
(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) (* (+ (sqrt (fma (* c -3.0) a (* b b))) b) (/ -3.0 (* (* c a) 3.0)))))
double code(double a, double b, double c) {
return (1.0 / a) / ((sqrt(fma((c * -3.0), a, (b * b))) + b) * (-3.0 / ((c * a) * 3.0)));
}
function code(a, b, c) return Float64(Float64(1.0 / a) / Float64(Float64(sqrt(fma(Float64(c * -3.0), a, Float64(b * b))) + b) * Float64(-3.0 / Float64(Float64(c * a) * 3.0)))) end
code[a_, b_, c_] := N[(N[(1.0 / a), $MachinePrecision] / N[(N[(N[Sqrt[N[(N[(c * -3.0), $MachinePrecision] * a + N[(b * b), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] + b), $MachinePrecision] * N[(-3.0 / N[(N[(c * a), $MachinePrecision] * 3.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\frac{1}{a}}{\left(\sqrt{\mathsf{fma}\left(c \cdot -3, a, b \cdot b\right)} + b\right) \cdot \frac{-3}{\left(c \cdot a\right) \cdot 3}}
\end{array}
Initial program 53.2%
Applied rewrites53.2%
lift-*.f64N/A
lift-/.f64N/A
associate-*l/N/A
metadata-evalN/A
lift--.f64N/A
flip--N/A
associate-/r/N/A
+-commutativeN/A
lower-*.f64N/A
Applied rewrites54.4%
Taylor expanded in c around 0
lower-*.f64N/A
lower-*.f6499.1
Applied rewrites99.1%
Final simplification99.1%
(FPCore (a b c)
:precision binary64
(let* ((t_0 (fma (* c -3.0) a (* b b))))
(if (<= (/ (- (sqrt (- (* b b) (* (* 3.0 a) c))) b) (* 3.0 a)) -0.04)
(/ (- t_0 (* b b)) (* (* 3.0 a) (+ (sqrt t_0) b)))
(/ 1.0 (/ (fma 1.5 (* (/ c b) a) (* -2.0 b)) c)))))
double code(double a, double b, double c) {
double t_0 = fma((c * -3.0), a, (b * b));
double tmp;
if (((sqrt(((b * b) - ((3.0 * a) * c))) - b) / (3.0 * a)) <= -0.04) {
tmp = (t_0 - (b * b)) / ((3.0 * a) * (sqrt(t_0) + b));
} else {
tmp = 1.0 / (fma(1.5, ((c / b) * a), (-2.0 * b)) / c);
}
return tmp;
}
function code(a, b, c) t_0 = fma(Float64(c * -3.0), a, Float64(b * b)) tmp = 0.0 if (Float64(Float64(sqrt(Float64(Float64(b * b) - Float64(Float64(3.0 * a) * c))) - b) / Float64(3.0 * a)) <= -0.04) tmp = Float64(Float64(t_0 - Float64(b * b)) / Float64(Float64(3.0 * a) * Float64(sqrt(t_0) + b))); 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_] := Block[{t$95$0 = N[(N[(c * -3.0), $MachinePrecision] * a + N[(b * b), $MachinePrecision]), $MachinePrecision]}, 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], -0.04], N[(N[(t$95$0 - N[(b * b), $MachinePrecision]), $MachinePrecision] / N[(N[(3.0 * a), $MachinePrecision] * N[(N[Sqrt[t$95$0], $MachinePrecision] + b), $MachinePrecision]), $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}
t_0 := \mathsf{fma}\left(c \cdot -3, a, b \cdot b\right)\\
\mathbf{if}\;\frac{\sqrt{b \cdot b - \left(3 \cdot a\right) \cdot c} - b}{3 \cdot a} \leq -0.04:\\
\;\;\;\;\frac{t\_0 - b \cdot b}{\left(3 \cdot a\right) \cdot \left(\sqrt{t\_0} + b\right)}\\
\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)) < -0.0400000000000000008Initial program 81.7%
lift-/.f64N/A
lift-*.f64N/A
associate-/r*N/A
clear-numN/A
associate-/r/N/A
lower-*.f64N/A
lower-/.f64N/A
clear-numN/A
associate-/r/N/A
lower-*.f64N/A
metadata-eval81.7
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
lower--.f6481.7
Applied rewrites81.8%
Applied rewrites82.4%
if -0.0400000000000000008 < (/.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 45.4%
lift-/.f64N/A
lift-*.f64N/A
associate-/r*N/A
clear-numN/A
associate-/r/N/A
lower-*.f64N/A
lower-/.f64N/A
clear-numN/A
associate-/r/N/A
lower-*.f64N/A
metadata-eval45.4
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
lower--.f6445.4
Applied rewrites45.4%
Applied rewrites45.4%
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-*.f6489.7
Applied rewrites89.7%
Final simplification88.1%
(FPCore (a b c) :precision binary64 (if (<= (/ (- (sqrt (- (* b b) (* (* 3.0 a) c))) b) (* 3.0 a)) -0.04) (* (- (sqrt (fma (* c -3.0) a (* b b))) 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)) <= -0.04) {
tmp = (sqrt(fma((c * -3.0), a, (b * b))) - 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)) <= -0.04) tmp = Float64(Float64(sqrt(fma(Float64(c * -3.0), a, Float64(b * b))) - 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], -0.04], N[(N[(N[Sqrt[N[(N[(c * -3.0), $MachinePrecision] * a + N[(b * b), $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 -0.04:\\
