
(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 7 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
(let* ((t_0 (* b (* b b))))
(fma
(fma
c
(* (* c c) (/ -2.0 (* (* b b) t_0)))
(/ (* -0.25 (* a (* (* c c) (* (* c c) 20.0)))) (* b (* t_0 t_0))))
(* a a)
(/ (fma (* c c) (/ a (* b b)) c) (- b)))))
double code(double a, double b, double c) {
double t_0 = b * (b * b);
return fma(fma(c, ((c * c) * (-2.0 / ((b * b) * t_0))), ((-0.25 * (a * ((c * c) * ((c * c) * 20.0)))) / (b * (t_0 * t_0)))), (a * a), (fma((c * c), (a / (b * b)), c) / -b));
}
function code(a, b, c) t_0 = Float64(b * Float64(b * b)) return fma(fma(c, Float64(Float64(c * c) * Float64(-2.0 / Float64(Float64(b * b) * t_0))), Float64(Float64(-0.25 * Float64(a * Float64(Float64(c * c) * Float64(Float64(c * c) * 20.0)))) / Float64(b * Float64(t_0 * t_0)))), Float64(a * a), Float64(fma(Float64(c * c), Float64(a / Float64(b * b)), c) / Float64(-b))) end
code[a_, b_, c_] := Block[{t$95$0 = N[(b * N[(b * b), $MachinePrecision]), $MachinePrecision]}, N[(N[(c * N[(N[(c * c), $MachinePrecision] * N[(-2.0 / N[(N[(b * b), $MachinePrecision] * t$95$0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(N[(-0.25 * N[(a * N[(N[(c * c), $MachinePrecision] * N[(N[(c * c), $MachinePrecision] * 20.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(b * N[(t$95$0 * t$95$0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[(a * a), $MachinePrecision] + N[(N[(N[(c * c), $MachinePrecision] * N[(a / N[(b * b), $MachinePrecision]), $MachinePrecision] + c), $MachinePrecision] / (-b)), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := b \cdot \left(b \cdot b\right)\\
\mathsf{fma}\left(\mathsf{fma}\left(c, \left(c \cdot c\right) \cdot \frac{-2}{\left(b \cdot b\right) \cdot t\_0}, \frac{-0.25 \cdot \left(a \cdot \left(\left(c \cdot c\right) \cdot \left(\left(c \cdot c\right) \cdot 20\right)\right)\right)}{b \cdot \left(t\_0 \cdot t\_0\right)}\right), a \cdot a, \frac{\mathsf{fma}\left(c \cdot c, \frac{a}{b \cdot b}, c\right)}{-b}\right)
\end{array}
\end{array}
Initial program 17.5%
Taylor expanded in a around 0
Applied rewrites97.3%
Applied rewrites97.3%
(FPCore (a b c)
:precision binary64
(-
(/
(/
(fma a (- (* c c)) (/ (* a (* -2.0 (* a (* c (* c c))))) (* b b)))
(* b b))
b)
(/ c b)))
double code(double a, double b, double c) {
return ((fma(a, -(c * c), ((a * (-2.0 * (a * (c * (c * c))))) / (b * b))) / (b * b)) / b) - (c / b);
}
function code(a, b, c) return Float64(Float64(Float64(fma(a, Float64(-Float64(c * c)), Float64(Float64(a * Float64(-2.0 * Float64(a * Float64(c * Float64(c * c))))) / Float64(b * b))) / Float64(b * b)) / b) - Float64(c / b)) end
code[a_, b_, c_] := N[(N[(N[(N[(a * (-N[(c * c), $MachinePrecision]) + N[(N[(a * N[(-2.0 * N[(a * N[(c * N[(c * c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision] - N[(c / b), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\frac{\mathsf{fma}\left(a, -c \cdot c, \frac{a \cdot \left(-2 \cdot \left(a \cdot \left(c \cdot \left(c \cdot c\right)\right)\right)\right)}{b \cdot b}\right)}{b \cdot b}}{b} - \frac{c}{b}
\end{array}
Initial program 17.5%
Taylor expanded in b around inf
lower-/.f64N/A
Applied rewrites96.7%
Applied rewrites96.7%
Taylor expanded in b around inf
Applied rewrites96.7%
Applied rewrites96.7%
Final simplification96.7%
(FPCore (a b c) :precision binary64 (/ (- (* (* -2.0 (* a a)) (/ (* c (* c c)) (* (* b b) (* b b)))) (fma (* c c) (/ a (* b b)) c)) b))
double code(double a, double b, double c) {
return (((-2.0 * (a * a)) * ((c * (c * c)) / ((b * b) * (b * b)))) - fma((c * c), (a / (b * b)), c)) / b;
}
