
(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 (+ (* -0.5625 (/ (* (pow c 3.0) (* a a)) (pow b 5.0))) (+ (fma -0.375 (/ a (/ (pow b 3.0) (* c c))) (/ (* c -0.5) b)) (* -0.5 (/ (* (pow (* c a) 4.0) 6.328125) (* a (* 3.0 (pow b 7.0))))))))
double code(double a, double b, double c) {
return (-0.5625 * ((pow(c, 3.0) * (a * a)) / pow(b, 5.0))) + (fma(-0.375, (a / (pow(b, 3.0) / (c * c))), ((c * -0.5) / b)) + (-0.5 * ((pow((c * a), 4.0) * 6.328125) / (a * (3.0 * pow(b, 7.0))))));
}
function code(a, b, c) return Float64(Float64(-0.5625 * Float64(Float64((c ^ 3.0) * Float64(a * a)) / (b ^ 5.0))) + Float64(fma(-0.375, Float64(a / Float64((b ^ 3.0) / Float64(c * c))), Float64(Float64(c * -0.5) / b)) + Float64(-0.5 * Float64(Float64((Float64(c * a) ^ 4.0) * 6.328125) / Float64(a * Float64(3.0 * (b ^ 7.0))))))) end
code[a_, b_, c_] := N[(N[(-0.5625 * N[(N[(N[Power[c, 3.0], $MachinePrecision] * N[(a * a), $MachinePrecision]), $MachinePrecision] / N[Power[b, 5.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(N[(-0.375 * N[(a / N[(N[Power[b, 3.0], $MachinePrecision] / N[(c * c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(N[(c * -0.5), $MachinePrecision] / b), $MachinePrecision]), $MachinePrecision] + N[(-0.5 * N[(N[(N[Power[N[(c * a), $MachinePrecision], 4.0], $MachinePrecision] * 6.328125), $MachinePrecision] / N[(a * N[(3.0 * N[Power[b, 7.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
-0.5625 \cdot \frac{{c}^{3} \cdot \left(a \cdot a\right)}{{b}^{5}} + \left(\mathsf{fma}\left(-0.375, \frac{a}{\frac{{b}^{3}}{c \cdot c}}, \frac{c \cdot -0.5}{b}\right) + -0.5 \cdot \frac{{\left(c \cdot a\right)}^{4} \cdot 6.328125}{a \cdot \left(3 \cdot {b}^{7}\right)}\right)
\end{array}
Initial program 19.9%
neg-sub019.9%
sqr-neg19.9%
associate-+l-19.9%
sub0-neg19.9%
neg-mul-119.9%
Simplified19.9%
div-inv20.0%
metadata-eval20.0%
*-commutative20.0%
add-sqr-sqrt19.9%
pow219.9%
Applied egg-rr19.9%
Taylor expanded in b around inf 96.8%
Simplified98.0%
Final simplification98.0%
(FPCore (a b c) :precision binary64 (+ (* -0.5625 (/ (* (pow c 3.0) (* a a)) (pow b 5.0))) (fma -0.375 (/ a (/ (pow b 3.0) (* c c))) (/ (* c -0.5) b))))
double code(double a, double b, double c) {
return (-0.5625 * ((pow(c, 3.0) * (a * a)) / pow(b, 5.0))) + fma(-0.375, (a / (pow(b, 3.0) / (c * c))), ((c * -0.5) / b));
}
function code(a, b, c) return Float64(Float64(-0.5625 * Float64(Float64((c ^ 3.0) * Float64(a * a)) / (b ^ 5.0))) + fma(-0.375, Float64(a / Float64((b ^ 3.0) / Float64(c * c))), Float64(Float64(c * -0.5) / b))) end
code[a_, b_, c_] := N[(N[(-0.5625 * N[(N[(N[Power[c, 3.0], $MachinePrecision] * N[(a * a), $MachinePrecision]), $MachinePrecision] / N[Power[b, 5.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(-0.375 * N[(a / N[(N[Power[b, 3.0], $MachinePrecision] / N[(c * c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(N[(c * -0.5), $MachinePrecision] / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
