
(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 (/ (/ (fma a (* c -4.0) 0.0) (* a 2.0)) (+ b (sqrt (fma -4.0 (* a c) (* b b))))))
double code(double a, double b, double c) {
return (fma(a, (c * -4.0), 0.0) / (a * 2.0)) / (b + sqrt(fma(-4.0, (a * c), (b * b))));
}
function code(a, b, c) return Float64(Float64(fma(a, Float64(c * -4.0), 0.0) / Float64(a * 2.0)) / Float64(b + sqrt(fma(-4.0, Float64(a * c), Float64(b * b))))) end
code[a_, b_, c_] := N[(N[(N[(a * N[(c * -4.0), $MachinePrecision] + 0.0), $MachinePrecision] / N[(a * 2.0), $MachinePrecision]), $MachinePrecision] / N[(b + N[Sqrt[N[(-4.0 * N[(a * c), $MachinePrecision] + N[(b * b), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\frac{\mathsf{fma}\left(a, c \cdot -4, 0\right)}{a \cdot 2}}{b + \sqrt{\mathsf{fma}\left(-4, a \cdot c, b \cdot b\right)}}
\end{array}
Initial program 57.8%
sub-negN/A
+-commutativeN/A
*-commutativeN/A
distribute-rgt-neg-inN/A
distribute-lft-neg-inN/A
associate-*r*N/A
accelerator-lowering-fma.f64N/A
*-lowering-*.f64N/A
metadata-evalN/A
*-lowering-*.f6457.8
Applied egg-rr57.8%
+-commutativeN/A
flip-+N/A
/-lowering-/.f64N/A
rem-square-sqrtN/A
sqr-negN/A
--lowering--.f64N/A
associate-*l*N/A
accelerator-lowering-fma.f64N/A
*-commutativeN/A
*-lowering-*.f64N/A
*-lowering-*.f64N/A
*-lowering-*.f64N/A
--lowering--.f64N/A
Applied egg-rr59.2%
associate-/l/N/A
associate-/r*N/A
/-lowering-/.f64N/A
/-lowering-/.f64N/A
associate--l+N/A
*-commutativeN/A
associate-*r*N/A
+-inversesN/A
accelerator-lowering-fma.f64N/A
*-commutativeN/A
*-lowering-*.f64N/A
*-commutativeN/A
*-lowering-*.f64N/A
sub-negN/A
remove-double-negN/A
+-commutativeN/A
+-lowering-+.f64N/A
Applied egg-rr99.5%
(FPCore (a b c) :precision binary64 (/ (fma a (* c -4.0) 0.0) (* (* a 2.0) (+ b (sqrt (fma -4.0 (* a c) (* b b)))))))
double code(double a, double b, double c) {
return fma(a, (c * -4.0), 0.0) / ((a * 2.0) * (b + sqrt(fma(-4.0, (a * c), (b * b)))));
}
function code(a, b, c) return Float64(fma(a, Float64(c * -4.0), 0.0) / Float64(Float64(a * 2.0) * Float64(b + sqrt(fma(-4.0, Float64(a * c), Float64(b * b)))))) end
code[a_, b_, c_] := N[(N[(a * N[(c * -4.0), $MachinePrecision] + 0.0), $MachinePrecision] / N[(N[(a * 2.0), $MachinePrecision] * N[(b + N[Sqrt[N[(-4.0 * N[(a * c), $MachinePrecision] + N[(b * b), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(a, c \cdot -4, 0\right)}{\left(a \cdot 2\right) \cdot \left(b + \sqrt{\mathsf{fma}\left(-4, a \cdot c, b \cdot b\right)}\right)}
\end{array}
Initial program 57.8%
sub-negN/A
+-commutativeN/A
*-commutativeN/A
distribute-rgt-neg-inN/A
distribute-lft-neg-inN/A
associate-*r*N/A
accelerator-lowering-fma.f64N/A
*-lowering-*.f64N/A
metadata-evalN/A
*-lowering-*.f6457.8
Applied egg-rr57.8%
+-commutativeN/A
flip-+N/A
/-lowering-/.f64N/A
rem-square-sqrtN/A
sqr-negN/A
--lowering--.f64N/A
associate-*l*N/A
accelerator-lowering-fma.f64N/A
*-commutativeN/A
*-lowering-*.f64N/A
*-lowering-*.f64N/A
*-lowering-*.f64N/A
--lowering--.f64N/A
Applied egg-rr59.2%
associate-/l/N/A
/-lowering-/.f64N/A
associate--l+N/A
*-commutativeN/A
associate-*r*N/A
+-inversesN/A
accelerator-lowering-fma.f64N/A
*-commutativeN/A
*-lowering-*.f64N/A
*-commutativeN/A
*-lowering-*.f64N/A
Applied egg-rr99.3%
Final simplification99.3%
(FPCore (a b c) :precision binary64 (if (<= b 26.5) (* (/ -0.5 a) (- b (sqrt (fma b b (* c (* a -4.0)))))) (- (fma a (/ (* c c) (* b (* b b))) (/ c b)))))
double code(double a, double b, double c) {
double tmp;
if (b <= 26.5) {
tmp = (-0.5 / a) * (b - sqrt(fma(b, b, (c * (a * -4.0)))));
} else {
tmp = -fma(a, ((c * c) / (b * (b * b))), (c / b));
}
return tmp;
}
function code(a, b, c) tmp = 0.0 if (b <= 26.5) tmp = Float64(Float64(-0.5 / a) * Float64(b - sqrt(fma(b, b, Float64(c * Float64(a * -4.0)))))); else tmp = Float64(-fma(a, Float64(Float64(c * c) / Float64(b * Float64(b * b))), Float64(c / b))); end return tmp end
code[a_, b_, c_] := If[LessEqual[b, 26.5], N[(N[(-0.5 / a), $MachinePrecision] * N[(b - N[Sqrt[N[(b * b + N[(c * N[(a * -4.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], (-N[(a * N[(N[(c * c), $MachinePrecision] / N[(b * N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(c / b), $MachinePrecision]), $MachinePrecision])]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq 26.5:\\
