
(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 (/ (* -2.0 c) (+ b (sqrt (* b (* b (fma (* a -4.0) (/ c (* b b)) 1.0)))))))
double code(double a, double b, double c) {
return (-2.0 * c) / (b + sqrt((b * (b * fma((a * -4.0), (c / (b * b)), 1.0)))));
}
function code(a, b, c) return Float64(Float64(-2.0 * c) / Float64(b + sqrt(Float64(b * Float64(b * fma(Float64(a * -4.0), Float64(c / Float64(b * b)), 1.0)))))) end
code[a_, b_, c_] := N[(N[(-2.0 * c), $MachinePrecision] / N[(b + N[Sqrt[N[(b * N[(b * N[(N[(a * -4.0), $MachinePrecision] * N[(c / N[(b * b), $MachinePrecision]), $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{-2 \cdot c}{b + \sqrt{b \cdot \left(b \cdot \mathsf{fma}\left(a \cdot -4, \frac{c}{b \cdot b}, 1\right)\right)}}
\end{array}
Initial program 16.6%
Applied egg-rr16.7%
flip--N/A
associate-*r/N/A
/-lowering-/.f64N/A
Applied egg-rr17.1%
Taylor expanded in a around 0
*-lowering-*.f6499.9
Simplified99.9%
Taylor expanded in b around inf
unpow2N/A
associate-*l*N/A
*-lowering-*.f64N/A
*-lowering-*.f64N/A
+-commutativeN/A
associate-/l*N/A
associate-*r*N/A
accelerator-lowering-fma.f64N/A
*-commutativeN/A
*-lowering-*.f64N/A
/-lowering-/.f64N/A
unpow2N/A
*-lowering-*.f6499.9
Simplified99.9%
(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(c * Float64(a * -4.0)))))) end
code[a_, b_, c_] := N[(N[(-2.0 * c), $MachinePrecision] / N[(b + N[Sqrt[N[(b * b + N[(c * N[(a * -4.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{-2 \cdot c}{b + \sqrt{\mathsf{fma}\left(b, b, c \cdot \left(a \cdot -4\right)\right)}}
\end{array}
Initial program 16.6%
Applied egg-rr16.7%
flip--N/A
associate-*r/N/A
/-lowering-/.f64N/A
Applied egg-rr17.1%
Taylor expanded in a around 0
*-lowering-*.f6499.9
Simplified99.9%
+-rgt-identityN/A
+-commutativeN/A
accelerator-lowering-fma.f64N/A
*-lowering-*.f64N/A
*-lowering-*.f6499.9
Applied egg-rr99.9%
(FPCore (a b c) :precision binary64 (/ (* -2.0 c) (fma b 2.0 (/ (* c (* -2.0 a)) b))))
double code(double a, double b, double c) {
return (-2.0 * c) / fma(b, 2.0, ((c * (-2.0 * a)) / b));
}
function code(a, b, c) return Float64(Float64(-2.0 * c) / fma(b, 2.0, Float64(Float64(c * Float64(-2.0 * a)) / b))) end
code[a_, b_, c_] := N[(N[(-2.0 * c), $MachinePrecision] / N[(b * 2.0 + N[(N[(c * N[(-2.0 * a), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{-2 \cdot c}{\mathsf{fma}\left(b, 2, \frac{c \cdot \left(-2 \cdot a\right)}{b}\right)}
\end{array}
Initial program 16.6%
Applied egg-rr16.7%
flip--N/A
associate-*r/N/A
/-lowering-/.f64N/A
Applied egg-rr17.1%
Taylor expanded in a around 0
*-lowering-*.f6499.9
Simplified99.9%
Taylor expanded in c around 0
+-commutativeN/A
*-commutativeN/A
*-commutativeN/A
associate-/l*N/A
associate-*r*N/A
*-commutativeN/A
accelerator-lowering-fma.f64N/A
*-commutativeN/A
associate-*r*N/A
associate-/l*N/A
*-commutativeN/A
associate-*r/N/A
/-lowering-/.f64N/A
*-commutativeN/A
*-commutativeN/A
associate-*l*N/A
*-lowering-*.f64N/A
*-lowering-*.f6496.0
Simplified96.0%
Final simplification96.0%
(FPCore (a b c) :precision binary64 (/ (* -2.0 c) (+ b (fma (/ c b) (* -2.0 a) b))))
double code(double a, double b, double c) {
return (-2.0 * c) / (b + fma((c / b), (-2.0 * a), b));
}
function code(a, b, c) return Float64(Float64(-2.0 * c) / Float64(b + fma(Float64(c / b), Float64(-2.0 * a), b))) end
code[a_, b_, c_] := N[(N[(-2.0 * c), $MachinePrecision] / N[(b + N[(N[(c / b), $MachinePrecision] * N[(-2.0 * a), $MachinePrecision] + b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{-2 \cdot c}{b + \mathsf{fma}\left(\frac{c}{b}, -2 \cdot a, b\right)}
\end{array}
Initial program 16.6%
Applied egg-rr16.7%
flip--N/A
associate-*r/N/A
/-lowering-/.f64N/A
Applied egg-rr17.1%
Taylor expanded in a around 0
*-lowering-*.f6499.9
Simplified99.9%
Taylor expanded in c around 0
+-commutativeN/A
associate-*r/N/A
*-commutativeN/A
associate-*r*N/A
associate-*l/N/A
associate-*r/N/A
*-commutativeN/A
associate-*l*N/A
accelerator-lowering-fma.f64N/A
/-lowering-/.f64N/A
*-lowering-*.f6496.0
Simplified96.0%
(FPCore (a b c) :precision binary64 (/ (fma (* c c) (/ a (* b b)) c) (- 0.0 b)))
double code(double a, double b, double c) {
return fma((c * c), (a / (b * b)), c) / (0.0 - b);
}
function code(a, b, c) return Float64(fma(Float64(c * c), Float64(a / Float64(b * b)), c) / Float64(0.0 - b)) end
code[a_, b_, c_] := N[(N[(N[(c * c), $MachinePrecision] * N[(a / N[(b * b), $MachinePrecision]), $MachinePrecision] + c), $MachinePrecision] / N[(0.0 - b), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(c \cdot c, \frac{a}{b \cdot b}, c\right)}{0 - b}
\end{array}
Initial program 16.6%
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-*.f6495.9
Simplified95.9%
Final simplification95.9%
(FPCore (a b c) :precision binary64 (/ (- 0.0 c) b))
double code(double a, double b, double c) {
return (0.0 - 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 = (0.0d0 - c) / b
end function
public static double code(double a, double b, double c) {
return (0.0 - c) / b;
}
def code(a, b, c): return (0.0 - c) / b
function code(a, b, c) return Float64(Float64(0.0 - c) / b) end
function tmp = code(a, b, c) tmp = (0.0 - c) / b; end
code[a_, b_, c_] := N[(N[(0.0 - c), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{0 - c}{b}
\end{array}
Initial program 16.6%
Taylor expanded in b around inf
mul-1-negN/A
neg-sub0N/A
--lowering--.f64N/A
/-lowering-/.f6491.1
Simplified91.1%
sub0-negN/A
neg-lowering-neg.f64N/A
/-lowering-/.f6491.1
Applied egg-rr91.1%
Final simplification91.1%
herbie shell --seed 2024198
(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)))