
(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 9 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)) (/ -4.0 (+ (sqrt (fma b b (* (* c -4.0) a))) b))))
double code(double a, double b, double c) {
return ((c * a) / (2.0 * a)) * (-4.0 / (sqrt(fma(b, b, ((c * -4.0) * a))) + b));
}
function code(a, b, c) return Float64(Float64(Float64(c * a) / Float64(2.0 * a)) * Float64(-4.0 / Float64(sqrt(fma(b, b, Float64(Float64(c * -4.0) * a))) + b))) end
code[a_, b_, c_] := N[(N[(N[(c * a), $MachinePrecision] / N[(2.0 * a), $MachinePrecision]), $MachinePrecision] * N[(-4.0 / N[(N[Sqrt[N[(b * b + N[(N[(c * -4.0), $MachinePrecision] * a), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] + b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{c \cdot a}{2 \cdot a} \cdot \frac{-4}{\sqrt{\mathsf{fma}\left(b, b, \left(c \cdot -4\right) \cdot a\right)} + b}
\end{array}
Initial program 55.3%
Applied rewrites54.9%
lift-*.f64N/A
lift--.f64N/A
flip--N/A
lift-+.f64N/A
lift-/.f64N/A
lift-*.f64N/A
associate-/r*N/A
Applied rewrites99.3%
lift-/.f64N/A
lift-*.f64N/A
*-rgt-identityN/A
lift-fma.f64N/A
+-rgt-identityN/A
lift-*.f64N/A
associate-*l*N/A
lift-*.f64N/A
times-fracN/A
lower-*.f64N/A
Applied rewrites99.5%
Final simplification99.5%
(FPCore (a b c) :precision binary64 (if (<= b 102.0) (/ (- (sqrt (fma b b (* (* c -4.0) a))) b) (* 2.0 a)) (/ (fma (* c -4.0) a 0.0) (* (fma 4.0 b (* (* (/ c b) a) -4.0)) a))))
double code(double a, double b, double c) {
double tmp;
if (b <= 102.0) {
tmp = (sqrt(fma(b, b, ((c * -4.0) * a))) - b) / (2.0 * a);
} else {
tmp = fma((c * -4.0), a, 0.0) / (fma(4.0, b, (((c / b) * a) * -4.0)) * a);
}
return tmp;
}
function code(a, b, c) tmp = 0.0 if (b <= 102.0) tmp = Float64(Float64(sqrt(fma(b, b, Float64(Float64(c * -4.0) * a))) - b) / Float64(2.0 * a)); else tmp = Float64(fma(Float64(c * -4.0), a, 0.0) / Float64(fma(4.0, b, Float64(Float64(Float64(c / b) * a) * -4.0)) * a)); end return tmp end
code[a_, b_, c_] := If[LessEqual[b, 102.0], N[(N[(N[Sqrt[N[(b * b + N[(N[(c * -4.0), $MachinePrecision] * a), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] / N[(2.0 * a), $MachinePrecision]), $MachinePrecision], N[(N[(N[(c * -4.0), $MachinePrecision] * a + 0.0), $MachinePrecision] / N[(N[(4.0 * b + N[(N[(N[(c / b), $MachinePrecision] * a), $MachinePrecision] * -4.0), $MachinePrecision]), $MachinePrecision] * a), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq 102:\\
\;\;\;\;\frac{\sqrt{\mathsf{fma}\left(b, b, \left(c \cdot -4\right) \cdot a\right)} - b}{2 \cdot a}\\
\mathbf{else}:\\
\;\;\;\;\frac{\mathsf{fma}\left(c \cdot -4, a, 0\right)}{\mathsf{fma}\left(4, b, \left(\frac{c}{b} \cdot a\right) \cdot -4\right) \cdot a}\\
\end{array}
\end{array}
if b < 102Initial program 81.1%
Applied rewrites81.2%
lift-*.f64N/A
*-commutativeN/A
lift--.f64N/A
sub-negN/A
distribute-lft-inN/A
lower-+.f64N/A
Applied rewrites80.4%
lift-+.f64N/A
lift-*.f64N/A
lift-neg.f64N/A
distribute-rgt-neg-outN/A
unsub-negN/A
lift-*.f64N/A
*-commutativeN/A
lift-/.f64N/A
metadata-evalN/A
associate-/r*N/A
lift-*.f64N/A
un-div-invN/A
lift-/.f64N/A
metadata-evalN/A
associate-/r*N/A
lift-*.f64N/A
associate-*l/N/A
metadata-evalN/A
distribute-lft-neg-inN/A
neg-mul-1N/A
remove-double-negN/A
Applied rewrites81.3%
if 102 < b Initial program 44.5%
Applied rewrites43.8%
lift-*.f64N/A
lift--.f64N/A
flip--N/A
lift-+.f64N/A
lift-/.f64N/A
lift-*.f64N/A
associate-/r*N/A
Applied rewrites99.3%
Taylor expanded in a around 0
lower-*.f64N/A
+-commutativeN/A
lower-fma.f64N/A
lower-*.f64N/A
associate-/l*N/A
lower-*.f64N/A
lower-/.f6492.6
Applied rewrites92.6%
Final simplification89.2%
