
(FPCore (a b c) :precision binary64 (/ (+ (- b) (sqrt (- (* b b) (* (* 4.0 a) c)))) (* 2.0 a)))
double code(double a, double b, double c) {
return (-b + sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * 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) - ((4.0d0 * a) * c)))) / (2.0d0 * a)
end function
public static double code(double a, double b, double c) {
return (-b + Math.sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * a);
}
def code(a, b, c): return (-b + math.sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * a)
function code(a, b, c) return Float64(Float64(Float64(-b) + sqrt(Float64(Float64(b * b) - Float64(Float64(4.0 * a) * c)))) / Float64(2.0 * a)) end
function tmp = code(a, b, c) tmp = (-b + sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * a); end
code[a_, b_, c_] := N[(N[((-b) + N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(N[(4.0 * a), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / N[(2.0 * a), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a}
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 4 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (a b c) :precision binary64 (/ (+ (- b) (sqrt (- (* b b) (* (* 4.0 a) c)))) (* 2.0 a)))
double code(double a, double b, double c) {
return (-b + sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * 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) - ((4.0d0 * a) * c)))) / (2.0d0 * a)
end function
public static double code(double a, double b, double c) {
return (-b + Math.sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * a);
}
def code(a, b, c): return (-b + math.sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * a)
function code(a, b, c) return Float64(Float64(Float64(-b) + sqrt(Float64(Float64(b * b) - Float64(Float64(4.0 * a) * c)))) / Float64(2.0 * a)) end
function tmp = code(a, b, c) tmp = (-b + sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * a); end
code[a_, b_, c_] := N[(N[((-b) + N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(N[(4.0 * a), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / N[(2.0 * a), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a}
\end{array}
(FPCore (a b c) :precision binary64 (/ (* -2.0 c) (+ b (sqrt (fma b b (* (* c a) -4.0))))))
double code(double a, double b, double c) {
return (-2.0 * c) / (b + sqrt(fma(b, b, ((c * a) * -4.0))));
}
function code(a, b, c) return Float64(Float64(-2.0 * c) / Float64(b + sqrt(fma(b, b, Float64(Float64(c * a) * -4.0))))) end
code[a_, b_, c_] := N[(N[(-2.0 * c), $MachinePrecision] / N[(b + N[Sqrt[N[(b * b + N[(N[(c * a), $MachinePrecision] * -4.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{-2 \cdot c}{b + \sqrt{\mathsf{fma}\left(b, b, \left(c \cdot a\right) \cdot -4\right)}}
\end{array}
Initial program 33.0%
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-eval33.1
Applied rewrites33.1%
lift-neg.f64N/A
lift-*.f64N/A
lift-*.f64N/A
lift-fma.f64N/A
lift-sqrt.f64N/A
+-commutativeN/A
flip-+N/A
lower-/.f64N/A
Applied rewrites33.7%
Applied rewrites99.6%
Taylor expanded in c around 0
lower-*.f6499.7
Applied rewrites99.7%
(FPCore (a b c) :precision binary64 (/ (fma (* c c) (/ a (* b b)) c) (- b)))
double code(double a, double b, double c) {
return fma((c * c), (a / (b * b)), c) / -b;
}
function code(a, b, c) return Float64(fma(Float64(c * c), Float64(a / Float64(b * b)), c) / Float64(-b)) end
code[a_, b_, c_] := N[(N[(N[(c * c), $MachinePrecision] * N[(a / N[(b * b), $MachinePrecision]), $MachinePrecision] + c), $MachinePrecision] / (-b)), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(c \cdot c, \frac{a}{b \cdot b}, c\right)}{-b}
\end{array}
Initial program 33.0%
Taylor expanded in b around inf
distribute-lft-outN/A
associate-/l*N/A
mul-1-negN/A
lower-neg.f64N/A
lower-/.f64N/A
+-commutativeN/A
*-commutativeN/A
associate-/l*N/A
lower-fma.f64N/A
unpow2N/A
lower-*.f64N/A
lower-/.f64N/A
unpow2N/A
lower-*.f6490.7
Applied rewrites90.7%
Final simplification90.7%
(FPCore (a b c) :precision binary64 (* c (/ (fma a c (* b b)) (- (* b (* b b))))))
double code(double a, double b, double c) {
return c * (fma(a, c, (b * b)) / -(b * (b * b)));
}
function code(a, b, c) return Float64(c * Float64(fma(a, c, Float64(b * b)) / Float64(-Float64(b * Float64(b * b))))) end
code[a_, b_, c_] := N[(c * N[(N[(a * c + N[(b * b), $MachinePrecision]), $MachinePrecision] / (-N[(b * N[(b * b), $MachinePrecision]), $MachinePrecision])), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
c \cdot \frac{\mathsf{fma}\left(a, c, b \cdot b\right)}{-b \cdot \left(b \cdot b\right)}
\end{array}
Initial program 33.0%
Taylor expanded in c around 0
lower-*.f64N/A
sub-negN/A
associate-*r/N/A
associate-*r*N/A
associate-*l/N/A
associate-*r/N/A
+-commutativeN/A
distribute-neg-fracN/A
metadata-evalN/A
lower-fma.f64N/A
Applied rewrites93.7%
Taylor expanded in a around 0
associate-*r/N/A
lower-/.f64N/A
mul-1-negN/A
lower-neg.f64N/A
cube-multN/A
unpow2N/A
lower-*.f64N/A
unpow2N/A
lower-*.f6490.5
Applied rewrites90.5%
Taylor expanded in b around 0
lower-/.f64N/A
distribute-lft-outN/A
mul-1-negN/A
lower-neg.f64N/A
lower-fma.f64N/A
unpow2N/A
lower-*.f64N/A
cube-multN/A
unpow2N/A
lower-*.f64N/A
unpow2N/A
lower-*.f6490.4
Applied rewrites90.4%
Final simplification90.4%
(FPCore (a b c) :precision binary64 (/ c (- b)))
double code(double a, double b, double c) {
return 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 = c / -b
end function
public static double code(double a, double b, double c) {
return c / -b;
}
def code(a, b, c): return c / -b
function code(a, b, c) return Float64(c / Float64(-b)) end
function tmp = code(a, b, c) tmp = c / -b; end
code[a_, b_, c_] := N[(c / (-b)), $MachinePrecision]
\begin{array}{l}
\\
\frac{c}{-b}
\end{array}
Initial program 33.0%
Taylor expanded in b around inf
mul-1-negN/A
distribute-neg-frac2N/A
lower-/.f64N/A
lower-neg.f6480.6
Applied rewrites80.6%
herbie shell --seed 2024216
(FPCore (a b c)
:name "Quadratic roots, 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) (* (* 4.0 a) c)))) (* 2.0 a)))