
(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
(-
(-
(fma
-2.0
(/ (pow c 3.0) (/ (pow b 5.0) (* a a)))
(/ (/ (* -5.0 (pow c 4.0)) (/ (pow b 6.0) (pow a 3.0))) b))
(/ c b))
(/ (* c c) (/ (pow b 3.0) a))))
double code(double a, double b, double c) {
return (fma(-2.0, (pow(c, 3.0) / (pow(b, 5.0) / (a * a))), (((-5.0 * pow(c, 4.0)) / (pow(b, 6.0) / pow(a, 3.0))) / b)) - (c / b)) - ((c * c) / (pow(b, 3.0) / a));
}
function code(a, b, c) return Float64(Float64(fma(-2.0, Float64((c ^ 3.0) / Float64((b ^ 5.0) / Float64(a * a))), Float64(Float64(Float64(-5.0 * (c ^ 4.0)) / Float64((b ^ 6.0) / (a ^ 3.0))) / b)) - Float64(c / b)) - Float64(Float64(c * c) / Float64((b ^ 3.0) / a))) end
code[a_, b_, c_] := N[(N[(N[(-2.0 * N[(N[Power[c, 3.0], $MachinePrecision] / N[(N[Power[b, 5.0], $MachinePrecision] / N[(a * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(N[(N[(-5.0 * N[Power[c, 4.0], $MachinePrecision]), $MachinePrecision] / N[(N[Power[b, 6.0], $MachinePrecision] / N[Power[a, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]), $MachinePrecision] - N[(c / b), $MachinePrecision]), $MachinePrecision] - N[(N[(c * c), $MachinePrecision] / N[(N[Power[b, 3.0], $MachinePrecision] / a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\left(\mathsf{fma}\left(-2, \frac{{c}^{3}}{\frac{{b}^{5}}{a \cdot a}}, \frac{\frac{-5 \cdot {c}^{4}}{\frac{{b}^{6}}{{a}^{3}}}}{b}\right) - \frac{c}{b}\right) - \frac{c \cdot c}{\frac{{b}^{3}}{a}}
\end{array}
Initial program 31.6%
/-rgt-identity31.6%
metadata-eval31.6%
associate-/l*31.6%
associate-*r/31.6%
+-commutative31.6%
unsub-neg31.6%
fma-neg31.6%
associate-*l*31.6%
*-commutative31.6%
distribute-rgt-neg-in31.6%
metadata-eval31.6%
associate-/r*31.6%
metadata-eval31.6%
metadata-eval31.6%
Simplified31.6%
Taylor expanded in a around 0 96.6%
Simplified96.6%
Taylor expanded in c around 0 96.6%
associate-/l*96.6%
associate-*r/96.6%
Simplified96.6%
Final simplification96.6%
(FPCore (a b c) :precision binary64 (- (fma -0.25 (/ (* (pow (* c a) 4.0) 20.0) (* a (pow b 7.0))) (- (* -2.0 (/ (pow c 3.0) (/ (pow b 5.0) (* a a)))) (/ c b))) (/ (* a (* c c)) (pow b 3.0))))
double code(double a, double b, double c) {
return fma(-0.25, ((pow((c * a), 4.0) * 20.0) / (a * pow(b, 7.0))), ((-2.0 * (pow(c, 3.0) / (pow(b, 5.0) / (a * a)))) - (c / b))) - ((a * (c * c)) / pow(b, 3.0));
}
function code(a, b, c) return Float64(fma(-0.25, Float64(Float64((Float64(c * a) ^ 4.0) * 20.0) / Float64(a * (b ^ 7.0))), Float64(Float64(-2.0 * Float64((c ^ 3.0) / Float64((b ^ 5.0) / Float64(a * a)))) - Float64(c / b))) - Float64(Float64(a * Float64(c * c)) / (b ^ 3.0))) end
