor expanded in a around 0
+-commutativeN/A
*-commutativeN/A
lower-fma.f64N/A
Applied rewrites98.3%
Final simplification98.3%
(FPCore (a b c)
:precision binary64
(/
(*
(fma
(fma
(/ (* (fma (* c a) -1.0546875 (* (* b b) -0.5625)) (* a a)) (pow b 6.0))
c
(* (/ a (* b b)) -0.375))
c
-0.5)
c)
b))
double code(double a, double b, double c) {
return (fma(fma(((fma((c * a), -1.0546875, ((b * b) * -0.5625)) * (a * a)) / pow(b, 6.0)), c, ((a / (b * b)) * -0.375)), c, -0.5) * c) / b;
}
function code(a, b, c) return Float64(Float64(fma(fma(Float64(Float64(fma(Float64(c * a), -1.0546875, Float64(Float64(b * b) * -0.5625)) * Float64(a * a)) / (b ^ 6.0)), c, Float64(Float64(a / Float64(b * b)) * -0.375)), c, -0.5) * c) / b) end
code[a_, b_, c_] := N[(N[(N[(N[(N[(N[(N[(N[(c * a), $MachinePrecision] * -1.0546875 + N[(N[(b * b), $MachinePrecision] * -0.5625), $MachinePrecision]), $MachinePrecision] * N[(a * a), $MachinePrecision]), $MachinePrecision] / N[Power[b, 6.0], $MachinePrecision]), $MachinePrecision] * c + N[(N[(a / N[(b * b), $MachinePrecision]), $MachinePrecision] * -0.375), $MachinePrecision]), $MachinePrecision] * c + -0.5), $MachinePrecision] * c), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\mathsf{fma}\left(\frac{\mathsf{fma}\left(c \cdot a, -1.0546875, \left(b \cdot b\right) \cdot -0.5625\right) \cdot \left(a \cdot a\right)}{{b}^{6}}, c, \frac{a}{b \cdot b} \cdot -0.375\right), c, -0.5\right) \cdot c}{b}
\end{array}
Initial program 19.1%
Taylor expanded in b around inf
Applied rewrites98.3%
Taylor expanded in c around 0
Applied rewrites98.2%
Taylor expanded in b around 0
Applied rewrites98.2%
Taylor expanded in a around 0
Applied rewrites98.2%
(FPCore (a b c) :precision binary64 (/ (fma (/ (* -0.375 (* c c)) b) (/ a b) (* (fma (/ (* (* c c) (* a a)) (pow b 4.0)) -0.5625 -0.5) c)) b))
double code(double a, double b, double c) {
return fma(((-0.375 * (c * c)) / b), (a / b), (fma((((c * c) * (a * a)) / pow(b, 4.0)), -0.5625, -0.5) * c)) / b;
}
function code(a, b, c) return Float64(fma(Float64(Float64(-0.375 * Float64(c * c)) / b), Float64(a / b), Float64(fma(Float64(Float64(Float64(c * c) * Float64(a * a)) / (b ^ 4.0)), -0.5625, -0.5) * c)) / b) end
code[a_, b_, c_] := N[(N[(N[(N[(-0.375 * N[(c * c), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision] * N[(a / b), $MachinePrecision] + N[(N[(N[(N[(N[(c * c), $MachinePrecision] * N[(a * a), $MachinePrecision]), $MachinePrecision] / N[Power[b, 4.0], $MachinePrecision]), $MachinePrecision] * -0.5625 + -0.5), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\frac{-0.375 \cdot \left(c \cdot c\right)}{b}, \frac{a}{b}, \mathsf{fma}\left(\frac{\left(c \cdot c\right) \cdot \left(a \cdot a\right)}{{b}^{4}}, -0.5625, -0.5\right) \cdot c\right)}{b}
\end{array}
Initial program 19.1%
Taylor expanded in b around inf
lower-/.f64N/A
Applied rewrites97.6%
Taylor expanded in c around 0
Applied rewrites97.6%
Final simplification97.6%
(FPCore (a b c)
:precision binary64
(/
(*
(fma
(/ (fma (/ (* (* a a) -0.5625) b) (/ c b) (* -0.375 a)) (* b b))
c
-0.5)
c)
b))
double code(double a, double b, double c) {
return (fma((fma((((a * a) * -0.5625) / b), (c / b), (-0.375 * a)) / (b * b)), c, -0.5) * c) / b;
