
(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 9 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
(fma
(fma
(fma
(* -0.16666666666666666 a)
(* (/ (pow c 4.0) (pow b 6.0)) (/ 6.328125 b))
(/ (* -0.5625 (pow c 3.0)) (pow b 5.0)))
a
(/ (* -0.375 (* c c)) (pow b 3.0)))
a
(* -0.5 (/ c b))))
double code(double a, double b, double c) {
return fma(fma(fma((-0.16666666666666666 * a), ((pow(c, 4.0) / pow(b, 6.0)) * (6.328125 / b)), ((-0.5625 * pow(c, 3.0)) / pow(b, 5.0))), a, ((-0.375 * (c * c)) / pow(b, 3.0))), a, (-0.5 * (c / b)));
}
function code(a, b, c) return fma(fma(fma(Float64(-0.16666666666666666 * a), Float64(Float64((c ^ 4.0) / (b ^ 6.0)) * Float64(6.328125 / b)), Float64(Float64(-0.5625 * (c ^ 3.0)) / (b ^ 5.0))), a, Float64(Float64(-0.375 * Float64(c * c)) / (b ^ 3.0))), a, Float64(-0.5 * Float64(c / b))) end
code[a_, b_, c_] := N[(N[(N[(N[(-0.16666666666666666 * a), $MachinePrecision] * N[(N[(N[Power[c, 4.0], $MachinePrecision] / N[Power[b, 6.0], $MachinePrecision]), $MachinePrecision] * N[(6.328125 / b), $MachinePrecision]), $MachinePrecision] + N[(N[(-0.5625 * N[Power[c, 3.0], $MachinePrecision]), $MachinePrecision] / N[Power[b, 5.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * a + N[(N[(-0.375 * N[(c * c), $MachinePrecision]), $MachinePrecision] / N[Power[b, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * a + N[(-0.5 * N[(c / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(-0.16666666666666666 \cdot a, \frac{{c}^{4}}{{b}^{6}} \cdot \frac{6.328125}{b}, \frac{-0.5625 \cdot {c}^{3}}{{b}^{5}}\right), a, \frac{-0.375 \cdot \left(c \cdot c\right)}{{b}^{3}}\right), a, -0.5 \cdot \frac{c}{b}\right)
\end{array}
Initial program 20.7%
Taylor expanded in a around 0
+-commutativeN/A
*-commutativeN/A
lower-fma.f64N/A
Applied rewrites97.2%
(FPCore (a b c)
:precision binary64
(fma
(/
(fma
(* -1.0546875 (pow c 4.0))
(* a a)
(* (* (* (fma (* a c) -0.5625 (* (* b b) -0.375)) c) c) (* b b)))
(pow b 7.0))
a
(* -0.5 (/ c b))))
double code(double a, double b, double c) {
return fma((fma((-1.0546875 * pow(c, 4.0)), (a * a), (((fma((a * c), -0.5625, ((b * b) * -0.375)) * c) * c) * (b * b))) / pow(b, 7.0)), a, (-0.5 * (c / b)));
}
function code(a, b, c) return fma(Float64(fma(Float64(-1.0546875 * (c ^ 4.0)), Float64(a * a), Float64(Float64(Float64(fma(Float64(a * c), -0.5625, Float64(Float64(b * b) * -0.375)) * c) * c) * Float64(b * b))) / (b ^ 7.0)), a, Float64(-0.5 * Float64(c / b))) end
code[a_, b_, c_] := N[(N[(N[(N[(-1.0546875 * N[Power[c, 4.0], $MachinePrecision]), $MachinePrecision] * N[(a * a), $MachinePrecision] + N[(N[(N[(N[(N[(a * c), $MachinePrecision] * -0.5625 + N[(N[(b * b), $MachinePrecision] * -0.375), $MachinePrecision]), $MachinePrecision] * c), $MachinePrecision] * c), $MachinePrecision] * N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[Power[b, 7.0], $MachinePrecision]), $MachinePrecision] * a + N[(-0.5 * N[(c / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(\frac{\mathsf{fma}\left(-1.0546875 \cdot {c}^{4}, a \cdot a, \left(\left(\mathsf{fma}\left(a \cdot c, -0.5625, \left(b \cdot b\right) \cdot -0.375\right) \cdot c\right) \cdot c\right) \cdot \left(b \cdot b\right)\right)}{{b}^{7}}, a, -0.5 \cdot \frac{c}{b}\right)
