
(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 7 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 (/ (/ (* c (* a 3.0)) (- (- b) (sqrt (fma b b (* c (* a -3.0)))))) (* a 3.0)))
double code(double a, double b, double c) {
return ((c * (a * 3.0)) / (-b - sqrt(fma(b, b, (c * (a * -3.0)))))) / (a * 3.0);
}
function code(a, b, c) return Float64(Float64(Float64(c * Float64(a * 3.0)) / Float64(Float64(-b) - sqrt(fma(b, b, Float64(c * Float64(a * -3.0)))))) / Float64(a * 3.0)) end
code[a_, b_, c_] := N[(N[(N[(c * N[(a * 3.0), $MachinePrecision]), $MachinePrecision] / N[((-b) - N[Sqrt[N[(b * b + N[(c * N[(a * -3.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(a * 3.0), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\frac{c \cdot \left(a \cdot 3\right)}{\left(-b\right) - \sqrt{\mathsf{fma}\left(b, b, c \cdot \left(a \cdot -3\right)\right)}}}{a \cdot 3}
\end{array}
Initial program 56.1%
neg-sub056.1%
associate-+l-56.1%
sub0-neg56.1%
neg-mul-156.1%
associate-*r/56.1%
metadata-eval56.1%
metadata-eval56.1%
times-frac56.1%
*-commutative56.1%
times-frac56.1%
associate-*l/56.1%
Simplified56.1%
flip-+55.9%
pow255.9%
add-sqr-sqrt57.4%
cancel-sign-sub-inv57.4%
fma-def57.2%
metadata-eval57.2%
*-commutative57.2%
cancel-sign-sub-inv57.2%
fma-def57.2%
metadata-eval57.2%
*-commutative57.2%
Applied egg-rr57.2%
*-commutative57.2%
associate-*r*57.2%
*-commutative57.2%
associate-*r*57.2%
Simplified57.2%
Taylor expanded in b around 0 99.3%
pow199.3%
Applied egg-rr99.3%
unpow199.3%
*-commutative99.3%
associate-*l*99.5%
Simplified99.5%
Final simplification99.5%
(FPCore (a b c) :precision binary64 (/ (* c a) (* a (- (- b) (sqrt (fma b b (* c (* a -3.0))))))))
double code(double a, double b, double c) {
return (c * a) / (a * (-b - sqrt(fma(b, b, (c * (a * -3.0))))));
}
function code(a, b, c) return Float64(Float64(c * a) / Float64(a * Float64(Float64(-b) - sqrt(fma(b, b, Float64(c * Float64(a * -3.0))))))) end
code[a_, b_, c_] := N[(N[(c * a), $MachinePrecision] / N[(a * N[((-b) - N[Sqrt[N[(b * b + N[(c * N[(a * -3.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{c \cdot a}{a \cdot \left(\left(-b\right) - \sqrt{\mathsf{fma}\left(b, b, c \cdot \left(a \cdot -3\right)\right)}\right)}
\end{array}
Initial program 56.1%
neg-sub056.1%
associate-+l-56.1%
sub0-neg56.1%
neg-mul-156.1%
associate-*r/56.1%
metadata-eval56.1%
metadata-eval56.1%
times-frac56.1%
*-commutative56.1%
times-frac56.1%
associate-*l/56.1%
Simplified56.1%
flip-+55.9%
pow255.9%
add-sqr-sqrt57.4%
cancel-sign-sub-inv57.4%
fma-def57.2%
metadata-eval57.2%
*-commutative57.2%
cancel-sign-sub-inv57.2%
fma-def57.2%
metadata-eval57.2%
*-commutative57.2%
Applied egg-rr57.2%
*-commutative57.2%
associate-*r*57.2%
*-commutative57.2%
associate-*r*57.2%
Simplified57.2%
Taylor expanded in b around 0 99.3%
div-inv99.1%
Applied egg-rr99.1%
*-commutative99.1%
times-frac99.1%
associate-*l*99.1%
*-lft-identity99.1%
times-frac99.3%
metadata-eval99.3%
Simplified99.3%
Final simplification99.3%
(FPCore (a b c) :precision binary64 (if (<= b 9.5) (* -0.3333333333333333 (/ (- b (sqrt (fma b b (* a (* c -3.0))))) a)) (+ (* -0.5 (/ c b)) (/ (* a -0.375) (/ (pow b 3.0) (* c c))))))