-0.5625 \cdot \frac{{c}^{3} \cdot \left(a \cdot a\right)}{{b}^{5}} + \mathsf{fma}\left(-0.375, \frac{a}{\frac{{b}^{3}}{c \cdot c}}, \frac{c \cdot -0.5}{b}\right)
\end{array}
Initial program 19.9%
neg-sub019.9%
sqr-neg19.9%
associate-+l-19.9%
sub0-neg19.9%
neg-mul-119.9%
Simplified19.9%
div-inv20.0%
metadata-eval20.0%
*-commutative20.0%
add-sqr-sqrt19.9%
pow219.9%
Applied egg-rr19.9%
Taylor expanded in b around inf 96.0%
+-commutative96.0%
Simplified97.2%
Final simplification97.2%
(FPCore (a b c) :precision binary64 (fma -0.5 (/ c b) (/ (* a -0.375) (/ (pow b 3.0) (* c c)))))
double code(double a, double b, double c) {
return fma(-0.5, (c / b), ((a * -0.375) / (pow(b, 3.0) / (c * c))));
}
function code(a, b, c) return fma(-0.5, Float64(c / b), Float64(Float64(a * -0.375) / Float64((b ^ 3.0) / Float64(c * c)))) end
code[a_, b_, c_] := N[(-0.5 * N[(c / b), $MachinePrecision] + N[(N[(a * -0.375), $MachinePrecision] / N[(N[Power[b, 3.0], $MachinePrecision] / N[(c * c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(-0.5, \frac{c}{b}, \frac{a \cdot -0.375}{\frac{{b}^{3}}{c \cdot c}}\right)
\end{array}
Initial program 19.9%
Taylor expanded in b around inf 95.3%
fma-def95.3%
*-commutative95.3%
associate-/l*95.3%
associate-*l/95.3%
unpow295.3%
Simplified95.3%
Final simplification95.3%
(FPCore (a b c) :precision binary64 (+ (* -0.375 (* (* c c) (/ a (pow b 3.0)))) (/ -0.5 (/ b c))))
double code(double a, double b, double c) {
return (-0.375 * ((c * c) * (a / pow(b, 3.0)))) + (-0.5 / (b / c));
}
real(8) function code(a, b, c)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: c
code = ((-0.375d0) * ((c * c) * (a / (b ** 3.0d0)))) + ((-0.5d0) / (b / c))
end function
public static double code(double a, double b, double c) {
return (-0.375 * ((c * c) * (a / Math.pow(b, 3.0)))) + (-0.5 / (b / c));
}
def code(a, b, c): return (-0.375 * ((c * c) * (a / math.pow(b, 3.0)))) + (-0.5 / (b / c))
function code(a, b, c) return Float64(Float64(-0.375 * Float64(Float64(c * c) * Float64(a / (b ^ 3.0)))) + Float64(-0.5 / Float64(b / c))) end
function tmp = code(a, b, c) tmp = (-0.375 * ((c * c) * (a / (b ^ 3.0)))) + (-0.5 / (b / c)); end
code[a_, b_, c_] := N[(N[(-0.375 * N[(N[(c * c), $MachinePrecision] * N[(a / N[Power[b, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(-0.5 / N[(b / c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
-0.375 \cdot \left(\left(c \cdot c\right) \cdot \frac{a}{{b}^{3}}\right) + \frac{-0.5}{\frac{b}{c}}
\end{array}
Initial program 19.9%
Taylor expanded in b around inf 94.7%
Taylor expanded in a around 0 95.3%
+-commutative95.3%
fma-def95.3%
associate-/l*95.3%
unpow295.3%
associate-*r/95.3%
Simplified95.3%
fma-udef95.3%
associate-/r/95.3%
associate-/l*94.9%
Applied egg-rr94.9%
Final simplification94.9%
(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 19.9%
Taylor expanded in b around inf 89.0%
Final simplification89.0%
herbie shell --seed 2023279
(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)))