\;\;\;\;\left(\sqrt{\mathsf{fma}\left(c \cdot -3, a, b \cdot b\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)) < -0.0400000000000000008Initial program 81.7%
lift-/.f64N/A
clear-numN/A
associate-/r/N/A
lower-*.f64N/A
lift-*.f64N/A
associate-/r*N/A
lower-/.f64N/A
metadata-eval81.8
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
lower--.f6481.8
Applied rewrites81.8%
if -0.0400000000000000008 < (/.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 45.4%
lift-/.f64N/A
lift-*.f64N/A
associate-/r*N/A
clear-numN/A
associate-/r/N/A
lower-*.f64N/A
lower-/.f64N/A
clear-numN/A
associate-/r/N/A
lower-*.f64N/A
metadata-eval45.4
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
lower--.f6445.4
Applied rewrites45.4%
Applied rewrites45.4%
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-*.f6489.7
Applied rewrites89.7%
Final simplification88.0%
(FPCore (a b c) :precision binary64 (if (<= (/ (- (sqrt (- (* b b) (* (* 3.0 a) c))) b) (* 3.0 a)) -0.04) (* (- (sqrt (fma (* c -3.0) a (* b b))) 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)) <= -0.04) {
tmp = (sqrt(fma((c * -3.0), a, (b * b))) - 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)) <= -0.04) tmp = Float64(Float64(sqrt(fma(Float64(c * -3.0), a, Float64(b * b))) - 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], -0.04], N[(N[(N[Sqrt[N[(N[(c * -3.0), $MachinePrecision] * a + N[(b * b), $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 -0.04:\\
\;\;\;\;\left(\sqrt{\mathsf{fma}\left(c \cdot -3, a, b \cdot b\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)) < -0.0400000000000000008Initial program 81.7%
lift-/.f64N/A
clear-numN/A
associate-/r/N/A
lower-*.f64N/A
lift-*.f64N/A
associate-/r*N/A
lower-/.f64N/A
metadata-eval81.8
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
lower--.f6481.8
Applied rewrites81.8%
if -0.0400000000000000008 < (/.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 45.4%
lift-/.f64N/A
lift-*.f64N/A
associate-/r*N/A
clear-numN/A
associate-/r/N/A
lower-*.f64N/A
lower-/.f64N/A
clear-numN/A
associate-/r/N/A
lower-*.f64N/A
metadata-eval45.4
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
lower--.f6445.4
Applied rewrites45.4%
Applied rewrites45.4%
Taylor expanded in a around 0
+-commutativeN/A
lower-fma.f64N/A
lower-/.f64N/A
lower-*.f64N/A
lower-/.f6489.6
Applied rewrites89.6%
Final simplification87.9%
(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 53.2%
lift-/.f64N/A
lift-*.f64N/A
associate-/r*N/A
clear-numN/A
associate-/r/N/A
lower-*.f64N/A
lower-/.f64N/A
clear-numN/A
associate-/r/N/A
lower-*.f64N/A
metadata-eval53.2
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
lower--.f6453.2
Applied rewrites53.2%
Applied rewrites53.2%
Taylor expanded in a around 0
+-commutativeN/A
lower-fma.f64N/A
lower-/.f64N/A
lower-*.f64N/A
lower-/.f6483.7
Applied rewrites83.7%
Final simplification83.7%
(FPCore (a b c) :precision binary64 (/ (* (fma -0.375 (* (/ c (* b b)) a) -0.5) c) b))
double code(double a, double b, double c) {
return (fma(-0.375, ((c / (b * b)) * a), -0.5) * c) / b;
}
function code(a, b, c) return Float64(Float64(fma(-0.375, Float64(Float64(c / Float64(b * b)) * a), -0.5) * c) / b) end
code[a_, b_, c_] := N[(N[(N[(-0.375 * N[(N[(c / N[(b * b), $MachinePrecision]), $MachinePrecision] * a), $MachinePrecision] + -0.5), $MachinePrecision] * c), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(-0.375, \frac{c}{b \cdot b} \cdot a, -0.5\right) \cdot c}{b}
\end{array}
Initial program 53.2%
Taylor expanded in b around inf
Applied rewrites92.8%
Taylor expanded in c around 0
Applied rewrites83.1%
Final simplification83.1%
(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 53.2%
Taylor expanded in c around 0
*-commutativeN/A
lower-*.f64N/A
lower-/.f6466.5
Applied rewrites66.5%
Final simplification66.5%
(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 53.2%
Taylor expanded in c around 0
*-commutativeN/A
lower-*.f64N/A
lower-/.f6466.5
Applied rewrites66.5%
Applied rewrites66.5%
Final simplification66.5%
herbie shell --seed 2024237
(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)))