
(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 6 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
(let* ((t_0 (pow (* a c) 4.0)))
(if (<= (/ (- (sqrt (- (* b b) (* (* 3.0 a) c))) b) (* 3.0 a)) -26.0)
(/ (- (sqrt (fma b b (* a (* c -3.0)))) b) (* 3.0 a))
(+
(* -0.5625 (/ (* (pow a 2.0) (pow c 3.0)) (pow b 5.0)))
(+
(* -0.5 (/ c b))
(+
(* -0.375 (/ (* a (pow c 2.0)) (pow b 3.0)))
(*
-0.16666666666666666
(/ (+ (* 5.0625 t_0) (* t_0 1.265625)) (* a (pow b 7.0))))))))))
double code(double a, double b, double c) {
double t_0 = pow((a * c), 4.0);
double tmp;
if (((sqrt(((b * b) - ((3.0 * a) * c))) - b) / (3.0 * a)) <= -26.0) {
tmp = (sqrt(fma(b, b, (a * (c * -3.0)))) - b) / (3.0 * a);
} else {
tmp = (-0.5625 * ((pow(a, 2.0) * pow(c, 3.0)) / pow(b, 5.0))) + ((-0.5 * (c / b)) + ((-0.375 * ((a * pow(c, 2.0)) / pow(b, 3.0))) + (-0.16666666666666666 * (((5.0625 * t_0) + (t_0 * 1.265625)) / (a * pow(b, 7.0))))));
}
return tmp;
}
function code(a, b, c) t_0 = Float64(a * c) ^ 4.0 tmp = 0.0 if (Float64(Float64(sqrt(Float64(Float64(b * b) - Float64(Float64(3.0 * a) * c))) - b) / Float64(3.0 * a)) <= -26.0) tmp = Float64(Float64(sqrt(fma(b, b, Float64(a * Float64(c * -3.0)))) - b) / Float64(3.0 * a)); else tmp = Float64(Float64(-0.5625 * Float64(Float64((a ^ 2.0) * (c ^ 3.0)) / (b ^ 5.0))) + Float64(Float64(-0.5 * Float64(c / b)) + Float64(Float64(-0.375 * Float64(Float64(a * (c ^ 2.0)) / (b ^ 3.0))) + Float64(-0.16666666666666666 * Float64(Float64(Float64(5.0625 * t_0) + Float64(t_0 * 1.265625)) / Float64(a * (b ^ 7.0))))))); end return tmp end
code[a_, b_, c_] := Block[{t$95$0 = N[Power[N[(a * c), $MachinePrecision], 4.0], $MachinePrecision]}, If[LessEqual[N[(N[(N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(N[(3.0 * a), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] / N[(3.0 * a), $MachinePrecision]), $MachinePrecision], -26.0], N[(N[(N[Sqrt[N[(b * b + N[(a * N[(c * -3.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] / N[(3.0 * a), $MachinePrecision]), $MachinePrecision], N[(N[(-0.5625 * N[(N[(N[Power[a, 2.0], $MachinePrecision] * N[Power[c, 3.0], $MachinePrecision]), $MachinePrecision] / N[Power[b, 5.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(N[(-0.5 * N[(c / b), $MachinePrecision]), $MachinePrecision] + N[(N[(-0.375 * N[(N[(a * N[Power[c, 2.0], $MachinePrecision]), $MachinePrecision] / N[Power[b, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(-0.16666666666666666 * N[(N[(N[(5.0625 * t$95$0), $MachinePrecision] + N[(t$95$0 * 1.265625), $MachinePrecision]), $MachinePrecision] / N[(a * N[Power[b, 7.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := {\left(a \cdot c\right)}^{4}\\
\mathbf{if}\;\frac{\sqrt{b \cdot b - \left(3 \cdot a\right) \cdot c} - b}{3 \cdot a} \leq -26:\\
\;\;\;\;\frac{\sqrt{\mathsf{fma}\left(b, b, a \cdot \left(c \cdot -3\right)\right)} - b}{3 \cdot a}\\
\mathbf{else}:\\
\;\;\;\;-0.5625 \cdot \frac{{a}^{2} \cdot {c}^{3}}{{b}^{5}} + \left(-0.5 \cdot \frac{c}{b} + \left(-0.375 \cdot \frac{a \cdot {c}^{2}}{{b}^{3}} + -0.16666666666666666 \cdot \frac{5.0625 \cdot t_0 + t_0 \cdot 1.265625}{a \cdot {b}^{7}}\right)\right)\\
