
(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 (- (fma -0.25 (/ (pow (* c a) 4.0) (/ (* a (pow b 7.0)) 20.0)) (- (/ (* -2.0 (* c (* (* c c) (* a a)))) (pow b 5.0)) (/ c b))) (/ (* c c) (/ (pow b 3.0) a))))
double code(double a, double b, double c) {
return fma(-0.25, (pow((c * a), 4.0) / ((a * pow(b, 7.0)) / 20.0)), (((-2.0 * (c * ((c * c) * (a * a)))) / pow(b, 5.0)) - (c / b))) - ((c * c) / (pow(b, 3.0) / a));
}
function code(a, b, c) return Float64(fma(-0.25, Float64((Float64(c * a) ^ 4.0) / Float64(Float64(a * (b ^ 7.0)) / 20.0)), Float64(Float64(Float64(-2.0 * Float64(c * Float64(Float64(c * c) * Float64(a * a)))) / (b ^ 5.0)) - Float64(c / b))) - Float64(Float64(c * c) / Float64((b ^ 3.0) / a))) end
code[a_, b_, c_] := N[(N[(-0.25 * N[(N[Power[N[(c * a), $MachinePrecision], 4.0], $MachinePrecision] / N[(N[(a * N[Power[b, 7.0], $MachinePrecision]), $MachinePrecision] / 20.0), $MachinePrecision]), $MachinePrecision] + N[(N[(N[(-2.0 * N[(c * N[(N[(c * c), $MachinePrecision] * N[(a * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[Power[b, 5.0], $MachinePrecision]), $MachinePrecision] - N[(c / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(N[(c * c), $MachinePrecision] / N[(N[Power[b, 3.0], $MachinePrecision] / a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(-0.25, \frac{{\left(c \cdot a\right)}^{4}}{\frac{a \cdot {b}^{7}}{20}}, \frac{-2 \cdot \left(c \cdot \left(\left(c \cdot c\right) \cdot \left(a \cdot a\right)\right)\right)}{{b}^{5}} - \frac{c}{b}\right) - \frac{c \cdot c}{\frac{{b}^{3}}{a}}
\end{array}
Initial program 18.1%
/-rgt-identity18.1%
metadata-eval18.1%
associate-/l*18.1%
associate-*r/18.1%
+-commutative18.1%
unsub-neg18.1%
fma-neg18.1%
associate-*l*18.1%
*-commutative18.1%
distribute-rgt-neg-in18.1%
metadata-eval18.1%
associate-/r*18.1%
metadata-eval18.1%
metadata-eval18.1%
Simplified18.1%
Taylor expanded in b around inf 97.9%
+-commutative97.9%
Simplified97.9%
Taylor expanded in c around 0 97.9%
distribute-rgt-out97.9%
associate-*r*97.9%
associate-/l*97.9%
metadata-eval97.9%
pow-sqr97.9%
unpow297.9%
unpow297.9%
metadata-eval97.9%
pow-sqr97.9%
swap-sqr97.9%
unpow297.9%
swap-sqr97.9%
unpow297.9%
unpow297.9%
swap-sqr97.9%
unpow297.9%
pow-sqr97.9%
metadata-eval97.9%
Simplified97.9%
pow-prod-down97.9%
pow297.9%
unpow297.9%
Applied egg-rr97.9%
Final simplification97.9%
(FPCore (a b c) :precision binary64 (- (- (/ (* -2.0 (* c (pow (* c a) 2.0))) (pow b 5.0)) (/ c b)) (/ (* c c) (/ (pow b 3.0) a))))
double code(double a, double b, double c) {
return (((-2.0 * (c * pow((c * a), 2.0))) / pow(b, 5.0)) - (c / b)) - ((c * c) / (pow(b, 3.0) / a));
}
real(8) function code(a, b, c)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: c
code = ((((-2.0d0) * (c * ((c * a) ** 2.0d0))) / (b ** 5.0d0)) - (c / b)) - ((c * c) / ((b ** 3.0d0) / a))
end function
public static double code(double a, double b, double c) {
return (((-2.0 * (c * Math.pow((c * a), 2.0))) / Math.pow(b, 5.0)) - (c / b)) - ((c * c) / (Math.pow(b, 3.0) / a));
}
def code(a, b, c): return (((-2.0 * (c * math.pow((c * a), 2.0))) / math.pow(b, 5.0)) - (c / b)) - ((c * c) / (math.pow(b, 3.0) / a))
