
(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 7 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 (/ (* 3.0 (* a c)) (* (* 3.0 a) (- (- 0.0 b) (sqrt (fma c (* a -3.0) (fma b b 0.0)))))))
double code(double a, double b, double c) {
return (3.0 * (a * c)) / ((3.0 * a) * ((0.0 - b) - sqrt(fma(c, (a * -3.0), fma(b, b, 0.0)))));
}
function code(a, b, c) return Float64(Float64(3.0 * Float64(a * c)) / Float64(Float64(3.0 * a) * Float64(Float64(0.0 - b) - sqrt(fma(c, Float64(a * -3.0), fma(b, b, 0.0)))))) end
code[a_, b_, c_] := N[(N[(3.0 * N[(a * c), $MachinePrecision]), $MachinePrecision] / N[(N[(3.0 * a), $MachinePrecision] * N[(N[(0.0 - b), $MachinePrecision] - N[Sqrt[N[(c * N[(a * -3.0), $MachinePrecision] + N[(b * b + 0.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{3 \cdot \left(a \cdot c\right)}{\left(3 \cdot a\right) \cdot \left(\left(0 - b\right) - \sqrt{\mathsf{fma}\left(c, a \cdot -3, \mathsf{fma}\left(b, b, 0\right)\right)}\right)}
\end{array}
Initial program 19.7%
Applied egg-rr19.9%
div-subN/A
frac-2negN/A
associate-/l/N/A
frac-2negN/A
associate-/l/N/A
Applied egg-rr20.2%
Taylor expanded in c around 0
*-lowering-*.f64N/A
*-lowering-*.f6499.2
Simplified99.2%
Final simplification99.2%
(FPCore (a b c) :precision binary64 (fma (/ (* a (* c c)) (* b (* b b))) -0.375 (/ (* c -0.5) b)))
double code(double a, double b, double c) {
return fma(((a * (c * c)) / (b * (b * b))), -0.375, ((c * -0.5) / b));
}
function code(a, b, c) return fma(Float64(Float64(a * Float64(c * c)) / Float64(b * Float64(b * b))), -0.375, Float64(Float64(c * -0.5) / b)) end
code[a_, b_, c_] := N[(N[(N[(a * N[(c * c), $MachinePrecision]), $MachinePrecision] / N[(b * N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * -0.375 + N[(N[(c * -0.5), $MachinePrecision] / b), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(\frac{a \cdot \left(c \cdot c\right)}{b \cdot \left(b \cdot b\right)}, -0.375, \frac{c \cdot -0.5}{b}\right)
\end{array}
Initial program 19.7%
Taylor expanded in a around 0
+-commutativeN/A
*-commutativeN/A
accelerator-lowering-fma.f64N/A
/-lowering-/.f64N/A
*-lowering-*.f64N/A
unpow2N/A
*-lowering-*.f64N/A
cube-multN/A
unpow2N/A
*-lowering-*.f64N/A
unpow2N/A
*-lowering-*.f64N/A
associate-*r/N/A
/-lowering-/.f64N/A
*-commutativeN/A
*-lowering-*.f6494.4
Simplified94.4%
(FPCore (a b c) :precision binary64 (/ (fma a (* -0.375 (/ (* c c) (* b b))) (* c -0.5)) b))
double code(double a, double b, double c) {
return fma(a, (-0.375 * ((c * c) / (b * b))), (c * -0.5)) / b;
}
function code(a, b, c) return Float64(fma(a, Float64(-0.375 * Float64(Float64(c * c) / Float64(b * b))), Float64(c * -0.5)) / b) end
code[a_, b_, c_] := N[(N[(a * N[(-0.375 * N[(N[(c * c), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(c * -0.5), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(a, -0.375 \cdot \frac{c \cdot c}{b \cdot b}, c \cdot -0.5\right)}{b}
\end{array}
Initial program 19.7%
Taylor expanded in b around inf
/-lowering-/.f64N/A
Simplified94.4%
(FPCore (a b c) :precision binary64 (/ 1.0 (fma -2.0 (/ b c) (/ (* a 1.5) b))))
double code(double a, double b, double c) {
return 1.0 / fma(-2.0, (b / c), ((a * 1.5) / b));
}
function code(a, b, c) return Float64(1.0 / fma(-2.0, Float64(b / c), Float64(Float64(a * 1.5) / b))) end
