
(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 5 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 (pow (* c a) 4.0)))
(fma
-1.0
(/ (* c c) (/ (pow b 3.0) a))
(fma
-0.25
(/ (+ (* 4.0 t_0) (* t_0 16.0)) (* a (pow b 7.0)))
(fma -1.0 (/ c b) (* -2.0 (/ (pow c 3.0) (/ (pow b 5.0) (* a a)))))))))
double code(double a, double b, double c) {
double t_0 = pow((c * a), 4.0);
return fma(-1.0, ((c * c) / (pow(b, 3.0) / a)), fma(-0.25, (((4.0 * t_0) + (t_0 * 16.0)) / (a * pow(b, 7.0))), fma(-1.0, (c / b), (-2.0 * (pow(c, 3.0) / (pow(b, 5.0) / (a * a)))))));
}
function code(a, b, c) t_0 = Float64(c * a) ^ 4.0 return fma(-1.0, Float64(Float64(c * c) / Float64((b ^ 3.0) / a)), fma(-0.25, Float64(Float64(Float64(4.0 * t_0) + Float64(t_0 * 16.0)) / Float64(a * (b ^ 7.0))), fma(-1.0, Float64(c / b), Float64(-2.0 * Float64((c ^ 3.0) / Float64((b ^ 5.0) / Float64(a * a))))))) end
code[a_, b_, c_] := Block[{t$95$0 = N[Power[N[(c * a), $MachinePrecision], 4.0], $MachinePrecision]}, N[(-1.0 * N[(N[(c * c), $MachinePrecision] / N[(N[Power[b, 3.0], $MachinePrecision] / a), $MachinePrecision]), $MachinePrecision] + N[(-0.25 * N[(N[(N[(4.0 * t$95$0), $MachinePrecision] + N[(t$95$0 * 16.0), $MachinePrecision]), $MachinePrecision] / N[(a * N[Power[b, 7.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(-1.0 * N[(c / b), $MachinePrecision] + N[(-2.0 * N[(N[Power[c, 3.0], $MachinePrecision] / N[(N[Power[b, 5.0], $MachinePrecision] / N[(a * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := {\left(c \cdot a\right)}^{4}\\
\mathsf{fma}\left(-1, \frac{c \cdot c}{\frac{{b}^{3}}{a}}, \mathsf{fma}\left(-0.25, \frac{4 \cdot t_0 + t_0 \cdot 16}{a \cdot {b}^{7}}, \mathsf{fma}\left(-1, \frac{c}{b}, -2 \cdot \frac{{c}^{3}}{\frac{{b}^{5}}{a \cdot a}}\right)\right)\right)
\end{array}
\end{array}
Initial program 25.9%
Taylor expanded in b around inf 96.4%
fma-def96.4%
associate-/l*96.4%
unpow296.4%
fma-def96.4%
Simplified96.4%
pow196.4%
pow-prod-down96.4%
Applied egg-rr96.4%
unpow196.4%
Simplified96.4%
Taylor expanded in c around 0 96.4%
metadata-eval96.4%
pow-sqr96.4%
unpow296.4%
unpow296.4%
metadata-eval96.4%
pow-plus96.4%
unpow396.4%
associate-*r*96.4%
unswap-sqr96.4%
swap-sqr96.4%
swap-sqr96.4%
unpow296.4%
unpow296.4%
pow-sqr96.4%
metadata-eval96.4%
Simplified96.4%
Final simplification96.4%
(FPCore (a b c)
:precision binary64
(-
(-
(fma
-0.25
(/ (pow a 3.0) (/ (pow b 7.0) (* (pow c 4.0) 20.0)))
(* -2.0 (* (* a a) (/ (pow c 3.0) (pow b 5.0)))))
(/ c b))
(* a (/ c (/ (pow b 3.0) c)))))
double code(double a, double b, double c) {
return (fma(-0.25, (pow(a, 3.0) / (pow(b, 7.0) / (pow(c, 4.0) * 20.0))), (-2.0 * ((a * a) * (pow(c, 3.0) / pow(b, 5.0))))) - (c / b)) - (a * (c / (pow(b, 3.0) / c)));
}
function code(a, b, c) return Float64(Float64(fma(-0.25, Float64((a ^ 3.0) / Float64((b ^ 7.0) / Float64((c ^ 4.0) * 20.0))), Float64(-2.0 * Float64(Float64(a * a) * Float64((c ^ 3.0) / (b ^ 5.0))))) - Float64(c / b)) - Float64(a * Float64(c / Float64((b ^ 3.0) / c)))) end
