
(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
(fma
a
(fma
(/ (* (/ (pow c 4.0) (pow b 6.0)) (* a 6.328125)) b)
-0.16666666666666666
(/ (* (* c (* c c)) -0.5625) (pow b 5.0)))
(/ (* (* c c) -0.375) (* b (* b b))))
(* -0.5 (/ c b))))
double code(double a, double b, double c) {
return fma(a, fma(a, fma((((pow(c, 4.0) / pow(b, 6.0)) * (a * 6.328125)) / b), -0.16666666666666666, (((c * (c * c)) * -0.5625) / pow(b, 5.0))), (((c * c) * -0.375) / (b * (b * b)))), (-0.5 * (c / b)));
}
function code(a, b, c) return fma(a, fma(a, fma(Float64(Float64(Float64((c ^ 4.0) / (b ^ 6.0)) * Float64(a * 6.328125)) / b), -0.16666666666666666, Float64(Float64(Float64(c * Float64(c * c)) * -0.5625) / (b ^ 5.0))), Float64(Float64(Float64(c * c) * -0.375) / Float64(b * Float64(b * b)))), Float64(-0.5 * Float64(c / b))) end
code[a_, b_, c_] := N[(a * N[(a * N[(N[(N[(N[(N[Power[c, 4.0], $MachinePrecision] / N[Power[b, 6.0], $MachinePrecision]), $MachinePrecision] * N[(a * 6.328125), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision] * -0.16666666666666666 + N[(N[(N[(c * N[(c * c), $MachinePrecision]), $MachinePrecision] * -0.5625), $MachinePrecision] / N[Power[b, 5.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(N[(N[(c * c), $MachinePrecision] * -0.375), $MachinePrecision] / N[(b * N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(-0.5 * N[(c / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(a, \mathsf{fma}\left(a, \mathsf{fma}\left(\frac{\frac{{c}^{4}}{{b}^{6}} \cdot \left(a \cdot 6.328125\right)}{b}, -0.16666666666666666, \frac{\left(c \cdot \left(c \cdot c\right)\right) \cdot -0.5625}{{b}^{5}}\right), \frac{\left(c \cdot c\right) \cdot -0.375}{b \cdot \left(b \cdot b\right)}\right), -0.5 \cdot \frac{c}{b}\right)
\end{array}
Initial program 15.6%
Taylor expanded in a around 0
Applied rewrites97.2%
Final simplification97.2%
(FPCore (a b c)
:precision binary64
(let* ((t_0 (* b (* b b))))
(fma
a
(fma
(fma
c
(* (* c c) (/ -0.5625 (* (* b b) t_0)))
(*
-0.16666666666666666
(/ (* (* a 6.328125) (* c (* c (* c c)))) (* b (* (* b b) (* b t_0))))))
a
(/ (* (* c c) -0.375) t_0))
(* -0.5 (/ c b)))))
double code(double a, double b, double c) {
double t_0 = b * (b * b);
return fma(a, fma(fma(c, ((c * c) * (-0.5625 / ((b * b) * t_0))), (-0.16666666666666666 * (((a * 6.328125) * (c * (c * (c * c)))) / (b * ((b * b) * (b * t_0)))))), a, (((c * c) * -0.375) / t_0)), (-0.5 * (c / b)));
}
function code(a, b, c) t_0 = Float64(b * Float64(b * b)) return fma(a, fma(fma(c, Float64(Float64(c * c) * Float64(-0.5625 / Float64(Float64(b * b) * t_0))), Float64(-0.16666666666666666 * Float64(Float64(Float64(a * 6.328125) * Float64(c * Float64(c * Float64(c * c)))) / Float64(b * Float64(Float64(b * b) * Float64(b * t_0)))))), a, Float64(Float64(Float64(c * c) * -0.375) / t_0)), Float64(-0.5 * Float64(c / b))) end