code[a_, b_, c_] := N[(1.0 / N[(-2.0 * N[(b / c), $MachinePrecision] + N[(N[(a * 1.5), $MachinePrecision] / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{1}{\mathsf{fma}\left(-2, \frac{b}{c}, \frac{a \cdot 1.5}{b}\right)}
\end{array}
Initial program 19.7%
Applied egg-rr19.7%
clear-numN/A
/-lowering-/.f64N/A
un-div-invN/A
associate-/r/N/A
*-lowering-*.f64N/A
Applied egg-rr19.7%
Taylor expanded in a around 0
accelerator-lowering-fma.f64N/A
/-lowering-/.f64N/A
associate-*r/N/A
/-lowering-/.f64N/A
*-lowering-*.f6494.3
Simplified94.3%
Final simplification94.3%
(FPCore (a b c) :precision binary64 (* c (/ (fma -0.375 (/ (* a c) (* b b)) -0.5) b)))
double code(double a, double b, double c) {
return c * (fma(-0.375, ((a * c) / (b * b)), -0.5) / b);
}
function code(a, b, c) return Float64(c * Float64(fma(-0.375, Float64(Float64(a * c) / Float64(b * b)), -0.5) / b)) end
code[a_, b_, c_] := N[(c * N[(N[(-0.375 * N[(N[(a * c), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision] + -0.5), $MachinePrecision] / b), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
c \cdot \frac{\mathsf{fma}\left(-0.375, \frac{a \cdot c}{b \cdot b}, -0.5\right)}{b}
\end{array}
Initial program 19.7%
Taylor expanded in c around 0
sub-negN/A
associate-*r/N/A
associate-*r*N/A
associate-*l/N/A
associate-*r/N/A
*-lowering-*.f64N/A
associate-*r/N/A
associate-*l/N/A
associate-*r*N/A
associate-*r/N/A
*-commutativeN/A
associate-/l*N/A
associate-*l*N/A
accelerator-lowering-fma.f64N/A
Simplified94.1%
Taylor expanded in b around inf
/-lowering-/.f64N/A
sub-negN/A
metadata-evalN/A
accelerator-lowering-fma.f64N/A
/-lowering-/.f64N/A
*-lowering-*.f64N/A
unpow2N/A
*-lowering-*.f6494.1
Simplified94.1%
(FPCore (a b c) :precision binary64 (/ (* c -0.5) b))
double code(double a, double b, double c) {
return (c * -0.5) / 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 * (-0.5d0)) / b
end function
public static double code(double a, double b, double c) {
return (c * -0.5) / b;
}
def code(a, b, c): return (c * -0.5) / b
function code(a, b, c) return Float64(Float64(c * -0.5) / b) end
function tmp = code(a, b, c) tmp = (c * -0.5) / b; end
code[a_, b_, c_] := N[(N[(c * -0.5), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{c \cdot -0.5}{b}
\end{array}
Initial program 19.7%
Taylor expanded in b around inf
associate-*r/N/A
/-lowering-/.f64N/A
*-commutativeN/A
*-lowering-*.f6489.0
Simplified89.0%
(FPCore (a b c) :precision binary64 (* c (/ -0.5 b)))
double code(double a, double b, double c) {
return c * (-0.5 / 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 * ((-0.5d0) / b)
end function
public static double code(double a, double b, double c) {
return c * (-0.5 / b);
}
def code(a, b, c): return c * (-0.5 / b)
function code(a, b, c) return Float64(c * Float64(-0.5 / b)) end
function tmp = code(a, b, c) tmp = c * (-0.5 / b); end
code[a_, b_, c_] := N[(c * N[(-0.5 / b), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
c \cdot \frac{-0.5}{b}
\end{array}
Initial program 19.7%
Taylor expanded in b around inf
associate-*r/N/A
/-lowering-/.f64N/A
*-commutativeN/A
*-lowering-*.f6489.0
Simplified89.0%
*-commutativeN/A
associate-*l/N/A
*-lowering-*.f64N/A
/-lowering-/.f6488.7
Applied egg-rr88.7%
Final simplification88.7%
herbie shell --seed 2024199
(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)))