
(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 9 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 (* (* c a) c)))
(/
(fma
(* (* -2.0 a) a)
(* (/ (* c c) (* b b)) (/ c (* b b)))
(fma
a
(fma -5.0 (/ (* t_0 t_0) (pow b 6.0)) (/ (* (- c) c) (* b b)))
(- c)))
b)))
double code(double a, double b, double c) {
double t_0 = (c * a) * c;
return fma(((-2.0 * a) * a), (((c * c) / (b * b)) * (c / (b * b))), fma(a, fma(-5.0, ((t_0 * t_0) / pow(b, 6.0)), ((-c * c) / (b * b))), -c)) / b;
}
function code(a, b, c) t_0 = Float64(Float64(c * a) * c) return Float64(fma(Float64(Float64(-2.0 * a) * a), Float64(Float64(Float64(c * c) / Float64(b * b)) * Float64(c / Float64(b * b))), fma(a, fma(-5.0, Float64(Float64(t_0 * t_0) / (b ^ 6.0)), Float64(Float64(Float64(-c) * c) / Float64(b * b))), Float64(-c))) / b) end
code[a_, b_, c_] := Block[{t$95$0 = N[(N[(c * a), $MachinePrecision] * c), $MachinePrecision]}, N[(N[(N[(N[(-2.0 * a), $MachinePrecision] * a), $MachinePrecision] * N[(N[(N[(c * c), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision] * N[(c / N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(a * N[(-5.0 * N[(N[(t$95$0 * t$95$0), $MachinePrecision] / N[Power[b, 6.0], $MachinePrecision]), $MachinePrecision] + N[(N[((-c) * c), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + (-c)), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \left(c \cdot a\right) \cdot c\\
\frac{\mathsf{fma}\left(\left(-2 \cdot a\right) \cdot a, \frac{c \cdot c}{b \cdot b} \cdot \frac{c}{b \cdot b}, \mathsf{fma}\left(a, \mathsf{fma}\left(-5, \frac{t\_0 \cdot t\_0}{{b}^{6}}, \frac{\left(-c\right) \cdot c}{b \cdot b}\right), -c\right)\right)}{b}
\end{array}
\end{array}
Initial program 21.3%
Taylor expanded in b around inf
Applied rewrites96.9%
Applied rewrites96.9%
Taylor expanded in a around 0
Applied rewrites96.9%
Applied rewrites96.9%
Final simplification96.9%
(FPCore (a b c) :precision binary64 (/ (* c (fma c (- (/ (* -2.0 (* (* a a) c)) (pow b 4.0)) (/ a (* b b))) -1.0)) b))
double code(double a, double b, double c) {
return (c * fma(c, (((-2.0 * ((a * a) * c)) / pow(b, 4.0)) - (a / (b * b))), -1.0)) / b;
}
function code(a, b, c) return Float64(Float64(c * fma(c, Float64(Float64(Float64(-2.0 * Float64(Float64(a * a) * c)) / (b ^ 4.0)) - Float64(a / Float64(b * b))), -1.0)) / b) end
code[a_, b_, c_] := N[(N[(c * N[(c * N[(N[(N[(-2.0 * N[(N[(a * a), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision] / N[Power[b, 4.0], $MachinePrecision]), $MachinePrecision] - N[(a / N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + -1.0), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{c \cdot \mathsf{fma}\left(c, \frac{-2 \cdot \left(\left(a \cdot a\right) \cdot c\right)}{{b}^{4}} - \frac{a}{b \cdot b}, -1\right)}{b}
\end{array}
Initial program 21.3%
Taylor expanded in b around inf
Applied rewrites96.9%
Taylor expanded in c around 0
Applied rewrites96.0%
(FPCore (a b c) :precision binary64 (* (fma (/ (fma (- a) (* b b) (* (* (* a a) c) -2.0)) (pow b 5.0)) c (/ -1.0 b)) c))
double code(double a, double b, double c) {
return fma((fma(-a, (b * b), (((a * a) * c) * -2.0)) / pow(b, 5.0)), c, (-1.0 / b)) * c;
}
function code(a, b, c) return Float64(fma(Float64(fma(Float64(-a), Float64(b * b), Float64(Float64(Float64(a * a) * c) * -2.0)) / (b ^ 5.0)), c, Float64(-1.0 / b)) * c) end
code[a_, b_, c_] := N[(N[(N[(N[((-a) * N[(b * b), $MachinePrecision] + N[(N[(N[(a * a), $MachinePrecision] * c), $MachinePrecision] * -2.0), $MachinePrecision]), $MachinePrecision] / N[Power[b, 5.0], $MachinePrecision]), $MachinePrecision] * c + N[(-1.0 / b), $MachinePrecision]), $MachinePrecision] * c), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(\frac{\mathsf{fma}\left(-a, b \cdot b, \left(\left(a \cdot a\right) \cdot c\right) \cdot -2\right)}{{b}^{5}}, c, \frac{-1}{b}\right) \cdot c
\end{array}
Initial program 21.3%
Taylor expanded in c around 0
*-commutativeN/A
lower-*.f64N/A
Applied rewrites95.7%
Taylor expanded in b around 0
Applied rewrites95.7%
(FPCore (a b c) :precision binary64 (* (/ (fma (- (fma b b (* c a))) (* b b) (* (* (* a a) -2.0) (* c c))) (pow b 5.0)) c))
double code(double a, double b, double c) {