(FPCore (a b c) :precision binary64 (* (/ (* c -4.0) (* (* 2.0 a) (+ (sqrt (fma b b (* (* c -4.0) a))) b))) a))
double code(double a, double b, double c) {
return ((c * -4.0) / ((2.0 * a) * (sqrt(fma(b, b, ((c * -4.0) * a))) + b))) * a;
}
function code(a, b, c) return Float64(Float64(Float64(c * -4.0) / Float64(Float64(2.0 * a) * Float64(sqrt(fma(b, b, Float64(Float64(c * -4.0) * a))) + b))) * a) end
code[a_, b_, c_] := N[(N[(N[(c * -4.0), $MachinePrecision] / N[(N[(2.0 * a), $MachinePrecision] * N[(N[Sqrt[N[(b * b + N[(N[(c * -4.0), $MachinePrecision] * a), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] + b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * a), $MachinePrecision]
\begin{array}{l}
\\
\frac{c \cdot -4}{\left(2 \cdot a\right) \cdot \left(\sqrt{\mathsf{fma}\left(b, b, \left(c \cdot -4\right) \cdot a\right)} + b\right)} \cdot a
\end{array}
Initial program 55.3%
Applied rewrites54.9%
lift-*.f64N/A
lift--.f64N/A
flip--N/A
lift-+.f64N/A
lift-/.f64N/A
lift-*.f64N/A
associate-/r*N/A
Applied rewrites99.3%
lift-/.f64N/A
lift-*.f64N/A
*-rgt-identityN/A
lift-fma.f64N/A
+-rgt-identityN/A
*-commutativeN/A
associate-/l*N/A
lower-*.f64N/A
lower-/.f6499.3
lift-*.f64N/A
*-commutativeN/A
lower-*.f6499.3
lift-*.f64N/A
*-commutativeN/A
lower-*.f6499.3
Applied rewrites99.4%
Final simplification99.4%
(FPCore (a b c) :precision binary64 (if (<= b 102.0) (/ (- (sqrt (fma b b (* (* c -4.0) a))) b) (* 2.0 a)) (/ (fma (* c c) (/ a (* b b)) c) (- b))))
double code(double a, double b, double c) {
double tmp;
if (b <= 102.0) {
tmp = (sqrt(fma(b, b, ((c * -4.0) * a))) - b) / (2.0 * a);
} else {
tmp = fma((c * c), (a / (b * b)), c) / -b;
}
return tmp;
}
function code(a, b, c) tmp = 0.0 if (b <= 102.0) tmp = Float64(Float64(sqrt(fma(b, b, Float64(Float64(c * -4.0) * a))) - b) / Float64(2.0 * a)); else tmp = Float64(fma(Float64(c * c), Float64(a / Float64(b * b)), c) / Float64(-b)); end return tmp end
code[a_, b_, c_] := If[LessEqual[b, 102.0], N[(N[(N[Sqrt[N[(b * b + N[(N[(c * -4.0), $MachinePrecision] * a), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] / N[(2.0 * a), $MachinePrecision]), $MachinePrecision], N[(N[(N[(c * c), $MachinePrecision] * N[(a / N[(b * b), $MachinePrecision]), $MachinePrecision] + c), $MachinePrecision] / (-b)), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq 102:\\
\;\;\;\;\frac{\sqrt{\mathsf{fma}\left(b, b, \left(c \cdot -4\right) \cdot a\right)} - b}{2 \cdot a}\\
\mathbf{else}:\\
\;\;\;\;\frac{\mathsf{fma}\left(c \cdot c, \frac{a}{b \cdot b}, c\right)}{-b}\\
\end{array}
\end{array}
if b < 102Initial program 81.1%
Applied rewrites81.2%
lift-*.f64N/A
*-commutativeN/A
lift--.f64N/A
sub-negN/A
distribute-lft-inN/A
lower-+.f64N/A
Applied rewrites80.4%
lift-+.f64N/A
lift-*.f64N/A
lift-neg.f64N/A
distribute-rgt-neg-outN/A
unsub-negN/A
lift-*.f64N/A
*-commutativeN/A
lift-/.f64N/A
metadata-evalN/A
associate-/r*N/A
lift-*.f64N/A
un-div-invN/A
lift-/.f64N/A
metadata-evalN/A
associate-/r*N/A
lift-*.f64N/A
associate-*l/N/A
metadata-evalN/A
distribute-lft-neg-inN/A
neg-mul-1N/A
remove-double-negN/A
Applied rewrites81.3%
if 102 < b Initial program 44.5%
Taylor expanded in a around 0
+-commutativeN/A
*-commutativeN/A
lower-fma.f64N/A
Applied rewrites97.3%
Taylor expanded in b around inf
distribute-lft-outN/A
associate-*r/N/A
mul-1-negN/A
distribute-neg-frac2N/A
lower-/.f64N/A
+-commutativeN/A
*-commutativeN/A
unpow2N/A
times-fracN/A
lower-fma.f64N/A
lower-/.f64N/A
unpow2N/A
lower-*.f64N/A
lower-/.f64N/A
lower-neg.f6492.5
Applied rewrites92.5%
Applied rewrites92.5%
Final simplification89.1%
