
(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 6 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
(let* ((t_0 (* c (* a c))))
(/
(fma
(/ (* t_0 (* a (* a t_0))) (* a (* (* b b) (* b (* b (* b b))))))
-5.0
(- (/ (* (* c c) (fma -2.0 (/ (* a (* a c)) (* b b)) (- a))) (* b b)) c))
b)))
double code(double a, double b, double c) {
double t_0 = c * (a * c);
return fma(((t_0 * (a * (a * t_0))) / (a * ((b * b) * (b * (b * (b * b)))))), -5.0, ((((c * c) * fma(-2.0, ((a * (a * c)) / (b * b)), -a)) / (b * b)) - c)) / b;
}
function code(a, b, c) t_0 = Float64(c * Float64(a * c)) return Float64(fma(Float64(Float64(t_0 * Float64(a * Float64(a * t_0))) / Float64(a * Float64(Float64(b * b) * Float64(b * Float64(b * Float64(b * b)))))), -5.0, Float64(Float64(Float64(Float64(c * c) * fma(-2.0, Float64(Float64(a * Float64(a * c)) / Float64(b * b)), Float64(-a))) / Float64(b * b)) - c)) / b) end
code[a_, b_, c_] := Block[{t$95$0 = N[(c * N[(a * c), $MachinePrecision]), $MachinePrecision]}, N[(N[(N[(N[(t$95$0 * N[(a * N[(a * t$95$0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(a * N[(N[(b * b), $MachinePrecision] * N[(b * N[(b * N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * -5.0 + N[(N[(N[(N[(c * c), $MachinePrecision] * N[(-2.0 * N[(N[(a * N[(a * c), $MachinePrecision]), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision] + (-a)), $MachinePrecision]), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision] - c), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := c \cdot \left(a \cdot c\right)\\
\frac{\mathsf{fma}\left(\frac{t\_0 \cdot \left(a \cdot \left(a \cdot t\_0\right)\right)}{a \cdot \left(\left(b \cdot b\right) \cdot \left(b \cdot \left(b \cdot \left(b \cdot b\right)\right)\right)\right)}, -5, \frac{\left(c \cdot c\right) \cdot \mathsf{fma}\left(-2, \frac{a \cdot \left(a \cdot c\right)}{b \cdot b}, -a\right)}{b \cdot b} - c\right)}{b}
\end{array}
\end{array}
Initial program 18.4%
Taylor expanded in b around inf
Applied rewrites97.5%
Applied rewrites97.6%
Taylor expanded in c around 0
Applied rewrites97.6%
Applied rewrites97.6%
(FPCore (a b c) :precision binary64 (/ (- (/ (* (* c c) (fma -2.0 (/ (* a (* a c)) (* b b)) (- a))) (* b b)) c) b))
double code(double a, double b, double c) {
return ((((c * c) * fma(-2.0, ((a * (a * c)) / (b * b)), -a)) / (b * b)) - c) / b;
}
function code(a, b, c) return Float64(Float64(Float64(Float64(Float64(c * c) * fma(-2.0, Float64(Float64(a * Float64(a * c)) / Float64(b * b)), Float64(-a))) / Float64(b * b)) - c) / b) end
code[a_, b_, c_] := N[(N[(N[(N[(N[(c * c), $MachinePrecision] * N[(-2.0 * N[(N[(a * N[(a * c), $MachinePrecision]), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision] + (-a)), $MachinePrecision]), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision] - c), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{\frac{\left(c \cdot c\right) \cdot \mathsf{fma}\left(-2, \frac{a \cdot \left(a \cdot c\right)}{b \cdot b}, -a\right)}{b \cdot b} - c}{b}
\end{array}
Initial program 18.4%
Taylor expanded in b around inf
lower-/.f64N/A
Applied rewrites96.7%
Applied rewrites96.4%
Applied rewrites96.7%
Applied rewrites96.7%
Final simplification96.7%
(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(Float64(c * c), Float64(a / Float64(b * b)), c) / Float64(-b)) end
code[a_, b_, c_] := N[(N[(N[(c * c), $MachinePrecision] * N[(a / N[(b * b), $MachinePrecision]), $MachinePrecision] + c), $MachinePrecision] / (-b)), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(c \cdot c, \frac{a}{b \cdot b}, c\right)}{-b}
\end{array}
Initial program 18.4%
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
associate-/l*N/A
lower-fma.f64N/A
unpow2N/A
lower-*.f64N/A
lower-/.f64N/A
unpow2N/A
lower-*.f6495.0
Applied rewrites95.0%
Final simplification95.0%
(FPCore (a b c) :precision binary64 (/ 1.0 (- (/ a b) (/ b c))))
double code(double a, double b, double c) {
return 1.0 / ((a / b) - (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 = 1.0d0 / ((a / b) - (b / c))
end function
public static double code(double a, double b, double c) {
return 1.0 / ((a / b) - (b / c));
}
def code(a, b, c): return 1.0 / ((a / b) - (b / c))
function code(a, b, c) return Float64(1.0 / Float64(Float64(a / b) - Float64(b / c))) end
function tmp = code(a, b, c) tmp = 1.0 / ((a / b) - (b / c)); end
code[a_, b_, c_] := N[(1.0 / N[(N[(a / b), $MachinePrecision] - N[(b / c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{1}{\frac{a}{b} - \frac{b}{c}}
\end{array}
Initial program 18.4%
lift--.f64N/A
sub-negN/A
lift-*.f64N/A
lower-fma.f64N/A
lift-*.f64N/A
distribute-lft-neg-inN/A
lift-*.f64N/A
*-commutativeN/A
distribute-rgt-neg-inN/A
associate-*l*N/A
lower-*.f64N/A
lower-*.f64N/A
metadata-eval18.5
Applied rewrites18.5%
lift-/.f64N/A
clear-numN/A
lower-/.f64N/A
lower-/.f6418.5
lift-*.f64N/A
*-commutativeN/A
lower-*.f6418.5
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
Applied rewrites18.4%
Taylor expanded in a around 0
+-commutativeN/A
mul-1-negN/A
unsub-negN/A
lower--.f64N/A
lower-/.f64N/A
lower-/.f6494.8
Applied rewrites94.8%
(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(c / Float64(-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 b around inf
mul-1-negN/A
distribute-neg-frac2N/A
lower-/.f64N/A
lower-neg.f6490.1
Applied rewrites90.1%
(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(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 b around inf
mul-1-negN/A
distribute-neg-frac2N/A
lower-/.f64N/A
lower-neg.f6490.1
Applied rewrites90.1%
Applied rewrites89.8%
Applied rewrites1.7%
herbie shell --seed 2024233
(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)))