
(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 8 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 (fma (/ (sqrt (fma (* a -4.0) c (* b b))) (fma (* a -4.0) c 0.0)) a (* (/ b c) -0.25))))
double code(double a, double b, double c) {
return 0.5 / fma((sqrt(fma((a * -4.0), c, (b * b))) / fma((a * -4.0), c, 0.0)), a, ((b / c) * -0.25));
}
function code(a, b, c) return Float64(0.5 / fma(Float64(sqrt(fma(Float64(a * -4.0), c, Float64(b * b))) / fma(Float64(a * -4.0), c, 0.0)), a, Float64(Float64(b / c) * -0.25))) end
code[a_, b_, c_] := N[(0.5 / N[(N[(N[Sqrt[N[(N[(a * -4.0), $MachinePrecision] * c + N[(b * b), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] / N[(N[(a * -4.0), $MachinePrecision] * c + 0.0), $MachinePrecision]), $MachinePrecision] * a + N[(N[(b / c), $MachinePrecision] * -0.25), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{0.5}{\mathsf{fma}\left(\frac{\sqrt{\mathsf{fma}\left(a \cdot -4, c, b \cdot b\right)}}{\mathsf{fma}\left(a \cdot -4, c, 0\right)}, a, \frac{b}{c} \cdot -0.25\right)}
\end{array}
Initial program 52.6%
lift-/.f64N/A
div-invN/A
lift-*.f64N/A
associate-/r*N/A
metadata-evalN/A
lift-+.f64N/A
flip-+N/A
clear-numN/A
frac-timesN/A
metadata-evalN/A
Applied rewrites52.6%
Applied rewrites53.9%
lift-*.f64N/A
*-commutativeN/A
lift-*.f64N/A
lift-+.f64N/A
distribute-lft-inN/A
distribute-rgt-inN/A
lower-fma.f64N/A
Applied rewrites99.3%
Taylor expanded in a around 0
lower-*.f64N/A
lower-/.f6499.4
Applied rewrites99.4%
Final simplification99.4%
(FPCore (a b c) :precision binary64 (/ (/ 0.5 a) (* (+ (sqrt (fma c (* a -4.0) (* b b))) b) (/ -0.25 (* c a)))))
double code(double a, double b, double c) {
return (0.5 / a) / ((sqrt(fma(c, (a * -4.0), (b * b))) + b) * (-0.25 / (c * a)));
}
function code(a, b, c) return Float64(Float64(0.5 / a) / Float64(Float64(sqrt(fma(c, Float64(a * -4.0), Float64(b * b))) + b) * Float64(-0.25 / Float64(c * a)))) end
code[a_, b_, c_] := N[(N[(0.5 / a), $MachinePrecision] / N[(N[(N[Sqrt[N[(c * N[(a * -4.0), $MachinePrecision] + N[(b * b), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] + b), $MachinePrecision] * N[(-0.25 / N[(c * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\frac{0.5}{a}}{\left(\sqrt{\mathsf{fma}\left(c, a \cdot -4, b \cdot b\right)} + b\right) \cdot \frac{-0.25}{c \cdot a}}
\end{array}
Initial program 52.6%
lift-/.f64N/A
div-invN/A
lift-*.f64N/A
associate-/r*N/A
metadata-evalN/A
lift-+.f64N/A
flip-+N/A
clear-numN/A
frac-timesN/A
metadata-evalN/A
Applied rewrites52.6%
Applied rewrites53.9%
lift-*.f64N/A
*-commutativeN/A
lift-*.f64N/A
lift-+.f64N/A
distribute-lft-inN/A
distribute-rgt-inN/A
lower-fma.f64N/A
Applied rewrites99.3%
lift-/.f64N/A
lift-fma.f64N/A
lift-*.f64N/A
distribute-rgt-outN/A
associate-/r*N/A
lift-/.f64N/A
lower-/.f64N/A