double code(double a, double b, double c) {
double tmp;
if (b <= 9.5) {
tmp = -0.3333333333333333 * ((b - sqrt(fma(b, b, (a * (c * -3.0))))) / a);
} else {
tmp = (-0.5 * (c / b)) + ((a * -0.375) / (pow(b, 3.0) / (c * c)));
}
return tmp;
}
function code(a, b, c) tmp = 0.0 if (b <= 9.5) tmp = Float64(-0.3333333333333333 * Float64(Float64(b - sqrt(fma(b, b, Float64(a * Float64(c * -3.0))))) / a)); else tmp = Float64(Float64(-0.5 * Float64(c / b)) + Float64(Float64(a * -0.375) / Float64((b ^ 3.0) / Float64(c * c)))); end return tmp end
code[a_, b_, c_] := If[LessEqual[b, 9.5], N[(-0.3333333333333333 * N[(N[(b - N[Sqrt[N[(b * b + N[(a * N[(c * -3.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / a), $MachinePrecision]), $MachinePrecision], N[(N[(-0.5 * N[(c / b), $MachinePrecision]), $MachinePrecision] + N[(N[(a * -0.375), $MachinePrecision] / N[(N[Power[b, 3.0], $MachinePrecision] / N[(c * c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq 9.5:\\
\;\;\;\;-0.3333333333333333 \cdot \frac{b - \sqrt{\mathsf{fma}\left(b, b, a \cdot \left(c \cdot -3\right)\right)}}{a}\\
\mathbf{else}:\\
\;\;\;\;-0.5 \cdot \frac{c}{b} + \frac{a \cdot -0.375}{\frac{{b}^{3}}{c \cdot c}}\\
\end{array}
\end{array}
if b < 9.5Initial program 79.0%
/-rgt-identity79.0%
metadata-eval79.0%
associate-/l*79.0%
associate-*r/79.0%
*-commutative79.0%
associate-*l/79.0%
associate-*r/79.0%
metadata-eval79.0%
metadata-eval79.0%
times-frac79.0%
neg-mul-179.0%
distribute-rgt-neg-in79.0%
times-frac79.0%
metadata-eval79.0%
neg-mul-179.0%
Simplified79.1%
if 9.5 < b Initial program 48.8%
neg-sub048.8%
associate-+l-48.8%
sub0-neg48.8%
neg-mul-148.8%
associate-*r/48.8%
metadata-eval48.8%
metadata-eval48.8%
times-frac48.8%
*-commutative48.8%
times-frac48.8%
associate-*l/48.8%
Simplified48.9%
Taylor expanded in b around inf 88.1%
fma-def88.1%
associate-*r/88.1%
*-commutative88.1%
associate-*r*88.1%
unpow288.1%
Simplified88.1%
fma-udef88.1%
associate-/l*88.1%
*-commutative88.1%
Applied egg-rr88.1%
Final simplification85.9%
(FPCore (a b c) :precision binary64 (if (<= b 9.5) (* (- (sqrt (fma b b (* a (* c -3.0)))) b) (/ 0.3333333333333333 a)) (+ (* -0.5 (/ c b)) (/ (* a -0.375) (/ (pow b 3.0) (* c c))))))
double code(double a, double b, double c) {
double tmp;
if (b <= 9.5) {
tmp = (sqrt(fma(b, b, (a * (c * -3.0)))) - b) * (0.3333333333333333 / a);
} else {
tmp = (-0.5 * (c / b)) + ((a * -0.375) / (pow(b, 3.0) / (c * c)));
}
return tmp;
}
function code(a, b, c) tmp = 0.0 if (b <= 9.5) tmp = Float64(Float64(sqrt(fma(b, b, Float64(a * Float64(c * -3.0)))) - b) * Float64(0.3333333333333333 / a)); else tmp = Float64(Float64(-0.5 * Float64(c / b)) + Float64(Float64(a * -0.375) / Float64((b ^ 3.0) / Float64(c * c)))); end return tmp end
code[a_, b_, c_] := If[LessEqual[b, 9.5], N[(N[(N[Sqrt[N[(b * b + N[(a * N[(c * -3.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] * N[(0.3333333333333333 / a), $MachinePrecision]), $MachinePrecision], N[(N[(-0.5 * N[(c / b), $MachinePrecision]), $MachinePrecision] + N[(N[(a * -0.375), $MachinePrecision] / N[(N[Power[b, 3.0], $MachinePrecision] / N[(c * c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq 9.5:\\