return (fma(-fma(b, b, (c * a)), (b * b), (((a * a) * -2.0) * (c * c))) / pow(b, 5.0)) * c;
}
function code(a, b, c) return Float64(Float64(fma(Float64(-fma(b, b, Float64(c * a))), Float64(b * b), Float64(Float64(Float64(a * a) * -2.0) * Float64(c * c))) / (b ^ 5.0)) * c) end
code[a_, b_, c_] := N[(N[(N[((-N[(b * b + N[(c * a), $MachinePrecision]), $MachinePrecision]) * N[(b * b), $MachinePrecision] + N[(N[(N[(a * a), $MachinePrecision] * -2.0), $MachinePrecision] * N[(c * c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[Power[b, 5.0], $MachinePrecision]), $MachinePrecision] * c), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(-\mathsf{fma}\left(b, b, c \cdot a\right), b \cdot b, \left(\left(a \cdot a\right) \cdot -2\right) \cdot \left(c \cdot c\right)\right)}{{b}^{5}} \cdot c
\end{array}
Initial program 21.3%
Taylor expanded in c around 0
*-commutativeN/A
lower-*.f64N/A
Applied rewrites95.7%
Taylor expanded in b around 0
Applied rewrites95.2%
(FPCore (a b c) :precision binary64 (/ (fma (/ c b) (/ (* c a) b) c) (- b)))
double code(double a, double b, double c) {
return fma((c / b), ((c * a) / b), c) / -b;
}
function code(a, b, c) return Float64(fma(Float64(c / b), Float64(Float64(c * a) / b), c) / Float64(-b)) end
code[a_, b_, c_] := N[(N[(N[(c / b), $MachinePrecision] * N[(N[(c * a), $MachinePrecision] / b), $MachinePrecision] + c), $MachinePrecision] / (-b)), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\frac{c}{b}, \frac{c \cdot a}{b}, c\right)}{-b}
\end{array}
Initial program 21.3%
Taylor expanded in a around 0
mul-1-negN/A
unsub-negN/A
associate-*r/N/A
unpow3N/A
unpow2N/A
associate-/r*N/A
div-subN/A
unsub-negN/A
mul-1-negN/A
distribute-lft-outN/A
associate-/l*N/A
mul-1-negN/A
lower-neg.f64N/A
lower-/.f64N/A
Applied rewrites93.8%
Final simplification93.8%
(FPCore (a b c) :precision binary64 (/ (* c (fma (- a) (/ c (* b b)) -1.0)) b))
double code(double a, double b, double c) {
return (c * fma(-a, (c / (b * b)), -1.0)) / b;
}
function code(a, b, c) return Float64(Float64(c * fma(Float64(-a), Float64(c / Float64(b * b)), -1.0)) / b) end
code[a_, b_, c_] := N[(N[(c * N[((-a) * N[(c / N[(b * b), $MachinePrecision]), $MachinePrecision] + -1.0), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{c \cdot \mathsf{fma}\left(-a, \frac{c}{b \cdot b}, -1\right)}{b}
\end{array}
Initial program 21.3%
Taylor expanded in b around inf
Applied rewrites96.9%
Taylor expanded in c around 0
Applied rewrites93.8%
(FPCore (a b c) :precision binary64 (* (/ (fma (- a) (/ c (* b b)) -1.0) b) c))
double code(double a, double b, double c) {
return (fma(-a, (c / (b * b)), -1.0) / b) * c;
}
function code(a, b, c) return Float64(Float64(fma(Float64(-a), Float64(c / Float64(b * b)), -1.0) / b) * c) end
code[a_, b_, c_] := N[(N[(N[((-a) * N[(c / N[(b * b), $MachinePrecision]), $MachinePrecision] + -1.0), $MachinePrecision] / b), $MachinePrecision] * c), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(-a, \frac{c}{b \cdot b}, -1\right)}{b} \cdot c
\end{array}
Initial program 21.3%
Taylor expanded in c around 0
*-commutativeN/A
sub-negN/A
distribute-neg-fracN/A
metadata-evalN/A
associate-*r/N/A
associate-*r*N/A
associate-*l/N/A
associate-*r/N/A
lower-*.f64N/A
Applied rewrites93.5%
Taylor expanded in b around inf
Applied rewrites93.5%
(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 21.3%
Taylor expanded in a around 0
associate-*r/N/A
lower-/.f64N/A
mul-1-negN/A
lower-neg.f6488.0
Applied rewrites88.0%
(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 21.3%
lift-/.f64N/A
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
div-subN/A
lower--.f64N/A
Applied rewrites21.0%
lift--.f64N/A
sub-negN/A
lift-/.f64N/A
clear-numN/A
associate-/r/N/A
lower-fma.f64N/A
lift-*.f64N/A
associate-/r*N/A
metadata-evalN/A
lower-/.f64N/A
lift-fma.f64N/A
lift-*.f64N/A
associate-*l*N/A
lift-*.f64N/A
lower-fma.f64N/A
lift-/.f64N/A
distribute-neg-frac2N/A
lower-/.f64N/A
lift-*.f64N/A
distribute-lft-neg-inN/A
metadata-evalN/A
Applied rewrites22.1%
Taylor expanded in a around 0
distribute-rgt-outN/A
metadata-evalN/A
associate-*l/N/A
mul0-rgt3.3
Applied rewrites3.3%
herbie shell --seed 2024307
(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)))