
(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 (/ (/ (+ (- (pow (- b) 2.0) (pow b 2.0)) (* c (* a 3.0))) (- (- b) (sqrt (+ (pow b 2.0) (* -3.0 (* c a)))))) (* a 3.0)))
double code(double a, double b, double c) {
return (((pow(-b, 2.0) - pow(b, 2.0)) + (c * (a * 3.0))) / (-b - sqrt((pow(b, 2.0) + (-3.0 * (c * a)))))) / (a * 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 = ((((-b ** 2.0d0) - (b ** 2.0d0)) + (c * (a * 3.0d0))) / (-b - sqrt(((b ** 2.0d0) + ((-3.0d0) * (c * a)))))) / (a * 3.0d0)
end function
public static double code(double a, double b, double c) {
return (((Math.pow(-b, 2.0) - Math.pow(b, 2.0)) + (c * (a * 3.0))) / (-b - Math.sqrt((Math.pow(b, 2.0) + (-3.0 * (c * a)))))) / (a * 3.0);
}
def code(a, b, c): return (((math.pow(-b, 2.0) - math.pow(b, 2.0)) + (c * (a * 3.0))) / (-b - math.sqrt((math.pow(b, 2.0) + (-3.0 * (c * a)))))) / (a * 3.0)
function code(a, b, c) return Float64(Float64(Float64(Float64((Float64(-b) ^ 2.0) - (b ^ 2.0)) + Float64(c * Float64(a * 3.0))) / Float64(Float64(-b) - sqrt(Float64((b ^ 2.0) + Float64(-3.0 * Float64(c * a)))))) / Float64(a * 3.0)) end
function tmp = code(a, b, c) tmp = ((((-b ^ 2.0) - (b ^ 2.0)) + (c * (a * 3.0))) / (-b - sqrt(((b ^ 2.0) + (-3.0 * (c * a)))))) / (a * 3.0); end
code[a_, b_, c_] := N[(N[(N[(N[(N[Power[(-b), 2.0], $MachinePrecision] - N[Power[b, 2.0], $MachinePrecision]), $MachinePrecision] + N[(c * N[(a * 3.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[((-b) - N[Sqrt[N[(N[Power[b, 2.0], $MachinePrecision] + N[(-3.0 * N[(c * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(a * 3.0), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\frac{\left({\left(-b\right)}^{2} - {b}^{2}\right) + c \cdot \left(a \cdot 3\right)}{\left(-b\right) - \sqrt{{b}^{2} + -3 \cdot \left(c \cdot a\right)}}}{a \cdot 3}
\end{array}
Initial program 18.2%
expm1-log1p-u18.2%
expm1-udef12.8%
associate-*l*12.8%
Applied egg-rr12.8%
flip-+12.7%
Applied egg-rr18.6%
associate--r-99.2%
associate-*r*99.4%
*-commutative99.4%
*-commutative99.4%
cancel-sign-sub-inv99.4%
metadata-eval99.4%
*-commutative99.4%
Simplified99.4%
Final simplification99.4%
(FPCore (a b c) :precision binary64 (if (<= (/ (- (sqrt (- (* b b) (* c (* a 3.0)))) b) (* a 3.0)) -5e-12) (/ (- (sqrt (fma b b (* a (* c -3.0)))) b) (* a 3.0)) (* -0.5 (/ c b))))
double code(double a, double b, double c) {
double tmp;
if (((sqrt(((b * b) - (c * (a * 3.0)))) - b) / (a * 3.0)) <= -5e-12) {
tmp = (sqrt(fma(b, b, (a * (c * -3.0)))) - b) / (a * 3.0);
} else {
tmp = -0.5 * (c / b);
}
return tmp;
}
function code(a, b, c) tmp = 0.0 if (Float64(Float64(sqrt(Float64(Float64(b * b) - Float64(c * Float64(a * 3.0)))) - b) / Float64(a * 3.0)) <= -5e-12) tmp = Float64(Float64(sqrt(fma(b, b, Float64(a * Float64(c * -3.0)))) - b) / Float64(a * 3.0)); else tmp = Float64(-0.5 * Float64(c / b)); end return tmp end
code[a_, b_, c_] := If[LessEqual[N[(N[(N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(c * N[(a * 3.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] / N[(a * 3.0), $MachinePrecision]), $MachinePrecision], -5e-12], N[(N[(N[Sqrt[N[(b * b + N[(a * N[(c * -3.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] / N[(a * 3.0), $MachinePrecision]), $MachinePrecision], N[(-0.5 * N[(c / b), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;\frac{\sqrt{b \cdot b - c \cdot \left(a \cdot 3\right)} - b}{a \cdot 3} \leq -5 \cdot 10^{-12}:\\
\;\;\;\;\frac{\sqrt{\mathsf{fma}\left(b, b, a \cdot \left(c \cdot -3\right)\right)} - b}{a \cdot 3}\\
\mathbf{else}:\\
\;\;\;\;-0.5 \cdot \frac{c}{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)) < -4.9999999999999997e-12Initial program 66.6%
+-commutative66.6%
sqr-neg66.6%
unsub-neg66.6%
div-sub65.7%
--rgt-identity65.7%
div-sub66.6%
Simplified66.7%