\end{array}
Initial program 20.7%
Taylor expanded in a around 0
+-commutativeN/A
*-commutativeN/A
lower-fma.f64N/A
Applied rewrites97.2%
Taylor expanded in b around 0
Applied rewrites97.2%
Taylor expanded in b around 0
Applied rewrites97.2%
(FPCore (a b c) :precision binary64 (fma (* (fma (* a (/ c (pow b 5.0))) -0.5625 (/ -0.375 (pow b 3.0))) (* c c)) a (* -0.5 (/ c b))))
double code(double a, double b, double c) {
return fma((fma((a * (c / pow(b, 5.0))), -0.5625, (-0.375 / pow(b, 3.0))) * (c * c)), a, (-0.5 * (c / b)));
}
function code(a, b, c) return fma(Float64(fma(Float64(a * Float64(c / (b ^ 5.0))), -0.5625, Float64(-0.375 / (b ^ 3.0))) * Float64(c * c)), a, Float64(-0.5 * Float64(c / b))) end
code[a_, b_, c_] := N[(N[(N[(N[(a * N[(c / N[Power[b, 5.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * -0.5625 + N[(-0.375 / N[Power[b, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[(c * c), $MachinePrecision]), $MachinePrecision] * a + N[(-0.5 * N[(c / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(\mathsf{fma}\left(a \cdot \frac{c}{{b}^{5}}, -0.5625, \frac{-0.375}{{b}^{3}}\right) \cdot \left(c \cdot c\right), a, -0.5 \cdot \frac{c}{b}\right)
\end{array}
Initial program 20.7%
Taylor expanded in a around 0
+-commutativeN/A
*-commutativeN/A
lower-fma.f64N/A
Applied rewrites97.2%
Taylor expanded in c around 0
Applied rewrites96.5%
(FPCore (a b c) :precision binary64 (fma (/ (* (* (fma (* a c) -0.5625 (* (* b b) -0.375)) c) c) (pow b 5.0)) a (* -0.5 (/ c b))))
double code(double a, double b, double c) {
return fma((((fma((a * c), -0.5625, ((b * b) * -0.375)) * c) * c) / pow(b, 5.0)), a, (-0.5 * (c / b)));
}
function code(a, b, c) return fma(Float64(Float64(Float64(fma(Float64(a * c), -0.5625, Float64(Float64(b * b) * -0.375)) * c) * c) / (b ^ 5.0)), a, Float64(-0.5 * Float64(c / b))) end
code[a_, b_, c_] := N[(N[(N[(N[(N[(N[(a * c), $MachinePrecision] * -0.5625 + N[(N[(b * b), $MachinePrecision] * -0.375), $MachinePrecision]), $MachinePrecision] * c), $MachinePrecision] * c), $MachinePrecision] / N[Power[b, 5.0], $MachinePrecision]), $MachinePrecision] * a + N[(-0.5 * N[(c / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(\frac{\left(\mathsf{fma}\left(a \cdot c, -0.5625, \left(b \cdot b\right) \cdot -0.375\right) \cdot c\right) \cdot c}{{b}^{5}}, a, -0.5 \cdot \frac{c}{b}\right)
\end{array}
Initial program 20.7%
Taylor expanded in a around 0
+-commutativeN/A
*-commutativeN/A
lower-fma.f64N/A
Applied rewrites97.2%
Taylor expanded in c around 0
Applied rewrites96.5%
Taylor expanded in b around 0
Applied rewrites96.5%
(FPCore (a b c) :precision binary64 (/ 0.3333333333333333 (fma (/ (fma (* a (/ c (* b b))) 0.375 0.5) b) a (* (/ b c) -0.6666666666666666))))
double code(double a, double b, double c) {
return 0.3333333333333333 / fma((fma((a * (c / (b * b))), 0.375, 0.5) / b), a, ((b / c) * -0.6666666666666666));
}
function code(a, b, c) return Float64(0.3333333333333333 / fma(Float64(fma(Float64(a * Float64(c / Float64(b * b))), 0.375, 0.5) / b), a, Float64(Float64(b / c) * -0.6666666666666666))) end
