
(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
(let* ((t_0 (sqrt (* c a))))
(*
4.0
(/ c (* 2.0 (- (- b) (sqrt (* (fma 2.0 t_0 b) (fma -2.0 t_0 b)))))))))
double code(double a, double b, double c) {
double t_0 = sqrt((c * a));
return 4.0 * (c / (2.0 * (-b - sqrt((fma(2.0, t_0, b) * fma(-2.0, t_0, b))))));
}
function code(a, b, c) t_0 = sqrt(Float64(c * a)) return Float64(4.0 * Float64(c / Float64(2.0 * Float64(Float64(-b) - sqrt(Float64(fma(2.0, t_0, b) * fma(-2.0, t_0, b))))))) end
code[a_, b_, c_] := Block[{t$95$0 = N[Sqrt[N[(c * a), $MachinePrecision]], $MachinePrecision]}, N[(4.0 * N[(c / N[(2.0 * N[((-b) - N[Sqrt[N[(N[(2.0 * t$95$0 + b), $MachinePrecision] * N[(-2.0 * t$95$0 + b), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sqrt{c \cdot a}\\
4 \cdot \frac{c}{2 \cdot \left(\left(-b\right) - \sqrt{\mathsf{fma}\left(2, t\_0, b\right) \cdot \mathsf{fma}\left(-2, t\_0, b\right)}\right)}
\end{array}
\end{array}
Initial program 14.6%
*-commutative14.6%
Simplified14.6%
add-sqr-sqrt14.6%
difference-of-squares14.8%
associate-*l*14.8%
sqrt-prod14.8%
metadata-eval14.8%
associate-*l*14.8%
sqrt-prod14.8%
metadata-eval14.8%
Applied egg-rr14.8%
*-commutative14.8%
cancel-sign-sub-inv14.8%
metadata-eval14.8%
Simplified14.8%
flip-+14.8%
pow214.8%
add-sqr-sqrt15.2%
+-commutative15.2%
*-commutative15.2%
fma-define15.2%
+-commutative15.2%
fma-define15.2%
Applied egg-rr15.2%
unpow215.2%
sqr-neg15.2%
unpow215.2%
fma-undefine15.2%
*-commutative15.2%
fma-define15.2%
fma-undefine15.2%
*-commutative15.2%
fma-define15.2%
Simplified15.2%
Taylor expanded in b around 0 99.5%
div-inv99.3%
Applied egg-rr99.3%
*-commutative99.3%
times-frac99.4%
*-lft-identity99.4%
associate-/l*99.4%
associate-*l*99.4%
times-frac99.9%
*-inverses99.9%
Simplified99.9%
Final simplification99.9%
(FPCore (a b c) :precision binary64 (- (/ c (- b)) (* a (/ (pow c 2.0) (pow b 3.0)))))
double code(double a, double b, double c) {
return (c / -b) - (a * (pow(c, 2.0) / pow(b, 3.0)));
}
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) - (a * ((c ** 2.0d0) / (b ** 3.0d0)))
end function
public static double code(double a, double b, double c) {
return (c / -b) - (a * (Math.pow(c, 2.0) / Math.pow(b, 3.0)));
}
def code(a, b, c): return (c / -b) - (a * (math.pow(c, 2.0) / math.pow(b, 3.0)))
function code(a, b, c) return Float64(Float64(c / Float64(-b)) - Float64(a * Float64((c ^ 2.0) / (b ^ 3.0)))) end
function tmp = code(a, b, c) tmp = (c / -b) - (a * ((c ^ 2.0) / (b ^ 3.0))); end
code[a_, b_, c_] := N[(N[(c / (-b)), $MachinePrecision] - N[(a * N[(N[Power[c, 2.0], $MachinePrecision] / N[Power[b, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{c}{-b} - a \cdot \frac{{c}^{2}}{{b}^{3}}
\end{array}
Initial program 14.6%
*-commutative14.6%
Simplified14.6%
Taylor expanded in b around inf 95.1%
Taylor expanded in a around 0 95.5%
mul-1-neg95.5%
unsub-neg95.5%
associate-*r/95.5%
mul-1-neg95.5%
associate-/l*95.5%
Simplified95.5%
Final simplification95.5%
(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 14.6%
*-commutative14.6%
Simplified14.6%
Taylor expanded in b around inf 92.3%
mul-1-neg92.3%
distribute-neg-frac92.3%
Simplified92.3%
Final simplification92.3%
(FPCore (a b c) :precision binary64 (/ 0.0 a))
double code(double a, double b, double c) {
return 0.0 / a;
}
real(8) function code(a, b, c)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: c
code = 0.0d0 / a
end function
public static double code(double a, double b, double c) {
return 0.0 / a;
}
def code(a, b, c): return 0.0 / a
function code(a, b, c) return Float64(0.0 / a) end
function tmp = code(a, b, c) tmp = 0.0 / a; end
code[a_, b_, c_] := N[(0.0 / a), $MachinePrecision]
\begin{array}{l}
\\
\frac{0}{a}
\end{array}
Initial program 14.6%
*-commutative14.6%
Simplified14.6%
add-sqr-sqrt14.6%
difference-of-squares14.8%
associate-*l*14.8%
sqrt-prod14.8%
metadata-eval14.8%
associate-*l*14.8%
sqrt-prod14.8%
metadata-eval14.8%
Applied egg-rr14.8%
*-commutative14.8%
cancel-sign-sub-inv14.8%
metadata-eval14.8%
Simplified14.8%
Taylor expanded in b around inf 3.3%
associate-*r/3.3%
distribute-rgt-out3.3%
metadata-eval3.3%
mul0-rgt3.3%
metadata-eval3.3%
Simplified3.3%
Final simplification3.3%
herbie shell --seed 2024050
(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)))