code[a_, b_, c_] := Block[{t$95$0 = N[(b * N[(b * b), $MachinePrecision]), $MachinePrecision]}, N[(a * N[(N[(c * N[(N[(c * c), $MachinePrecision] * N[(-0.5625 / N[(N[(b * b), $MachinePrecision] * t$95$0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(-0.16666666666666666 * N[(N[(N[(a * 6.328125), $MachinePrecision] * N[(c * N[(c * N[(c * c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(b * N[(N[(b * b), $MachinePrecision] * N[(b * t$95$0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * a + N[(N[(N[(c * c), $MachinePrecision] * -0.375), $MachinePrecision] / t$95$0), $MachinePrecision]), $MachinePrecision] + N[(-0.5 * N[(c / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := b \cdot \left(b \cdot b\right)\\
\mathsf{fma}\left(a, \mathsf{fma}\left(\mathsf{fma}\left(c, \left(c \cdot c\right) \cdot \frac{-0.5625}{\left(b \cdot b\right) \cdot t\_0}, -0.16666666666666666 \cdot \frac{\left(a \cdot 6.328125\right) \cdot \left(c \cdot \left(c \cdot \left(c \cdot c\right)\right)\right)}{b \cdot \left(\left(b \cdot b\right) \cdot \left(b \cdot t\_0\right)\right)}\right), a, \frac{\left(c \cdot c\right) \cdot -0.375}{t\_0}\right), -0.5 \cdot \frac{c}{b}\right)
\end{array}
\end{array}
Initial program 15.6%
Taylor expanded in a around 0
Applied rewrites97.2%
Applied rewrites97.2%
Final simplification97.2%
(FPCore (a b c)
:precision binary64
(let* ((t_0 (* (* b b) (* b b))) (t_1 (* c (* c c))))
(/
(+
(fma
(* (* c t_1) -1.0546875)
(/ (* a (* a a)) (* (* b b) t_0))
(fma
-0.375
(/ (* c (* a c)) (* b b))
(/ (* (* a a) (* t_1 -0.5625)) t_0)))
(* c -0.5))
b)))
double code(double a, double b, double c) {
double t_0 = (b * b) * (b * b);
double t_1 = c * (c * c);
return (fma(((c * t_1) * -1.0546875), ((a * (a * a)) / ((b * b) * t_0)), fma(-0.375, ((c * (a * c)) / (b * b)), (((a * a) * (t_1 * -0.5625)) / t_0))) + (c * -0.5)) / b;
}
function code(a, b, c) t_0 = Float64(Float64(b * b) * Float64(b * b)) t_1 = Float64(c * Float64(c * c)) return Float64(Float64(fma(Float64(Float64(c * t_1) * -1.0546875), Float64(Float64(a * Float64(a * a)) / Float64(Float64(b * b) * t_0)), fma(-0.375, Float64(Float64(c * Float64(a * c)) / Float64(b * b)), Float64(Float64(Float64(a * a) * Float64(t_1 * -0.5625)) / t_0))) + Float64(c * -0.5)) / b) end
code[a_, b_, c_] := Block[{t$95$0 = N[(N[(b * b), $MachinePrecision] * N[(b * b), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[(c * N[(c * c), $MachinePrecision]), $MachinePrecision]}, N[(N[(N[(N[(N[(c * t$95$1), $MachinePrecision] * -1.0546875), $MachinePrecision] * N[(N[(a * N[(a * a), $MachinePrecision]), $MachinePrecision] / N[(N[(b * b), $MachinePrecision] * t$95$0), $MachinePrecision]), $MachinePrecision] + N[(-0.375 * N[(N[(c * N[(a * c), $MachinePrecision]), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision] + N[(N[(N[(a * a), $MachinePrecision] * N[(t$95$1 * -0.5625), $MachinePrecision]), $MachinePrecision] / t$95$0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(c * -0.5), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \left(b \cdot b\right) \cdot \left(b \cdot b\right)\\
t_1 := c \cdot \left(c \cdot c\right)\\
