
(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 (/ (* (/ 0.5 a) (* a (* c -4.0))) (+ b (sqrt (fma a (* c -4.0) (* b b))))))
double code(double a, double b, double c) {
return ((0.5 / a) * (a * (c * -4.0))) / (b + sqrt(fma(a, (c * -4.0), (b * b))));
}
function code(a, b, c) return Float64(Float64(Float64(0.5 / a) * Float64(a * Float64(c * -4.0))) / Float64(b + sqrt(fma(a, Float64(c * -4.0), Float64(b * b))))) end
code[a_, b_, c_] := N[(N[(N[(0.5 / a), $MachinePrecision] * N[(a * N[(c * -4.0), $MachinePrecision]), $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{0.5}{a} \cdot \left(a \cdot \left(c \cdot -4\right)\right)}{b + \sqrt{\mathsf{fma}\left(a, c \cdot -4, b \cdot b\right)}}
\end{array}
Initial program 15.6%
Applied rewrites15.6%
lift--.f64N/A
lift-/.f64N/A
lift-/.f64N/A
sub-divN/A
clear-numN/A
lower-/.f64N/A
lower-/.f64N/A
Applied rewrites16.1%
Taylor expanded in b around 0
*-commutativeN/A
rem-square-sqrtN/A
unpow2N/A
associate-*r*N/A
lower-*.f64N/A
unpow2N/A
rem-square-sqrtN/A
lower-*.f6499.3
Applied rewrites99.3%
lift-/.f64N/A
lift-*.f64N/A
lift-/.f64N/A
associate-/r/N/A
lift-/.f64N/A
associate-*r/N/A
lower-/.f64N/A
Applied rewrites99.5%
(FPCore (a b c) :precision binary64 (/ (* -4.0 (* a c)) (* a (* 2.0 (+ b (sqrt (fma -4.0 (* a c) (* b b))))))))
double code(double a, double b, double c) {
return (-4.0 * (a * c)) / (a * (2.0 * (b + sqrt(fma(-4.0, (a * c), (b * b))))));
}
function code(a, b, c) return Float64(Float64(-4.0 * Float64(a * c)) / Float64(a * Float64(2.0 * Float64(b + sqrt(fma(-4.0, Float64(a * c), Float64(b * b))))))) end
code[a_, b_, c_] := N[(N[(-4.0 * N[(a * c), $MachinePrecision]), $MachinePrecision] / N[(a * N[(2.0 * N[(b + N[Sqrt[N[(-4.0 * N[(a * c), $MachinePrecision] + N[(b * b), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{-4 \cdot \left(a \cdot c\right)}{a \cdot \left(2 \cdot \left(b + \sqrt{\mathsf{fma}\left(-4, a \cdot c, b \cdot b\right)}\right)\right)}
\end{array}
Initial program 15.6%
Applied rewrites15.6%
lift--.f64N/A
lift-/.f64N/A
lift-/.f64N/A
sub-divN/A
clear-numN/A
lower-/.f64N/A
lower-/.f64N/A
Applied rewrites16.1%
lift-/.f64N/A
lift-/.f64N/A
clear-numN/A
lift-/.f64N/A
associate-/l/N/A
*-commutativeN/A
lift-*.f64N/A
lower-/.f6416.0
Applied rewrites16.0%
Taylor expanded in b around 0
lower-*.f64N/A
*-commutativeN/A
lower-*.f6499.5
Applied rewrites99.5%
Final simplification99.5%
(FPCore (a b c) :precision binary64 (- (/ c (- b)) (/ (* a (* c c)) (* b (* b b)))))
double code(double a, double b, double c) {
return (c / -b) - ((a * (c * c)) / (b * (b * 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) - ((a * (c * c)) / (b * (b * b)))
end function
public static double code(double a, double b, double c) {
return (c / -b) - ((a * (c * c)) / (b * (b * b)));
}
def code(a, b, c): return (c / -b) - ((a * (c * c)) / (b * (b * b)))
function code(a, b, c) return Float64(Float64(c / Float64(-b)) - Float64(Float64(a * Float64(c * c)) / Float64(b * Float64(b * b)))) end
function tmp = code(a, b, c) tmp = (c / -b) - ((a * (c * c)) / (b * (b * b))); end
code[a_, b_, c_] := N[(N[(c / (-b)), $MachinePrecision] - N[(N[(a * N[(c * c), $MachinePrecision]), $MachinePrecision] / N[(b * N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{c}{-b} - \frac{a \cdot \left(c \cdot c\right)}{b \cdot \left(b \cdot b\right)}
\end{array}
Initial program 15.6%
lift-sqrt.f64N/A
lift--.f64N/A
flip--N/A
clear-numN/A
sqrt-divN/A
metadata-evalN/A
lower-/.f64N/A
lower-sqrt.f64N/A
clear-numN/A
flip--N/A
lift--.f64N/A
Applied rewrites16.0%
Taylor expanded in a around 0
mul-1-negN/A
unsub-negN/A
lower--.f64N/A
associate-*r/N/A
lower-/.f64N/A
mul-1-negN/A
lower-neg.f64N/A
lower-/.f64N/A
lower-*.f64N/A
unpow2N/A
lower-*.f64N/A
cube-multN/A
unpow2N/A
lower-*.f64N/A
unpow2N/A
lower-*.f6495.1
Applied rewrites95.1%
Final simplification95.1%
(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 15.6%
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-*.f6495.1
Applied rewrites95.1%
Final simplification95.1%
(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 15.6%
Applied rewrites15.6%
lift--.f64N/A
lift-/.f64N/A
lift-/.f64N/A
sub-divN/A
clear-numN/A
lower-/.f64N/A
lower-/.f64N/A
Applied rewrites16.1%
Taylor expanded in a around 0
+-commutativeN/A
mul-1-negN/A
unsub-negN/A
lower--.f64N/A
lower-/.f64N/A
lower-/.f6494.9
Applied rewrites94.9%
(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 15.6%
Taylor expanded in b around inf
mul-1-negN/A
distribute-neg-frac2N/A
lower-/.f64N/A
lower-neg.f6491.6
Applied rewrites91.6%
(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 15.6%
Applied rewrites15.6%
lift--.f64N/A
sub-negN/A
lift-/.f64N/A
lift-/.f64N/A
associate-/l/N/A
lift-*.f64N/A
times-fracN/A
lower-fma.f64N/A
Applied rewrites16.2%
Taylor expanded in c around 0
distribute-rgt-outN/A
metadata-evalN/A
mul0-rgt3.3
Applied rewrites3.3%
herbie shell --seed 2024226
(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)))