
(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
(if (<= b -1.55e+159)
(/ b (- a))
(if (<= b -2.8e-257)
(/ (- (sqrt (fma a (* c -4.0) (* b b))) b) (* a 2.0))
(if (<= b 5.8e+77)
(/ (* c -2.0) (+ b (sqrt (fma c (* a -4.0) (* b b)))))
(/ c (- b))))))
double code(double a, double b, double c) {
double tmp;
if (b <= -1.55e+159) {
tmp = b / -a;
} else if (b <= -2.8e-257) {
tmp = (sqrt(fma(a, (c * -4.0), (b * b))) - b) / (a * 2.0);
} else if (b <= 5.8e+77) {
tmp = (c * -2.0) / (b + sqrt(fma(c, (a * -4.0), (b * b))));
} else {
tmp = c / -b;
}
return tmp;
}
function code(a, b, c) tmp = 0.0 if (b <= -1.55e+159) tmp = Float64(b / Float64(-a)); elseif (b <= -2.8e-257) tmp = Float64(Float64(sqrt(fma(a, Float64(c * -4.0), Float64(b * b))) - b) / Float64(a * 2.0)); elseif (b <= 5.8e+77) tmp = Float64(Float64(c * -2.0) / Float64(b + sqrt(fma(c, Float64(a * -4.0), Float64(b * b))))); else tmp = Float64(c / Float64(-b)); end return tmp end
code[a_, b_, c_] := If[LessEqual[b, -1.55e+159], N[(b / (-a)), $MachinePrecision], If[LessEqual[b, -2.8e-257], N[(N[(N[Sqrt[N[(a * N[(c * -4.0), $MachinePrecision] + N[(b * b), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] / N[(a * 2.0), $MachinePrecision]), $MachinePrecision], If[LessEqual[b, 5.8e+77], N[(N[(c * -2.0), $MachinePrecision] / N[(b + N[Sqrt[N[(c * N[(a * -4.0), $MachinePrecision] + N[(b * b), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(c / (-b)), $MachinePrecision]]]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq -1.55 \cdot 10^{+159}:\\
\;\;\;\;\frac{b}{-a}\\
\mathbf{elif}\;b \leq -2.8 \cdot 10^{-257}:\\
\;\;\;\;\frac{\sqrt{\mathsf{fma}\left(a, c \cdot -4, b \cdot b\right)} - b}{a \cdot 2}\\
\mathbf{elif}\;b \leq 5.8 \cdot 10^{+77}:\\
\;\;\;\;\frac{c \cdot -2}{b + \sqrt{\mathsf{fma}\left(c, a \cdot -4, b \cdot b\right)}}\\
\mathbf{else}:\\
\;\;\;\;\frac{c}{-b}\\
\end{array}
\end{array}
if b < -1.5499999999999999e159Initial program 47.5%
Taylor expanded in b around -inf
mul-1-negN/A
distribute-neg-frac2N/A
mul-1-negN/A
lower-/.f64N/A
mul-1-negN/A
lower-neg.f6497.4
Applied rewrites97.4%
if -1.5499999999999999e159 < b < -2.80000000000000001e-257Initial program 85.1%
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
lower--.f6485.1
lift--.f64N/A
sub-negN/A
+-commutativeN/A
lift-*.f64N/A
distribute-lft-neg-inN/A
lift-*.f64N/A
*-commutativeN/A
distribute-rgt-neg-inN/A
associate-*l*N/A
lower-fma.f64N/A
lower-*.f64N/A
metadata-eval85.1
Applied rewrites85.1%
if -2.80000000000000001e-257 < b < 5.8000000000000003e77Initial program 51.0%
Applied rewrites42.3%
Taylor expanded in b around 0
lower-*.f64N/A
lower-*.f6470.6
Applied rewrites70.6%
lift-/.f64N/A
lift-*.f64N/A
associate-/r*N/A
lift-*.f64N/A
*-commutativeN/A
metadata-evalN/A
distribute-lft-neg-inN/A
lift-*.f64N/A
associate-/l/N/A
associate-/r*N/A
lower-/.f64N/A
Applied rewrites78.7%
Taylor expanded in b around 0
*-commutativeN/A
lower-*.f6485.7
Applied rewrites85.7%
if 5.8000000000000003e77 < b Initial program 10.4%
Taylor expanded in b around inf
mul-1-negN/A
distribute-neg-frac2N/A
lower-/.f64N/A
lower-neg.f6496.6
Applied rewrites96.6%
Final simplification89.8%
(FPCore (a b c)
:precision binary64
(if (<= b -6.8e-82)
(fma b (/ c (* b b)) (/ b (- a)))
(if (<= b 5.8e+77)
