
(FPCore (a b c) :precision binary64 (/ (+ (- b) (sqrt (- (* b b) (* (* 3.0 a) c)))) (* 3.0 a)))
double code(double a, double b, double c) {
return (-b + sqrt(((b * b) - ((3.0 * a) * c)))) / (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 = (-b + sqrt(((b * b) - ((3.0d0 * a) * c)))) / (3.0d0 * a)
end function
public static double code(double a, double b, double c) {
return (-b + Math.sqrt(((b * b) - ((3.0 * a) * c)))) / (3.0 * a);
}
def code(a, b, c): return (-b + math.sqrt(((b * b) - ((3.0 * a) * c)))) / (3.0 * a)
function code(a, b, c) return Float64(Float64(Float64(-b) + sqrt(Float64(Float64(b * b) - Float64(Float64(3.0 * a) * c)))) / Float64(3.0 * a)) end
function tmp = code(a, b, c) tmp = (-b + sqrt(((b * b) - ((3.0 * a) * c)))) / (3.0 * a); end
code[a_, b_, c_] := N[(N[((-b) + N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(N[(3.0 * a), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / N[(3.0 * a), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\left(-b\right) + \sqrt{b \cdot b - \left(3 \cdot a\right) \cdot c}}{3 \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) (* (* 3.0 a) c)))) (* 3.0 a)))
double code(double a, double b, double c) {
return (-b + sqrt(((b * b) - ((3.0 * a) * c)))) / (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 = (-b + sqrt(((b * b) - ((3.0d0 * a) * c)))) / (3.0d0 * a)
end function
public static double code(double a, double b, double c) {
return (-b + Math.sqrt(((b * b) - ((3.0 * a) * c)))) / (3.0 * a);
}
def code(a, b, c): return (-b + math.sqrt(((b * b) - ((3.0 * a) * c)))) / (3.0 * a)
function code(a, b, c) return Float64(Float64(Float64(-b) + sqrt(Float64(Float64(b * b) - Float64(Float64(3.0 * a) * c)))) / Float64(3.0 * a)) end
function tmp = code(a, b, c) tmp = (-b + sqrt(((b * b) - ((3.0 * a) * c)))) / (3.0 * a); end
code[a_, b_, c_] := N[(N[((-b) + N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(N[(3.0 * a), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / N[(3.0 * a), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\left(-b\right) + \sqrt{b \cdot b - \left(3 \cdot a\right) \cdot c}}{3 \cdot a}
\end{array}
(FPCore (a b c) :precision binary64 (+ (fma -0.5625 (* (/ a (/ (pow b 5.0) a)) (pow c 3.0)) (fma -0.5 (/ c b) (/ -0.375 (/ (/ (pow b 3.0) (* c c)) a)))) (/ (* (/ -0.16666666666666666 (pow b 7.0)) (pow (* a c) 4.0)) (* a 0.1580246913580247))))
double code(double a, double b, double c) {
return fma(-0.5625, ((a / (pow(b, 5.0) / a)) * pow(c, 3.0)), fma(-0.5, (c / b), (-0.375 / ((pow(b, 3.0) / (c * c)) / a)))) + (((-0.16666666666666666 / pow(b, 7.0)) * pow((a * c), 4.0)) / (a * 0.1580246913580247));
}
function code(a, b, c) return Float64(fma(-0.5625, Float64(Float64(a / Float64((b ^ 5.0) / a)) * (c ^ 3.0)), fma(-0.5, Float64(c / b), Float64(-0.375 / Float64(Float64((b ^ 3.0) / Float64(c * c)) / a)))) + Float64(Float64(Float64(-0.16666666666666666 / (b ^ 7.0)) * (Float64(a * c) ^ 4.0)) / Float64(a * 0.1580246913580247))) end