(FPCore (a b c) :precision binary64 (if (<= b 102.0) (* (- (sqrt (fma (* c -4.0) a (* b b))) b) (/ 0.5 a)) (/ (fma (* c c) (/ a (* b b)) c) (- b))))
double code(double a, double b, double c) {
double tmp;
if (b <= 102.0) {
tmp = (sqrt(fma((c * -4.0), a, (b * b))) - b) * (0.5 / a);
} else {
tmp = fma((c * c), (a / (b * b)), c) / -b;
}
return tmp;
}
function code(a, b, c) tmp = 0.0 if (b <= 102.0) tmp = Float64(Float64(sqrt(fma(Float64(c * -4.0), a, Float64(b * b))) - b) * Float64(0.5 / a)); else tmp = Float64(fma(Float64(c * c), Float64(a / Float64(b * b)), c) / Float64(-b)); end return tmp end
code[a_, b_, c_] := If[LessEqual[b, 102.0], N[(N[(N[Sqrt[N[(N[(c * -4.0), $MachinePrecision] * a + N[(b * b), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] * N[(0.5 / a), $MachinePrecision]), $MachinePrecision], N[(N[(N[(c * c), $MachinePrecision] * N[(a / N[(b * b), $MachinePrecision]), $MachinePrecision] + c), $MachinePrecision] / (-b)), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq 102:\\
\;\;\;\;\left(\sqrt{\mathsf{fma}\left(c \cdot -4, a, b \cdot b\right)} - b\right) \cdot \frac{0.5}{a}\\
\mathbf{else}:\\
\;\;\;\;\frac{\mathsf{fma}\left(c \cdot c, \frac{a}{b \cdot b}, c\right)}{-b}\\
\end{array}
\end{array}
if b < 102Initial program 81.1%
lift-/.f64N/A
clear-numN/A
associate-/r/N/A
lower-*.f64N/A
lift-*.f64N/A
associate-/r*N/A
metadata-evalN/A
lower-/.f6481.2
lift-+.f64N/A
+-commutativeN/A
lift-neg.f64N/A
unsub-negN/A
lower--.f6481.2
Applied rewrites81.2%
if 102 < b Initial program 44.5%
Taylor expanded in a around 0
+-commutativeN/A
*-commutativeN/A
lower-fma.f64N/A
Applied rewrites97.3%
Taylor expanded in b around inf
distribute-lft-outN/A
associate-*r/N/A
mul-1-negN/A
distribute-neg-frac2N/A
lower-/.f64N/A
+-commutativeN/A
*-commutativeN/A
unpow2N/A
times-fracN/A
lower-fma.f64N/A
lower-/.f64N/A
unpow2N/A
lower-*.f64N/A
lower-/.f64N/A
lower-neg.f6492.5
Applied rewrites92.5%
Applied rewrites92.5%
Final simplification89.1%
(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 55.3%
Taylor expanded in a around 0
+-commutativeN/A
*-commutativeN/A
lower-fma.f64N/A
Applied rewrites91.3%
Taylor expanded in b around inf
distribute-lft-outN/A
associate-*r/N/A
mul-1-negN/A
distribute-neg-frac2N/A
lower-/.f64N/A
+-commutativeN/A
*-commutativeN/A
unpow2N/A
times-fracN/A
lower-fma.f64N/A
lower-/.f64N/A
unpow2N/A
lower-*.f64N/A
lower-/.f64N/A
lower-neg.f6482.9
Applied rewrites82.9%
Applied rewrites82.9%
(FPCore (a b c) :precision binary64 (/ (* (fma (- a) (/ c (* b b)) -1.0) c) b))
double code(double a, double b, double c) {
return (fma(-a, (c / (b * b)), -1.0) * c) / b;
}
function code(a, b, c) return Float64(Float64(fma(Float64(-a), Float64(c / Float64(b * b)), -1.0) * c) / b) end
code[a_, b_, c_] := N[(N[(N[((-a) * N[(c / N[(b * b), $MachinePrecision]), $MachinePrecision] + -1.0), $MachinePrecision] * c), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{\mathsf{fma}\left(-a, \frac{c}{b \cdot b}, -1\right) \cdot c}{b}
\end{array}
Initial program 55.3%
Taylor expanded in b around inf
lower-/.f64N/A
Applied rewrites88.7%
Taylor expanded in c around 0
Applied rewrites82.8%
(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 55.3%
Taylor expanded in c around 0
associate-*r/N/A
lower-/.f64N/A
mul-1-negN/A
lower-neg.f6464.8
Applied rewrites64.8%
(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 55.3%
Applied rewrites54.9%
lift-*.f64N/A
*-commutativeN/A
lift--.f64N/A
sub-negN/A
distribute-lft-inN/A
lower-+.f64N/A
Applied rewrites54.7%
Taylor expanded in c around 0
distribute-rgt-outN/A
metadata-evalN/A
mul0-rgt3.2
Applied rewrites3.2%
herbie shell --seed 2024276
(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)))