if -4.9999999999999997e-12 < (/.f64 (+.f64 (neg.f64 b) (sqrt.f64 (-.f64 (*.f64 b b) (*.f64 (*.f64 3 a) c)))) (*.f64 3 a)) Initial program 5.2%
Taylor expanded in b around inf 99.2%
Final simplification92.3%
(FPCore (a b c) :precision binary64 (let* ((t_0 (/ (- (sqrt (- (* b b) (* c (* a 3.0)))) b) (* a 3.0)))) (if (<= t_0 -5e-12) t_0 (* -0.5 (/ c b)))))
double code(double a, double b, double c) {
double t_0 = (sqrt(((b * b) - (c * (a * 3.0)))) - b) / (a * 3.0);
double tmp;
if (t_0 <= -5e-12) {
tmp = t_0;
} else {
tmp = -0.5 * (c / 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) - (c * (a * 3.0d0)))) - b) / (a * 3.0d0)
if (t_0 <= (-5d-12)) then
tmp = t_0
else
tmp = (-0.5d0) * (c / b)
end if
code = tmp
end function
public static double code(double a, double b, double c) {
double t_0 = (Math.sqrt(((b * b) - (c * (a * 3.0)))) - b) / (a * 3.0);
double tmp;
if (t_0 <= -5e-12) {
tmp = t_0;
} else {
tmp = -0.5 * (c / b);
}
return tmp;
}
def code(a, b, c): t_0 = (math.sqrt(((b * b) - (c * (a * 3.0)))) - b) / (a * 3.0) tmp = 0 if t_0 <= -5e-12: tmp = t_0 else: tmp = -0.5 * (c / b) return tmp
function code(a, b, c) t_0 = Float64(Float64(sqrt(Float64(Float64(b * b) - Float64(c * Float64(a * 3.0)))) - b) / Float64(a * 3.0)) tmp = 0.0 if (t_0 <= -5e-12) tmp = t_0; else tmp = Float64(-0.5 * Float64(c / b)); end return tmp end
function tmp_2 = code(a, b, c) t_0 = (sqrt(((b * b) - (c * (a * 3.0)))) - b) / (a * 3.0); tmp = 0.0; if (t_0 <= -5e-12) tmp = t_0; else tmp = -0.5 * (c / b); end tmp_2 = tmp; end
code[a_, b_, c_] := Block[{t$95$0 = N[(N[(N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(c * N[(a * 3.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] / N[(a * 3.0), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[t$95$0, -5e-12], t$95$0, N[(-0.5 * N[(c / b), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{\sqrt{b \cdot b - c \cdot \left(a \cdot 3\right)} - b}{a \cdot 3}\\
\mathbf{if}\;t_0 \leq -5 \cdot 10^{-12}:\\
\;\;\;\;t_0\\
\mathbf{else}:\\
\;\;\;\;-0.5 \cdot \frac{c}{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)) < -4.9999999999999997e-12Initial program 66.6%
if -4.9999999999999997e-12 < (/.f64 (+.f64 (neg.f64 b) (sqrt.f64 (-.f64 (*.f64 b b) (*.f64 (*.f64 3 a) c)))) (*.f64 3 a)) Initial program 5.2%
Taylor expanded in b around inf 99.2%
Final simplification92.3%
(FPCore (a b c) :precision binary64 (+ (* -0.5 (/ c b)) (* -0.375 (/ (* a (pow c 2.0)) (pow b 3.0)))))
double code(double a, double b, double c) {
return (-0.5 * (c / b)) + (-0.375 * ((a * pow(c, 2.0)) / 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 = ((-0.5d0) * (c / b)) + ((-0.375d0) * ((a * (c ** 2.0d0)) / (b ** 3.0d0)))
end function
public static double code(double a, double b, double c) {
return (-0.5 * (c / b)) + (-0.375 * ((a * Math.pow(c, 2.0)) / Math.pow(b, 3.0)));
}
def code(a, b, c): return (-0.5 * (c / b)) + (-0.375 * ((a * math.pow(c, 2.0)) / math.pow(b, 3.0)))
function code(a, b, c) return Float64(Float64(-0.5 * Float64(c / b)) + Float64(-0.375 * Float64(Float64(a * (c ^ 2.0)) / (b ^ 3.0)))) end
function tmp = code(a, b, c) tmp = (-0.5 * (c / b)) + (-0.375 * ((a * (c ^ 2.0)) / (b ^ 3.0))); end
code[a_, b_, c_] := 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}
\\
-0.5 \cdot \frac{c}{b} + -0.375 \cdot \frac{a \cdot {c}^{2}}{{b}^{3}}
\end{array}
Initial program 18.2%
Taylor expanded in b around inf 95.1%
Final simplification95.1%
(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 18.2%
Taylor expanded in b around inf 90.1%
Final simplification90.1%
herbie shell --seed 2024010
(FPCore (a b c)
:name "Cubic critical, wide range"
:precision binary64
:pre (and (and (and (< 4.930380657631324e-32 a) (< a 2.028240960365167e+31)) (and (< 4.930380657631324e-32 b) (< b 2.028240960365167e+31))) (and (< 4.930380657631324e-32 c) (< c 2.028240960365167e+31)))
(/ (+ (- b) (sqrt (- (* b b) (* (* 3.0 a) c)))) (* 3.0 a)))