\end{array}
\end{array}
if (/.f64 (+.f64 (neg.f64 b) (sqrt.f64 (-.f64 (*.f64 b b) (*.f64 (*.f64 3 a) c)))) (*.f64 3 a)) < -26Initial program 91.2%
+-commutative91.2%
sqr-neg91.2%
unsub-neg91.2%
div-sub90.3%
--rgt-identity90.3%
div-sub91.2%
Simplified91.2%
if -26 < (/.f64 (+.f64 (neg.f64 b) (sqrt.f64 (-.f64 (*.f64 b b) (*.f64 (*.f64 3 a) c)))) (*.f64 3 a)) Initial program 50.3%
Taylor expanded in b around inf 94.7%
*-commutative94.7%
unpow-prod-down94.7%
pow-prod-down94.7%
pow-pow94.7%
metadata-eval94.7%
metadata-eval94.7%
Applied egg-rr94.7%
expm1-log1p-u94.7%
expm1-udef93.7%
pow-prod-down93.7%
Applied egg-rr93.7%
expm1-def94.7%
expm1-log1p94.7%
Simplified94.7%
Final simplification94.4%
(FPCore (a b c)
:precision binary64
(if (<= (/ (- (sqrt (- (* b b) (* (* 3.0 a) c))) b) (* 3.0 a)) -26.0)
(/ (- (sqrt (fma b b (* a (* c -3.0)))) b) (* 3.0 a))
(+
(* -0.5625 (/ (* (pow a 2.0) (pow c 3.0)) (pow b 5.0)))
(+ (* -0.5 (/ c b)) (* -0.375 (/ (* a (pow c 2.0)) (pow b 3.0)))))))
double code(double a, double b, double c) {
double tmp;
if (((sqrt(((b * b) - ((3.0 * a) * c))) - b) / (3.0 * a)) <= -26.0) {
tmp = (sqrt(fma(b, b, (a * (c * -3.0)))) - b) / (3.0 * a);
} else {
tmp = (-0.5625 * ((pow(a, 2.0) * pow(c, 3.0)) / pow(b, 5.0))) + ((-0.5 * (c / b)) + (-0.375 * ((a * pow(c, 2.0)) / pow(b, 3.0))));
}
return tmp;
}
function code(a, b, c) tmp = 0.0 if (Float64(Float64(sqrt(Float64(Float64(b * b) - Float64(Float64(3.0 * a) * c))) - b) / Float64(3.0 * a)) <= -26.0) tmp = Float64(Float64(sqrt(fma(b, b, Float64(a * Float64(c * -3.0)))) - b) / Float64(3.0 * a)); else tmp = Float64(Float64(-0.5625 * Float64(Float64((a ^ 2.0) * (c ^ 3.0)) / (b ^ 5.0))) + Float64(Float64(-0.5 * Float64(c / b)) + Float64(-0.375 * Float64(Float64(a * (c ^ 2.0)) / (b ^ 3.0))))); end return tmp end
code[a_, b_, c_] := If[LessEqual[N[(N[(N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(N[(3.0 * a), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] / N[(3.0 * a), $MachinePrecision]), $MachinePrecision], -26.0], N[(N[(N[Sqrt[N[(b * b + N[(a * N[(c * -3.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] / N[(3.0 * a), $MachinePrecision]), $MachinePrecision], N[(N[(-0.5625 * N[(N[(N[Power[a, 2.0], $MachinePrecision] * N[Power[c, 3.0], $MachinePrecision]), $MachinePrecision] / N[Power[b, 5.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(N[(-0.5 * N[(c / b), $MachinePrecision]), $MachinePrecision] + N[(-0.375 * N[(N[(a * N[Power[c, 2.0], $MachinePrecision]), $MachinePrecision] / N[Power[b, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;\frac{\sqrt{b \cdot b - \left(3 \cdot a\right) \cdot c} - b}{3 \cdot a} \leq -26:\\
\;\;\;\;\frac{\sqrt{\mathsf{fma}\left(b, b, a \cdot \left(c \cdot -3\right)\right)} - b}{3 \cdot a}\\
\mathbf{else}:\\
\;\;\;\;-0.5625 \cdot \frac{{a}^{2} \cdot {c}^{3}}{{b}^{5}} + \left(-0.5 \cdot \frac{c}{b} + -0.375 \cdot \frac{a \cdot {c}^{2}}{{b}^{3}}\right)\\
\end{array}
\end{array}