\;\;\;\;\left(\sqrt{\mathsf{fma}\left(b, b, a \cdot \left(c \cdot -3\right)\right)} - b\right) \cdot \frac{0.3333333333333333}{a}\\
\mathbf{else}:\\
\;\;\;\;-0.5 \cdot \frac{c}{b} + \frac{a \cdot -0.375}{\frac{{b}^{3}}{c \cdot c}}\\
\end{array}
\end{array}
if b < 9.5Initial program 79.0%
neg-sub079.0%
associate-+l-79.0%
sub0-neg79.0%
neg-mul-179.0%
associate-*r/79.0%
*-commutative79.0%
metadata-eval79.0%
metadata-eval79.0%
times-frac79.0%
*-commutative79.0%
times-frac79.0%
Simplified79.1%
if 9.5 < b Initial program 48.8%
neg-sub048.8%
associate-+l-48.8%
sub0-neg48.8%
neg-mul-148.8%
associate-*r/48.8%
metadata-eval48.8%
metadata-eval48.8%
times-frac48.8%
*-commutative48.8%
times-frac48.8%
associate-*l/48.8%
Simplified48.9%
Taylor expanded in b around inf 88.1%
fma-def88.1%
associate-*r/88.1%
*-commutative88.1%
associate-*r*88.1%
unpow288.1%
Simplified88.1%
fma-udef88.1%
associate-/l*88.1%
*-commutative88.1%
Applied egg-rr88.1%
Final simplification85.9%
(FPCore (a b c) :precision binary64 (if (<= b 9.5) (/ (- (sqrt (- (* b b) (* 3.0 (* c a)))) b) (* a 3.0)) (+ (* -0.5 (/ c b)) (/ (* a -0.375) (/ (pow b 3.0) (* c c))))))
double code(double a, double b, double c) {
double tmp;
if (b <= 9.5) {
tmp = (sqrt(((b * b) - (3.0 * (c * a)))) - b) / (a * 3.0);
} else {
tmp = (-0.5 * (c / b)) + ((a * -0.375) / (pow(b, 3.0) / (c * c)));
}
return tmp;
}
real(8) function code(a, b, c)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: c
real(8) :: tmp
if (b <= 9.5d0) then
tmp = (sqrt(((b * b) - (3.0d0 * (c * a)))) - b) / (a * 3.0d0)
else
tmp = ((-0.5d0) * (c / b)) + ((a * (-0.375d0)) / ((b ** 3.0d0) / (c * c)))
end if
code = tmp
end function
public static double code(double a, double b, double c) {
double tmp;
if (b <= 9.5) {
tmp = (Math.sqrt(((b * b) - (3.0 * (c * a)))) - b) / (a * 3.0);
} else {
tmp = (-0.5 * (c / b)) + ((a * -0.375) / (Math.pow(b, 3.0) / (c * c)));
}
return tmp;
}
def code(a, b, c): tmp = 0 if b <= 9.5: tmp = (math.sqrt(((b * b) - (3.0 * (c * a)))) - b) / (a * 3.0) else: tmp = (-0.5 * (c / b)) + ((a * -0.375) / (math.pow(b, 3.0) / (c * c))) return tmp
function code(a, b, c) tmp = 0.0 if (b <= 9.5) tmp = Float64(Float64(sqrt(Float64(Float64(b * b) - Float64(3.0 * Float64(c * a)))) - b) / Float64(a * 3.0)); else tmp = Float64(Float64(-0.5 * Float64(c / b)) + Float64(Float64(a * -0.375) / Float64((b ^ 3.0) / Float64(c * c)))); end return tmp end
function tmp_2 = code(a, b, c) tmp = 0.0; if (b <= 9.5) tmp = (sqrt(((b * b) - (3.0 * (c * a)))) - b) / (a * 3.0); else tmp = (-0.5 * (c / b)) + ((a * -0.375) / ((b ^ 3.0) / (c * c))); end tmp_2 = tmp; end
code[a_, b_, c_] := If[LessEqual[b, 9.5], N[(N[(N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(3.0 * N[(c * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] / N[(a * 3.0), $MachinePrecision]), $MachinePrecision], N[(N[(-0.5 * N[(c / b), $MachinePrecision]), $MachinePrecision] + N[(N[(a * -0.375), $MachinePrecision] / N[(N[Power[b, 3.0], $MachinePrecision] / N[(c * c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq 9.5:\\