(/ (* c -2.0) (+ b (sqrt (fma c (* a -4.0) (* b b)))))
(/ c (- b)))))
double code(double a, double b, double c) {
double tmp;
if (b <= -6.8e-82) {
tmp = fma(b, (c / (b * b)), (b / -a));
} else if (b <= 5.8e+77) {
tmp = (c * -2.0) / (b + sqrt(fma(c, (a * -4.0), (b * b))));
} else {
tmp = c / -b;
}
return tmp;
}
function code(a, b, c) tmp = 0.0 if (b <= -6.8e-82) tmp = fma(b, Float64(c / Float64(b * b)), Float64(b / Float64(-a))); elseif (b <= 5.8e+77) tmp = Float64(Float64(c * -2.0) / Float64(b + sqrt(fma(c, Float64(a * -4.0), Float64(b * b))))); else tmp = Float64(c / Float64(-b)); end return tmp end
code[a_, b_, c_] := If[LessEqual[b, -6.8e-82], N[(b * N[(c / N[(b * b), $MachinePrecision]), $MachinePrecision] + N[(b / (-a)), $MachinePrecision]), $MachinePrecision], If[LessEqual[b, 5.8e+77], N[(N[(c * -2.0), $MachinePrecision] / N[(b + N[Sqrt[N[(c * N[(a * -4.0), $MachinePrecision] + N[(b * b), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(c / (-b)), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq -6.8 \cdot 10^{-82}:\\
\;\;\;\;\mathsf{fma}\left(b, \frac{c}{b \cdot b}, \frac{b}{-a}\right)\\
\mathbf{elif}\;b \leq 5.8 \cdot 10^{+77}:\\
\;\;\;\;\frac{c \cdot -2}{b + \sqrt{\mathsf{fma}\left(c, a \cdot -4, b \cdot b\right)}}\\
\mathbf{else}:\\
\;\;\;\;\frac{c}{-b}\\
\end{array}
\end{array}
if b < -6.7999999999999995e-82Initial program 68.8%
Taylor expanded in b around -inf
mul-1-negN/A
distribute-rgt-inN/A
distribute-neg-inN/A
associate-*l/N/A
*-lft-identityN/A
*-commutativeN/A
mul-1-negN/A
distribute-rgt-neg-outN/A
remove-double-negN/A
lower-fma.f64N/A
lower-/.f64N/A
unpow2N/A
lower-*.f64N/A
distribute-neg-frac2N/A
mul-1-negN/A
lower-/.f64N/A
mul-1-negN/A
lower-neg.f6486.0
Applied rewrites86.0%
if -6.7999999999999995e-82 < b < 5.8000000000000003e77Initial program 59.6%
Applied rewrites49.1%
Taylor expanded in b around 0
lower-*.f64N/A
lower-*.f6470.5
Applied rewrites70.5%
lift-/.f64N/A
lift-*.f64N/A
associate-/r*N/A
lift-*.f64N/A
*-commutativeN/A
metadata-evalN/A
distribute-lft-neg-inN/A
lift-*.f64N/A
associate-/l/N/A
associate-/r*N/A
lower-/.f64N/A
Applied rewrites78.3%
Taylor expanded in b around 0
*-commutativeN/A
lower-*.f6483.5
Applied rewrites83.5%
if 5.8000000000000003e77 < b Initial program 10.4%
Taylor expanded in b around inf
mul-1-negN/A
distribute-neg-frac2N/A
lower-/.f64N/A
lower-neg.f6496.6
Applied rewrites96.6%
(FPCore (a b c)
:precision binary64
(if (<= b -4e-92)
(fma b (/ c (* b b)) (/ b (- a)))
(if (<= b 1.25e-100)
(/ (- (sqrt (* -4.0 (* a c))) b) (* a 2.0))
(/ c (- b)))))
double code(double a, double b, double c) {
double tmp;
if (b <= -4e-92) {
tmp = fma(b, (c / (b * b)), (b / -a));
} else if (b <= 1.25e-100) {
tmp = (sqrt((-4.0 * (a * c))) - b) / (a * 2.0);
} else {
tmp = c / -b;
}
return tmp;
}
function code(a, b, c) tmp = 0.0 if (b <= -4e-92) tmp = fma(b, Float64(c / Float64(b * b)), Float64(b / Float64(-a))); elseif (b <= 1.25e-100) tmp = Float64(Float64(sqrt(Float64(-4.0 * Float64(a * c))) - b) / Float64(a * 2.0)); else tmp = Float64(c / Float64(-b)); end return tmp end
code[a_, b_, c_] := If[LessEqual[b, -4e-92], N[(b * N[(c / N[(b * b), $MachinePrecision]), $MachinePrecision] + N[(b / (-a)), $MachinePrecision]), $MachinePrecision], If[LessEqual[b, 1.25e-100], N[(N[(N[Sqrt[N[(-4.0 * N[(a * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] / N[(a * 2.0), $MachinePrecision]), $MachinePrecision], N[(c / (-b)), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq -4 \cdot 10^{-92}:\\
