
(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 8 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 (* (/ -1.0 (* a -3.0)) (/ (* c (* a -3.0)) (+ (sqrt (fma (* c a) -3.0 (* b b))) b))))
double code(double a, double b, double c) {
return (-1.0 / (a * -3.0)) * ((c * (a * -3.0)) / (sqrt(fma((c * a), -3.0, (b * b))) + b));
}
function code(a, b, c) return Float64(Float64(-1.0 / Float64(a * -3.0)) * Float64(Float64(c * Float64(a * -3.0)) / Float64(sqrt(fma(Float64(c * a), -3.0, Float64(b * b))) + b))) end
code[a_, b_, c_] := N[(N[(-1.0 / N[(a * -3.0), $MachinePrecision]), $MachinePrecision] * N[(N[(c * N[(a * -3.0), $MachinePrecision]), $MachinePrecision] / N[(N[Sqrt[N[(N[(c * a), $MachinePrecision] * -3.0 + N[(b * b), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] + b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{-1}{a \cdot -3} \cdot \frac{c \cdot \left(a \cdot -3\right)}{\sqrt{\mathsf{fma}\left(c \cdot a, -3, b \cdot b\right)} + b}
\end{array}
Initial program 30.3%
lift-/.f64N/A
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
div-subN/A
lower--.f64N/A
Applied rewrites29.7%
Applied rewrites30.3%
lift-neg.f64N/A
lift--.f64N/A
flip--N/A
lift-+.f64N/A
distribute-neg-frac2N/A
lift-sqrt.f64N/A
lift-sqrt.f64N/A
rem-square-sqrtN/A
lift-*.f64N/A
lift--.f64N/A
lower-/.f64N/A
Applied rewrites99.1%
lift-fma.f64N/A
+-rgt-identityN/A
*-commutativeN/A
lift-*.f64N/A
associate-*r*N/A
lift-*.f64N/A
lower-*.f6499.3
Applied rewrites99.3%
Final simplification99.3%
(FPCore (a b c) :precision binary64 (* (/ -0.3333333333333333 a) (/ (fma (* c a) -3.0 0.0) (- (- b) (sqrt (fma (* c a) -3.0 (* b b)))))))
double code(double a, double b, double c) {
return (-0.3333333333333333 / a) * (fma((c * a), -3.0, 0.0) / (-b - sqrt(fma((c * a), -3.0, (b * b)))));
}
function code(a, b, c) return Float64(Float64(-0.3333333333333333 / a) * Float64(fma(Float64(c * a), -3.0, 0.0) / Float64(Float64(-b) - sqrt(fma(Float64(c * a), -3.0, Float64(b * b)))))) end
code[a_, b_, c_] := N[(N[(-0.3333333333333333 / a), $MachinePrecision] * N[(N[(N[(c * a), $MachinePrecision] * -3.0 + 0.0), $MachinePrecision] / N[((-b) - N[Sqrt[N[(N[(c * a), $MachinePrecision] * -3.0 + N[(b * b), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{-0.3333333333333333}{a} \cdot \frac{\mathsf{fma}\left(c \cdot a, -3, 0\right)}{\left(-b\right) - \sqrt{\mathsf{fma}\left(c \cdot a, -3, b \cdot b\right)}}
\end{array}
Initial program 30.3%
lift-/.f64N/A
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
div-subN/A
lower--.f64N/A
Applied rewrites29.7%
Applied rewrites30.3%
lift-neg.f64N/A
lift--.f64N/A
flip--N/A
lift-+.f64N/A
distribute-neg-frac2N/A
lift-sqrt.f64N/A
lift-sqrt.f64N/A
rem-square-sqrtN/A
lift-*.f64N/A
lift--.f64N/A
lower-/.f64N/A
Applied rewrites99.1%
lift-/.f64N/A
lift-*.f64N/A
associate-/r*N/A
metadata-evalN/A
metadata-evalN/A
lower-/.f64N/A
metadata-eval99.0
Applied rewrites99.0%
Final simplification99.0%
(FPCore (a b c) :precision binary64 (/ (fma (* -0.375 a) (* (/ c (* b b)) c) (* -0.5 c)) b))
double code(double a, double b, double c) {
return fma((-0.375 * a), ((c / (b * b)) * c), (-0.5 * c)) / b;
}
function code(a, b, c) return Float64(fma(Float64(-0.375 * a), Float64(Float64(c / Float64(b * b)) * c), Float64(-0.5 * c)) / b) end
code[a_, b_, c_] := N[(N[(N[(-0.375 * a), $MachinePrecision] * N[(N[(c / N[(b * b), $MachinePrecision]), $MachinePrecision] * c), $MachinePrecision] + N[(-0.5 * c), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(-0.375 \cdot a, \frac{c}{b \cdot b} \cdot c, -0.5 \cdot c\right)}{b}
\end{array}
Initial program 30.3%
Taylor expanded in b around inf
lower-/.f64N/A
+-commutativeN/A
associate-/l*N/A
associate-*r*N/A
lower-fma.f64N/A
lower-*.f64N/A
unpow2N/A
associate-/l*N/A
lower-*.f64N/A
lower-/.f64N/A
unpow2N/A
lower-*.f64N/A
lower-*.f6491.0
Applied rewrites91.0%
Final simplification91.0%
(FPCore (a b c) :precision binary64 (/ (* (fma (* -0.375 a) (/ c (* b b)) -0.5) c) b))
double code(double a, double b, double c) {
return (fma((-0.375 * a), (c / (b * b)), -0.5) * c) / b;
}
