
(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 8 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 (/ (* a -3.0) (+ b (sqrt (fma c (* a -3.0) (* b b)))))) (* a 3.0)))
double code(double a, double b, double c) {
return (c * ((a * -3.0) / (b + sqrt(fma(c, (a * -3.0), (b * b)))))) / (a * 3.0);
}
function code(a, b, c) return Float64(Float64(c * Float64(Float64(a * -3.0) / Float64(b + sqrt(fma(c, Float64(a * -3.0), Float64(b * b)))))) / Float64(a * 3.0)) end
code[a_, b_, c_] := N[(N[(c * N[(N[(a * -3.0), $MachinePrecision] / N[(b + N[Sqrt[N[(c * N[(a * -3.0), $MachinePrecision] + N[(b * b), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(a * 3.0), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{c \cdot \frac{a \cdot -3}{b + \sqrt{\mathsf{fma}\left(c, a \cdot -3, b \cdot b\right)}}}{a \cdot 3}
\end{array}
Initial program 29.8%
lift-*.f64N/A
lift-*.f64N/A
lift-*.f64N/A
sub-negN/A
lift-*.f64N/A
lower-fma.f64N/A
lift-*.f64N/A
distribute-lft-neg-inN/A
lift-*.f64N/A
*-commutativeN/A
distribute-rgt-neg-inN/A
associate-*l*N/A
lower-*.f64N/A
lower-*.f64N/A
metadata-eval29.9
Applied rewrites29.9%
Applied rewrites99.4%
lift-*.f64N/A
lift-*.f64N/A
lift--.f64N/A
lift-neg.f64N/A
lift-*.f64N/A
lift-*.f64N/A
lift-fma.f64N/A
lift-sqrt.f64N/A
lift--.f64N/A
lift-*.f64N/A
lift-*.f64N/A
lift-neg.f64N/A
Applied rewrites99.4%
Final simplification99.4%
(FPCore (a b c) :precision binary64 (/ (* c (* a 3.0)) (* (- (- b) (sqrt (fma c (* a -3.0) (* b b)))) (* a 3.0))))
double code(double a, double b, double c) {
return (c * (a * 3.0)) / ((-b - sqrt(fma(c, (a * -3.0), (b * b)))) * (a * 3.0));
}
function code(a, b, c) return Float64(Float64(c * Float64(a * 3.0)) / Float64(Float64(Float64(-b) - sqrt(fma(c, Float64(a * -3.0), Float64(b * b)))) * Float64(a * 3.0))) end
code[a_, b_, c_] := N[(N[(c * N[(a * 3.0), $MachinePrecision]), $MachinePrecision] / N[(N[((-b) - N[Sqrt[N[(c * N[(a * -3.0), $MachinePrecision] + N[(b * b), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * N[(a * 3.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{c \cdot \left(a \cdot 3\right)}{\left(\left(-b\right) - \sqrt{\mathsf{fma}\left(c, a \cdot -3, b \cdot b\right)}\right) \cdot \left(a \cdot 3\right)}
\end{array}
Initial program 29.8%
lift-*.f64N/A
lift-*.f64N/A
lift-*.f64N/A
sub-negN/A
lift-*.f64N/A
lower-fma.f64N/A
lift-*.f64N/A
distribute-lft-neg-inN/A
lift-*.f64N/A
*-commutativeN/A
distribute-rgt-neg-inN/A
associate-*l*N/A
lower-*.f64N/A
lower-*.f64N/A
metadata-eval29.9
Applied rewrites29.9%
Applied rewrites99.4%
Applied rewrites99.4%
Final simplification99.4%
(FPCore (a b c) :precision binary64 (fma (/ (* a (* c -0.375)) (* b (* b b))) c (/ (* c -0.5) b)))
double code(double a, double b, double c) {
return fma(((a * (c * -0.375)) / (b * (b * b))), c, ((c * -0.5) / b));
}
function code(a, b, c) return fma(Float64(Float64(a * Float64(c * -0.375)) / Float64(b * Float64(b * b))), c, Float64(Float64(c * -0.5) / b)) end
code[a_, b_, c_] := N[(N[(N[(a * N[(c * -0.375), $MachinePrecision]), $MachinePrecision] / N[(b * N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * c + N[(N[(c * -0.5), $MachinePrecision] / b), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(\frac{a \cdot \left(c \cdot -0.375\right)}{b \cdot \left(b \cdot b\right)}, c, \frac{c \cdot -0.5}{b}\right)
\end{array}
Initial program 29.8%
Taylor expanded in c around 0
sub-negN/A
distribute-lft-inN/A
associate-*r/N/A
associate-*r*N/A
associate-*l/N/A
associate-*r/N/A
distribute-lft-inN/A
lower-*.f64N/A
associate-*r/N/A
associate-*l/N/A
