
(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 5 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 (* a -4.0) 0.0) (* a 2.0)) (+ b (sqrt (fma a (* c -4.0) (* b b))))))
double code(double a, double b, double c) {
return (fma(c, (a * -4.0), 0.0) / (a * 2.0)) / (b + sqrt(fma(a, (c * -4.0), (b * b))));
}
function code(a, b, c) return Float64(Float64(fma(c, Float64(a * -4.0), 0.0) / Float64(a * 2.0)) / Float64(b + sqrt(fma(a, Float64(c * -4.0), Float64(b * b))))) end
code[a_, b_, c_] := N[(N[(N[(c * N[(a * -4.0), $MachinePrecision] + 0.0), $MachinePrecision] / N[(a * 2.0), $MachinePrecision]), $MachinePrecision] / N[(b + N[Sqrt[N[(a * N[(c * -4.0), $MachinePrecision] + N[(b * b), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\frac{\mathsf{fma}\left(c, a \cdot -4, 0\right)}{a \cdot 2}}{b + \sqrt{\mathsf{fma}\left(a, c \cdot -4, b \cdot b\right)}}
\end{array}
Initial program 31.7%
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-eval31.8
Applied rewrites31.8%
lift-/.f64N/A
clear-numN/A
metadata-evalN/A
lower-/.f64N/A
metadata-evalN/A
lower-/.f6431.8
lift-*.f64N/A
*-commutativeN/A
lower-*.f6431.8
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
lower--.f6431.8
Applied rewrites31.7%
lift-/.f64N/A
lift-/.f64N/A
lift-*.f64N/A
*-commutativeN/A
lift-*.f64N/A
clear-numN/A
lift--.f64N/A
Applied rewrites99.7%
Final simplification99.7%
(FPCore (a b c) :precision binary64 (/ (fma c (* a -4.0) 0.0) (* a (* 2.0 (+ b (sqrt (fma a (* c -4.0) (* b b))))))))
double code(double a, double b, double c) {
return fma(c, (a * -4.0), 0.0) / (a * (2.0 * (b + sqrt(fma(a, (c * -4.0), (b * b))))));
}
function code(a, b, c) return Float64(fma(c, Float64(a * -4.0), 0.0) / Float64(a * Float64(2.0 * Float64(b + sqrt(fma(a, Float64(c * -4.0), Float64(b * b))))))) end
code[a_, b_, c_] := N[(N[(c * N[(a * -4.0), $MachinePrecision] + 0.0), $MachinePrecision] / N[(a * N[(2.0 * N[(b + N[Sqrt[N[(a * N[(c * -4.0), $MachinePrecision] + N[(b * b), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(c, a \cdot -4, 0\right)}{a \cdot \left(2 \cdot \left(b + \sqrt{\mathsf{fma}\left(a, c \cdot -4, b \cdot b\right)}\right)\right)}
\end{array}
Initial program 31.7%
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-eval31.8
Applied rewrites31.8%
lift-/.f64N/A
clear-numN/A
metadata-evalN/A
lower-/.f64N/A
metadata-evalN/A
lower-/.f6431.8
lift-*.f64N/A
*-commutativeN/A
lower-*.f6431.8
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
lower--.f6431.8
Applied rewrites31.7%
Applied rewrites99.4%
Final simplification99.4%
(FPCore (a b c) :precision binary64 (/ 1.0 (/ (- (/ (* c a) b) b) c)))
double code(double a, double b, double c) {
return 1.0 / ((((c * 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 / ((((c * a) / b) - b) / c)
end function
public static double code(double a, double b, double c) {
return 1.0 / ((((c * a) / b) - b) / c);
}
def code(a, b, c): return 1.0 / ((((c * a) / b) - b) / c)
function code(a, b, c) return Float64(1.0 / Float64(Float64(Float64(Float64(c * a) / b) - b) / c)) end
function tmp = code(a, b, c) tmp = 1.0 / ((((c * a) / b) - b) / c); end
code[a_, b_, c_] := N[(1.0 / N[(N[(N[(N[(c * a), $MachinePrecision] / b), $MachinePrecision] - b), $MachinePrecision] / c), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{1}{\frac{\frac{c \cdot a}{b} - b}{c}}
\end{array}
Initial program 31.7%
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-eval31.8
Applied rewrites31.8%
lift-/.f64N/A
clear-numN/A
metadata-evalN/A
lower-/.f64N/A
metadata-evalN/A
lower-/.f6431.8
lift-*.f64N/A
*-commutativeN/A
lower-*.f6431.8
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
lower--.f6431.8
Applied rewrites31.7%
Taylor expanded in c around 0
lower-/.f64N/A
+-commutativeN/A
mul-1-negN/A
unsub-negN/A
lower--.f64N/A
lower-/.f64N/A
lower-*.f6491.1
Applied rewrites91.1%
Final simplification91.1%
(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 31.7%
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-eval31.8
Applied rewrites31.8%
lift-/.f64N/A
clear-numN/A
metadata-evalN/A
lower-/.f64N/A
metadata-evalN/A
lower-/.f6431.8
lift-*.f64N/A
*-commutativeN/A
lower-*.f6431.8
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
lower--.f6431.8
Applied rewrites31.7%
Taylor expanded in a around 0
+-commutativeN/A
mul-1-negN/A
unsub-negN/A
lower--.f64N/A
lower-/.f64N/A
lower-/.f6491.1
Applied rewrites91.1%
(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 31.7%
Taylor expanded in b around inf
mul-1-negN/A
distribute-neg-frac2N/A
lower-/.f64N/A
lower-neg.f6481.2
Applied rewrites81.2%
Final simplification81.2%
herbie shell --seed 2024219
(FPCore (a b c)
:name "Quadratic roots, medium range"
:precision binary64
:pre (and (and (and (< 1.1102230246251565e-16 a) (< a 9007199254740992.0)) (and (< 1.1102230246251565e-16 b) (< b 9007199254740992.0))) (and (< 1.1102230246251565e-16 c) (< c 9007199254740992.0)))
(/ (+ (- b) (sqrt (- (* b b) (* (* 4.0 a) c)))) (* 2.0 a)))