
(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 3 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) a) (- (- b) (sqrt (+ (* c (* a -3.0)) (* b b))))))
double code(double a, double b, double c) {
return ((c * a) / a) / (-b - sqrt(((c * (a * -3.0)) + (b * 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 * a) / a) / (-b - sqrt(((c * (a * (-3.0d0))) + (b * b))))
end function
public static double code(double a, double b, double c) {
return ((c * a) / a) / (-b - Math.sqrt(((c * (a * -3.0)) + (b * b))));
}
def code(a, b, c): return ((c * a) / a) / (-b - math.sqrt(((c * (a * -3.0)) + (b * b))))
function code(a, b, c) return Float64(Float64(Float64(c * a) / a) / Float64(Float64(-b) - sqrt(Float64(Float64(c * Float64(a * -3.0)) + Float64(b * b))))) end
function tmp = code(a, b, c) tmp = ((c * a) / a) / (-b - sqrt(((c * (a * -3.0)) + (b * b)))); end
code[a_, b_, c_] := N[(N[(N[(c * a), $MachinePrecision] / a), $MachinePrecision] / N[((-b) - N[Sqrt[N[(N[(c * N[(a * -3.0), $MachinePrecision]), $MachinePrecision] + N[(b * b), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\frac{c \cdot a}{a}}{\left(-b\right) - \sqrt{c \cdot \left(a \cdot -3\right) + b \cdot b}}
\end{array}
Initial program 15.0%
add-cbrt-cube15.0%
pow314.9%
*-commutative14.9%
*-commutative14.9%
Applied egg-rr14.9%
flip-+14.8%
add-sqr-sqrt15.1%
rem-cbrt-cube15.6%
rem-cbrt-cube15.6%
Applied egg-rr15.6%
sqr-neg15.6%
associate-+l-99.4%
+-inverses99.4%
+-commutative99.4%
sub-neg99.4%
+-commutative99.4%
associate-*r*99.4%
distribute-rgt-neg-in99.4%
metadata-eval99.4%
*-commutative99.4%
associate-*r*99.4%
fma-def99.4%
*-commutative99.4%
Simplified99.4%
div-inv99.4%
+-rgt-identity99.4%
*-commutative99.4%
Applied egg-rr99.4%
Simplified99.8%
fma-udef99.8%
Applied egg-rr99.8%
Final simplification99.8%
(FPCore (a b c) :precision binary64 (/ (/ (* c a) a) (+ (* 1.5 (/ (* c a) b)) (* b -2.0))))
double code(double a, double b, double c) {
return ((c * a) / a) / ((1.5 * ((c * a) / b)) + (b * -2.0));
}
real(8) function code(a, b, c)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: c
code = ((c * a) / a) / ((1.5d0 * ((c * a) / b)) + (b * (-2.0d0)))
end function
public static double code(double a, double b, double c) {
return ((c * a) / a) / ((1.5 * ((c * a) / b)) + (b * -2.0));
}
def code(a, b, c): return ((c * a) / a) / ((1.5 * ((c * a) / b)) + (b * -2.0))
function code(a, b, c) return Float64(Float64(Float64(c * a) / a) / Float64(Float64(1.5 * Float64(Float64(c * a) / b)) + Float64(b * -2.0))) end
function tmp = code(a, b, c) tmp = ((c * a) / a) / ((1.5 * ((c * a) / b)) + (b * -2.0)); end
code[a_, b_, c_] := N[(N[(N[(c * a), $MachinePrecision] / a), $MachinePrecision] / N[(N[(1.5 * N[(N[(c * a), $MachinePrecision] / b), $MachinePrecision]), $MachinePrecision] + N[(b * -2.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\frac{c \cdot a}{a}}{1.5 \cdot \frac{c \cdot a}{b} + b \cdot -2}
\end{array}
Initial program 15.0%
add-cbrt-cube15.0%
pow314.9%
*-commutative14.9%
*-commutative14.9%
Applied egg-rr14.9%
flip-+14.8%
add-sqr-sqrt15.1%
rem-cbrt-cube15.6%
rem-cbrt-cube15.6%
Applied egg-rr15.6%
sqr-neg15.6%
associate-+l-99.4%
+-inverses99.4%
+-commutative99.4%
sub-neg99.4%
+-commutative99.4%
associate-*r*99.4%
distribute-rgt-neg-in99.4%
metadata-eval99.4%
*-commutative99.4%
associate-*r*99.4%
fma-def99.4%
*-commutative99.4%
Simplified99.4%
div-inv99.4%
+-rgt-identity99.4%
*-commutative99.4%
Applied egg-rr99.4%
Simplified99.8%
Taylor expanded in b around inf 96.7%
Final simplification96.7%
(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 15.0%
/-rgt-identity15.0%
metadata-eval15.0%
associate-/l*15.0%
associate-*r/15.0%
*-commutative15.0%
associate-*l/15.0%
associate-*r/15.0%
metadata-eval15.0%
metadata-eval15.0%
times-frac15.0%
neg-mul-115.0%
distribute-rgt-neg-in15.0%
times-frac15.0%
metadata-eval15.0%
neg-mul-115.0%
Simplified15.0%
Taylor expanded in b around inf 92.4%
Final simplification92.4%
herbie shell --seed 2023240
(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)))