
(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 9 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 (/ 0.5 (fma (fma (fma (/ c (pow b 3.0)) 0.5 (/ (* (* c c) a) (pow b 5.0))) a (/ 0.5 b)) a (* (/ b c) -0.5))))
double code(double a, double b, double c) {
return 0.5 / fma(fma(fma((c / pow(b, 3.0)), 0.5, (((c * c) * a) / pow(b, 5.0))), a, (0.5 / b)), a, ((b / c) * -0.5));
}
function code(a, b, c) return Float64(0.5 / fma(fma(fma(Float64(c / (b ^ 3.0)), 0.5, Float64(Float64(Float64(c * c) * a) / (b ^ 5.0))), a, Float64(0.5 / b)), a, Float64(Float64(b / c) * -0.5))) end
code[a_, b_, c_] := N[(0.5 / N[(N[(N[(N[(c / N[Power[b, 3.0], $MachinePrecision]), $MachinePrecision] * 0.5 + N[(N[(N[(c * c), $MachinePrecision] * a), $MachinePrecision] / N[Power[b, 5.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * a + N[(0.5 / b), $MachinePrecision]), $MachinePrecision] * a + N[(N[(b / c), $MachinePrecision] * -0.5), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{0.5}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\frac{c}{{b}^{3}}, 0.5, \frac{\left(c \cdot c\right) \cdot a}{{b}^{5}}\right), a, \frac{0.5}{b}\right), a, \frac{b}{c} \cdot -0.5\right)}
\end{array}
Initial program 18.4%
lift-/.f64N/A
clear-numN/A
lift-*.f64N/A
associate-/l*N/A
associate-/r*N/A
metadata-evalN/A
lower-/.f64N/A
lower-/.f6418.4
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
lower--.f6418.4
Applied rewrites18.4%
lift--.f64N/A
flip--N/A
lift-sqrt.f64N/A
lift-sqrt.f64N/A
rem-square-sqrtN/A
lift-*.f64N/A
div-subN/A
lower--.f64N/A
lower-/.f64N/A
lower-+.f64N/A
lower-/.f64N/A
Applied rewrites18.7%
Taylor expanded in a around 0
+-commutativeN/A
*-commutativeN/A
lower-fma.f64N/A
Applied rewrites97.2%
(FPCore (a b c)
:precision binary64
(*
(fma
(fma
(/ (* (fma (* c a) -5.0 (* (* b b) -2.0)) (* a a)) (pow b 7.0))
c
(/ (- a) (pow b 3.0)))
c
(/ -1.0 b))
c))
double code(double a, double b, double c) {
return fma(fma(((fma((c * a), -5.0, ((b * b) * -2.0)) * (a * a)) / pow(b, 7.0)), c, (-a / pow(b, 3.0))), c, (-1.0 / b)) * c;
}
function code(a, b, c) return Float64(fma(fma(Float64(Float64(fma(Float64(c * a), -5.0, Float64(Float64(b * b) * -2.0)) * Float64(a * a)) / (b ^ 7.0)), 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[(c * a), $MachinePrecision] * -5.0 + N[(N[(b * b), $MachinePrecision] * -2.0), $MachinePrecision]), $MachinePrecision] * N[(a * a), $MachinePrecision]), $MachinePrecision] / N[Power[b, 7.0], $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(\frac{\mathsf{fma}\left(c \cdot a, -5, \left(b \cdot b\right) \cdot -2\right) \cdot \left(a \cdot a\right)}{{b}^{7}}, c, \frac{-a}{{b}^{3}}\right), c, \frac{-1}{b}\right) \cdot c
\end{array}
Initial program 18.4%
Taylor expanded in c around 0
Applied rewrites97.1%
Taylor expanded in b around 0
Applied rewrites97.1%
Taylor expanded in a around 0
Applied rewrites97.1%
(FPCore (a b c) :precision binary64 (/ (- (/ (* (* (* (pow c 3.0) a) a) -2.0) (pow b 4.0)) (fma (/ c b) (/ (* c a) b) c)) b))