if (/.f64 (+.f64 (neg.f64 b) (sqrt.f64 (-.f64 (*.f64 b b) (*.f64 (*.f64 3 a) c)))) (*.f64 3 a)) < -26Initial program 91.2%
+-commutative91.2%
sqr-neg91.2%
unsub-neg91.2%
div-sub90.3%
--rgt-identity90.3%
div-sub91.2%
Simplified91.2%
if -26 < (/.f64 (+.f64 (neg.f64 b) (sqrt.f64 (-.f64 (*.f64 b b) (*.f64 (*.f64 3 a) c)))) (*.f64 3 a)) Initial program 50.3%
Taylor expanded in b around inf 92.2%
Final simplification92.1%
(FPCore (a b c) :precision binary64 (let* ((t_0 (/ (- (sqrt (- (* b b) (* (* 3.0 a) c))) b) (* 3.0 a)))) (if (<= t_0 -0.0008) t_0 (/ (* c -0.5) b))))
double code(double a, double b, double c) {
double t_0 = (sqrt(((b * b) - ((3.0 * a) * c))) - b) / (3.0 * a);
double tmp;
if (t_0 <= -0.0008) {
tmp = t_0;
} else {
tmp = (c * -0.5) / b;
}
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) :: t_0
real(8) :: tmp
t_0 = (sqrt(((b * b) - ((3.0d0 * a) * c))) - b) / (3.0d0 * a)
if (t_0 <= (-0.0008d0)) then
tmp = t_0
else
tmp = (c * (-0.5d0)) / b
end if
code = tmp
end function
public static double code(double a, double b, double c) {
double t_0 = (Math.sqrt(((b * b) - ((3.0 * a) * c))) - b) / (3.0 * a);
double tmp;
if (t_0 <= -0.0008) {
tmp = t_0;
} else {
tmp = (c * -0.5) / b;
}
return tmp;
}
def code(a, b, c): t_0 = (math.sqrt(((b * b) - ((3.0 * a) * c))) - b) / (3.0 * a) tmp = 0 if t_0 <= -0.0008: tmp = t_0 else: tmp = (c * -0.5) / b return tmp
function code(a, b, c) t_0 = Float64(Float64(sqrt(Float64(Float64(b * b) - Float64(Float64(3.0 * a) * c))) - b) / Float64(3.0 * a)) tmp = 0.0 if (t_0 <= -0.0008) tmp = t_0; else tmp = Float64(Float64(c * -0.5) / b); end return tmp end
function tmp_2 = code(a, b, c) t_0 = (sqrt(((b * b) - ((3.0 * a) * c))) - b) / (3.0 * a); tmp = 0.0; if (t_0 <= -0.0008) tmp = t_0; else tmp = (c * -0.5) / b; end tmp_2 = tmp; end
code[a_, b_, c_] := Block[{t$95$0 = N[(N[(N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(N[(3.0 * a), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] / N[(3.0 * a), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[t$95$0, -0.0008], t$95$0, N[(N[(c * -0.5), $MachinePrecision] / b), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{\sqrt{b \cdot b - \left(3 \cdot a\right) \cdot c} - b}{3 \cdot a}\\
\mathbf{if}\;t_0 \leq -0.0008:\\
\;\;\;\;t_0\\
\mathbf{else}:\\
\;\;\;\;\frac{c \cdot -0.5}{b}\\
\end{array}
\end{array}
if (/.f64 (+.f64 (neg.f64 b) (sqrt.f64 (-.f64 (*.f64 b b) (*.f64 (*.f64 3 a) c)))) (*.f64 3 a)) < -8.00000000000000038e-4Initial program 75.3%
if -8.00000000000000038e-4 < (/.f64 (+.f64 (neg.f64 b) (sqrt.f64 (-.f64 (*.f64 b b) (*.f64 (*.f64 3 a) c)))) (*.f64 3 a)) Initial program 41.7%
Taylor expanded in b around inf 76.0%
*-commutative76.0%
associate-*l/76.0%
Simplified76.0%
Final simplification75.8%
(FPCore (a b c) :precision binary64 (if (<= b 1.05) (/ (- (sqrt (fma b b (* a (* c -3.0)))) b) (* 3.0 a)) (+ (* -0.5 (/ c b)) (* -0.375 (/ (* a (pow c 2.0)) (pow b 3.0))))))
double code(double a, double b, double c) {
double tmp;
if (b <= 1.05) {
tmp = (sqrt(fma(b, b, (a * (c * -3.0)))) - b) / (3.0 * a);
} else {
tmp = (-0.5 * (c / b)) + (-0.375 * ((a * pow(c, 2.0)) / pow(b, 3.0)));
