
(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 5 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 (/ (- c) (+ (sqrt (fma b b (* (* c -3.0) a))) b)))
double code(double a, double b, double c) {
return -c / (sqrt(fma(b, b, ((c * -3.0) * a))) + b);
}
function code(a, b, c) return Float64(Float64(-c) / Float64(sqrt(fma(b, b, Float64(Float64(c * -3.0) * a))) + b)) end
code[a_, b_, c_] := N[((-c) / N[(N[Sqrt[N[(b * b + N[(N[(c * -3.0), $MachinePrecision] * a), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] + b), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{-c}{\sqrt{\mathsf{fma}\left(b, b, \left(c \cdot -3\right) \cdot a\right)} + b}
\end{array}
Initial program 53.7%
lift-/.f64N/A
clear-numN/A
lift-*.f64N/A
associate-/l*N/A
associate-/r*N/A
lower-/.f64N/A
metadata-evalN/A
lower-/.f6453.7
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
lower--.f6453.7
Applied rewrites53.7%
lift-/.f64N/A
lift-/.f64N/A
associate-/r/N/A
lift--.f64N/A
flip--N/A
associate-*r/N/A
lower-/.f64N/A
Applied rewrites54.9%
Taylor expanded in c around 0
mul-1-negN/A
lower-neg.f6499.5
Applied rewrites99.5%
lift-*.f64N/A
lift-fma.f64N/A
+-commutativeN/A
lower-fma.f64N/A
lower-*.f6499.5
lift-*.f64N/A
*-commutativeN/A
lower-*.f6499.5
Applied rewrites99.5%
(FPCore (a b c) :precision binary64 (/ (- c) (fma (* (/ c b) a) -1.5 (* 2.0 b))))
double code(double a, double b, double c) {
return -c / fma(((c / b) * a), -1.5, (2.0 * b));
}
function code(a, b, c) return Float64(Float64(-c) / fma(Float64(Float64(c / b) * a), -1.5, Float64(2.0 * b))) end
code[a_, b_, c_] := N[((-c) / N[(N[(N[(c / b), $MachinePrecision] * a), $MachinePrecision] * -1.5 + N[(2.0 * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{-c}{\mathsf{fma}\left(\frac{c}{b} \cdot a, -1.5, 2 \cdot b\right)}
\end{array}
Initial program 53.7%
lift-/.f64N/A
clear-numN/A
lift-*.f64N/A
associate-/l*N/A
associate-/r*N/A
lower-/.f64N/A
metadata-evalN/A
lower-/.f6453.7
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
lower--.f6453.7
Applied rewrites53.7%
lift-/.f64N/A
lift-/.f64N/A
associate-/r/N/A
lift--.f64N/A
flip--N/A
associate-*r/N/A
lower-/.f64N/A
Applied rewrites54.9%
Taylor expanded in c around 0
mul-1-negN/A
lower-neg.f6499.5
Applied rewrites99.5%
Taylor expanded in c around 0
*-commutativeN/A
lower-fma.f64N/A
associate-/l*N/A
lower-*.f64N/A
lower-/.f64N/A
lower-*.f6482.7
Applied rewrites82.7%
Final simplification82.7%
(FPCore (a b c) :precision binary64 (/ (- c) (+ (fma (* (/ c b) a) -1.5 b) b)))
double code(double a, double b, double c) {
return -c / (fma(((c / b) * a), -1.5, b) + b);
}
function code(a, b, c) return Float64(Float64(-c) / Float64(fma(Float64(Float64(c / b) * a), -1.5, b) + b)) end
code[a_, b_, c_] := N[((-c) / N[(N[(N[(N[(c / b), $MachinePrecision] * a), $MachinePrecision] * -1.5 + b), $MachinePrecision] + b), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{-c}{\mathsf{fma}\left(\frac{c}{b} \cdot a, -1.5, b\right) + b}
\end{array}
Initial program 53.7%
lift-/.f64N/A
clear-numN/A
lift-*.f64N/A
associate-/l*N/A
associate-/r*N/A
lower-/.f64N/A
metadata-evalN/A
lower-/.f6453.7
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
lower--.f6453.7
Applied rewrites53.7%
lift-/.f64N/A
lift-/.f64N/A
associate-/r/N/A
lift--.f64N/A
flip--N/A
associate-*r/N/A
lower-/.f64N/A
Applied rewrites54.9%
Taylor expanded in c around 0
mul-1-negN/A
lower-neg.f6499.5
Applied rewrites99.5%
Taylor expanded in c around 0
+-commutativeN/A
*-commutativeN/A
lower-fma.f64N/A
associate-/l*N/A
lower-*.f64N/A
lower-/.f6482.7
Applied rewrites82.7%
Final simplification82.7%
(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 53.7%
Taylor expanded in c around 0
*-commutativeN/A
lower-*.f64N/A
lower-/.f6465.9
Applied rewrites65.9%
Final simplification65.9%
(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 53.7%
Taylor expanded in c around 0
*-commutativeN/A
lower-*.f64N/A
lower-/.f6465.9
Applied rewrites65.9%
Applied rewrites65.9%
Final simplification65.9%
herbie shell --seed 2024236
(FPCore (a b c)
:name "Cubic critical, narrow range"
:precision binary64
:pre (and (and (and (< 1.0536712127723509e-8 a) (< a 94906265.62425156)) (and (< 1.0536712127723509e-8 b) (< b 94906265.62425156))) (and (< 1.0536712127723509e-8 c) (< c 94906265.62425156)))
(/ (+ (- b) (sqrt (- (* b b) (* (* 3.0 a) c)))) (* 3.0 a)))