
(FPCore (a b c) :precision binary64 (/ (+ (- b) (sqrt (- (* b b) (* (* 4.0 a) c)))) (* 2.0 a)))
double code(double a, double b, double c) {
return (-b + sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * 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) - ((4.0d0 * a) * c)))) / (2.0d0 * a)
end function
public static double code(double a, double b, double c) {
return (-b + Math.sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * a);
}
def code(a, b, c): return (-b + math.sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * a)
function code(a, b, c) return Float64(Float64(Float64(-b) + sqrt(Float64(Float64(b * b) - Float64(Float64(4.0 * a) * c)))) / Float64(2.0 * a)) end
function tmp = code(a, b, c) tmp = (-b + sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * a); end
code[a_, b_, c_] := N[(N[((-b) + N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(N[(4.0 * a), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / N[(2.0 * a), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \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) (* (* 4.0 a) c)))) (* 2.0 a)))
double code(double a, double b, double c) {
return (-b + sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * 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) - ((4.0d0 * a) * c)))) / (2.0d0 * a)
end function
public static double code(double a, double b, double c) {
return (-b + Math.sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * a);
}
def code(a, b, c): return (-b + math.sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * a)
function code(a, b, c) return Float64(Float64(Float64(-b) + sqrt(Float64(Float64(b * b) - Float64(Float64(4.0 * a) * c)))) / Float64(2.0 * a)) end
function tmp = code(a, b, c) tmp = (-b + sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * a); end
code[a_, b_, c_] := N[(N[((-b) + N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(N[(4.0 * a), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / N[(2.0 * a), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a}
\end{array}
(FPCore (a b c)
:precision binary64
(/
(fma
(/ (* (* c c) (* (* a a) c)) (pow b 4.0))
-2.0
(fma
-1.0
(fma a (/ (* c c) (* b b)) c)
(* -0.25 (/ (* 20.0 (* (pow a 4.0) (pow c 4.0))) (* (pow b 6.0) a)))))
b))
double code(double a, double b, double c) {
return fma((((c * c) * ((a * a) * c)) / pow(b, 4.0)), -2.0, fma(-1.0, fma(a, ((c * c) / (b * b)), c), (-0.25 * ((20.0 * (pow(a, 4.0) * pow(c, 4.0))) / (pow(b, 6.0) * a))))) / b;
}
function code(a, b, c) return Float64(fma(Float64(Float64(Float64(c * c) * Float64(Float64(a * a) * c)) / (b ^ 4.0)), -2.0, fma(-1.0, fma(a, Float64(Float64(c * c) / Float64(b * b)), c), Float64(-0.25 * Float64(Float64(20.0 * Float64((a ^ 4.0) * (c ^ 4.0))) / Float64((b ^ 6.0) * a))))) / b) end
code[a_, b_, c_] := N[(N[(N[(N[(N[(c * c), $MachinePrecision] * N[(N[(a * a), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision] / N[Power[b, 4.0], $MachinePrecision]), $MachinePrecision] * -2.0 + N[(-1.0 * N[(a * N[(N[(c * c), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision] + c), $MachinePrecision] + N[(-0.25 * N[(N[(20.0 * N[(N[Power[a, 4.0], $MachinePrecision] * N[Power[c, 4.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(N[Power[b, 6.0], $MachinePrecision] * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\frac{\left(c \cdot c\right) \cdot \left(\left(a \cdot a\right) \cdot c\right)}{{b}^{4}}, -2, \mathsf{fma}\left(-1, \mathsf{fma}\left(a, \frac{c \cdot c}{b \cdot b}, c\right), -0.25 \cdot \frac{20 \cdot \left({a}^{4} \cdot {c}^{4}\right)}{{b}^{6} \cdot a}\right)\right)}{b}
\end{array}
Initial program 22.0%
Taylor expanded in c around 0
*-commutativeN/A
lower-*.f64N/A
Applied rewrites96.7%
Taylor expanded in a around 0
Applied rewrites96.7%
Taylor expanded in b around inf
lower-/.f64N/A
Applied rewrites97.0%
