
(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 6 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) (* (+ (sqrt (fma b b (* (* -3.0 a) c))) b) (* 3.0 a))) c))
double code(double a, double b, double c) {
return ((-3.0 * a) / ((sqrt(fma(b, b, ((-3.0 * a) * c))) + b) * (3.0 * a))) * c;
}
function code(a, b, c) return Float64(Float64(Float64(-3.0 * a) / Float64(Float64(sqrt(fma(b, b, Float64(Float64(-3.0 * a) * c))) + b) * Float64(3.0 * a))) * c) end
code[a_, b_, c_] := N[(N[(N[(-3.0 * a), $MachinePrecision] / N[(N[(N[Sqrt[N[(b * b + N[(N[(-3.0 * a), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] + b), $MachinePrecision] * N[(3.0 * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * c), $MachinePrecision]
\begin{array}{l}
\\
\frac{-3 \cdot a}{\left(\sqrt{\mathsf{fma}\left(b, b, \left(-3 \cdot a\right) \cdot c\right)} + b\right) \cdot \left(3 \cdot a\right)} \cdot c
\end{array}
Initial program 54.3%
lift-/.f64N/A
clear-numN/A
lower-/.f64N/A
lower-/.f6454.3
lift-*.f64N/A
*-commutativeN/A
lower-*.f6454.3
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
lower--.f6454.3
Applied rewrites54.3%
lift-/.f64N/A
lift-/.f64N/A
lift-*.f64N/A
*-commutativeN/A
clear-numN/A
lift--.f64N/A
flip--N/A
associate-/l/N/A
lower-/.f64N/A
Applied rewrites55.7%
lift--.f64N/A
lift-fma.f64N/A
associate--l+N/A
*-commutativeN/A
lift-*.f64N/A
associate-*r*N/A
metadata-evalN/A
distribute-rgt-neg-inN/A
*-commutativeN/A
lift-*.f64N/A
+-inversesN/A
lower-fma.f64N/A
lift-*.f64N/A
distribute-lft-neg-inN/A
metadata-evalN/A
lower-*.f6499.4
lift-*.f64N/A
*-commutativeN/A
lower-*.f6499.4
Applied rewrites99.4%
lift-/.f64N/A
lift-fma.f64N/A
+-rgt-identityN/A
*-commutativeN/A
associate-/l*N/A
lower-*.f64N/A
lower-/.f6499.4
lift-*.f64N/A
*-commutativeN/A
lower-*.f6499.4
lift-*.f64N/A
*-commutativeN/A
lower-*.f6499.4
Applied rewrites99.4%
Final simplification99.4%
(FPCore (a b c) :precision binary64 (if (<= (/ (- (sqrt (- (* b b) (* (* 3.0 a) c))) b) (* 3.0 a)) -0.0057) (* (- (sqrt (fma b b (* (* -3.0 a) c))) b) (/ 0.3333333333333333 a)) (/ 1.0 (/ (fma 1.5 (* (/ c b) a) (* -2.0 b)) c))))
double code(double a, double b, double c) {
double tmp;
if (((sqrt(((b * b) - ((3.0 * a) * c))) - b) / (3.0 * a)) <= -0.0057) {
tmp = (sqrt(fma(b, b, ((-3.0 * a) * c))) - b) * (0.3333333333333333 / a);
} else {
tmp = 1.0 / (fma(1.5, ((c / b) * a), (-2.0 * b)) / c);
}
return tmp;
}
function code(a, b, c) tmp = 0.0 if (Float64(Float64(sqrt(Float64(Float64(b * b) - Float64(Float64(3.0 * a) * c))) - b) / Float64(3.0 * a)) <= -0.0057) tmp = Float64(Float64(sqrt(fma(b, b, Float64(Float64(-3.0 * a) * c))) - b) * Float64(0.3333333333333333 / a)); else tmp = Float64(1.0 / Float64(fma(1.5, Float64(Float64(c / b) * a), Float64(-2.0 * b)) / c)); end return tmp end
code[a_, b_, c_] := If[LessEqual[N[(N[(N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(N[(3.0 * a), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] / N[(3.0 * a), $MachinePrecision]), $MachinePrecision], -0.0057], N[(N[(N[Sqrt[N[(b * b + N[(N[(-3.0 * a), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] * N[(0.3333333333333333 / a), $MachinePrecision]), $MachinePrecision], N[(1.0 / N[(N[(1.5 * N[(N[(c / b), $MachinePrecision] * a), $MachinePrecision] + N[(-2.0 * b), $MachinePrecision]), $MachinePrecision] / c), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;\frac{\sqrt{b \cdot b - \left(3 \cdot a\right) \cdot c} - b}{3 \cdot a} \leq -0.0057:\\