\;\;\;\;\frac{\sqrt{b \cdot b - 3 \cdot \left(c \cdot a\right)} - b}{a \cdot 3}\\
\mathbf{else}:\\
\;\;\;\;-0.5 \cdot \frac{c}{b} + \frac{a \cdot -0.375}{\frac{{b}^{3}}{c \cdot c}}\\
\end{array}
\end{array}
if b < 9.5Initial program 79.0%
neg-sub079.0%
associate-+l-79.0%
sub0-neg79.0%
neg-mul-179.0%
associate-*r/79.0%
metadata-eval79.0%
metadata-eval79.0%
times-frac79.0%
*-commutative79.0%
times-frac79.0%
associate-*l/79.0%
Simplified79.0%
if 9.5 < b Initial program 48.8%
neg-sub048.8%
associate-+l-48.8%
sub0-neg48.8%
neg-mul-148.8%
associate-*r/48.8%
metadata-eval48.8%
metadata-eval48.8%
times-frac48.8%
*-commutative48.8%
times-frac48.8%
associate-*l/48.8%
Simplified48.9%
Taylor expanded in b around inf 88.1%
fma-def88.1%
associate-*r/88.1%
*-commutative88.1%
associate-*r*88.1%
unpow288.1%
Simplified88.1%
fma-udef88.1%
associate-/l*88.1%
*-commutative88.1%
Applied egg-rr88.1%
Final simplification85.9%
(FPCore (a b c) :precision binary64 (+ (* -0.5 (/ c b)) (/ (* a -0.375) (/ (pow b 3.0) (* c c)))))
double code(double a, double b, double c) {
return (-0.5 * (c / b)) + ((a * -0.375) / (pow(b, 3.0) / (c * c)));
}
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)) + ((a * (-0.375d0)) / ((b ** 3.0d0) / (c * c)))
end function
public static double code(double a, double b, double c) {
return (-0.5 * (c / b)) + ((a * -0.375) / (Math.pow(b, 3.0) / (c * c)));
}
def code(a, b, c): return (-0.5 * (c / b)) + ((a * -0.375) / (math.pow(b, 3.0) / (c * c)))
function code(a, b, c) return Float64(Float64(-0.5 * Float64(c / b)) + Float64(Float64(a * -0.375) / Float64((b ^ 3.0) / Float64(c * c)))) end
function tmp = code(a, b, c) tmp = (-0.5 * (c / b)) + ((a * -0.375) / ((b ^ 3.0) / (c * c))); end
code[a_, b_, c_] := N[(N[(-0.5 * N[(c / b), $MachinePrecision]), $MachinePrecision] + N[(N[(a * -0.375), $MachinePrecision] / N[(N[Power[b, 3.0], $MachinePrecision] / N[(c * c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
-0.5 \cdot \frac{c}{b} + \frac{a \cdot -0.375}{\frac{{b}^{3}}{c \cdot c}}
\end{array}
Initial program 56.1%
neg-sub056.1%
associate-+l-56.1%
sub0-neg56.1%
neg-mul-156.1%
associate-*r/56.1%
metadata-eval56.1%
metadata-eval56.1%
times-frac56.1%
*-commutative56.1%
times-frac56.1%
associate-*l/56.1%
Simplified56.2%
Taylor expanded in b around inf 82.2%
fma-def82.2%
associate-*r/82.2%
*-commutative82.2%
associate-*r*82.2%
unpow282.2%
Simplified82.2%
fma-udef82.2%
associate-/l*82.2%
*-commutative82.2%
Applied egg-rr82.2%
Final simplification82.2%
(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 56.1%
neg-sub056.1%
associate-+l-56.1%
sub0-neg56.1%
neg-mul-156.1%
associate-*r/56.1%
metadata-eval56.1%
metadata-eval56.1%
times-frac56.1%
*-commutative56.1%
times-frac56.1%
associate-*l/56.1%
Simplified56.2%
Taylor expanded in b around inf 64.2%
Final simplification64.2%
herbie shell --seed 2023229
(FPCore (a b c)
:name "Cubic critical, narrow range"
:precision binary64
:pre (and (and (and (< 1.0536712127723509e-8 a) (< a 94906265.62425156)) (and (< 1.0536712127723509e-8 b) (< b 94906265.62425156))) (and (< 1.0536712127723509e-8 c) (< c 94906265.62425156)))
(/ (+ (- b) (sqrt (- (* b b) (* (* 3.0 a) c)))) (* 3.0 a)))