lift-/.f64N/A
div-invN/A
lift-/.f64N/A
div-invN/A
Applied rewrites99.2%
Final simplification99.2%
(FPCore (a b c) :precision binary64 (/ 0.5 (/ (* (+ (sqrt (fma (* a -4.0) c (* b b))) b) a) (fma (* a -4.0) c 0.0))))
double code(double a, double b, double c) {
return 0.5 / (((sqrt(fma((a * -4.0), c, (b * b))) + b) * a) / fma((a * -4.0), c, 0.0));
}
function code(a, b, c) return Float64(0.5 / Float64(Float64(Float64(sqrt(fma(Float64(a * -4.0), c, Float64(b * b))) + b) * a) / fma(Float64(a * -4.0), c, 0.0))) end
code[a_, b_, c_] := N[(0.5 / N[(N[(N[(N[Sqrt[N[(N[(a * -4.0), $MachinePrecision] * c + N[(b * b), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] + b), $MachinePrecision] * a), $MachinePrecision] / N[(N[(a * -4.0), $MachinePrecision] * c + 0.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{0.5}{\frac{\left(\sqrt{\mathsf{fma}\left(a \cdot -4, c, b \cdot b\right)} + b\right) \cdot a}{\mathsf{fma}\left(a \cdot -4, c, 0\right)}}
\end{array}
Initial program 52.6%
lift-/.f64N/A
div-invN/A
lift-*.f64N/A
associate-/r*N/A
metadata-evalN/A
lift-+.f64N/A
flip-+N/A
clear-numN/A
frac-timesN/A
metadata-evalN/A
Applied rewrites52.6%
Applied rewrites53.9%
lift-*.f64N/A
lift-*.f64N/A
associate-*l*N/A
lift-pow.f64N/A
unpow-1N/A
associate-*l/N/A
lower-/.f64N/A
lower-*.f64N/A
lower-*.f6453.9
lift--.f64N/A
lift-fma.f64N/A
associate--l+N/A
Applied rewrites99.2%
Final simplification99.2%
(FPCore (a b c) :precision binary64 (/ 0.5 (* (* (/ -0.25 (* c a)) (+ (sqrt (fma (* a -4.0) c (* b b))) b)) a)))
double code(double a, double b, double c) {
return 0.5 / (((-0.25 / (c * a)) * (sqrt(fma((a * -4.0), c, (b * b))) + b)) * a);
}
function code(a, b, c) return Float64(0.5 / Float64(Float64(Float64(-0.25 / Float64(c * a)) * Float64(sqrt(fma(Float64(a * -4.0), c, Float64(b * b))) + b)) * a)) end
code[a_, b_, c_] := N[(0.5 / N[(N[(N[(-0.25 / N[(c * a), $MachinePrecision]), $MachinePrecision] * N[(N[Sqrt[N[(N[(a * -4.0), $MachinePrecision] * c + N[(b * b), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] + b), $MachinePrecision]), $MachinePrecision] * a), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{0.5}{\left(\frac{-0.25}{c \cdot a} \cdot \left(\sqrt{\mathsf{fma}\left(a \cdot -4, c, b \cdot b\right)} + b\right)\right) \cdot a}
\end{array}
Initial program 52.6%
lift-/.f64N/A
div-invN/A
lift-*.f64N/A
associate-/r*N/A
metadata-evalN/A
lift-+.f64N/A
flip-+N/A
clear-numN/A
frac-timesN/A
metadata-evalN/A
Applied rewrites52.6%
Applied rewrites53.9%
Taylor expanded in a around 0
lower-/.f64N/A
lower-*.f6499.2
Applied rewrites99.2%
Final simplification99.2%
(FPCore (a b c) :precision binary64 (if (<= b 18.5) (* (- (sqrt (fma b b (* (* a -4.0) c))) b) (/ 0.5 a)) (/ 0.5 (/ (fma 0.5 (* (/ c b) a) (* -0.5 b)) c))))
double code(double a, double b, double c) {