\frac{\mathsf{fma}\left(\left(c \cdot t\_1\right) \cdot -1.0546875, \frac{a \cdot \left(a \cdot a\right)}{\left(b \cdot b\right) \cdot t\_0}, \mathsf{fma}\left(-0.375, \frac{c \cdot \left(a \cdot c\right)}{b \cdot b}, \frac{\left(a \cdot a\right) \cdot \left(t\_1 \cdot -0.5625\right)}{t\_0}\right)\right) + c \cdot -0.5}{b}
\end{array}
\end{array}
Initial program 15.6%
Taylor expanded in a around 0
Applied rewrites97.2%
Applied rewrites97.2%
Taylor expanded in b around inf
Applied rewrites97.2%
Applied rewrites97.2%
Final simplification97.2%
(FPCore (a b c)
:precision binary64
(let* ((t_0 (* (* b b) (* b b))) (t_1 (* c (* c c))))
(/
(fma
(* (* c t_1) (/ (* a (* a a)) (* (* b b) t_0)))
-1.0546875
(fma
(* t_1 -0.5625)
(/ (* a a) t_0)
(fma (* c (* a c)) (/ -0.375 (* b b)) (* c -0.5))))
b)))
double code(double a, double b, double c) {
double t_0 = (b * b) * (b * b);
double t_1 = c * (c * c);
return fma(((c * t_1) * ((a * (a * a)) / ((b * b) * t_0))), -1.0546875, fma((t_1 * -0.5625), ((a * a) / t_0), fma((c * (a * c)), (-0.375 / (b * b)), (c * -0.5)))) / b;
}
function code(a, b, c) t_0 = Float64(Float64(b * b) * Float64(b * b)) t_1 = Float64(c * Float64(c * c)) return Float64(fma(Float64(Float64(c * t_1) * Float64(Float64(a * Float64(a * a)) / Float64(Float64(b * b) * t_0))), -1.0546875, fma(Float64(t_1 * -0.5625), Float64(Float64(a * a) / t_0), fma(Float64(c * Float64(a * c)), Float64(-0.375 / Float64(b * b)), Float64(c * -0.5)))) / b) end
code[a_, b_, c_] := Block[{t$95$0 = N[(N[(b * b), $MachinePrecision] * N[(b * b), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[(c * N[(c * c), $MachinePrecision]), $MachinePrecision]}, N[(N[(N[(N[(c * t$95$1), $MachinePrecision] * N[(N[(a * N[(a * a), $MachinePrecision]), $MachinePrecision] / N[(N[(b * b), $MachinePrecision] * t$95$0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * -1.0546875 + N[(N[(t$95$1 * -0.5625), $MachinePrecision] * N[(N[(a * a), $MachinePrecision] / t$95$0), $MachinePrecision] + N[(N[(c * N[(a * c), $MachinePrecision]), $MachinePrecision] * N[(-0.375 / N[(b * b), $MachinePrecision]), $MachinePrecision] + N[(c * -0.5), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \left(b \cdot b\right) \cdot \left(b \cdot b\right)\\
t_1 := c \cdot \left(c \cdot c\right)\\
\frac{\mathsf{fma}\left(\left(c \cdot t\_1\right) \cdot \frac{a \cdot \left(a \cdot a\right)}{\left(b \cdot b\right) \cdot t\_0}, -1.0546875, \mathsf{fma}\left(t\_1 \cdot -0.5625, \frac{a \cdot a}{t\_0}, \mathsf{fma}\left(c \cdot \left(a \cdot c\right), \frac{-0.375}{b \cdot b}, c \cdot -0.5\right)\right)\right)}{b}
\end{array}
\end{array}
Initial program 15.6%
Taylor expanded in a around 0
Applied rewrites97.2%
Applied rewrites97.2%
Taylor expanded in b around inf
Applied rewrites97.2%
Applied rewrites97.2%
Final simplification97.2%
(FPCore (a b c) :precision binary64 (fma a (/ (fma -0.375 (* c c) (/ (* (* c (* c c)) (* a -0.5625)) (* b b))) (* b (* b b))) (* -0.5 (/ c b))))
double code(double a, double b, double c) {
return fma(a, (fma(-0.375, (c * c), (((c * (c * c)) * (a * -0.5625)) / (b * b))) / (b * (b * b))), (-0.5 * (c / b)));
}