code[a_, b_, c_] := N[(0.3333333333333333 / N[(N[(N[(N[(a * N[(c / N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * 0.375 + 0.5), $MachinePrecision] / b), $MachinePrecision] * a + N[(N[(b / c), $MachinePrecision] * -0.6666666666666666), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{0.3333333333333333}{\mathsf{fma}\left(\frac{\mathsf{fma}\left(a \cdot \frac{c}{b \cdot b}, 0.375, 0.5\right)}{b}, a, \frac{b}{c} \cdot -0.6666666666666666\right)}
\end{array}
Initial program 20.7%
lift-/.f64N/A
clear-numN/A
lift-*.f64N/A
associate-/l*N/A
associate-/r*N/A
lower-/.f64N/A
metadata-evalN/A
lower-/.f6420.7
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
lower--.f6420.7
Applied rewrites20.7%
Taylor expanded in a around 0
+-commutativeN/A
*-commutativeN/A
lower-fma.f64N/A
Applied rewrites96.1%
Taylor expanded in b around inf
Applied rewrites96.1%
(FPCore (a b c) :precision binary64 (/ (fma (* a -0.375) (/ (* c c) (* b b)) (* -0.5 c)) b))
double code(double a, double b, double c) {
return fma((a * -0.375), ((c * c) / (b * b)), (-0.5 * c)) / b;
}
function code(a, b, c) return Float64(fma(Float64(a * -0.375), Float64(Float64(c * c) / Float64(b * b)), Float64(-0.5 * c)) / b) end
code[a_, b_, c_] := N[(N[(N[(a * -0.375), $MachinePrecision] * N[(N[(c * c), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision] + N[(-0.5 * c), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(a \cdot -0.375, \frac{c \cdot c}{b \cdot b}, -0.5 \cdot c\right)}{b}
\end{array}
Initial program 20.7%
Taylor expanded in b around inf
lower-/.f64N/A
Applied rewrites96.4%
Taylor expanded in c around 0
Applied rewrites94.2%
Applied rewrites94.3%
(FPCore (a b c) :precision binary64 (/ (* (fma (* a (/ c (* b b))) -0.375 -0.5) c) b))
double code(double a, double b, double c) {
return (fma((a * (c / (b * b))), -0.375, -0.5) * c) / b;
}
function code(a, b, c) return Float64(Float64(fma(Float64(a * Float64(c / Float64(b * b))), -0.375, -0.5) * c) / b) end
code[a_, b_, c_] := N[(N[(N[(N[(a * N[(c / N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * -0.375 + -0.5), $MachinePrecision] * c), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(a \cdot \frac{c}{b \cdot b}, -0.375, -0.5\right) \cdot c}{b}
\end{array}
Initial program 20.7%
Taylor expanded in b around inf
lower-/.f64N/A
Applied rewrites96.4%
Taylor expanded in c around 0
Applied rewrites94.2%
Applied rewrites94.3%
Taylor expanded in c around 0
Applied rewrites94.2%
(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 20.7%
Taylor expanded in a around 0
lower-*.f64N/A
lower-/.f6488.3
Applied rewrites88.3%
(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 20.7%
lift-/.f64N/A
clear-numN/A
lift-*.f64N/A
associate-/l*N/A
associate-/r*N/A
lower-/.f64N/A
metadata-evalN/A
lower-/.f6420.7
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
lower--.f6420.7
Applied rewrites20.7%
Applied rewrites20.6%
Taylor expanded in a around 0
distribute-rgt-outN/A
metadata-evalN/A
associate-*l/N/A
mul0-rgt3.3
Applied rewrites3.3%
herbie shell --seed 2024307
(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)))