double code(double a, double b, double c) {
return (((((pow(c, 3.0) * a) * a) * -2.0) / pow(b, 4.0)) - fma((c / b), ((c * a) / b), c)) / b;
}
function code(a, b, c) return Float64(Float64(Float64(Float64(Float64(Float64((c ^ 3.0) * a) * a) * -2.0) / (b ^ 4.0)) - fma(Float64(c / b), Float64(Float64(c * a) / b), c)) / b) end
code[a_, b_, c_] := N[(N[(N[(N[(N[(N[(N[Power[c, 3.0], $MachinePrecision] * a), $MachinePrecision] * a), $MachinePrecision] * -2.0), $MachinePrecision] / N[Power[b, 4.0], $MachinePrecision]), $MachinePrecision] - N[(N[(c / b), $MachinePrecision] * N[(N[(c * a), $MachinePrecision] / b), $MachinePrecision] + c), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{\frac{\left(\left({c}^{3} \cdot a\right) \cdot a\right) \cdot -2}{{b}^{4}} - \mathsf{fma}\left(\frac{c}{b}, \frac{c \cdot a}{b}, c\right)}{b}
\end{array}
Initial program 18.4%
Taylor expanded in b around inf
lower-/.f64N/A
Applied rewrites96.8%
(FPCore (a b c) :precision binary64 (/ (* (fma (- (/ (* -2.0 (* (* a a) c)) (pow b 4.0)) (/ a (* b b))) c -1.0) c) b))
double code(double a, double b, double c) {
return (fma((((-2.0 * ((a * a) * c)) / pow(b, 4.0)) - (a / (b * b))), c, -1.0) * c) / b;
}
function code(a, b, c) return Float64(Float64(fma(Float64(Float64(Float64(-2.0 * Float64(Float64(a * a) * c)) / (b ^ 4.0)) - Float64(a / Float64(b * b))), c, -1.0) * c) / b) end
code[a_, b_, c_] := N[(N[(N[(N[(N[(N[(-2.0 * N[(N[(a * a), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision] / N[Power[b, 4.0], $MachinePrecision]), $MachinePrecision] - N[(a / N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * c + -1.0), $MachinePrecision] * c), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(\frac{-2 \cdot \left(\left(a \cdot a\right) \cdot c\right)}{{b}^{4}} - \frac{a}{b \cdot b}, c, -1\right) \cdot c}{b}
\end{array}
Initial program 18.4%
Taylor expanded in c around 0
Applied rewrites97.1%
Taylor expanded in b around inf
lower-/.f64N/A
Applied rewrites96.8%
Taylor expanded in c around 0
Applied rewrites96.7%
(FPCore (a b c) :precision binary64 (/ 0.5 (fma (fma (* 0.5 (/ c (pow b 3.0))) a (/ 0.5 b)) a (* (/ b c) -0.5))))
double code(double a, double b, double c) {
return 0.5 / fma(fma((0.5 * (c / pow(b, 3.0))), a, (0.5 / b)), a, ((b / c) * -0.5));
}
function code(a, b, c) return Float64(0.5 / fma(fma(Float64(0.5 * Float64(c / (b ^ 3.0))), a, Float64(0.5 / b)), a, Float64(Float64(b / c) * -0.5))) end
code[a_, b_, c_] := N[(0.5 / N[(N[(N[(0.5 * N[(c / N[Power[b, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * a + N[(0.5 / b), $MachinePrecision]), $MachinePrecision] * a + N[(N[(b / c), $MachinePrecision] * -0.5), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{0.5}{\mathsf{fma}\left(\mathsf{fma}\left(0.5 \cdot \frac{c}{{b}^{3}}, a, \frac{0.5}{b}\right), a, \frac{b}{c} \cdot -0.5\right)}
\end{array}
Initial program 18.4%
lift-/.f64N/A
clear-numN/A
lift-*.f64N/A
associate-/l*N/A
associate-/r*N/A
metadata-evalN/A
lower-/.f64N/A
lower-/.f6418.4
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
