
(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 (/ (/ (* (* c a) -2.0) a) (+ (sqrt (fma a (* -4.0 c) (* b b))) b)))
double code(double a, double b, double c) {
return (((c * a) * -2.0) / a) / (sqrt(fma(a, (-4.0 * c), (b * b))) + b);
}
function code(a, b, c) return Float64(Float64(Float64(Float64(c * a) * -2.0) / a) / Float64(sqrt(fma(a, Float64(-4.0 * c), Float64(b * b))) + b)) end
code[a_, b_, c_] := N[(N[(N[(N[(c * a), $MachinePrecision] * -2.0), $MachinePrecision] / a), $MachinePrecision] / N[(N[Sqrt[N[(a * N[(-4.0 * c), $MachinePrecision] + N[(b * b), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] + b), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\frac{\left(c \cdot a\right) \cdot -2}{a}}{\sqrt{\mathsf{fma}\left(a, -4 \cdot c, b \cdot b\right)} + b}
\end{array}
Initial program 17.3%
lift-/.f64N/A
clear-numN/A
lift-*.f64N/A
associate-/l*N/A
associate-/r*N/A
metadata-evalN/A
lower-/.f64N/A
lower-/.f6417.3
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
lower--.f6417.3
Applied rewrites17.3%
lift-/.f64N/A
lift-/.f64N/A
associate-/r/N/A
lift--.f64N/A
flip--N/A
lift-+.f64N/A
frac-timesN/A
lower-/.f64N/A
Applied rewrites99.4%
lift-/.f64N/A
lift-*.f64N/A
associate-/r*N/A
lower-/.f64N/A
lower-/.f6499.7
lift-*.f64N/A
lift-fma.f64N/A
+-rgt-identityN/A
lift-*.f64N/A
associate-*l*N/A
associate-*r*N/A
metadata-evalN/A
metadata-evalN/A
lower-*.f64N/A
metadata-evalN/A
*-commutativeN/A
lower-*.f6499.7
Applied rewrites99.7%
Final simplification99.7%
(FPCore (a b c) :precision binary64 (/ (* (* c a) -2.0) (* (+ (sqrt (fma a (* -4.0 c) (* b b))) b) a)))
double code(double a, double b, double c) {
return ((c * a) * -2.0) / ((sqrt(fma(a, (-4.0 * c), (b * b))) + b) * a);
}
function code(a, b, c) return Float64(Float64(Float64(c * a) * -2.0) / Float64(Float64(sqrt(fma(a, Float64(-4.0 * c), Float64(b * b))) + b) * a)) end
code[a_, b_, c_] := N[(N[(N[(c * a), $MachinePrecision] * -2.0), $MachinePrecision] / N[(N[(N[Sqrt[N[(a * N[(-4.0 * c), $MachinePrecision] + N[(b * b), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] + b), $MachinePrecision] * a), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\left(c \cdot a\right) \cdot -2}{\left(\sqrt{\mathsf{fma}\left(a, -4 \cdot c, b \cdot b\right)} + b\right) \cdot a}
\end{array}
Initial program 17.3%
lift-/.f64N/A
clear-numN/A
lift-*.f64N/A
associate-/l*N/A
associate-/r*N/A
metadata-evalN/A
lower-/.f64N/A
lower-/.f6417.3
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
lower--.f6417.3
Applied rewrites17.3%
lift-/.f64N/A
lift-/.f64N/A
associate-/r/N/A
lift--.f64N/A
flip--N/A
lift-+.f64N/A
frac-timesN/A
lower-/.f64N/A
Applied rewrites99.4%
lift-*.f64N/A
lift-fma.f64N/A
+-rgt-identityN/A
lift-*.f64N/A
associate-*l*N/A
associate-*r*N/A
metadata-evalN/A
metadata-evalN/A
lower-*.f64N/A
metadata-evalN/A
*-commutativeN/A
lower-*.f6499.4
lift-*.f64N/A
*-commutativeN/A
lower-*.f6499.4
lift-fma.f64N/A
*-commutativeN/A
lower-fma.f6499.4
lift-*.f64N/A
*-commutativeN/A
lower-*.f6499.4
Applied rewrites99.4%
Final simplification99.4%
(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 17.3%
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 rewrites95.5%
Applied rewrites95.5%
Final simplification95.5%
(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 17.3%
Taylor expanded in a around 0
associate-*r/N/A
lower-/.f64N/A
mul-1-negN/A
lower-neg.f6490.7
Applied rewrites90.7%
(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 17.3%
Applied rewrites14.8%
lift-*.f64N/A
*-commutativeN/A
lift--.f64N/A
sub-negN/A
distribute-lft-inN/A
lower-fma.f64N/A
Applied rewrites19.1%
Taylor expanded in c around 0
distribute-rgt-outN/A
metadata-evalN/A
mul0-rgt3.3
Applied rewrites3.3%
herbie shell --seed 2024282
(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)))