double tmp;
if (b <= 18.5) {
tmp = (sqrt(fma(b, b, ((a * -4.0) * c))) - b) * (0.5 / a);
} else {
tmp = 0.5 / (fma(0.5, ((c / b) * a), (-0.5 * b)) / c);
}
return tmp;
}
function code(a, b, c) tmp = 0.0 if (b <= 18.5) tmp = Float64(Float64(sqrt(fma(b, b, Float64(Float64(a * -4.0) * c))) - b) * Float64(0.5 / a)); else tmp = Float64(0.5 / Float64(fma(0.5, Float64(Float64(c / b) * a), Float64(-0.5 * b)) / c)); end return tmp end
code[a_, b_, c_] := If[LessEqual[b, 18.5], N[(N[(N[Sqrt[N[(b * b + N[(N[(a * -4.0), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] * N[(0.5 / a), $MachinePrecision]), $MachinePrecision], N[(0.5 / N[(N[(0.5 * N[(N[(c / b), $MachinePrecision] * a), $MachinePrecision] + N[(-0.5 * b), $MachinePrecision]), $MachinePrecision] / c), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq 18.5:\\
\;\;\;\;\left(\sqrt{\mathsf{fma}\left(b, b, \left(a \cdot -4\right) \cdot c\right)} - b\right) \cdot \frac{0.5}{a}\\
\mathbf{else}:\\
\;\;\;\;\frac{0.5}{\frac{\mathsf{fma}\left(0.5, \frac{c}{b} \cdot a, -0.5 \cdot b\right)}{c}}\\
\end{array}
\end{array}
if b < 18.5Initial program 79.3%
lift-/.f64N/A
clear-numN/A
associate-/r/N/A
lower-*.f64N/A
lift-*.f64N/A
associate-/r*N/A
metadata-evalN/A
lower-/.f6479.3
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
lower--.f6479.3
Applied rewrites79.3%
lift-fma.f64N/A
+-commutativeN/A
lift-*.f64N/A
lift-*.f64N/A
associate-*l*N/A
*-commutativeN/A
associate-*l*N/A
lift-*.f64N/A
+-rgt-identityN/A
lift-fma.f64N/A
lower-fma.f6479.4
lift-fma.f64N/A
+-rgt-identityN/A
*-commutativeN/A
lower-*.f6479.4
lift-*.f64N/A
*-commutativeN/A
lower-*.f6479.4
Applied rewrites79.4%
if 18.5 < b Initial program 43.5%
lift-/.f64N/A
div-invN/A
lift-*.f64N/A
associate-/r*N/A
metadata-evalN/A
lift-+.f64N/A
flip-+N/A
clear-numN/A
frac-timesN/A
metadata-evalN/A
Applied rewrites43.5%
Taylor expanded in c around 0
lower-/.f64N/A
+-commutativeN/A
lower-fma.f64N/A
associate-/l*N/A
lower-*.f64N/A
lower-/.f64N/A
lower-*.f6490.5
Applied rewrites90.5%
Final simplification87.7%
(FPCore (a b c) :precision binary64 (if (<= b 18.5) (* (- (sqrt (fma b b (* (* a -4.0) c))) b) (/ 0.5 a)) (/ 0.5 (fma (/ a b) 0.5 (* -0.5 (/ b c))))))
double code(double a, double b, double c) {
double tmp;
if (b <= 18.5) {
tmp = (sqrt(fma(b, b, ((a * -4.0) * c))) - b) * (0.5 / a);
} else {
tmp = 0.5 / fma((a / b), 0.5, (-0.5 * (b / c)));
}
return tmp;
}
function code(a, b, c) tmp = 0.0 if (b <= 18.5) tmp = Float64(Float64(sqrt(fma(b, b, Float64(Float64(a * -4.0) * c))) - b) * Float64(0.5 / a)); else tmp = Float64(0.5 / fma(Float64(a / b), 0.5, Float64(-0.5 * Float64(b / c)))); end return tmp end