code[a_, b_, c_] := N[(N[(-0.5625 * N[(N[(a / N[(N[Power[b, 5.0], $MachinePrecision] / a), $MachinePrecision]), $MachinePrecision] * N[Power[c, 3.0], $MachinePrecision]), $MachinePrecision] + N[(-0.5 * N[(c / b), $MachinePrecision] + N[(-0.375 / N[(N[(N[Power[b, 3.0], $MachinePrecision] / N[(c * c), $MachinePrecision]), $MachinePrecision] / a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(N[(N[(-0.16666666666666666 / N[Power[b, 7.0], $MachinePrecision]), $MachinePrecision] * N[Power[N[(a * c), $MachinePrecision], 4.0], $MachinePrecision]), $MachinePrecision] / N[(a * 0.1580246913580247), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(-0.5625, \frac{a}{\frac{{b}^{5}}{a}} \cdot {c}^{3}, \mathsf{fma}\left(-0.5, \frac{c}{b}, \frac{-0.375}{\frac{\frac{{b}^{3}}{c \cdot c}}{a}}\right)\right) + \frac{\frac{-0.16666666666666666}{{b}^{7}} \cdot {\left(a \cdot c\right)}^{4}}{a \cdot 0.1580246913580247}
\end{array}
Initial program 28.6%
neg-sub028.6%
sqr-neg28.6%
associate-+l-28.6%
sub0-neg28.6%
neg-mul-128.6%
Simplified28.6%
div-inv28.6%
metadata-eval28.6%
*-commutative28.6%
add-sqr-sqrt28.6%
pow228.6%
Applied egg-rr28.6%
Taylor expanded in b around inf 95.8%
Simplified96.8%
associate-*r/96.8%
associate-/r*96.8%
metadata-eval96.8%
div-inv96.8%
metadata-eval96.8%
Applied egg-rr96.8%
Final simplification96.8%
(FPCore (a b c) :precision binary64 (fma -0.5625 (* a (/ (pow c 3.0) (/ (pow b 5.0) a))) (fma -0.375 (/ a (/ (/ (pow b 3.0) c) c)) (/ -0.5 (/ b c)))))
double code(double a, double b, double c) {
return fma(-0.5625, (a * (pow(c, 3.0) / (pow(b, 5.0) / a))), fma(-0.375, (a / ((pow(b, 3.0) / c) / c)), (-0.5 / (b / c))));
}
function code(a, b, c) return fma(-0.5625, Float64(a * Float64((c ^ 3.0) / Float64((b ^ 5.0) / a))), fma(-0.375, Float64(a / Float64(Float64((b ^ 3.0) / c) / c)), Float64(-0.5 / Float64(b / c)))) end
code[a_, b_, c_] := N[(-0.5625 * N[(a * N[(N[Power[c, 3.0], $MachinePrecision] / N[(N[Power[b, 5.0], $MachinePrecision] / a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(-0.375 * N[(a / N[(N[(N[Power[b, 3.0], $MachinePrecision] / c), $MachinePrecision] / c), $MachinePrecision]), $MachinePrecision] + N[(-0.5 / N[(b / c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(-0.5625, a \cdot \frac{{c}^{3}}{\frac{{b}^{5}}{a}}, \mathsf{fma}\left(-0.375, \frac{a}{\frac{\frac{{b}^{3}}{c}}{c}}, \frac{-0.5}{\frac{b}{c}}\right)\right)
\end{array}
Initial program 28.6%
neg-sub028.6%
sqr-neg28.6%
associate-+l-28.6%
sub0-neg28.6%
neg-mul-128.6%
Simplified28.6%
clear-num28.6%
inv-pow28.6%
Applied egg-rr28.6%
div-sub28.1%
unpow-128.1%
unpow-128.1%
Applied egg-rr28.1%
Taylor expanded in b around inf 95.7%
fma-def95.7%
*-commutative95.7%
unpow295.7%
associate-*r*95.7%
*-commutative95.7%
associate-*l/95.7%
*-commutative95.7%
*-commutative95.7%
associate-/l*95.7%
+-commutative95.7%
fma-def95.7%
associate-/l*95.7%
unpow295.7%
associate-/r*95.7%
associate-*r/95.7%
associate-/l*95.3%
Simplified95.3%
Final simplification95.3%