code[a_, b_, c_] := N[(N[(-0.25 * N[(N[(N[Power[N[(c * a), $MachinePrecision], 4.0], $MachinePrecision] * 20.0), $MachinePrecision] / N[(a * N[Power[b, 7.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(N[(-2.0 * N[(N[Power[c, 3.0], $MachinePrecision] / N[(N[Power[b, 5.0], $MachinePrecision] / N[(a * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(c / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(N[(a * N[(c * c), $MachinePrecision]), $MachinePrecision] / N[Power[b, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(-0.25, \frac{{\left(c \cdot a\right)}^{4} \cdot 20}{a \cdot {b}^{7}}, -2 \cdot \frac{{c}^{3}}{\frac{{b}^{5}}{a \cdot a}} - \frac{c}{b}\right) - \frac{a \cdot \left(c \cdot c\right)}{{b}^{3}}
\end{array}
Initial program 31.6%
*-commutative31.6%
+-commutative31.6%
unsub-neg31.6%
fma-neg31.6%
associate-*l*31.6%
*-commutative31.6%
distribute-rgt-neg-in31.6%
metadata-eval31.6%
Simplified31.6%
fma-udef31.6%
*-commutative31.6%
metadata-eval31.6%
cancel-sign-sub-inv31.6%
associate-*l*31.6%
*-un-lft-identity31.6%
prod-diff31.6%
Applied egg-rr31.5%
*-rgt-identity31.5%
fma-neg31.4%
fma-udef31.4%
*-rgt-identity31.4%
*-rgt-identity31.4%
associate--r-31.6%
associate--r+31.6%
+-inverses31.6%
neg-sub031.6%
associate-*r*31.6%
distribute-rgt-neg-in31.6%
metadata-eval31.6%
*-commutative31.6%
associate-*r*31.6%
Simplified31.6%
div-sub31.3%
Applied egg-rr31.3%
Taylor expanded in b around inf 96.6%
Simplified96.6%
Final simplification96.6%
(FPCore (a b c) :precision binary64 (- (- (* -2.0 (/ (pow c 3.0) (/ (pow b 5.0) (* a a)))) (/ c b)) (/ (* a (* c c)) (pow b 3.0))))
double code(double a, double b, double c) {
return ((-2.0 * (pow(c, 3.0) / (pow(b, 5.0) / (a * a)))) - (c / b)) - ((a * (c * c)) / pow(b, 3.0));
}
real(8) function code(a, b, c)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: c
code = (((-2.0d0) * ((c ** 3.0d0) / ((b ** 5.0d0) / (a * a)))) - (c / b)) - ((a * (c * c)) / (b ** 3.0d0))
end function
public static double code(double a, double b, double c) {
return ((-2.0 * (Math.pow(c, 3.0) / (Math.pow(b, 5.0) / (a * a)))) - (c / b)) - ((a * (c * c)) / Math.pow(b, 3.0));
}
def code(a, b, c): return ((-2.0 * (math.pow(c, 3.0) / (math.pow(b, 5.0) / (a * a)))) - (c / b)) - ((a * (c * c)) / math.pow(b, 3.0))
function code(a, b, c) return Float64(Float64(Float64(-2.0 * Float64((c ^ 3.0) / Float64((b ^ 5.0) / Float64(a * a)))) - Float64(c / b)) - Float64(Float64(a * Float64(c * c)) / (b ^ 3.0))) end
function tmp = code(a, b, c) tmp = ((-2.0 * ((c ^ 3.0) / ((b ^ 5.0) / (a * a)))) - (c / b)) - ((a * (c * c)) / (b ^ 3.0)); end
code[a_, b_, c_] := N[(N[(N[(-2.0 * N[(N[Power[c, 3.0], $MachinePrecision] / N[(N[Power[b, 5.0], $MachinePrecision] / N[(a * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(c / b), $MachinePrecision]), $MachinePrecision] - N[(N[(a * N[(c * c), $MachinePrecision]), $MachinePrecision] / N[Power[b, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\left(-2 \cdot \frac{{c}^{3}}{\frac{{b}^{5}}{a \cdot a}} - \frac{c}{b}\right) - \frac{a \cdot \left(c \cdot c\right)}{{b}^{3}}
\end{array}
Initial program 31.6%
*-commutative31.6%