}
function code(a, b, c) return Float64(Float64(fma(Float64(fma(Float64(Float64(Float64(a * a) * -0.5625) / b), Float64(c / b), Float64(-0.375 * a)) / Float64(b * b)), c, -0.5) * c) / b) end
code[a_, b_, c_] := N[(N[(N[(N[(N[(N[(N[(N[(a * a), $MachinePrecision] * -0.5625), $MachinePrecision] / b), $MachinePrecision] * N[(c / b), $MachinePrecision] + N[(-0.375 * a), $MachinePrecision]), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision] * c + -0.5), $MachinePrecision] * c), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\frac{\mathsf{fma}\left(\frac{\left(a \cdot a\right) \cdot -0.5625}{b}, \frac{c}{b}, -0.375 \cdot a\right)}{b \cdot b}, c, -0.5\right) \cdot c}{b}
\end{array}
Initial program 19.1%
Taylor expanded in b around inf
lower-/.f64N/A
Applied rewrites97.6%
Taylor expanded in c around 0
Applied rewrites97.5%
Taylor expanded in b around inf
Applied rewrites97.5%
(FPCore (a b c) :precision binary64 (/ (fma (/ (* -0.375 (* c c)) b) (/ a b) (* -0.5 c)) b))
double code(double a, double b, double c) {
return fma(((-0.375 * (c * c)) / b), (a / b), (-0.5 * c)) / b;
}
function code(a, b, c) return Float64(fma(Float64(Float64(-0.375 * Float64(c * c)) / b), Float64(a / b), Float64(-0.5 * c)) / b) end
code[a_, b_, c_] := N[(N[(N[(N[(-0.375 * N[(c * c), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision] * N[(a / b), $MachinePrecision] + N[(-0.5 * c), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\frac{-0.375 \cdot \left(c \cdot c\right)}{b}, \frac{a}{b}, -0.5 \cdot c\right)}{b}
\end{array}
Initial program 19.1%
Taylor expanded in b around inf
lower-/.f64N/A
+-commutativeN/A
associate-*r/N/A
unpow2N/A
*-commutativeN/A
associate-*r*N/A
times-fracN/A
lower-fma.f64N/A
lower-/.f64N/A
*-commutativeN/A
lower-*.f64N/A
unpow2N/A
lower-*.f64N/A
lower-/.f64N/A
lower-*.f6496.0
Applied rewrites96.0%
Final simplification96.0%
(FPCore (a b c) :precision binary64 (/ (* (fma (* (/ a (* b b)) -0.375) c -0.5) c) b))
double code(double a, double b, double c) {
return (fma(((a / (b * b)) * -0.375), c, -0.5) * c) / b;
}
function code(a, b, c) return Float64(Float64(fma(Float64(Float64(a / Float64(b * b)) * -0.375), c, -0.5) * c) / b) end
code[a_, b_, c_] := N[(N[(N[(N[(N[(a / N[(b * b), $MachinePrecision]), $MachinePrecision] * -0.375), $MachinePrecision] * c + -0.5), $MachinePrecision] * c), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\frac{a}{b \cdot b} \cdot -0.375, c, -0.5\right) \cdot c}{b}
\end{array}
Initial program 19.1%
Taylor expanded in b around inf
lower-/.f64N/A
Applied rewrites97.6%
Taylor expanded in c around 0
Applied rewrites97.5%
Taylor expanded in c around 0
Applied rewrites96.0%
(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 19.1%
Taylor expanded in c around 0
*-commutativeN/A
lower-*.f64N/A
lower-/.f6489.9
Applied rewrites89.9%
(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 19.1%
Taylor expanded in c around 0
*-commutativeN/A
lower-*.f64N/A
lower-/.f6489.9
Applied rewrites89.9%
Applied rewrites89.6%
Final simplification89.6%
herbie shell --seed 2024276
(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)))