function code(a, b, c) return Float64(Float64(Float64(Float64(-2.0 * Float64(a * a)) * Float64(Float64(c * Float64(c * c)) / Float64(Float64(b * b) * Float64(b * b)))) - fma(Float64(c * c), Float64(a / Float64(b * b)), c)) / b) end
code[a_, b_, c_] := N[(N[(N[(N[(-2.0 * N[(a * a), $MachinePrecision]), $MachinePrecision] * N[(N[(c * N[(c * c), $MachinePrecision]), $MachinePrecision] / N[(N[(b * b), $MachinePrecision] * N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(N[(c * c), $MachinePrecision] * N[(a / N[(b * b), $MachinePrecision]), $MachinePrecision] + c), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{\left(-2 \cdot \left(a \cdot a\right)\right) \cdot \frac{c \cdot \left(c \cdot c\right)}{\left(b \cdot b\right) \cdot \left(b \cdot b\right)} - \mathsf{fma}\left(c \cdot c, \frac{a}{b \cdot b}, c\right)}{b}
\end{array}
Initial program 17.5%
Taylor expanded in b around inf
lower-/.f64N/A
Applied rewrites96.7%
(FPCore (a b c) :precision binary64 (/ (- (/ (* (* c c) (fma -2.0 (/ (* c (* a a)) (* b b)) (- a))) (* b b)) c) b))
double code(double a, double b, double c) {
return ((((c * c) * fma(-2.0, ((c * (a * a)) / (b * b)), -a)) / (b * b)) - c) / b;
}
function code(a, b, c) return Float64(Float64(Float64(Float64(Float64(c * c) * fma(-2.0, Float64(Float64(c * Float64(a * a)) / Float64(b * b)), Float64(-a))) / Float64(b * b)) - c) / b) end
code[a_, b_, c_] := N[(N[(N[(N[(N[(c * c), $MachinePrecision] * N[(-2.0 * N[(N[(c * N[(a * a), $MachinePrecision]), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision] + (-a)), $MachinePrecision]), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision] - c), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{\frac{\left(c \cdot c\right) \cdot \mathsf{fma}\left(-2, \frac{c \cdot \left(a \cdot a\right)}{b \cdot b}, -a\right)}{b \cdot b} - c}{b}
\end{array}
Initial program 17.5%
Taylor expanded in b around inf
lower-/.f64N/A
Applied rewrites96.7%
Applied rewrites96.7%
Taylor expanded in b around inf
Applied rewrites96.7%
Taylor expanded in c around 0
Applied rewrites96.7%
Final simplification96.7%
(FPCore (a b c) :precision binary64 (- (fma a (/ (* c c) (* b (* b b))) (/ c b))))
double code(double a, double b, double c) {
return -fma(a, ((c * c) / (b * (b * b))), (c / b));
}
function code(a, b, c) return Float64(-fma(a, Float64(Float64(c * c) / Float64(b * Float64(b * b))), Float64(c / b))) end
code[a_, b_, c_] := (-N[(a * N[(N[(c * c), $MachinePrecision] / N[(b * N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(c / b), $MachinePrecision]), $MachinePrecision])
\begin{array}{l}
\\
-\mathsf{fma}\left(a, \frac{c \cdot c}{b \cdot \left(b \cdot b\right)}, \frac{c}{b}\right)
\end{array}
Initial program 17.5%
Taylor expanded in b around inf
mul-1-negN/A
distribute-neg-frac2N/A
lower-/.f64N/A
lower-neg.f6490.6
Applied rewrites90.6%
Taylor expanded in a around 0
+-commutativeN/A
mul-1-negN/A
mul-1-negN/A
distribute-neg-outN/A
lower-neg.f64N/A
associate-/l*N/A
lower-fma.f64N/A
lower-/.f64N/A
unpow2N/A
lower-*.f64N/A
cube-multN/A
unpow2N/A
lower-*.f64N/A
unpow2N/A
lower-*.f64N/A
lower-/.f6495.1
Applied rewrites95.1%
(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 17.5%
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-*.f6495.1
Applied rewrites95.1%
Final simplification95.1%
(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(-Float64(c / 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 17.5%
Taylor expanded in b around inf
mul-1-negN/A
distribute-neg-frac2N/A
lower-/.f64N/A
lower-neg.f6490.6
Applied rewrites90.6%
Final simplification90.6%
herbie shell --seed 2024234
(FPCore (a b c)
:name "Quadratic roots, 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) (* (* 4.0 a) c)))) (* 2.0 a)))