\;\;\;\;\mathsf{fma}\left(b, \frac{c}{b \cdot b}, \frac{b}{-a}\right)\\
\mathbf{elif}\;b \leq 1.25 \cdot 10^{-100}:\\
\;\;\;\;\frac{\sqrt{-4 \cdot \left(a \cdot c\right)} - b}{a \cdot 2}\\
\mathbf{else}:\\
\;\;\;\;\frac{c}{-b}\\
\end{array}
\end{array}
if b < -3.99999999999999995e-92Initial program 69.5%
Taylor expanded in b around -inf
mul-1-negN/A
distribute-rgt-inN/A
distribute-neg-inN/A
associate-*l/N/A
*-lft-identityN/A
*-commutativeN/A
mul-1-negN/A
distribute-rgt-neg-outN/A
remove-double-negN/A
lower-fma.f64N/A
lower-/.f64N/A
unpow2N/A
lower-*.f64N/A
distribute-neg-frac2N/A
mul-1-negN/A
lower-/.f64N/A
mul-1-negN/A
lower-neg.f6485.3
Applied rewrites85.3%
if -3.99999999999999995e-92 < b < 1.25e-100Initial program 80.6%
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
lower--.f6480.6
lift--.f64N/A
sub-negN/A
+-commutativeN/A
lift-*.f64N/A
distribute-lft-neg-inN/A
lift-*.f64N/A
*-commutativeN/A
distribute-rgt-neg-inN/A
associate-*l*N/A
lower-fma.f64N/A
lower-*.f64N/A
metadata-eval80.6
Applied rewrites80.6%
Taylor expanded in a around inf
lower-*.f64N/A
lower-*.f6479.4
Applied rewrites79.4%
if 1.25e-100 < b Initial program 15.1%
Taylor expanded in b around inf
mul-1-negN/A
distribute-neg-frac2N/A
lower-/.f64N/A
lower-neg.f6484.7
Applied rewrites84.7%
Final simplification83.5%
(FPCore (a b c)
:precision binary64
(if (<= b -4e-92)
(fma b (/ c (* b b)) (/ b (- a)))
(if (<= b 1.25e-100)
(* (/ 0.5 a) (- (sqrt (* a (* c -4.0))) b))
(/ c (- b)))))
double code(double a, double b, double c) {
double tmp;
if (b <= -4e-92) {
tmp = fma(b, (c / (b * b)), (b / -a));
} else if (b <= 1.25e-100) {
tmp = (0.5 / a) * (sqrt((a * (c * -4.0))) - b);
} else {
tmp = c / -b;
}
return tmp;
}
function code(a, b, c) tmp = 0.0 if (b <= -4e-92) tmp = fma(b, Float64(c / Float64(b * b)), Float64(b / Float64(-a))); elseif (b <= 1.25e-100) tmp = Float64(Float64(0.5 / a) * Float64(sqrt(Float64(a * Float64(c * -4.0))) - b)); else tmp = Float64(c / Float64(-b)); end return tmp end
code[a_, b_, c_] := If[LessEqual[b, -4e-92], N[(b * N[(c / N[(b * b), $MachinePrecision]), $MachinePrecision] + N[(b / (-a)), $MachinePrecision]), $MachinePrecision], If[LessEqual[b, 1.25e-100], N[(N[(0.5 / a), $MachinePrecision] * N[(N[Sqrt[N[(a * N[(c * -4.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision]), $MachinePrecision], N[(c / (-b)), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq -4 \cdot 10^{-92}:\\
\;\;\;\;\mathsf{fma}\left(b, \frac{c}{b \cdot b}, \frac{b}{-a}\right)\\
\mathbf{elif}\;b \leq 1.25 \cdot 10^{-100}:\\
\;\;\;\;\frac{0.5}{a} \cdot \left(\sqrt{a \cdot \left(c \cdot -4\right)} - b\right)\\
\mathbf{else}:\\
\;\;\;\;\frac{c}{-b}\\
\end{array}
\end{array}
if b < -3.99999999999999995e-92Initial program 69.5%
Taylor expanded in b around -inf
mul-1-negN/A
distribute-rgt-inN/A
distribute-neg-inN/A
associate-*l/N/A
*-lft-identityN/A
*-commutativeN/A
mul-1-negN/A
distribute-rgt-neg-outN/A
remove-double-negN/A
lower-fma.f64N/A
lower-/.f64N/A
unpow2N/A
lower-*.f64N/A
distribute-neg-frac2N/A
mul-1-negN/A
lower-/.f64N/A
mul-1-negN/A