+-commutative31.6%
unsub-neg31.6%
fma-neg31.6%
associate-*l*31.6%
*-commutative31.6%
distribute-rgt-neg-in31.6%
metadata-eval31.6%
Simplified31.6%
fma-udef31.6%
*-commutative31.6%
metadata-eval31.6%
cancel-sign-sub-inv31.6%
associate-*l*31.6%
*-un-lft-identity31.6%
prod-diff31.6%
Applied egg-rr31.5%
*-rgt-identity31.5%
fma-neg31.4%
fma-udef31.4%
*-rgt-identity31.4%
*-rgt-identity31.4%
associate--r-31.6%
associate--r+31.6%
+-inverses31.6%
neg-sub031.6%
associate-*r*31.6%
distribute-rgt-neg-in31.6%
metadata-eval31.6%
*-commutative31.6%
associate-*r*31.6%
Simplified31.6%
div-sub31.3%
Applied egg-rr31.3%
Taylor expanded in b around inf 94.7%
+-commutative94.7%
mul-1-neg94.7%
unsub-neg94.7%
+-commutative94.7%
mul-1-neg94.7%
unsub-neg94.7%
associate-/l*94.7%
unpow294.7%
*-commutative94.7%
unpow294.7%
Simplified94.7%
Final simplification94.7%
(FPCore (a b c) :precision binary64 (- (/ (- c) b) (/ (* c c) (/ (pow b 3.0) a))))
double code(double a, double b, double c) {
return (-c / b) - ((c * c) / (pow(b, 3.0) / a));
}
real(8) function code(a, b, c)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: c
code = (-c / b) - ((c * c) / ((b ** 3.0d0) / a))
end function
public static double code(double a, double b, double c) {
return (-c / b) - ((c * c) / (Math.pow(b, 3.0) / a));
}
def code(a, b, c): return (-c / b) - ((c * c) / (math.pow(b, 3.0) / a))
function code(a, b, c) return Float64(Float64(Float64(-c) / b) - Float64(Float64(c * c) / Float64((b ^ 3.0) / a))) end
function tmp = code(a, b, c) tmp = (-c / b) - ((c * c) / ((b ^ 3.0) / a)); end
code[a_, b_, c_] := N[(N[((-c) / b), $MachinePrecision] - N[(N[(c * c), $MachinePrecision] / N[(N[Power[b, 3.0], $MachinePrecision] / a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{-c}{b} - \frac{c \cdot c}{\frac{{b}^{3}}{a}}
\end{array}
Initial program 31.6%
/-rgt-identity31.6%
metadata-eval31.6%
associate-/l*31.6%
associate-*r/31.6%
+-commutative31.6%
unsub-neg31.6%
fma-neg31.6%
associate-*l*31.6%
*-commutative31.6%
distribute-rgt-neg-in31.6%
metadata-eval31.6%
associate-/r*31.6%
metadata-eval31.6%
metadata-eval31.6%
Simplified31.6%
Taylor expanded in b around inf 90.9%
+-commutative90.9%
mul-1-neg90.9%
unsub-neg90.9%
mul-1-neg90.9%
distribute-neg-frac90.9%
associate-/l*90.9%
unpow290.9%
Simplified90.9%
Final simplification90.9%
(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 31.6%
/-rgt-identity31.6%
metadata-eval31.6%
associate-/l*31.6%
associate-*r/31.6%
+-commutative31.6%
unsub-neg31.6%
fma-neg31.6%
associate-*l*31.6%
*-commutative31.6%
distribute-rgt-neg-in31.6%
metadata-eval31.6%
associate-/r*31.6%
metadata-eval31.6%
metadata-eval31.6%
Simplified31.6%
Taylor expanded in b around inf 81.0%
mul-1-neg81.0%
distribute-neg-frac81.0%
Simplified81.0%
Final simplification81.0%
herbie shell --seed 2023224
(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)))