
(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 15 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
(if (<= b -8.5e+143)
(/ (/ (- (- b) b) a) 3.0)
(if (<= b 6e-73)
(/ (- (sqrt (fma (* a -3.0) c (* b b))) b) (* a 3.0))
(/ (* c -0.5) b))))
double code(double a, double b, double c) {
double tmp;
if (b <= -8.5e+143) {
tmp = ((-b - b) / a) / 3.0;
} else if (b <= 6e-73) {
tmp = (sqrt(fma((a * -3.0), c, (b * b))) - b) / (a * 3.0);
} else {
tmp = (c * -0.5) / b;
}
return tmp;
}
function code(a, b, c) tmp = 0.0 if (b <= -8.5e+143) tmp = Float64(Float64(Float64(Float64(-b) - b) / a) / 3.0); elseif (b <= 6e-73) tmp = Float64(Float64(sqrt(fma(Float64(a * -3.0), c, Float64(b * b))) - b) / Float64(a * 3.0)); else tmp = Float64(Float64(c * -0.5) / b); end return tmp end
code[a_, b_, c_] := If[LessEqual[b, -8.5e+143], N[(N[(N[((-b) - b), $MachinePrecision] / a), $MachinePrecision] / 3.0), $MachinePrecision], If[LessEqual[b, 6e-73], N[(N[(N[Sqrt[N[(N[(a * -3.0), $MachinePrecision] * c + N[(b * b), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] / N[(a * 3.0), $MachinePrecision]), $MachinePrecision], N[(N[(c * -0.5), $MachinePrecision] / b), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq -8.5 \cdot 10^{+143}:\\
\;\;\;\;\frac{\frac{\left(-b\right) - b}{a}}{3}\\
\mathbf{elif}\;b \leq 6 \cdot 10^{-73}:\\
\;\;\;\;\frac{\sqrt{\mathsf{fma}\left(a \cdot -3, c, b \cdot b\right)} - b}{a \cdot 3}\\
\mathbf{else}:\\
\;\;\;\;\frac{c \cdot -0.5}{b}\\
\end{array}
\end{array}
if b < -8.4999999999999998e143Initial program 47.0%
lift--.f64N/A
sub-negN/A
+-commutativeN/A
lift-*.f64N/A
distribute-lft-neg-inN/A
lower-fma.f64N/A
lift-*.f64N/A
*-commutativeN/A
distribute-rgt-neg-inN/A
lower-*.f64N/A
metadata-eval47.1
Applied rewrites47.1%
lift-/.f64N/A
lift-*.f64N/A
*-commutativeN/A
associate-/r*N/A
lower-/.f64N/A
lower-/.f6447.1
lift-+.f64N/A
+-commutativeN/A
lift-fma.f64N/A
lift-*.f64N/A
associate-*r*N/A
lift-*.f64N/A
lift-fma.f64N/A
lift-neg.f64N/A
unsub-negN/A
lower--.f6447.1
Applied rewrites47.1%
Taylor expanded in b around -inf
mul-1-negN/A
lower-neg.f6497.3
Applied rewrites97.3%
if -8.4999999999999998e143 < b < 6e-73Initial program 79.1%
lift--.f64N/A
sub-negN/A
+-commutativeN/A
lift-*.f64N/A
distribute-lft-neg-inN/A
lower-fma.f64N/A
lift-*.f64N/A
*-commutativeN/A
distribute-rgt-neg-inN/A
lower-*.f64N/A
metadata-eval79.1
Applied rewrites79.1%
if 6e-73 < b Initial program 15.5%
Taylor expanded in b around inf
associate-*r/N/A
lower-/.f64N/A
*-commutativeN/A
lower-*.f6487.6
Applied rewrites87.6%
Final simplification85.0%
(FPCore (a b c)
:precision binary64
(if (<= b -8.5e+143)
(/ (/ (- (- b) b) a) 3.0)
(if (<= b 6e-73)
(/ (* (- (sqrt (fma c (* a -3.0) (* b b))) b) 0.3333333333333333) a)
(/ (* c -0.5) b))))
double code(double a, double b, double c) {
double tmp;