Applied rewrites97.0%
Final simplification97.0%
(FPCore (a b c)
:precision binary64
(*
(fma
(fma
(fma
(/ (* (* (* (* a a) c) a) 20.0) (pow b 7.0))
-0.25
(/ (* -2.0 (* a a)) (pow b 5.0)))
c
(/ (- a) (pow b 3.0)))
c
(/ -1.0 b))
c))
double code(double a, double b, double c) {
return fma(fma(fma((((((a * a) * c) * a) * 20.0) / pow(b, 7.0)), -0.25, ((-2.0 * (a * a)) / pow(b, 5.0))), c, (-a / pow(b, 3.0))), c, (-1.0 / b)) * c;
}
function code(a, b, c) return Float64(fma(fma(fma(Float64(Float64(Float64(Float64(Float64(a * a) * c) * a) * 20.0) / (b ^ 7.0)), -0.25, Float64(Float64(-2.0 * Float64(a * a)) / (b ^ 5.0))), c, Float64(Float64(-a) / (b ^ 3.0))), c, Float64(-1.0 / b)) * c) end
code[a_, b_, c_] := N[(N[(N[(N[(N[(N[(N[(N[(N[(a * a), $MachinePrecision] * c), $MachinePrecision] * a), $MachinePrecision] * 20.0), $MachinePrecision] / N[Power[b, 7.0], $MachinePrecision]), $MachinePrecision] * -0.25 + N[(N[(-2.0 * N[(a * a), $MachinePrecision]), $MachinePrecision] / N[Power[b, 5.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * c + N[((-a) / N[Power[b, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * c + N[(-1.0 / b), $MachinePrecision]), $MachinePrecision] * c), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\frac{\left(\left(\left(a \cdot a\right) \cdot c\right) \cdot a\right) \cdot 20}{{b}^{7}}, -0.25, \frac{-2 \cdot \left(a \cdot a\right)}{{b}^{5}}\right), c, \frac{-a}{{b}^{3}}\right), c, \frac{-1}{b}\right) \cdot c
\end{array}
Initial program 22.0%
Taylor expanded in c around 0
*-commutativeN/A
lower-*.f64N/A
Applied rewrites96.7%
Taylor expanded in a around 0
Applied rewrites96.7%
Applied rewrites96.7%
Final simplification96.7%
(FPCore (a b c) :precision binary64 (/ (fma (/ (* (pow c 3.0) (* a a)) (pow b 4.0)) -2.0 (fma (/ (* (* c c) a) (* b b)) -1.0 (- c))) b))
double code(double a, double b, double c) {
return fma(((pow(c, 3.0) * (a * a)) / pow(b, 4.0)), -2.0, fma((((c * c) * a) / (b * b)), -1.0, -c)) / b;
}
function code(a, b, c) return Float64(fma(Float64(Float64((c ^ 3.0) * Float64(a * a)) / (b ^ 4.0)), -2.0, fma(Float64(Float64(Float64(c * c) * a) / Float64(b * b)), -1.0, Float64(-c))) / b) end
code[a_, b_, c_] := N[(N[(N[(N[(N[Power[c, 3.0], $MachinePrecision] * N[(a * a), $MachinePrecision]), $MachinePrecision] / N[Power[b, 4.0], $MachinePrecision]), $MachinePrecision] * -2.0 + N[(N[(N[(N[(c * c), $MachinePrecision] * a), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision] * -1.0 + (-c)), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\frac{{c}^{3} \cdot \left(a \cdot a\right)}{{b}^{4}}, -2, \mathsf{fma}\left(\frac{\left(c \cdot c\right) \cdot a}{b \cdot b}, -1, -c\right)\right)}{b}
\end{array}
Initial program 22.0%
Taylor expanded in b around inf
lower-/.f64N/A
Applied rewrites95.9%
Final simplification95.9%
(FPCore (a b c) :precision binary64 (/ (- (- c) (fma (/ (* (pow c 3.0) (* a a)) (pow b 4.0)) 2.0 (/ (* (* c c) a) (* b b)))) b))
double code(double a, double b, double c) {
return (-c - fma(((pow(c, 3.0) * (a * a)) / pow(b, 4.0)), 2.0, (((c * c) * a) / (b * b)))) / b;
}
function code(a, b, c) return Float64(Float64(Float64(-c) - fma(Float64(Float64((c ^ 3.0) * Float64(a * a)) / (b ^ 4.0)), 2.0, Float64(Float64(Float64(c * c) * a) / Float64(b * b)))) / b) end
code[a_, b_, c_] := N[(N[((-c) - N[(N[(N[(N[Power[c, 3.0], $MachinePrecision] * N[(a * a), $MachinePrecision]), $MachinePrecision] / N[Power[b, 4.0], $MachinePrecision]), $MachinePrecision] * 2.0 + N[(N[(N[(c * c), $MachinePrecision] * a), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{\left(-c\right) - \mathsf{fma}\left(\frac{{c}^{3} \cdot \left(a \cdot a\right)}{{b}^{4}}, 2, \frac{\left(c \cdot c\right) \cdot a}{b \cdot b}\right)}{b}
\end{array}
Initial program 22.0%
Taylor expanded in c around 0
*-commutativeN/A
lower-*.f64N/A
Applied rewrites95.6%
Taylor expanded in b around -inf
