
(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 6 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 (/ (/ (fma c (* a -4.0) 0.0) (* a 2.0)) (+ b (sqrt (fma c (* a -4.0) (* b b))))))
double code(double a, double b, double c) {
return (fma(c, (a * -4.0), 0.0) / (a * 2.0)) / (b + sqrt(fma(c, (a * -4.0), (b * b))));
}
function code(a, b, c) return Float64(Float64(fma(c, Float64(a * -4.0), 0.0) / Float64(a * 2.0)) / Float64(b + sqrt(fma(c, Float64(a * -4.0), Float64(b * b))))) end
code[a_, b_, c_] := N[(N[(N[(c * N[(a * -4.0), $MachinePrecision] + 0.0), $MachinePrecision] / N[(a * 2.0), $MachinePrecision]), $MachinePrecision] / N[(b + N[Sqrt[N[(c * N[(a * -4.0), $MachinePrecision] + N[(b * b), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\frac{\mathsf{fma}\left(c, a \cdot -4, 0\right)}{a \cdot 2}}{b + \sqrt{\mathsf{fma}\left(c, a \cdot -4, b \cdot b\right)}}
\end{array}
Initial program 30.9%
Applied egg-rr31.3%
sub-divN/A
associate-/l/N/A
/-lowering-/.f64N/A
--lowering--.f64N/A
+-commutativeN/A
associate-*r*N/A
*-commutativeN/A
associate-*l*N/A
accelerator-lowering-fma.f64N/A
*-lowering-*.f64N/A
*-lowering-*.f64N/A
*-lowering-*.f64N/A
*-lowering-*.f64N/A
Applied egg-rr31.6%
associate-/r*N/A
/-lowering-/.f64N/A
/-lowering-/.f64N/A
associate--l+N/A
associate-*r*N/A
*-commutativeN/A
associate-*r*N/A
+-inversesN/A
accelerator-lowering-fma.f64N/A
*-lowering-*.f64N/A
*-lowering-*.f64N/A
+-lowering-+.f64N/A
sqrt-lowering-sqrt.f64N/A
associate-*r*N/A
*-commutativeN/A
associate-*r*N/A
accelerator-lowering-fma.f64N/A
Applied egg-rr99.6%
(FPCore (a b c) :precision binary64 (* (fma (* c a) 4.0 0.0) (/ 1.0 (* (+ b (sqrt (fma c (* a -4.0) (* b b)))) (* a -2.0)))))
double code(double a, double b, double c) {
return fma((c * a), 4.0, 0.0) * (1.0 / ((b + sqrt(fma(c, (a * -4.0), (b * b)))) * (a * -2.0)));
}
function code(a, b, c) return Float64(fma(Float64(c * a), 4.0, 0.0) * Float64(1.0 / Float64(Float64(b + sqrt(fma(c, Float64(a * -4.0), Float64(b * b)))) * Float64(a * -2.0)))) end
code[a_, b_, c_] := N[(N[(N[(c * a), $MachinePrecision] * 4.0 + 0.0), $MachinePrecision] * N[(1.0 / N[(N[(b + N[Sqrt[N[(c * N[(a * -4.0), $MachinePrecision] + N[(b * b), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * N[(a * -2.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(c \cdot a, 4, 0\right) \cdot \frac{1}{\left(b + \sqrt{\mathsf{fma}\left(c, a \cdot -4, b \cdot b\right)}\right) \cdot \left(a \cdot -2\right)}
\end{array}
Initial program 30.9%
Applied egg-rr31.3%
sub-divN/A
associate-/l/N/A
/-lowering-/.f64N/A
--lowering--.f64N/A
+-commutativeN/A
associate-*r*N/A
*-commutativeN/A
associate-*l*N/A
accelerator-lowering-fma.f64N/A
*-lowering-*.f64N/A
*-lowering-*.f64N/A
*-lowering-*.f64N/A
*-lowering-*.f64N/A
Applied egg-rr31.6%
frac-2negN/A
div-invN/A
*-lowering-*.f64N/A
associate--l+N/A
+-inversesN/A
distribute-neg-inN/A
associate-*r*N/A
*-commutativeN/A
distribute-rgt-neg-inN/A
metadata-evalN/A
metadata-evalN/A
metadata-evalN/A
accelerator-lowering-fma.f64N/A
*-lowering-*.f64N/A
metadata-evalN/A
/-lowering-/.f64N/A
Applied egg-rr99.4%
(FPCore (a b c) :precision binary64 (/ (* -4.0 (* c a)) (* (* a 2.0) (+ b (sqrt (fma a (* c -4.0) (* b b)))))))
double code(double a, double b, double c) {
return (-4.0 * (c * a)) / ((a * 2.0) * (b + sqrt(fma(a, (c * -4.0), (b * b)))));
}
function code(a, b, c) return Float64(Float64(-4.0 * Float64(c * a)) / Float64(Float64(a * 2.0) * Float64(b + sqrt(fma(a, Float64(c * -4.0), Float64(b * b)))))) 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[(a * N[(c * -4.0), $MachinePrecision] + N[(b * b), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{-4 \cdot \left(c \cdot a\right)}{\left(a \cdot 2\right) \cdot \left(b + \sqrt{\mathsf{fma}\left(a, c \cdot -4, b \cdot b\right)}\right)}
\end{array}
Initial program 30.9%
Applied egg-rr31.3%
sub-divN/A
associate-/l/N/A
/-lowering-/.f64N/A
--lowering--.f64N/A
+-commutativeN/A
associate-*r*N/A
*-commutativeN/A
associate-*l*N/A
accelerator-lowering-fma.f64N/A
*-lowering-*.f64N/A
*-lowering-*.f64N/A
*-lowering-*.f64N/A
*-lowering-*.f64N/A
Applied egg-rr31.6%
Taylor expanded in a around 0
*-lowering-*.f64N/A
*-lowering-*.f6499.4
Simplified99.4%
Final simplification99.4%
(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 30.9%
Taylor expanded in a around 0
Simplified96.6%
Taylor expanded in a around 0
sub-negN/A
mul-1-negN/A
distribute-neg-outN/A
neg-lowering-neg.f64N/A
associate-/l*N/A
accelerator-lowering-fma.f64N/A
/-lowering-/.f64N/A
unpow2N/A
*-lowering-*.f64N/A
cube-multN/A
unpow2N/A
*-lowering-*.f64N/A
unpow2N/A
*-lowering-*.f64N/A
/-lowering-/.f6491.0
Simplified91.0%
(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 30.9%
Taylor expanded in b around inf
distribute-lft-outN/A
associate-/l*N/A
mul-1-negN/A
neg-lowering-neg.f64N/A
/-lowering-/.f64N/A
+-commutativeN/A
*-commutativeN/A
associate-/l*N/A
accelerator-lowering-fma.f64N/A
unpow2N/A
*-lowering-*.f64N/A
/-lowering-/.f64N/A
unpow2N/A
*-lowering-*.f6491.0
Simplified91.0%
Final simplification91.0%
(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 30.9%
Taylor expanded in b around inf
mul-1-negN/A
distribute-neg-frac2N/A
/-lowering-/.f64N/A
neg-lowering-neg.f6481.6
Simplified81.6%
Final simplification81.6%
herbie shell --seed 2024198
(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)))