associate-*r*N/A
associate-*r/N/A
*-commutativeN/A
associate-/l*N/A
associate-*l*N/A
Applied rewrites92.3%
lift-*.f64N/A
lift-*.f64N/A
lift-/.f64N/A
lift-*.f64N/A
lift-/.f64N/A
distribute-rgt-inN/A
lift-/.f64N/A
associate-*l/N/A
associate-*r/N/A
lift-/.f64N/A
lift-*.f64N/A
lower-fma.f64N/A
Applied rewrites92.6%
(FPCore (a b c) :precision binary64 (/ (fma a (/ (* -0.375 (* c c)) (* b b)) (* c -0.5)) b))
double code(double a, double b, double c) {
return fma(a, ((-0.375 * (c * c)) / (b * b)), (c * -0.5)) / b;
}
function code(a, b, c) return Float64(fma(a, Float64(Float64(-0.375 * Float64(c * c)) / Float64(b * b)), Float64(c * -0.5)) / b) end
code[a_, b_, c_] := N[(N[(a * N[(N[(-0.375 * N[(c * c), $MachinePrecision]), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision] + N[(c * -0.5), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(a, \frac{-0.375 \cdot \left(c \cdot c\right)}{b \cdot b}, c \cdot -0.5\right)}{b}
\end{array}
Initial program 29.8%
Taylor expanded in b around inf
lower-/.f64N/A
Applied rewrites92.6%
Final simplification92.6%
(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(a * Float64(c / Float64(b * b))), -0.5)) / b) end
code[a_, b_, c_] := N[(N[(c * N[(-0.375 * N[(a * N[(c / N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + -0.5), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{c \cdot \mathsf{fma}\left(-0.375, a \cdot \frac{c}{b \cdot b}, -0.5\right)}{b}
\end{array}
Initial program 29.8%
Taylor expanded in b around inf
lower-/.f64N/A
Applied rewrites92.6%
Taylor expanded in c around 0
lower-*.f64N/A
sub-negN/A
metadata-evalN/A
lower-fma.f64N/A
associate-/l*N/A
lower-*.f64N/A
lower-/.f64N/A
unpow2N/A
lower-*.f6492.5
Applied rewrites92.5%
(FPCore (a b c) :precision binary64 (* c (/ (fma -0.375 (/ (* c a) (* b b)) -0.5) b)))
double code(double a, double b, double c) {
return c * (fma(-0.375, ((c * a) / (b * b)), -0.5) / b);
}
function code(a, b, c) return Float64(c * Float64(fma(-0.375, Float64(Float64(c * a) / Float64(b * b)), -0.5) / b)) end
code[a_, b_, c_] := N[(c * N[(N[(-0.375 * N[(N[(c * a), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision] + -0.5), $MachinePrecision] / b), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
c \cdot \frac{\mathsf{fma}\left(-0.375, \frac{c \cdot a}{b \cdot b}, -0.5\right)}{b}
\end{array}
Initial program 29.8%
Taylor expanded in c around 0
sub-negN/A
distribute-lft-inN/A
associate-*r/N/A
associate-*r*N/A
associate-*l/N/A
associate-*r/N/A
distribute-lft-inN/A
lower-*.f64N/A
associate-*r/N/A
associate-*l/N/A
associate-*r*N/A
associate-*r/N/A
*-commutativeN/A
associate-/l*N/A
associate-*l*N/A
Applied rewrites92.3%
Taylor expanded in b around inf
lower-/.f64N/A
sub-negN/A
metadata-evalN/A
lower-fma.f64N/A
lower-/.f64N/A
lower-*.f64N/A
unpow2N/A
lower-*.f6492.3
Applied rewrites92.3%
Final simplification92.3%
(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 29.8%
Taylor expanded in b around inf
lower-*.f64N/A
lower-/.f6483.0
Applied rewrites83.0%
(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 29.8%
lift-*.f64N/A
lift-*.f64N/A
lift-*.f64N/A
sub-negN/A
lift-*.f64N/A
lower-fma.f64N/A
lift-*.f64N/A
distribute-lft-neg-inN/A
lift-*.f64N/A
*-commutativeN/A
distribute-rgt-neg-inN/A
associate-*l*N/A
lower-*.f64N/A
lower-*.f64N/A
metadata-eval29.9
Applied rewrites29.9%
Applied rewrites31.8%
Taylor expanded in c around 0
distribute-rgt-outN/A
metadata-evalN/A
mul0-rgt3.2
Applied rewrites3.2%
herbie shell --seed 2024214
(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)))