
(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 (let* ((t_0 (* c (* a -3.0)))) (* (/ t_0 (+ b (sqrt (fma b b t_0)))) (/ 1.0 (/ a 0.3333333333333333)))))
double code(double a, double b, double c) {
double t_0 = c * (a * -3.0);
return (t_0 / (b + sqrt(fma(b, b, t_0)))) * (1.0 / (a / 0.3333333333333333));
}
function code(a, b, c) t_0 = Float64(c * Float64(a * -3.0)) return Float64(Float64(t_0 / Float64(b + sqrt(fma(b, b, t_0)))) * Float64(1.0 / Float64(a / 0.3333333333333333))) end
code[a_, b_, c_] := Block[{t$95$0 = N[(c * N[(a * -3.0), $MachinePrecision]), $MachinePrecision]}, N[(N[(t$95$0 / N[(b + N[Sqrt[N[(b * b + t$95$0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[(1.0 / N[(a / 0.3333333333333333), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := c \cdot \left(a \cdot -3\right)\\
\frac{t_0}{b + \sqrt{\mathsf{fma}\left(b, b, t_0\right)}} \cdot \frac{1}{\frac{a}{0.3333333333333333}}
\end{array}
\end{array}
Initial program 19.8%
neg-sub019.8%
associate-+l-19.8%
sub0-neg19.8%
neg-mul-119.8%
associate-*r/19.8%
*-commutative19.8%
metadata-eval19.8%
metadata-eval19.8%
times-frac19.8%
*-commutative19.8%
times-frac19.8%
Simplified19.9%
clear-num19.9%
inv-pow19.9%
Applied egg-rr19.9%
unpow-119.9%
Simplified19.9%
flip--19.7%
add-sqr-sqrt20.3%
Applied egg-rr20.3%
associate-*r*20.3%
*-commutative20.3%
associate-*l*20.3%
+-commutative20.3%
associate-*r*20.3%
*-commutative20.3%
associate-*l*20.3%
Simplified20.3%
Taylor expanded in b around 0 99.1%
*-commutative99.1%
associate-*r*99.1%
Simplified99.1%
Final simplification99.1%
(FPCore (a b c) :precision binary64 (* (/ 1.0 (/ a 0.3333333333333333)) (/ (* -3.0 (* c a)) (+ b (sqrt (fma b b (* c (* a -3.0))))))))
double code(double a, double b, double c) {
return (1.0 / (a / 0.3333333333333333)) * ((-3.0 * (c * a)) / (b + sqrt(fma(b, b, (c * (a * -3.0))))));
}
function code(a, b, c) return Float64(Float64(1.0 / Float64(a / 0.3333333333333333)) * Float64(Float64(-3.0 * Float64(c * a)) / Float64(b + sqrt(fma(b, b, Float64(c * Float64(a * -3.0))))))) end
code[a_, b_, c_] := N[(N[(1.0 / N[(a / 0.3333333333333333), $MachinePrecision]), $MachinePrecision] * N[(N[(-3.0 * N[(c * a), $MachinePrecision]), $MachinePrecision] / N[(b + N[Sqrt[N[(b * b + N[(c * N[(a * -3.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{1}{\frac{a}{0.3333333333333333}} \cdot \frac{-3 \cdot \left(c \cdot a\right)}{b + \sqrt{\mathsf{fma}\left(b, b, c \cdot \left(a \cdot -3\right)\right)}}
\end{array}
Initial program 19.8%
neg-sub019.8%
associate-+l-19.8%
sub0-neg19.8%
neg-mul-119.8%
associate-*r/19.8%
*-commutative19.8%
metadata-eval19.8%
metadata-eval19.8%
times-frac19.8%
*-commutative19.8%
times-frac19.8%
Simplified19.9%
clear-num19.9%
inv-pow19.9%
Applied egg-rr19.9%
unpow-119.9%
Simplified19.9%
flip--19.7%
add-sqr-sqrt20.3%
Applied egg-rr20.3%
associate-*r*20.3%
*-commutative20.3%
associate-*l*20.3%
+-commutative20.3%
associate-*r*20.3%
*-commutative20.3%
associate-*l*20.3%
Simplified20.3%
Taylor expanded in b around 0 99.1%
Final simplification99.1%
(FPCore (a b c) :precision binary64 (fma -0.5 (/ c b) (/ (* (* a -0.375) (* c c)) (pow b 3.0))))
double code(double a, double b, double c) {
return fma(-0.5, (c / b), (((a * -0.375) * (c * c)) / pow(b, 3.0)));
}
function code(a, b, c) return fma(-0.5, Float64(c / b), Float64(Float64(Float64(a * -0.375) * Float64(c * c)) / (b ^ 3.0))) end
code[a_, b_, c_] := N[(-0.5 * N[(c / b), $MachinePrecision] + N[(N[(N[(a * -0.375), $MachinePrecision] * N[(c * c), $MachinePrecision]), $MachinePrecision] / N[Power[b, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(-0.5, \frac{c}{b}, \frac{\left(a \cdot -0.375\right) \cdot \left(c \cdot c\right)}{{b}^{3}}\right)
\end{array}
Initial program 19.8%
neg-sub019.8%
associate-+l-19.8%
sub0-neg19.8%
neg-mul-119.8%
associate-*r/19.8%
metadata-eval19.8%
metadata-eval19.8%
times-frac19.8%
*-commutative19.8%
times-frac19.8%
associate-*l/19.8%
Simplified19.9%
Taylor expanded in b around inf 94.1%
fma-def94.1%
associate-*r/94.1%
*-commutative94.1%
associate-*r*94.1%
unpow294.1%
Simplified94.1%
Final simplification94.1%
(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 19.8%
neg-sub019.8%
associate-+l-19.8%
sub0-neg19.8%
neg-mul-119.8%
associate-*r/19.8%
metadata-eval19.8%
metadata-eval19.8%
times-frac19.8%
*-commutative19.8%
times-frac19.8%
associate-*l/19.8%
Simplified19.9%
Taylor expanded in b around inf 89.1%
Final simplification89.1%
(FPCore (a b c) :precision binary64 0.0)
double code(double a, double b, double c) {
return 0.0;
}
real(8) function code(a, b, c)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: c
code = 0.0d0
end function
public static double code(double a, double b, double c) {
return 0.0;
}
def code(a, b, c): return 0.0
function code(a, b, c) return 0.0 end
function tmp = code(a, b, c) tmp = 0.0; end
code[a_, b_, c_] := 0.0
\begin{array}{l}
\\
0
\end{array}
Initial program 19.8%
neg-sub019.8%
associate-+l-19.8%
sub0-neg19.8%
neg-mul-119.8%
associate-*r/19.8%
*-commutative19.8%
metadata-eval19.8%
metadata-eval19.8%
times-frac19.8%
*-commutative19.8%
times-frac19.8%
Simplified19.9%
clear-num19.9%
inv-pow19.9%
Applied egg-rr19.9%
unpow-119.9%
Simplified19.9%
*-un-lft-identity19.9%
add-sqr-sqrt20.3%
prod-diff21.1%
add-sqr-sqrt20.9%
add-sqr-sqrt21.1%
Applied egg-rr21.1%
Taylor expanded in a around 0 3.3%
associate-*r/3.3%
distribute-rgt1-in3.3%
metadata-eval3.3%
mul0-lft3.3%
metadata-eval3.3%
div03.3%
Simplified3.3%
Final simplification3.3%
herbie shell --seed 2023249
(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)))