
(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 7 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
(/
(fma
(* (pow c 4.0) -5.0)
(* a a)
(* (* b b) (* (* c c) (fma (* -2.0 c) a (* (- b) b)))))
(pow b 7.0))
a
(/ (- c) b)))
double code(double a, double b, double c) {
return fma((fma((pow(c, 4.0) * -5.0), (a * a), ((b * b) * ((c * c) * fma((-2.0 * c), a, (-b * b))))) / pow(b, 7.0)), a, (-c / b));
}
function code(a, b, c) return fma(Float64(fma(Float64((c ^ 4.0) * -5.0), Float64(a * a), Float64(Float64(b * b) * Float64(Float64(c * c) * fma(Float64(-2.0 * c), a, Float64(Float64(-b) * b))))) / (b ^ 7.0)), a, Float64(Float64(-c) / b)) end
code[a_, b_, c_] := N[(N[(N[(N[(N[Power[c, 4.0], $MachinePrecision] * -5.0), $MachinePrecision] * N[(a * a), $MachinePrecision] + N[(N[(b * b), $MachinePrecision] * N[(N[(c * c), $MachinePrecision] * N[(N[(-2.0 * c), $MachinePrecision] * a + N[((-b) * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[Power[b, 7.0], $MachinePrecision]), $MachinePrecision] * a + N[((-c) / b), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(\frac{\mathsf{fma}\left({c}^{4} \cdot -5, a \cdot a, \left(b \cdot b\right) \cdot \left(\left(c \cdot c\right) \cdot \mathsf{fma}\left(-2 \cdot c, a, \left(-b\right) \cdot b\right)\right)\right)}{{b}^{7}}, a, \frac{-c}{b}\right)
\end{array}
Initial program 17.8%
Taylor expanded in a around 0
+-commutativeN/A
*-commutativeN/A
lower-fma.f64N/A
Applied rewrites98.9%
Taylor expanded in b around 0
Applied rewrites98.9%
Taylor expanded in b around 0
Applied rewrites98.9%
Final simplification98.9%
(FPCore (a b c) :precision binary64 (fma c (* (* (fma (* (- a) b) b (* (* (* a a) c) -2.0)) (pow b -5.0)) c) (/ (- c) b)))
double code(double a, double b, double c) {
return fma(c, ((fma((-a * b), b, (((a * a) * c) * -2.0)) * pow(b, -5.0)) * c), (-c / b));
}
function code(a, b, c) return fma(c, Float64(Float64(fma(Float64(Float64(-a) * b), b, Float64(Float64(Float64(a * a) * c) * -2.0)) * (b ^ -5.0)) * c), Float64(Float64(-c) / b)) end
code[a_, b_, c_] := N[(c * N[(N[(N[(N[((-a) * b), $MachinePrecision] * b + N[(N[(N[(a * a), $MachinePrecision] * c), $MachinePrecision] * -2.0), $MachinePrecision]), $MachinePrecision] * N[Power[b, -5.0], $MachinePrecision]), $MachinePrecision] * c), $MachinePrecision] + N[((-c) / b), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(c, \left(\mathsf{fma}\left(\left(-a\right) \cdot b, b, \left(\left(a \cdot a\right) \cdot c\right) \cdot -2\right) \cdot {b}^{-5}\right) \cdot c, \frac{-c}{b}\right)
\end{array}
Initial program 17.8%
Taylor expanded in c around 0
*-commutativeN/A
lower-*.f64N/A
Applied rewrites97.8%
Taylor expanded in b around 0
Applied rewrites97.8%
Applied rewrites98.2%
Final simplification98.2%
(FPCore (a b c) :precision binary64 (* (fma (* (fma (* (- a) b) b (* (* (* a a) c) -2.0)) (pow b -5.0)) c (/ -1.0 b)) c))
double code(double a, double b, double c) {
return fma((fma((-a * b), b, (((a * a) * c) * -2.0)) * pow(b, -5.0)), c, (-1.0 / b)) * c;
}
function code(a, b, c) return Float64(fma(Float64(fma(Float64(Float64(-a) * b), b, Float64(Float64(Float64(a * a) * c) * -2.0)) * (b ^ -5.0)), c, Float64(-1.0 / b)) * c) end
code[a_, b_, c_] := N[(N[(N[(N[(N[((-a) * b), $MachinePrecision] * b + N[(N[(N[(a * a), $MachinePrecision] * c), $MachinePrecision] * -2.0), $MachinePrecision]), $MachinePrecision] * N[Power[b, -5.0], $MachinePrecision]), $MachinePrecision] * c + N[(-1.0 / b), $MachinePrecision]), $MachinePrecision] * c), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(\mathsf{fma}\left(\left(-a\right) \cdot b, b, \left(\left(a \cdot a\right) \cdot c\right) \cdot -2\right) \cdot {b}^{-5}, c, \frac{-1}{b}\right) \cdot c
\end{array}
Initial program 17.8%
Taylor expanded in c around 0
*-commutativeN/A
lower-*.f64N/A
Applied rewrites97.8%
Taylor expanded in b around 0
Applied rewrites97.8%
Applied rewrites97.8%
(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 17.8%
Taylor expanded in a around 0
+-commutativeN/A
*-commutativeN/A
lower-fma.f64N/A
Applied rewrites98.9%
Taylor expanded in b around 0
Applied rewrites98.9%
Taylor expanded in a around 0
+-commutativeN/A
mul-1-negN/A
mul-1-negN/A
distribute-neg-outN/A
lower-neg.f64N/A
associate-/l*N/A
lower-fma.f64N/A
lower-/.f64N/A
unpow2N/A
lower-*.f64N/A
lower-pow.f64N/A
lower-/.f6496.8
Applied rewrites96.8%
(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 17.8%
Taylor expanded in b around inf
distribute-lft-outN/A
associate-/l*N/A
mul-1-negN/A
lower-neg.f64N/A
lower-/.f64N/A
+-commutativeN/A
*-commutativeN/A
unpow2N/A
associate-*l*N/A
*-commutativeN/A
unpow2N/A
times-fracN/A
lower-fma.f64N/A
lower-/.f64N/A
lower-/.f64N/A
*-commutativeN/A
lower-*.f6496.8
Applied rewrites96.8%
Applied rewrites96.8%
Final simplification96.8%
(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 17.8%
Taylor expanded in c around 0
associate-*r/N/A
lower-/.f64N/A
mul-1-negN/A
lower-neg.f6491.1
Applied rewrites91.1%
(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 17.8%
lift-/.f64N/A
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
div-subN/A
lower--.f64N/A
Applied rewrites17.3%
lift--.f64N/A
sub-negN/A
lift-/.f64N/A
div-invN/A
*-commutativeN/A
lower-fma.f64N/A
metadata-evalN/A
lift-*.f64N/A
associate-/r*N/A
metadata-evalN/A
metadata-evalN/A
lower-/.f64N/A
lift-fma.f64N/A
*-commutativeN/A
lift-*.f64N/A
*-commutativeN/A
associate-*r*N/A
lower-fma.f64N/A
*-commutativeN/A
lower-*.f64N/A
lift-/.f64N/A
Applied rewrites18.8%
Taylor expanded in c around 0
distribute-rgt-outN/A
metadata-evalN/A
mul0-rgt3.3
Applied rewrites3.3%
herbie shell --seed 2024276
(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)))