code[a_, b_, c_] := N[(N[(N[(-0.25 * N[(N[Power[a, 3.0], $MachinePrecision] / N[(N[Power[b, 7.0], $MachinePrecision] / N[(N[Power[c, 4.0], $MachinePrecision] * 20.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(-2.0 * N[(N[(a * a), $MachinePrecision] * N[(N[Power[c, 3.0], $MachinePrecision] / N[Power[b, 5.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(c / b), $MachinePrecision]), $MachinePrecision] - N[(a * N[(c / N[(N[Power[b, 3.0], $MachinePrecision] / c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\left(\mathsf{fma}\left(-0.25, \frac{{a}^{3}}{\frac{{b}^{7}}{{c}^{4} \cdot 20}}, -2 \cdot \left(\left(a \cdot a\right) \cdot \frac{{c}^{3}}{{b}^{5}}\right)\right) - \frac{c}{b}\right) - a \cdot \frac{c}{\frac{{b}^{3}}{c}}
\end{array}
Initial program 25.9%
Taylor expanded in a around 0 96.4%
Simplified96.4%
Taylor expanded in b around 0 96.4%
associate-/l*96.4%
distribute-rgt-out96.4%
metadata-eval96.4%
Simplified96.4%
Final simplification96.4%
(FPCore (a b c) :precision binary64 (- (fma -2.0 (* (* a a) (/ (pow c 3.0) (pow b 5.0))) (/ (- c) b)) (* a (/ c (/ (pow b 3.0) c)))))
double code(double a, double b, double c) {
return fma(-2.0, ((a * a) * (pow(c, 3.0) / pow(b, 5.0))), (-c / b)) - (a * (c / (pow(b, 3.0) / c)));
}
function code(a, b, c) return Float64(fma(-2.0, Float64(Float64(a * a) * Float64((c ^ 3.0) / (b ^ 5.0))), Float64(Float64(-c) / b)) - Float64(a * Float64(c / Float64((b ^ 3.0) / c)))) end
code[a_, b_, c_] := N[(N[(-2.0 * N[(N[(a * a), $MachinePrecision] * N[(N[Power[c, 3.0], $MachinePrecision] / N[Power[b, 5.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[((-c) / b), $MachinePrecision]), $MachinePrecision] - N[(a * N[(c / N[(N[Power[b, 3.0], $MachinePrecision] / c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(-2, \left(a \cdot a\right) \cdot \frac{{c}^{3}}{{b}^{5}}, \frac{-c}{b}\right) - a \cdot \frac{c}{\frac{{b}^{3}}{c}}
\end{array}
Initial program 25.9%
Taylor expanded in b around inf 95.1%
+-commutative95.1%
mul-1-neg95.1%
unsub-neg95.1%
+-commutative95.1%
fma-def95.1%
associate-/l*95.1%
associate-/r/95.1%
unpow295.1%
mul-1-neg95.1%
distribute-neg-frac95.1%
associate-/l*95.1%
associate-/r/95.1%
unpow295.1%
associate-/l*95.1%
Simplified95.1%
Final simplification95.1%
(FPCore (a b c) :precision binary64 (- (/ (- c) b) (* a (/ c (/ (pow b 3.0) c)))))
double code(double a, double b, double c) {
return (-c / b) - (a * (c / (pow(b, 3.0) / c)));
}
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) - (a * (c / ((b ** 3.0d0) / c)))
end function
public static double code(double a, double b, double c) {
return (-c / b) - (a * (c / (Math.pow(b, 3.0) / c)));
}
def code(a, b, c): return (-c / b) - (a * (c / (math.pow(b, 3.0) / c)))
function code(a, b, c) return Float64(Float64(Float64(-c) / b) - Float64(a * Float64(c / Float64((b ^ 3.0) / c)))) end
function tmp = code(a, b, c) tmp = (-c / b) - (a * (c / ((b ^ 3.0) / c))); end
code[a_, b_, c_] := N[(N[((-c) / b), $MachinePrecision] - N[(a * N[(c / N[(N[Power[b, 3.0], $MachinePrecision] / c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{-c}{b} - a \cdot \frac{c}{\frac{{b}^{3}}{c}}
\end{array}
Initial program 25.9%
Taylor expanded in b around inf 92.7%
+-commutative92.7%
mul-1-neg92.7%
unsub-neg92.7%
mul-1-neg92.7%
distribute-neg-frac92.7%
associate-/l*92.7%
associate-/r/92.7%
unpow292.7%
associate-/l*92.7%
Simplified92.7%
Final simplification92.7%
(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 25.9%
Taylor expanded in b around inf 85.2%
mul-1-neg85.2%
distribute-neg-frac85.2%
Simplified85.2%
Final simplification85.2%
herbie shell --seed 2023274
(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)))