}
return tmp;
}
function code(a, b, c) tmp = 0.0 if (b <= 1.05) tmp = Float64(Float64(sqrt(fma(b, b, Float64(a * Float64(c * -3.0)))) - b) / Float64(3.0 * a)); else tmp = Float64(Float64(-0.5 * Float64(c / b)) + Float64(-0.375 * Float64(Float64(a * (c ^ 2.0)) / (b ^ 3.0)))); end return tmp end
code[a_, b_, c_] := If[LessEqual[b, 1.05], N[(N[(N[Sqrt[N[(b * b + N[(a * N[(c * -3.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] / N[(3.0 * a), $MachinePrecision]), $MachinePrecision], N[(N[(-0.5 * N[(c / b), $MachinePrecision]), $MachinePrecision] + N[(-0.375 * N[(N[(a * N[Power[c, 2.0], $MachinePrecision]), $MachinePrecision] / N[Power[b, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq 1.05:\\
\;\;\;\;\frac{\sqrt{\mathsf{fma}\left(b, b, a \cdot \left(c \cdot -3\right)\right)} - b}{3 \cdot a}\\
\mathbf{else}:\\
\;\;\;\;-0.5 \cdot \frac{c}{b} + -0.375 \cdot \frac{a \cdot {c}^{2}}{{b}^{3}}\\
\end{array}
\end{array}
if b < 1.05000000000000004Initial program 84.8%
+-commutative84.8%
sqr-neg84.8%
unsub-neg84.8%
div-sub84.8%
--rgt-identity84.8%
div-sub84.8%
Simplified85.0%
if 1.05000000000000004 < b Initial program 48.2%
Taylor expanded in b around inf 87.7%
Final simplification87.3%
(FPCore (a b c) :precision binary64 (* c (/ -0.5 b)))
double code(double a, double b, double c) {
return c * (-0.5 / 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 * ((-0.5d0) / b)
end function
public static double code(double a, double b, double c) {
return c * (-0.5 / b);
}
def code(a, b, c): return c * (-0.5 / b)
function code(a, b, c) return Float64(c * Float64(-0.5 / b)) end
function tmp = code(a, b, c) tmp = c * (-0.5 / b); end
code[a_, b_, c_] := N[(c * N[(-0.5 / b), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
c \cdot \frac{-0.5}{b}
\end{array}
Initial program 53.6%
+-commutative53.6%
sqr-neg53.6%
unsub-neg53.6%
div-sub53.2%
--rgt-identity53.2%
div-sub53.6%
Simplified53.7%
Taylor expanded in b around inf 35.5%
+-commutative35.5%
fma-def35.5%
*-commutative35.5%
associate-/l*35.5%
Simplified35.5%
div-inv35.5%
*-commutative35.5%
Applied egg-rr35.5%
Taylor expanded in c around 0 65.9%
associate-*r/65.9%
*-rgt-identity65.9%
times-frac65.8%
/-rgt-identity65.8%
Simplified65.8%
Final simplification65.8%
(FPCore (a b c) :precision binary64 (/ (* c -0.5) b))
double code(double a, double b, double c) {
return (c * -0.5) / 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 * (-0.5d0)) / b
end function
public static double code(double a, double b, double c) {
return (c * -0.5) / b;
}
def code(a, b, c): return (c * -0.5) / b
function code(a, b, c) return Float64(Float64(c * -0.5) / b) end
function tmp = code(a, b, c) tmp = (c * -0.5) / b; end
code[a_, b_, c_] := N[(N[(c * -0.5), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{c \cdot -0.5}{b}
\end{array}
Initial program 53.6%
Taylor expanded in b around inf 65.9%
*-commutative65.9%
associate-*l/65.9%
Simplified65.9%
Final simplification65.9%
herbie shell --seed 2023331
(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)))