function code(a, b, c) return fma(a, Float64(fma(-0.375, Float64(c * c), Float64(Float64(Float64(c * Float64(c * c)) * Float64(a * -0.5625)) / Float64(b * b))) / Float64(b * Float64(b * b))), Float64(-0.5 * Float64(c / b))) end
code[a_, b_, c_] := N[(a * N[(N[(-0.375 * N[(c * c), $MachinePrecision] + N[(N[(N[(c * N[(c * c), $MachinePrecision]), $MachinePrecision] * N[(a * -0.5625), $MachinePrecision]), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(b * N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(-0.5 * N[(c / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(a, \frac{\mathsf{fma}\left(-0.375, c \cdot c, \frac{\left(c \cdot \left(c \cdot c\right)\right) \cdot \left(a \cdot -0.5625\right)}{b \cdot b}\right)}{b \cdot \left(b \cdot b\right)}, -0.5 \cdot \frac{c}{b}\right)
\end{array}
Initial program 15.6%
Taylor expanded in a around 0
Applied rewrites97.2%
Taylor expanded in b around inf
Applied rewrites96.4%
Final simplification96.4%
(FPCore (a b c) :precision binary64 (/ (fma a (/ (* (* c c) -0.375) (* b b)) (* c -0.5)) b))
double code(double a, double b, double c) {
return fma(a, (((c * c) * -0.375) / (b * b)), (c * -0.5)) / b;
}
function code(a, b, c) return Float64(fma(a, Float64(Float64(Float64(c * c) * -0.375) / Float64(b * b)), Float64(c * -0.5)) / b) end
code[a_, b_, c_] := N[(N[(a * N[(N[(N[(c * c), $MachinePrecision] * -0.375), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision] + N[(c * -0.5), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(a, \frac{\left(c \cdot c\right) \cdot -0.375}{b \cdot b}, c \cdot -0.5\right)}{b}
\end{array}
Initial program 15.6%
Taylor expanded in b around inf
lower-/.f64N/A
Applied rewrites94.8%
(FPCore (a b c) :precision binary64 (/ (* c (fma -0.375 (/ (* a c) (* b b)) -0.5)) b))
double code(double a, double b, double c) {
return (c * fma(-0.375, ((a * c) / (b * b)), -0.5)) / b;
}
function code(a, b, c) return Float64(Float64(c * fma(-0.375, Float64(Float64(a * c) / Float64(b * b)), -0.5)) / b) end
code[a_, b_, c_] := N[(N[(c * N[(-0.375 * N[(N[(a * c), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision] + -0.5), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{c \cdot \mathsf{fma}\left(-0.375, \frac{a \cdot c}{b \cdot b}, -0.5\right)}{b}
\end{array}
Initial program 15.6%
Taylor expanded in a around 0
Applied rewrites97.2%
Applied rewrites97.2%
Taylor expanded in b around inf
Applied rewrites97.2%
Taylor expanded in c around 0
Applied rewrites94.8%
Final simplification94.8%
(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 15.6%
Taylor expanded in b around inf
lower-*.f64N/A
lower-/.f6491.6
Applied rewrites91.6%
(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 15.6%
lift-/.f64N/A
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
div-subN/A
lower--.f64N/A
Applied rewrites15.4%
lift--.f64N/A
lift-/.f64N/A
lift-/.f64N/A
frac-subN/A
lower-/.f64N/A
Applied rewrites17.1%
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%
Taylor expanded in a around 0
Applied rewrites3.3%
herbie shell --seed 2024226
(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)))