\;\;\;\;\frac{-0.5}{a} \cdot \left(b - \sqrt{\mathsf{fma}\left(b, b, c \cdot \left(a \cdot -4\right)\right)}\right)\\
\mathbf{else}:\\
\;\;\;\;-\mathsf{fma}\left(a, \frac{c \cdot c}{b \cdot \left(b \cdot b\right)}, \frac{c}{b}\right)\\
\end{array}
\end{array}
if b < 26.5Initial program 82.4%
Applied egg-rr82.6%
if 26.5 < b Initial program 47.2%
Taylor expanded in b around inf
Simplified94.9%
Taylor expanded in a around 0
+-commutativeN/A
mul-1-negN/A
mul-1-negN/A
distribute-neg-outN/A
neg-lowering-neg.f64N/A
associate-/l*N/A
accelerator-lowering-fma.f64N/A
/-lowering-/.f64N/A
unpow2N/A
*-lowering-*.f64N/A
cube-multN/A
unpow2N/A
*-lowering-*.f64N/A
unpow2N/A
*-lowering-*.f64N/A
/-lowering-/.f6487.9
Simplified87.9%
(FPCore (a b c) :precision binary64 (- (fma a (/ (* c c) (* b (* b b))) (/ c b))))
double code(double a, double b, double c) {
return -fma(a, ((c * c) / (b * (b * b))), (c / b));
}
function code(a, b, c) return Float64(-fma(a, Float64(Float64(c * c) / Float64(b * Float64(b * b))), Float64(c / b))) end
code[a_, b_, c_] := (-N[(a * N[(N[(c * c), $MachinePrecision] / N[(b * N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(c / b), $MachinePrecision]), $MachinePrecision])
\begin{array}{l}
\\
-\mathsf{fma}\left(a, \frac{c \cdot c}{b \cdot \left(b \cdot b\right)}, \frac{c}{b}\right)
\end{array}
Initial program 57.8%
Taylor expanded in b around inf
Simplified89.5%
Taylor expanded in a around 0
+-commutativeN/A
mul-1-negN/A
mul-1-negN/A
distribute-neg-outN/A
neg-lowering-neg.f64N/A
associate-/l*N/A
accelerator-lowering-fma.f64N/A
/-lowering-/.f64N/A
unpow2N/A
*-lowering-*.f64N/A
cube-multN/A
unpow2N/A
*-lowering-*.f64N/A
unpow2N/A
*-lowering-*.f64N/A
/-lowering-/.f6479.3
Simplified79.3%
(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 57.8%
Taylor expanded in b around inf
distribute-lft-outN/A
associate-/l*N/A
mul-1-negN/A
neg-lowering-neg.f64N/A
/-lowering-/.f64N/A
+-commutativeN/A
*-commutativeN/A
associate-/l*N/A
accelerator-lowering-fma.f64N/A
unpow2N/A
*-lowering-*.f64N/A
/-lowering-/.f64N/A
unpow2N/A
*-lowering-*.f6479.3
Simplified79.3%
Final simplification79.3%
(FPCore (a b c) :precision binary64 (/ c (/ (* b b) (- b))))
double code(double a, double b, double c) {
return 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 * b) / -b)
end function
public static double code(double a, double b, double c) {
return c / ((b * b) / -b);
}
def code(a, b, c): return c / ((b * b) / -b)
function code(a, b, c) return Float64(c / Float64(Float64(b * b) / Float64(-b))) end
function tmp = code(a, b, c) tmp = c / ((b * b) / -b); end
code[a_, b_, c_] := N[(c / N[(N[(b * b), $MachinePrecision] / (-b)), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{c}{\frac{b \cdot b}{-b}}
\end{array}
Initial program 57.8%
Taylor expanded in b around inf
mul-1-negN/A
distribute-neg-frac2N/A
/-lowering-/.f64N/A
neg-lowering-neg.f6462.1
Simplified62.1%
neg-sub0N/A
flip--N/A
metadata-evalN/A
neg-sub0N/A
/-lowering-/.f64N/A
distribute-rgt-neg-inN/A
*-lowering-*.f64N/A
neg-lowering-neg.f64N/A
+-lowering-+.f6462.1
Applied egg-rr62.1%
Final simplification62.1%
(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 57.8%
Taylor expanded in b around inf
mul-1-negN/A
distribute-neg-frac2N/A
/-lowering-/.f64N/A
neg-lowering-neg.f6462.1
Simplified62.1%
Final simplification62.1%
(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 57.8%
+-commutativeN/A
unsub-negN/A
div-subN/A
--lowering--.f64N/A
Applied egg-rr57.0%
sub-negN/A
associate-/r*N/A
div-invN/A
metadata-evalN/A
accelerator-lowering-fma.f64N/A
/-lowering-/.f64N/A
sqrt-lowering-sqrt.f64N/A
+-commutativeN/A
*-commutativeN/A
associate-*l*N/A
accelerator-lowering-fma.f64N/A
*-lowering-*.f64N/A
*-lowering-*.f64N/A
distribute-neg-frac2N/A
/-lowering-/.f64N/A
*-commutativeN/A
distribute-lft-neg-inN/A
metadata-evalN/A
Applied egg-rr57.0%
Taylor expanded in c around 0
distribute-rgt-outN/A
metadata-evalN/A
mul0-rgt3.2
Simplified3.2%
herbie shell --seed 2024199
(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)))