
(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 4 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 (/ (/ (* 4.0 (* c a)) (- (- b) (sqrt (* c (+ (/ (pow b 2.0) c) (* a -4.0)))))) (* a 2.0)))
double code(double a, double b, double c) {
return ((4.0 * (c * a)) / (-b - sqrt((c * ((pow(b, 2.0) / c) + (a * -4.0)))))) / (a * 2.0);
}
real(8) function code(a, b, c)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: c
code = ((4.0d0 * (c * a)) / (-b - sqrt((c * (((b ** 2.0d0) / c) + (a * (-4.0d0))))))) / (a * 2.0d0)
end function
public static double code(double a, double b, double c) {
return ((4.0 * (c * a)) / (-b - Math.sqrt((c * ((Math.pow(b, 2.0) / c) + (a * -4.0)))))) / (a * 2.0);
}
def code(a, b, c): return ((4.0 * (c * a)) / (-b - math.sqrt((c * ((math.pow(b, 2.0) / c) + (a * -4.0)))))) / (a * 2.0)
function code(a, b, c) return Float64(Float64(Float64(4.0 * Float64(c * a)) / Float64(Float64(-b) - sqrt(Float64(c * Float64(Float64((b ^ 2.0) / c) + Float64(a * -4.0)))))) / Float64(a * 2.0)) end
function tmp = code(a, b, c) tmp = ((4.0 * (c * a)) / (-b - sqrt((c * (((b ^ 2.0) / c) + (a * -4.0)))))) / (a * 2.0); end
code[a_, b_, c_] := N[(N[(N[(4.0 * N[(c * a), $MachinePrecision]), $MachinePrecision] / N[((-b) - N[Sqrt[N[(c * N[(N[(N[Power[b, 2.0], $MachinePrecision] / c), $MachinePrecision] + N[(a * -4.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(a * 2.0), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\frac{4 \cdot \left(c \cdot a\right)}{\left(-b\right) - \sqrt{c \cdot \left(\frac{{b}^{2}}{c} + a \cdot -4\right)}}}{a \cdot 2}
\end{array}
Initial program 16.7%
*-commutative16.7%
Simplified16.7%
Taylor expanded in c around inf 16.6%
flip-+16.5%
pow216.5%
add-sqr-sqrt17.0%
cancel-sign-sub-inv17.0%
metadata-eval17.0%
cancel-sign-sub-inv17.0%
metadata-eval17.0%
Applied egg-rr17.0%
Taylor expanded in b around 0 99.4%
*-commutative99.4%
Simplified99.4%
Final simplification99.4%
(FPCore (a b c) :precision binary64 (/ (- (* (- a) (pow (/ c b) 2.0)) c) b))
double code(double a, double b, double c) {
return ((-a * pow((c / b), 2.0)) - 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 = ((-a * ((c / b) ** 2.0d0)) - c) / b
end function
public static double code(double a, double b, double c) {
return ((-a * Math.pow((c / b), 2.0)) - c) / b;
}
def code(a, b, c): return ((-a * math.pow((c / b), 2.0)) - c) / b
function code(a, b, c) return Float64(Float64(Float64(Float64(-a) * (Float64(c / b) ^ 2.0)) - c) / b) end
function tmp = code(a, b, c) tmp = ((-a * ((c / b) ^ 2.0)) - c) / b; end
code[a_, b_, c_] := N[(N[(N[((-a) * N[Power[N[(c / b), $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision] - c), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{\left(-a\right) \cdot {\left(\frac{c}{b}\right)}^{2} - c}{b}
\end{array}
Initial program 16.7%
*-commutative16.7%
Simplified16.7%
Taylor expanded in c around 0 96.1%
associate-*r/96.1%
neg-mul-196.1%
distribute-rgt-neg-in96.1%
Simplified96.1%
Taylor expanded in a around inf 95.8%
pow195.8%
mul-1-neg95.8%
Applied egg-rr95.8%
unpow195.8%
distribute-neg-frac295.8%
Simplified95.8%
Taylor expanded in b around inf 96.4%
neg-mul-196.4%
+-commutative96.4%
unsub-neg96.4%
mul-1-neg96.4%
associate-/l*96.4%
unpow296.4%
unpow296.4%
times-frac96.4%
sqr-neg96.4%
unpow296.4%
distribute-lft-neg-in96.4%
unpow296.4%
sqr-neg96.4%
unpow296.4%
Simplified96.4%
(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(c / Float64(-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 16.7%
*-commutative16.7%
Simplified16.7%
Taylor expanded in b around inf 91.4%
associate-*r/91.4%
mul-1-neg91.4%
Simplified91.4%
Final simplification91.4%
(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 16.7%
*-commutative16.7%
Simplified16.7%
Taylor expanded in c around 0 96.1%
associate-*r/96.1%
neg-mul-196.1%
distribute-rgt-neg-in96.1%
Simplified96.1%
Taylor expanded in a around 0 91.1%
expm1-log1p-u81.2%
expm1-undefine19.6%
Applied egg-rr19.6%
sub-neg19.6%
log1p-undefine19.6%
rem-exp-log29.6%
associate-*r/29.6%
*-commutative29.6%
associate-*r/29.6%
mul-1-neg29.6%
unsub-neg29.6%
metadata-eval29.6%
Simplified29.6%
Taylor expanded in c around 0 3.3%
Final simplification3.3%
herbie shell --seed 2024092
(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)))