function code(a, b, c) return Float64(Float64(fma(Float64(-0.375 * a), Float64(c / Float64(b * b)), -0.5) * c) / b) end
code[a_, b_, c_] := N[(N[(N[(N[(-0.375 * a), $MachinePrecision] * N[(c / N[(b * b), $MachinePrecision]), $MachinePrecision] + -0.5), $MachinePrecision] * c), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(-0.375 \cdot a, \frac{c}{b \cdot b}, -0.5\right) \cdot c}{b}
\end{array}
Initial program 30.3%
Taylor expanded in b around inf
lower-/.f64N/A
+-commutativeN/A
associate-/l*N/A
associate-*r*N/A
lower-fma.f64N/A
lower-*.f64N/A
unpow2N/A
associate-/l*N/A
lower-*.f64N/A
lower-/.f64N/A
unpow2N/A
lower-*.f64N/A
lower-*.f6491.0
Applied rewrites91.0%
Taylor expanded in c around 0
Applied rewrites91.0%
Final simplification91.0%
(FPCore (a b c) :precision binary64 (* (/ (fma (* -0.375 a) (/ c (* b b)) -0.5) b) c))
double code(double a, double b, double c) {
return (fma((-0.375 * a), (c / (b * b)), -0.5) / b) * c;
}
function code(a, b, c) return Float64(Float64(fma(Float64(-0.375 * a), Float64(c / Float64(b * b)), -0.5) / b) * c) end
code[a_, b_, c_] := N[(N[(N[(N[(-0.375 * a), $MachinePrecision] * N[(c / N[(b * b), $MachinePrecision]), $MachinePrecision] + -0.5), $MachinePrecision] / b), $MachinePrecision] * c), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(-0.375 \cdot a, \frac{c}{b \cdot b}, -0.5\right)}{b} \cdot c
\end{array}
Initial program 30.3%
Taylor expanded in c around 0
*-commutativeN/A
lower-*.f64N/A
Applied rewrites93.5%
Taylor expanded in b around inf
Applied rewrites90.7%
Final simplification90.7%
(FPCore (a b c) :precision binary64 (* (/ c b) -0.5))
double code(double a, double b, double c) {
return (c / b) * -0.5;
}
real(8) function code(a, b, c)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: c
code = (c / b) * (-0.5d0)
end function
public static double code(double a, double b, double c) {
return (c / b) * -0.5;
}
def code(a, b, c): return (c / b) * -0.5
function code(a, b, c) return Float64(Float64(c / b) * -0.5) end
function tmp = code(a, b, c) tmp = (c / b) * -0.5; end
code[a_, b_, c_] := N[(N[(c / b), $MachinePrecision] * -0.5), $MachinePrecision]
\begin{array}{l}
\\
\frac{c}{b} \cdot -0.5
\end{array}
Initial program 30.3%
Taylor expanded in c around 0
*-commutativeN/A
lower-*.f64N/A
lower-/.f6482.2
Applied rewrites82.2%
(FPCore (a b c) :precision binary64 (* (/ -0.5 b) c))
double code(double a, double b, double c) {
return (-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 = ((-0.5d0) / b) * c
end function
public static double code(double a, double b, double c) {
return (-0.5 / b) * c;
}
def code(a, b, c): return (-0.5 / b) * c
function code(a, b, c) return Float64(Float64(-0.5 / b) * c) end
function tmp = code(a, b, c) tmp = (-0.5 / b) * c; end
code[a_, b_, c_] := N[(N[(-0.5 / b), $MachinePrecision] * c), $MachinePrecision]
\begin{array}{l}
\\
\frac{-0.5}{b} \cdot c
\end{array}
Initial program 30.3%
Taylor expanded in c around 0
*-commutativeN/A
lower-*.f64N/A
Applied rewrites93.5%
Taylor expanded in c around 0
Applied rewrites82.0%
(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 30.3%
lift-/.f64N/A
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
div-subN/A
lower--.f64N/A
Applied rewrites29.7%
lift--.f64N/A
sub-negN/A
+-commutativeN/A
lift-/.f64N/A
div-invN/A
distribute-lft-neg-inN/A
lower-fma.f64N/A
lower-neg.f64N/A
lift-*.f64N/A
*-commutativeN/A
associate-/r*N/A
lower-/.f64N/A
metadata-eval29.8
lift-/.f64N/A
clear-numN/A
associate-/r/N/A
lower-*.f64N/A
lift-*.f64N/A
*-commutativeN/A
associate-/r*N/A
lower-/.f64N/A
metadata-eval31.9
lift-fma.f64N/A
Applied rewrites31.9%
Taylor expanded in c around 0
distribute-rgt-outN/A
metadata-evalN/A
mul0-rgt3.2
Applied rewrites3.2%
herbie shell --seed 2024235
(FPCore (a b c)
:name "Cubic critical, medium range"
:precision binary64
:pre (and (and (and (< 1.1102230246251565e-16 a) (< a 9007199254740992.0)) (and (< 1.1102230246251565e-16 b) (< b 9007199254740992.0))) (and (< 1.1102230246251565e-16 c) (< c 9007199254740992.0)))
(/ (+ (- b) (sqrt (- (* b b) (* (* 3.0 a) c)))) (* 3.0 a)))