Applied rewrites95.9%
Final simplification95.9%
(FPCore (a b c) :precision binary64 (* (fma (fma (* (/ c (pow b 5.0)) (* a a)) -2.0 (/ (/ a (* b b)) (- b))) c (/ -1.0 b)) c))
double code(double a, double b, double c) {
return fma(fma(((c / pow(b, 5.0)) * (a * a)), -2.0, ((a / (b * b)) / -b)), c, (-1.0 / b)) * c;
}
function code(a, b, c) return Float64(fma(fma(Float64(Float64(c / (b ^ 5.0)) * Float64(a * a)), -2.0, Float64(Float64(a / Float64(b * b)) / Float64(-b))), c, Float64(-1.0 / b)) * c) end
code[a_, b_, c_] := N[(N[(N[(N[(N[(c / N[Power[b, 5.0], $MachinePrecision]), $MachinePrecision] * N[(a * a), $MachinePrecision]), $MachinePrecision] * -2.0 + N[(N[(a / N[(b * b), $MachinePrecision]), $MachinePrecision] / (-b)), $MachinePrecision]), $MachinePrecision] * c + N[(-1.0 / b), $MachinePrecision]), $MachinePrecision] * c), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(\mathsf{fma}\left(\frac{c}{{b}^{5}} \cdot \left(a \cdot a\right), -2, \frac{\frac{a}{b \cdot b}}{-b}\right), c, \frac{-1}{b}\right) \cdot c
\end{array}
Initial program 22.0%
Taylor expanded in c around 0
*-commutativeN/A
lower-*.f64N/A
Applied rewrites95.6%
Applied rewrites95.6%
Final simplification95.6%
(FPCore (a b c) :precision binary64 (fma -1.0 (/ (* (* c c) a) (pow b 3.0)) (/ (- c) b)))
double code(double a, double b, double c) {
return fma(-1.0, (((c * c) * a) / pow(b, 3.0)), (-c / b));
}
function code(a, b, c) return fma(-1.0, Float64(Float64(Float64(c * c) * a) / (b ^ 3.0)), Float64(Float64(-c) / b)) end
code[a_, b_, c_] := N[(-1.0 * N[(N[(N[(c * c), $MachinePrecision] * a), $MachinePrecision] / N[Power[b, 3.0], $MachinePrecision]), $MachinePrecision] + N[((-c) / b), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(-1, \frac{\left(c \cdot c\right) \cdot a}{{b}^{3}}, \frac{-c}{b}\right)
\end{array}
Initial program 22.0%
Taylor expanded in a around 0
+-commutativeN/A
lower-fma.f64N/A
lower-/.f64N/A
*-commutativeN/A
lower-*.f64N/A
unpow2N/A
lower-*.f64N/A
lower-pow.f64N/A
associate-*r/N/A
lower-/.f64N/A
mul-1-negN/A
lower-neg.f6494.0
Applied rewrites94.0%
(FPCore (a b c) :precision binary64 (/ (fma a (/ (* c c) (* b b)) c) (- b)))
double code(double a, double b, double c) {
return fma(a, ((c * c) / (b * b)), c) / -b;
}
function code(a, b, c) return Float64(fma(a, Float64(Float64(c * c) / Float64(b * b)), c) / Float64(-b)) end
code[a_, b_, c_] := N[(N[(a * N[(N[(c * c), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision] + c), $MachinePrecision] / (-b)), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(a, \frac{c \cdot c}{b \cdot b}, c\right)}{-b}
\end{array}
Initial program 22.0%
Taylor expanded in c around 0
*-commutativeN/A
lower-*.f64N/A
Applied rewrites96.7%
Taylor expanded in a around 0
Applied rewrites96.7%
Taylor expanded in b around inf
distribute-lft-outN/A
associate-*r/N/A
mul-1-negN/A
lower-neg.f64N/A
lower-/.f64N/A
+-commutativeN/A
associate-/l*N/A
lower-fma.f64N/A
lower-/.f64N/A
unpow2N/A
lower-*.f64N/A
unpow2N/A
lower-*.f6494.0
Applied rewrites94.0%
Final simplification94.0%
(FPCore (a b c) :precision binary64 (/ (- c) b))
double code(double a, double b, double c) {
return -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 = -c / b
end function
public static double code(double a, double b, double c) {
return -c / b;
}
def code(a, b, c): return -c / b
function code(a, b, c) return Float64(Float64(-c) / b) end
function tmp = code(a, b, c) tmp = -c / b; end
code[a_, b_, c_] := N[((-c) / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{-c}{b}
\end{array}
Initial program 22.0%
Taylor expanded in a around 0
associate-*r/N/A
lower-/.f64N/A
mul-1-negN/A
lower-neg.f6487.6
Applied rewrites87.6%
herbie shell --seed 2024312
(FPCore (a b c)
:name "Quadratic roots, 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) (* (* 4.0 a) c)))) (* 2.0 a)))