\;\;\;\;\left(\sqrt{\mathsf{fma}\left(b, b, \left(-3 \cdot a\right) \cdot c\right)} - b\right) \cdot \frac{0.3333333333333333}{a}\\
\mathbf{else}:\\
\;\;\;\;\frac{1}{\frac{\mathsf{fma}\left(1.5, \frac{c}{b} \cdot a, -2 \cdot b\right)}{c}}\\
\end{array}
\end{array}
if (/.f64 (+.f64 (neg.f64 b) (sqrt.f64 (-.f64 (*.f64 b b) (*.f64 (*.f64 #s(literal 3 binary64) a) c)))) (*.f64 #s(literal 3 binary64) a)) < -0.0057000000000000002Initial program 79.6%
lift-/.f64N/A
lift-*.f64N/A
associate-/l/N/A
div-invN/A
lower-*.f64N/A
Applied rewrites79.6%
Applied rewrites79.6%
if -0.0057000000000000002 < (/.f64 (+.f64 (neg.f64 b) (sqrt.f64 (-.f64 (*.f64 b b) (*.f64 (*.f64 #s(literal 3 binary64) a) c)))) (*.f64 #s(literal 3 binary64) a)) Initial program 42.6%
lift-/.f64N/A
clear-numN/A
lower-/.f64N/A
lower-/.f6442.6
lift-*.f64N/A
*-commutativeN/A
lower-*.f6442.6
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
lower--.f6442.6
Applied rewrites42.6%
Taylor expanded in c around 0
lower-/.f64N/A
+-commutativeN/A
lower-fma.f64N/A
associate-/l*N/A
lower-*.f64N/A
lower-/.f64N/A
lower-*.f6490.5
Applied rewrites90.5%
Final simplification87.1%
(FPCore (a b c) :precision binary64 (if (<= (/ (- (sqrt (- (* b b) (* (* 3.0 a) c))) b) (* 3.0 a)) -0.0057) (* (- (sqrt (fma b b (* (* -3.0 a) c))) b) (/ 0.3333333333333333 a)) (/ 1.0 (fma 1.5 (/ a b) (* (/ b c) -2.0)))))
double code(double a, double b, double c) {
double tmp;
if (((sqrt(((b * b) - ((3.0 * a) * c))) - b) / (3.0 * a)) <= -0.0057) {
tmp = (sqrt(fma(b, b, ((-3.0 * a) * c))) - b) * (0.3333333333333333 / a);
} else {
tmp = 1.0 / fma(1.5, (a / b), ((b / c) * -2.0));
}
return tmp;
}
function code(a, b, c) tmp = 0.0 if (Float64(Float64(sqrt(Float64(Float64(b * b) - Float64(Float64(3.0 * a) * c))) - b) / Float64(3.0 * a)) <= -0.0057) tmp = Float64(Float64(sqrt(fma(b, b, Float64(Float64(-3.0 * a) * c))) - b) * Float64(0.3333333333333333 / a)); else tmp = Float64(1.0 / fma(1.5, Float64(a / b), Float64(Float64(b / c) * -2.0))); end return tmp end
code[a_, b_, c_] := If[LessEqual[N[(N[(N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(N[(3.0 * a), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] / N[(3.0 * a), $MachinePrecision]), $MachinePrecision], -0.0057], N[(N[(N[Sqrt[N[(b * b + N[(N[(-3.0 * a), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] * N[(0.3333333333333333 / a), $MachinePrecision]), $MachinePrecision], N[(1.0 / N[(1.5 * N[(a / b), $MachinePrecision] + N[(N[(b / c), $MachinePrecision] * -2.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;\frac{\sqrt{b \cdot b - \left(3 \cdot a\right) \cdot c} - b}{3 \cdot a} \leq -0.0057:\\
\;\;\;\;\left(\sqrt{\mathsf{fma}\left(b, b, \left(-3 \cdot a\right) \cdot c\right)} - b\right) \cdot \frac{0.3333333333333333}{a}\\
\mathbf{else}:\\
\;\;\;\;\frac{1}{\mathsf{fma}\left(1.5, \frac{a}{b}, \frac{b}{c} \cdot -2\right)}\\
\end{array}
\end{array}
if (/.f64 (+.f64 (neg.f64 b) (sqrt.f64 (-.f64 (*.f64 b b) (*.f64 (*.f64 #s(literal 3 binary64) a) c)))) (*.f64 #s(literal 3 binary64) a)) < -0.0057000000000000002Initial program 79.6%
lift-/.f64N/A
lift-*.f64N/A
associate-/l/N/A
div-invN/A
lower-*.f64N/A
Applied rewrites79.6%
Applied rewrites79.6%
if -0.0057000000000000002 < (/.f64 (+.f64 (neg.f64 b) (sqrt.f64 (-.f64 (*.f64 b b) (*.f64 (*.f64 #s(literal 3 binary64) a) c)))) (*.f64 #s(literal 3 binary64) a)) Initial program 42.6%
lift-/.f64N/A
clear-numN/A
lower-/.f64N/A
lower-/.f6442.6
lift-*.f64N/A
*-commutativeN/A
lower-*.f6442.6