lower-neg.f6485.3
Applied rewrites85.3%
if -3.99999999999999995e-92 < b < 1.25e-100Initial program 80.6%
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
lower--.f6480.6
lift--.f64N/A
sub-negN/A
+-commutativeN/A
lift-*.f64N/A
distribute-lft-neg-inN/A
lift-*.f64N/A
*-commutativeN/A
distribute-rgt-neg-inN/A
associate-*l*N/A
lower-fma.f64N/A
lower-*.f64N/A
metadata-eval80.6
Applied rewrites80.6%
Taylor expanded in a around 0
unpow2N/A
lower-*.f645.0
Applied rewrites5.0%
Taylor expanded in a around inf
lower-*.f64N/A
*-commutativeN/A
lower-*.f6479.4
Applied rewrites79.4%
lift-/.f64N/A
div-invN/A
*-commutativeN/A
lower-*.f64N/A
metadata-evalN/A
lift-*.f64N/A
associate-/r*N/A
metadata-evalN/A
metadata-evalN/A
lower-/.f6479.2
Applied rewrites79.2%
if 1.25e-100 < b Initial program 15.1%
Taylor expanded in b around inf
mul-1-negN/A
distribute-neg-frac2N/A
lower-/.f64N/A
lower-neg.f6484.7
Applied rewrites84.7%
(FPCore (a b c) :precision binary64 (if (<= b 4.5e-301) (/ b (- a)) (/ c (- b))))
double code(double a, double b, double c) {
double tmp;
if (b <= 4.5e-301) {
tmp = b / -a;
} else {
tmp = c / -b;
}
return tmp;
}
real(8) function code(a, b, c)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: c
real(8) :: tmp
if (b <= 4.5d-301) then
tmp = b / -a
else
tmp = c / -b
end if
code = tmp
end function
public static double code(double a, double b, double c) {
double tmp;
if (b <= 4.5e-301) {
tmp = b / -a;
} else {
tmp = c / -b;
}
return tmp;
}
def code(a, b, c): tmp = 0 if b <= 4.5e-301: tmp = b / -a else: tmp = c / -b return tmp
function code(a, b, c) tmp = 0.0 if (b <= 4.5e-301) tmp = Float64(b / Float64(-a)); else tmp = Float64(c / Float64(-b)); end return tmp end
function tmp_2 = code(a, b, c) tmp = 0.0; if (b <= 4.5e-301) tmp = b / -a; else tmp = c / -b; end tmp_2 = tmp; end
code[a_, b_, c_] := If[LessEqual[b, 4.5e-301], N[(b / (-a)), $MachinePrecision], N[(c / (-b)), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq 4.5 \cdot 10^{-301}:\\
\;\;\;\;\frac{b}{-a}\\
\mathbf{else}:\\
\;\;\;\;\frac{c}{-b}\\
\end{array}
\end{array}
if b < 4.5000000000000002e-301Initial program 73.8%
Taylor expanded in b around -inf
mul-1-negN/A
distribute-neg-frac2N/A
mul-1-negN/A
lower-/.f64N/A
mul-1-negN/A
lower-neg.f6465.2
Applied rewrites65.2%
if 4.5000000000000002e-301 < b Initial program 29.9%
Taylor expanded in b around inf
mul-1-negN/A
distribute-neg-frac2N/A
lower-/.f64N/A
lower-neg.f6468.1
Applied rewrites68.1%
(FPCore (a b c) :precision binary64 (/ b (- a)))
double code(double a, double b, double c) {
return b / -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 / -a
end function
public static double code(double a, double b, double c) {
return b / -a;
}
def code(a, b, c): return b / -a
function code(a, b, c) return Float64(b / Float64(-a)) end
function tmp = code(a, b, c) tmp = b / -a; end
code[a_, b_, c_] := N[(b / (-a)), $MachinePrecision]
\begin{array}{l}
\\
\frac{b}{-a}
\end{array}
Initial program 53.1%
Taylor expanded in b around -inf
mul-1-negN/A
distribute-neg-frac2N/A
mul-1-negN/A
lower-/.f64N/A
mul-1-negN/A
lower-neg.f6435.7
Applied rewrites35.7%
herbie shell --seed 2024221
(FPCore (a b c)
:name "Quadratic roots, full range"
:precision binary64
(/ (+ (- b) (sqrt (- (* b b) (* (* 4.0 a) c)))) (* 2.0 a)))