function code(a, b, c) return Float64(Float64(Float64(Float64(-2.0 * Float64(c * (Float64(c * a) ^ 2.0))) / (b ^ 5.0)) - Float64(c / b)) - Float64(Float64(c * c) / Float64((b ^ 3.0) / a))) end
function tmp = code(a, b, c) tmp = (((-2.0 * (c * ((c * a) ^ 2.0))) / (b ^ 5.0)) - (c / b)) - ((c * c) / ((b ^ 3.0) / a)); end
code[a_, b_, c_] := N[(N[(N[(N[(-2.0 * N[(c * N[Power[N[(c * a), $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[Power[b, 5.0], $MachinePrecision]), $MachinePrecision] - N[(c / b), $MachinePrecision]), $MachinePrecision] - N[(N[(c * c), $MachinePrecision] / N[(N[Power[b, 3.0], $MachinePrecision] / a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\left(\frac{-2 \cdot \left(c \cdot {\left(c \cdot a\right)}^{2}\right)}{{b}^{5}} - \frac{c}{b}\right) - \frac{c \cdot c}{\frac{{b}^{3}}{a}}
\end{array}
Initial program 18.1%
/-rgt-identity18.1%
metadata-eval18.1%
associate-/l*18.1%
associate-*r/18.1%
+-commutative18.1%
unsub-neg18.1%
fma-neg18.1%
associate-*l*18.1%
*-commutative18.1%
distribute-rgt-neg-in18.1%
metadata-eval18.1%
associate-/r*18.1%
metadata-eval18.1%
metadata-eval18.1%
Simplified18.1%
Taylor expanded in b around inf 97.0%
+-commutative97.0%
mul-1-neg97.0%
unsub-neg97.0%
Simplified97.0%
Final simplification97.0%
(FPCore (a b c) :precision binary64 (- (/ (- c) b) (/ (* c c) (/ (pow b 3.0) a))))
double code(double a, double b, double c) {
return (-c / b) - ((c * c) / (pow(b, 3.0) / a));
}
real(8) function code(a, b, c)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: c
code = (-c / b) - ((c * c) / ((b ** 3.0d0) / a))
end function
public static double code(double a, double b, double c) {
return (-c / b) - ((c * c) / (Math.pow(b, 3.0) / a));
}
def code(a, b, c): return (-c / b) - ((c * c) / (math.pow(b, 3.0) / a))
function code(a, b, c) return Float64(Float64(Float64(-c) / b) - Float64(Float64(c * c) / Float64((b ^ 3.0) / a))) end
function tmp = code(a, b, c) tmp = (-c / b) - ((c * c) / ((b ^ 3.0) / a)); end
code[a_, b_, c_] := N[(N[((-c) / b), $MachinePrecision] - N[(N[(c * c), $MachinePrecision] / N[(N[Power[b, 3.0], $MachinePrecision] / a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{-c}{b} - \frac{c \cdot c}{\frac{{b}^{3}}{a}}
\end{array}
Initial program 18.1%
/-rgt-identity18.1%
metadata-eval18.1%
associate-/l*18.1%
associate-*r/18.1%
+-commutative18.1%
unsub-neg18.1%
fma-neg18.1%
associate-*l*18.1%
*-commutative18.1%
distribute-rgt-neg-in18.1%
metadata-eval18.1%
associate-/r*18.1%
metadata-eval18.1%
metadata-eval18.1%
Simplified18.1%
Taylor expanded in b around inf 95.4%
+-commutative95.4%
mul-1-neg95.4%
unsub-neg95.4%
mul-1-neg95.4%
associate-/l*95.4%
unpow295.4%
Simplified95.4%
Final simplification95.4%
(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 18.1%
/-rgt-identity18.1%
metadata-eval18.1%
associate-/l*18.1%
associate-*r/18.1%
+-commutative18.1%
unsub-neg18.1%
fma-neg18.1%
associate-*l*18.1%
*-commutative18.1%
distribute-rgt-neg-in18.1%
metadata-eval18.1%
associate-/r*18.1%
metadata-eval18.1%
metadata-eval18.1%
Simplified18.1%
Taylor expanded in b around inf 90.3%
mul-1-neg90.3%
Simplified90.3%
Final simplification90.3%
herbie shell --seed 2023181
(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)))