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
lower--.f6442.6
Applied rewrites42.6%
Taylor expanded in a around 0
+-commutativeN/A
lower-fma.f64N/A
lower-/.f64N/A
lower-*.f64N/A
lower-/.f6490.5
Applied rewrites90.5%
Final simplification87.1%
(FPCore (a b c) :precision binary64 (* (/ (* a c) (* (+ (sqrt (fma b b (* (* -3.0 a) c))) b) (* 3.0 a))) -3.0))
double code(double a, double b, double c) {
return ((a * c) / ((sqrt(fma(b, b, ((-3.0 * a) * c))) + b) * (3.0 * a))) * -3.0;
}
function code(a, b, c) return Float64(Float64(Float64(a * c) / Float64(Float64(sqrt(fma(b, b, Float64(Float64(-3.0 * a) * c))) + b) * Float64(3.0 * a))) * -3.0) end
code[a_, b_, c_] := N[(N[(N[(a * c), $MachinePrecision] / N[(N[(N[Sqrt[N[(b * b + N[(N[(-3.0 * a), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] + b), $MachinePrecision] * N[(3.0 * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * -3.0), $MachinePrecision]
\begin{array}{l}
\\
\frac{a \cdot c}{\left(\sqrt{\mathsf{fma}\left(b, b, \left(-3 \cdot a\right) \cdot c\right)} + b\right) \cdot \left(3 \cdot a\right)} \cdot -3
\end{array}
Initial program 54.3%
lift-/.f64N/A
clear-numN/A
lower-/.f64N/A
lower-/.f6454.3
lift-*.f64N/A
*-commutativeN/A
lower-*.f6454.3
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
lower--.f6454.3
Applied rewrites54.3%
lift-/.f64N/A
lift-/.f64N/A
lift-*.f64N/A
*-commutativeN/A
clear-numN/A
lift--.f64N/A
flip--N/A
associate-/l/N/A
lower-/.f64N/A
Applied rewrites55.7%
lift--.f64N/A
lift-fma.f64N/A
associate--l+N/A
*-commutativeN/A
lift-*.f64N/A
associate-*r*N/A
metadata-evalN/A
distribute-rgt-neg-inN/A
*-commutativeN/A
lift-*.f64N/A
+-inversesN/A
lower-fma.f64N/A
lift-*.f64N/A
distribute-lft-neg-inN/A
metadata-evalN/A
lower-*.f6499.4
lift-*.f64N/A
*-commutativeN/A
lower-*.f6499.4
Applied rewrites99.4%
lift-/.f64N/A
lift-fma.f64N/A
+-rgt-identityN/A
lift-*.f64N/A
associate-*l*N/A
associate-/l*N/A
lower-*.f64N/A
lower-/.f64N/A
*-commutativeN/A
lower-*.f6499.2
lift-*.f64N/A
*-commutativeN/A
lower-*.f6499.2
Applied rewrites99.2%
Final simplification99.2%
(FPCore (a b c) :precision binary64 (/ 1.0 (fma 1.5 (/ a b) (* (/ b c) -2.0))))
double code(double a, double b, double c) {
return 1.0 / fma(1.5, (a / b), ((b / c) * -2.0));
}
function code(a, b, c) return Float64(1.0 / fma(1.5, Float64(a / b), Float64(Float64(b / c) * -2.0))) end
code[a_, b_, c_] := N[(1.0 / N[(1.5 * N[(a / b), $MachinePrecision] + N[(N[(b / c), $MachinePrecision] * -2.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{1}{\mathsf{fma}\left(1.5, \frac{a}{b}, \frac{b}{c} \cdot -2\right)}
\end{array}
Initial program 54.3%
lift-/.f64N/A
clear-numN/A
lower-/.f64N/A
lower-/.f6454.3
lift-*.f64N/A
*-commutativeN/A
lower-*.f6454.3
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
lower--.f6454.3
Applied rewrites54.3%
Taylor expanded in a around 0
+-commutativeN/A
lower-fma.f64N/A
lower-/.f64N/A
lower-*.f64N/A
lower-/.f6482.0
Applied rewrites82.0%
Final simplification82.0%
(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 54.3%
Taylor expanded in a around 0
lower-*.f64N/A
lower-/.f6464.9
Applied rewrites64.9%
herbie shell --seed 2024332
(FPCore (a b c)
:name "Cubic critical, narrow range"
:precision binary64
:pre (and (and (and (< 1.0536712127723509e-8 a) (< a 94906265.62425156)) (and (< 1.0536712127723509e-8 b) (< b 94906265.62425156))) (and (< 1.0536712127723509e-8 c) (< c 94906265.62425156)))
(/ (+ (- b) (sqrt (- (* b b) (* (* 3.0 a) c)))) (* 3.0 a)))