
(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 8 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 (/ (/ (* a (* c 4.0)) (* a 2.0)) (- (- b) (sqrt (fma a (* c -4.0) (* b b))))))
double code(double a, double b, double c) {
return ((a * (c * 4.0)) / (a * 2.0)) / (-b - sqrt(fma(a, (c * -4.0), (b * b))));
}
function code(a, b, c) return Float64(Float64(Float64(a * Float64(c * 4.0)) / Float64(a * 2.0)) / Float64(Float64(-b) - sqrt(fma(a, Float64(c * -4.0), Float64(b * b))))) end
code[a_, b_, c_] := N[(N[(N[(a * N[(c * 4.0), $MachinePrecision]), $MachinePrecision] / N[(a * 2.0), $MachinePrecision]), $MachinePrecision] / N[((-b) - N[Sqrt[N[(a * N[(c * -4.0), $MachinePrecision] + N[(b * b), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\frac{a \cdot \left(c \cdot 4\right)}{a \cdot 2}}{\left(-b\right) - \sqrt{\mathsf{fma}\left(a, c \cdot -4, b \cdot b\right)}}
\end{array}
Initial program 35.5%
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-eval35.4
Applied rewrites35.4%
lift-/.f64N/A
lift-+.f64N/A
flip-+N/A
associate-/l/N/A
lower-/.f64N/A
Applied rewrites36.3%
Taylor expanded in b around 0
lower-*.f64N/A
lower-*.f6499.4
Applied rewrites99.4%
lift-/.f64N/A
lift-*.f64N/A
associate-/r*N/A
lower-/.f64N/A
Applied rewrites99.6%
Final simplification99.6%
(FPCore (a b c) :precision binary64 (/ (* 4.0 (* c a)) (* (* a 2.0) (- (- b) (sqrt (fma b b (* a (* c -4.0))))))))
double code(double a, double b, double c) {
return (4.0 * (c * a)) / ((a * 2.0) * (-b - sqrt(fma(b, b, (a * (c * -4.0))))));
}
function code(a, b, c) return Float64(Float64(4.0 * Float64(c * a)) / Float64(Float64(a * 2.0) * Float64(Float64(-b) - sqrt(fma(b, b, Float64(a * Float64(c * -4.0))))))) end
code[a_, b_, c_] := N[(N[(4.0 * N[(c * a), $MachinePrecision]), $MachinePrecision] / N[(N[(a * 2.0), $MachinePrecision] * N[((-b) - N[Sqrt[N[(b * b + N[(a * N[(c * -4.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{4 \cdot \left(c \cdot a\right)}{\left(a \cdot 2\right) \cdot \left(\left(-b\right) - \sqrt{\mathsf{fma}\left(b, b, a \cdot \left(c \cdot -4\right)\right)}\right)}
\end{array}
Initial program 35.5%
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-eval35.4
Applied rewrites35.4%
lift-/.f64N/A
lift-+.f64N/A
flip-+N/A
associate-/l/N/A
lower-/.f64N/A
Applied rewrites36.3%
Taylor expanded in b around 0
lower-*.f64N/A
lower-*.f6499.4
Applied rewrites99.4%
lift-*.f64N/A
lift-fma.f64N/A
+-commutativeN/A
lift-*.f64N/A
*-commutativeN/A
metadata-evalN/A
distribute-lft-neg-inN/A
distribute-rgt-neg-inN/A
*-commutativeN/A
lower-fma.f64N/A
distribute-lft-neg-inN/A
distribute-lft-neg-inN/A
metadata-evalN/A
*-commutativeN/A
associate-*l*N/A
lower-*.f64N/A
lower-*.f6499.4
Applied rewrites99.4%
Final simplification99.4%
(FPCore (a b c) :precision binary64 (/ (* 4.0 (* c a)) (fma -4.0 (* b a) (/ (* 4.0 (* c (* a a))) b))))
double code(double a, double b, double c) {
return (4.0 * (c * a)) / fma(-4.0, (b * a), ((4.0 * (c * (a * a))) / b));
}
function code(a, b, c) return Float64(Float64(4.0 * Float64(c * a)) / fma(-4.0, Float64(b * a), Float64(Float64(4.0 * Float64(c * Float64(a * a))) / b))) end
code[a_, b_, c_] := N[(N[(4.0 * N[(c * a), $MachinePrecision]), $MachinePrecision] / N[(-4.0 * N[(b * a), $MachinePrecision] + N[(N[(4.0 * N[(c * N[(a * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{4 \cdot \left(c \cdot a\right)}{\mathsf{fma}\left(-4, b \cdot a, \frac{4 \cdot \left(c \cdot \left(a \cdot a\right)\right)}{b}\right)}
\end{array}
Initial program 35.5%
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-eval35.4
Applied rewrites35.4%
lift-/.f64N/A
lift-+.f64N/A
flip-+N/A
associate-/l/N/A
lower-/.f64N/A
Applied rewrites36.3%
Taylor expanded in b around 0
lower-*.f64N/A
lower-*.f6499.4
Applied rewrites99.4%
Taylor expanded in c around 0
lower-fma.f64N/A
lower-*.f64N/A
associate-*r/N/A
lower-/.f64N/A
lower-*.f64N/A
lower-*.f64N/A
unpow2N/A
lower-*.f6490.3
Applied rewrites90.3%
Final simplification90.3%
(FPCore (a b c) :precision binary64 (let* ((t_0 (* 4.0 (* c a)))) (/ t_0 (* a (fma -4.0 b (/ t_0 b))))))
double code(double a, double b, double c) {
double t_0 = 4.0 * (c * a);
return t_0 / (a * fma(-4.0, b, (t_0 / b)));
}
function code(a, b, c) t_0 = Float64(4.0 * Float64(c * a)) return Float64(t_0 / Float64(a * fma(-4.0, b, Float64(t_0 / b)))) end
code[a_, b_, c_] := Block[{t$95$0 = N[(4.0 * N[(c * a), $MachinePrecision]), $MachinePrecision]}, N[(t$95$0 / N[(a * N[(-4.0 * b + N[(t$95$0 / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := 4 \cdot \left(c \cdot a\right)\\
\frac{t\_0}{a \cdot \mathsf{fma}\left(-4, b, \frac{t\_0}{b}\right)}
\end{array}
\end{array}
Initial program 35.5%
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-eval35.4
Applied rewrites35.4%
lift-/.f64N/A
lift-+.f64N/A
flip-+N/A
associate-/l/N/A
lower-/.f64N/A
Applied rewrites36.3%
Taylor expanded in b around 0
lower-*.f64N/A
lower-*.f6499.4
Applied rewrites99.4%
Taylor expanded in a around 0
lower-*.f64N/A
lower-fma.f64N/A
associate-*r/N/A
lower-/.f64N/A
lower-*.f64N/A
lower-*.f6490.3
Applied rewrites90.3%
Final simplification90.3%
(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 35.5%
Applied rewrites35.0%
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-/.f6490.2
Applied rewrites90.2%
(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 35.5%
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-*.f6490.1
Applied rewrites90.1%
Final simplification90.1%
(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(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 35.5%
Taylor expanded in b around inf
mul-1-negN/A
distribute-neg-frac2N/A
lower-/.f64N/A
lower-neg.f6478.6
Applied rewrites78.6%
(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 / 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 35.5%
Taylor expanded in b around inf
mul-1-negN/A
distribute-neg-frac2N/A
lower-/.f64N/A
lower-neg.f6478.6
Applied rewrites78.6%
Applied rewrites78.5%
Applied rewrites1.6%
herbie shell --seed 2024227
(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)))