if (b <= -8.5e+143) {
tmp = ((-b - b) / a) / 3.0;
} else if (b <= 6e-73) {
tmp = ((sqrt(fma(c, (a * -3.0), (b * b))) - b) * 0.3333333333333333) / a;
} else {
tmp = (c * -0.5) / b;
}
return tmp;
}
function code(a, b, c) tmp = 0.0 if (b <= -8.5e+143) tmp = Float64(Float64(Float64(Float64(-b) - b) / a) / 3.0); elseif (b <= 6e-73) tmp = Float64(Float64(Float64(sqrt(fma(c, Float64(a * -3.0), Float64(b * b))) - b) * 0.3333333333333333) / a); else tmp = Float64(Float64(c * -0.5) / b); end return tmp end
code[a_, b_, c_] := If[LessEqual[b, -8.5e+143], N[(N[(N[((-b) - b), $MachinePrecision] / a), $MachinePrecision] / 3.0), $MachinePrecision], If[LessEqual[b, 6e-73], N[(N[(N[(N[Sqrt[N[(c * N[(a * -3.0), $MachinePrecision] + N[(b * b), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] * 0.3333333333333333), $MachinePrecision] / a), $MachinePrecision], N[(N[(c * -0.5), $MachinePrecision] / b), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq -8.5 \cdot 10^{+143}:\\
\;\;\;\;\frac{\frac{\left(-b\right) - b}{a}}{3}\\
\mathbf{elif}\;b \leq 6 \cdot 10^{-73}:\\
\;\;\;\;\frac{\left(\sqrt{\mathsf{fma}\left(c, a \cdot -3, b \cdot b\right)} - b\right) \cdot 0.3333333333333333}{a}\\
\mathbf{else}:\\
\;\;\;\;\frac{c \cdot -0.5}{b}\\
\end{array}
\end{array}
if b < -8.4999999999999998e143Initial program 44.7%
lift--.f64N/A
sub-negN/A
+-commutativeN/A
lift-*.f64N/A
distribute-lft-neg-inN/A
lower-fma.f64N/A
lift-*.f64N/A
*-commutativeN/A
distribute-rgt-neg-inN/A
lower-*.f64N/A
metadata-eval44.8
Applied rewrites44.8%
lift-/.f64N/A
lift-*.f64N/A
*-commutativeN/A
associate-/r*N/A
lower-/.f64N/A
lower-/.f6444.8
lift-+.f64N/A
+-commutativeN/A
lift-fma.f64N/A
lift-*.f64N/A
associate-*r*N/A
lift-*.f64N/A
lift-fma.f64N/A
lift-neg.f64N/A
unsub-negN/A
lower--.f6444.7
Applied rewrites44.7%
Taylor expanded in b around -inf
mul-1-negN/A
lower-neg.f6496.8
Applied rewrites96.8%
if -8.4999999999999998e143 < b < 6e-73Initial program 81.7%
lift--.f64N/A
sub-negN/A
+-commutativeN/A
lift-*.f64N/A
distribute-lft-neg-inN/A
lower-fma.f64N/A
lift-*.f64N/A
*-commutativeN/A
distribute-rgt-neg-inN/A
lower-*.f64N/A
metadata-eval81.7
Applied rewrites81.7%
lift-/.f64N/A
lift-*.f64N/A
associate-/r*N/A
lower-/.f64N/A
Applied rewrites81.6%
lift-*.f64N/A
lift-fma.f64N/A
*-commutativeN/A
lift-*.f64N/A
*-commutativeN/A
associate-*r*N/A
metadata-evalN/A
distribute-lft-neg-inN/A
lower-fma.f64N/A
distribute-lft-neg-inN/A
metadata-evalN/A
*-commutativeN/A
lift-*.f64N/A
lift-*.f6481.6
Applied rewrites81.6%
if 6e-73 < b Initial program 18.8%
Taylor expanded in b around inf
associate-*r/N/A
lower-/.f64N/A
*-commutativeN/A
lower-*.f6484.7
Applied rewrites84.7%
herbie shell --seed 2024228
(FPCore (a b c)
:name "Cubic critical"
:precision binary64
(/ (+ (- b) (sqrt (- (* b b) (* (* 3.0 a) c)))) (* 3.0 a)))