code[a_, b_, c_] := If[LessEqual[b, 18.5], N[(N[(N[Sqrt[N[(b * b + N[(N[(a * -4.0), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] * N[(0.5 / a), $MachinePrecision]), $MachinePrecision], N[(0.5 / N[(N[(a / b), $MachinePrecision] * 0.5 + N[(-0.5 * N[(b / c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq 18.5:\\
\;\;\;\;\left(\sqrt{\mathsf{fma}\left(b, b, \left(a \cdot -4\right) \cdot c\right)} - b\right) \cdot \frac{0.5}{a}\\
\mathbf{else}:\\
\;\;\;\;\frac{0.5}{\mathsf{fma}\left(\frac{a}{b}, 0.5, -0.5 \cdot \frac{b}{c}\right)}\\
\end{array}
\end{array}
if b < 18.5Initial program 79.3%
lift-/.f64N/A
clear-numN/A
associate-/r/N/A
lower-*.f64N/A
lift-*.f64N/A
associate-/r*N/A
metadata-evalN/A
lower-/.f6479.3
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
lower--.f6479.3
Applied rewrites79.3%
lift-fma.f64N/A
+-commutativeN/A
lift-*.f64N/A
lift-*.f64N/A
associate-*l*N/A
*-commutativeN/A
associate-*l*N/A
lift-*.f64N/A
+-rgt-identityN/A
lift-fma.f64N/A
lower-fma.f6479.4
lift-fma.f64N/A
+-rgt-identityN/A
*-commutativeN/A
lower-*.f6479.4
lift-*.f64N/A
*-commutativeN/A
lower-*.f6479.4
Applied rewrites79.4%
if 18.5 < b Initial program 43.5%
lift-/.f64N/A
div-invN/A
lift-*.f64N/A
associate-/r*N/A
metadata-evalN/A
lift-+.f64N/A
flip-+N/A
clear-numN/A
frac-timesN/A
metadata-evalN/A
Applied rewrites43.5%
Taylor expanded in a around 0
+-commutativeN/A
*-commutativeN/A
lower-fma.f64N/A
lower-/.f64N/A
*-commutativeN/A
lower-*.f64N/A
lower-/.f6490.5
Applied rewrites90.5%
Final simplification87.7%
(FPCore (a b c) :precision binary64 (/ 0.5 (fma (/ a b) 0.5 (* -0.5 (/ b c)))))
double code(double a, double b, double c) {
return 0.5 / fma((a / b), 0.5, (-0.5 * (b / c)));
}
function code(a, b, c) return Float64(0.5 / fma(Float64(a / b), 0.5, Float64(-0.5 * Float64(b / c)))) end
code[a_, b_, c_] := N[(0.5 / N[(N[(a / b), $MachinePrecision] * 0.5 + N[(-0.5 * N[(b / c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{0.5}{\mathsf{fma}\left(\frac{a}{b}, 0.5, -0.5 \cdot \frac{b}{c}\right)}
\end{array}
Initial program 52.6%
lift-/.f64N/A
div-invN/A
lift-*.f64N/A
associate-/r*N/A
metadata-evalN/A
lift-+.f64N/A
flip-+N/A
clear-numN/A
frac-timesN/A
metadata-evalN/A
Applied rewrites52.6%
Taylor expanded in a around 0
+-commutativeN/A
*-commutativeN/A
lower-fma.f64N/A
lower-/.f64N/A
*-commutativeN/A
lower-*.f64N/A
lower-/.f6483.4
Applied rewrites83.4%
Final simplification83.4%
(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 52.6%
Taylor expanded in a around 0
associate-*r/N/A
lower-/.f64N/A
mul-1-negN/A
lower-neg.f6466.8
Applied rewrites66.8%
herbie shell --seed 2024304
(FPCore (a b c)
:name "Quadratic roots, narrow range"
:precision binary64
:pre (and (and (and (< 1.0536712127723509e-8 a) (< a 94906265.62425156)) (and (< 1.0536712127723509e-8 b) (< b 94906265.62425156))) (and (< 1.0536712127723509e-8 c) (< c 94906265.62425156)))
(/ (+ (- b) (sqrt (- (* b b) (* (* 4.0 a) c)))) (* 2.0 a)))