lower--.f6418.4
Applied rewrites18.4%
Taylor expanded in a around 0
+-commutativeN/A
*-commutativeN/A
lower-fma.f64N/A
Applied rewrites96.5%
(FPCore (a b c) :precision binary64 (- (fma a (/ (* c c) (pow b 3.0)) (/ c b))))
double code(double a, double b, double c) {
return -fma(a, ((c * c) / pow(b, 3.0)), (c / b));
}
function code(a, b, c) return Float64(-fma(a, Float64(Float64(c * c) / (b ^ 3.0)), Float64(c / b))) end
code[a_, b_, c_] := (-N[(a * N[(N[(c * c), $MachinePrecision] / N[Power[b, 3.0], $MachinePrecision]), $MachinePrecision] + N[(c / b), $MachinePrecision]), $MachinePrecision])
\begin{array}{l}
\\
-\mathsf{fma}\left(a, \frac{c \cdot c}{{b}^{3}}, \frac{c}{b}\right)
\end{array}
Initial program 18.4%
Taylor expanded in c around 0
Applied rewrites97.1%
Taylor expanded in a around 0
distribute-lft-outN/A
mul-1-negN/A
lower-neg.f64N/A
+-commutativeN/A
associate-/l*N/A
lower-fma.f64N/A
lower-/.f64N/A
unpow2N/A
lower-*.f64N/A
lower-pow.f64N/A
lower-/.f6495.2
Applied rewrites95.2%
(FPCore (a b c) :precision binary64 (/ (fma c (/ (* c a) (* b b)) c) (- b)))
double code(double a, double b, double c) {
return fma(c, ((c * a) / (b * b)), c) / -b;
}
function code(a, b, c) return Float64(fma(c, Float64(Float64(c * a) / Float64(b * b)), c) / Float64(-b)) end
code[a_, b_, c_] := N[(N[(c * N[(N[(c * a), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision] + c), $MachinePrecision] / (-b)), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(c, \frac{c \cdot a}{b \cdot b}, c\right)}{-b}
\end{array}
Initial program 18.4%
Taylor expanded in a around 0
mul-1-negN/A
unsub-negN/A
associate-*r/N/A
unpow3N/A
unpow2N/A
associate-/r*N/A
div-subN/A
unsub-negN/A
mul-1-negN/A
distribute-lft-outN/A
associate-/l*N/A
mul-1-negN/A
lower-neg.f64N/A
lower-/.f64N/A
Applied rewrites95.1%
Applied rewrites95.1%
Final simplification95.1%
(FPCore (a b c) :precision binary64 (/ (* (fma a (/ c (* b b)) 1.0) c) (- b)))
double code(double a, double b, double c) {
return (fma(a, (c / (b * b)), 1.0) * c) / -b;
}
function code(a, b, c) return Float64(Float64(fma(a, Float64(c / Float64(b * b)), 1.0) * c) / Float64(-b)) end
code[a_, b_, c_] := N[(N[(N[(a * N[(c / N[(b * b), $MachinePrecision]), $MachinePrecision] + 1.0), $MachinePrecision] * c), $MachinePrecision] / (-b)), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(a, \frac{c}{b \cdot b}, 1\right) \cdot c}{-b}
\end{array}
Initial program 18.4%
Taylor expanded in a around 0
mul-1-negN/A
unsub-negN/A
associate-*r/N/A
unpow3N/A
unpow2N/A
associate-/r*N/A
div-subN/A
unsub-negN/A
mul-1-negN/A
distribute-lft-outN/A
associate-/l*N/A
mul-1-negN/A
lower-neg.f64N/A
lower-/.f64N/A
Applied rewrites95.1%
Taylor expanded in c around 0
Applied rewrites95.1%
Final simplification95.1%
(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 18.4%
Taylor expanded in a around 0
associate-*r/N/A
lower-/.f64N/A
mul-1-negN/A
lower-neg.f6490.2
Applied rewrites90.2%
herbie shell --seed 2024296
(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)))