(FPCore (a b c) :precision binary64 (fma -0.5625 (/ (* a a) (/ (pow b 5.0) (pow c 3.0))) (fma -0.5 (/ c b) (* -0.375 (/ a (/ (pow b 3.0) (* c c)))))))
double code(double a, double b, double c) {
return fma(-0.5625, ((a * a) / (pow(b, 5.0) / pow(c, 3.0))), fma(-0.5, (c / b), (-0.375 * (a / (pow(b, 3.0) / (c * c))))));
}
function code(a, b, c) return fma(-0.5625, Float64(Float64(a * a) / Float64((b ^ 5.0) / (c ^ 3.0))), fma(-0.5, Float64(c / b), Float64(-0.375 * Float64(a / Float64((b ^ 3.0) / Float64(c * c)))))) end
code[a_, b_, c_] := N[(-0.5625 * N[(N[(a * a), $MachinePrecision] / N[(N[Power[b, 5.0], $MachinePrecision] / N[Power[c, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(-0.5 * N[(c / b), $MachinePrecision] + N[(-0.375 * N[(a / N[(N[Power[b, 3.0], $MachinePrecision] / N[(c * c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(-0.5625, \frac{a \cdot a}{\frac{{b}^{5}}{{c}^{3}}}, \mathsf{fma}\left(-0.5, \frac{c}{b}, -0.375 \cdot \frac{a}{\frac{{b}^{3}}{c \cdot c}}\right)\right)
\end{array}
Initial program 28.6%
sqr-neg28.6%
sqr-neg28.6%
associate-*l*28.6%
Simplified28.6%
Taylor expanded in b around inf 95.7%
fma-def95.7%
associate-/l*95.7%
unpow295.7%
fma-def95.7%
associate-/l*95.7%
unpow295.7%
Simplified95.7%
Final simplification95.7%
(FPCore (a b c) :precision binary64 (fma -0.375 (* (* c c) (/ a (pow b 3.0))) (* -0.5 (/ c b))))
double code(double a, double b, double c) {
return fma(-0.375, ((c * c) * (a / pow(b, 3.0))), (-0.5 * (c / b)));
}
function code(a, b, c) return fma(-0.375, Float64(Float64(c * c) * Float64(a / (b ^ 3.0))), Float64(-0.5 * Float64(c / b))) end
code[a_, b_, c_] := N[(-0.375 * N[(N[(c * c), $MachinePrecision] * N[(a / N[Power[b, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(-0.5 * N[(c / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(-0.375, \left(c \cdot c\right) \cdot \frac{a}{{b}^{3}}, -0.5 \cdot \frac{c}{b}\right)
\end{array}
Initial program 28.6%
sqr-neg28.6%
sqr-neg28.6%
associate-*l*28.6%
Simplified28.6%
Taylor expanded in b around inf 93.0%
+-commutative93.0%
fma-def93.0%
associate-/l*93.0%
associate-/r/93.0%
unpow293.0%
Simplified93.0%
Final simplification93.0%
(FPCore (a b c) :precision binary64 (* -0.5 (/ c b)))
double code(double a, double b, double c) {
return -0.5 * (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 = (-0.5d0) * (c / b)
end function
public static double code(double a, double b, double c) {
return -0.5 * (c / b);
}
def code(a, b, c): return -0.5 * (c / b)
function code(a, b, c) return Float64(-0.5 * Float64(c / b)) end
function tmp = code(a, b, c) tmp = -0.5 * (c / b); end
code[a_, b_, c_] := N[(-0.5 * N[(c / b), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
-0.5 \cdot \frac{c}{b}
\end{array}
Initial program 28.6%
sqr-neg28.6%
sqr-neg28.6%
associate-*l*28.6%
Simplified28.6%
Taylor expanded in b around inf 83.8%
Final simplification83.8%
herbie shell --seed 2023275
(FPCore (a b c)
:name "Cubic critical, 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) (* (* 3.0 a) c)))) (* 3.0 a)))