
(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 5 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) 20.0) (* a (pow b 7.0))) (fma -2.0 (* (* a a) (/ (pow c 3.0) (pow b 5.0))) (- (/ c b)))) (* a (/ (* c c) (pow b 3.0)))))
double code(double a, double b, double c) {
return fma(-0.25, ((pow((c * a), 4.0) * 20.0) / (a * pow(b, 7.0))), fma(-2.0, ((a * a) * (pow(c, 3.0) / pow(b, 5.0))), -(c / b))) - (a * ((c * c) / pow(b, 3.0)));
}
function code(a, b, c) return Float64(fma(-0.25, Float64(Float64((Float64(c * a) ^ 4.0) * 20.0) / Float64(a * (b ^ 7.0))), fma(-2.0, Float64(Float64(a * a) * Float64((c ^ 3.0) / (b ^ 5.0))), Float64(-Float64(c / b)))) - Float64(a * Float64(Float64(c * c) / (b ^ 3.0)))) end
code[a_, b_, c_] := N[(N[(-0.25 * N[(N[(N[Power[N[(c * a), $MachinePrecision], 4.0], $MachinePrecision] * 20.0), $MachinePrecision] / N[(a * N[Power[b, 7.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(-2.0 * N[(N[(a * a), $MachinePrecision] * N[(N[Power[c, 3.0], $MachinePrecision] / N[Power[b, 5.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + (-N[(c / b), $MachinePrecision])), $MachinePrecision]), $MachinePrecision] - N[(a * N[(N[(c * c), $MachinePrecision] / N[Power[b, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(-0.25, \frac{{\left(c \cdot a\right)}^{4} \cdot 20}{a \cdot {b}^{7}}, \mathsf{fma}\left(-2, \left(a \cdot a\right) \cdot \frac{{c}^{3}}{{b}^{5}}, -\frac{c}{b}\right)\right) - a \cdot \frac{c \cdot c}{{b}^{3}}
\end{array}
Initial program 15.0%
neg-sub015.0%
associate-+l-15.0%
sub0-neg15.0%
neg-mul-115.0%
associate-*l/15.0%
*-commutative15.0%
associate-/r*15.0%
/-rgt-identity15.0%
metadata-eval15.0%
Simplified15.0%
fma-udef15.0%
associate-*l*15.0%
*-commutative15.0%
Applied egg-rr15.0%
add-cbrt-cube15.0%
fma-def15.0%
*-commutative15.0%
fma-def15.0%
*-commutative15.0%
fma-def15.0%
*-commutative15.0%
Applied egg-rr15.0%
associate-*l*15.0%
cube-unmult15.0%
Simplified15.0%
Taylor expanded in b around inf 98.5%
Simplified98.5%
Final simplification98.5%
(FPCore (a b c) :precision binary64 (- (- (* -2.0 (* (* a a) (/ (pow c 3.0) (pow b 5.0)))) (/ c b)) (/ (* c c) (/ (pow b 3.0) a))))
double code(double a, double b, double c) {
return ((-2.0 * ((a * a) * (pow(c, 3.0) / 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) * ((a * a) * ((c ** 3.0d0) / (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 * ((a * a) * (Math.pow(c, 3.0) / Math.pow(b, 5.0)))) - (c / b)) - ((c * c) / (Math.pow(b, 3.0) / a));
}
def code(a, b, c): return ((-2.0 * ((a * a) * (math.pow(c, 3.0) / math.pow(b, 5.0)))) - (c / b)) - ((c * c) / (math.pow(b, 3.0) / a))
function code(a, b, c) return Float64(Float64(Float64(-2.0 * Float64(Float64(a * a) * Float64((c ^ 3.0) / (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 * ((a * a) * ((c ^ 3.0) / (b ^ 5.0)))) - (c / b)) - ((c * c) / ((b ^ 3.0) / a)); end
code[a_, b_, c_] := N[(N[(N[(-2.0 * N[(N[(a * a), $MachinePrecision] * N[(N[Power[c, 3.0], $MachinePrecision] / N[Power[b, 5.0], $MachinePrecision]), $MachinePrecision]), $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(-2 \cdot \left(\left(a \cdot a\right) \cdot \frac{{c}^{3}}{{b}^{5}}\right) - \frac{c}{b}\right) - \frac{c \cdot c}{\frac{{b}^{3}}{a}}
\end{array}
Initial program 15.0%
neg-sub015.0%
associate-+l-15.0%
sub0-neg15.0%
neg-mul-115.0%
associate-*l/15.0%
*-commutative15.0%
associate-/r*15.0%
/-rgt-identity15.0%
metadata-eval15.0%
Simplified15.0%
fma-udef15.0%
associate-*l*15.0%
*-commutative15.0%
Applied egg-rr15.0%
Taylor expanded in b around inf 97.7%
+-commutative97.7%
mul-1-neg97.7%
unpow297.7%
unsub-neg97.7%
+-commutative97.7%
mul-1-neg97.7%
unsub-neg97.7%
associate-/l*97.7%
associate-/r/97.7%
unpow297.7%
Simplified97.7%
Final simplification97.7%
(FPCore (a b c) :precision binary64 (- (/ (* (* c a) (- c)) (pow b 3.0)) (/ c b)))
double code(double a, double b, double c) {
return (((c * a) * -c) / pow(b, 3.0)) - (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 = (((c * a) * -c) / (b ** 3.0d0)) - (c / b)
end function
public static double code(double a, double b, double c) {
return (((c * a) * -c) / Math.pow(b, 3.0)) - (c / b);
}
def code(a, b, c): return (((c * a) * -c) / math.pow(b, 3.0)) - (c / b)
function code(a, b, c) return Float64(Float64(Float64(Float64(c * a) * Float64(-c)) / (b ^ 3.0)) - Float64(c / b)) end
function tmp = code(a, b, c) tmp = (((c * a) * -c) / (b ^ 3.0)) - (c / b); end
code[a_, b_, c_] := N[(N[(N[(N[(c * a), $MachinePrecision] * (-c)), $MachinePrecision] / N[Power[b, 3.0], $MachinePrecision]), $MachinePrecision] - N[(c / b), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\left(c \cdot a\right) \cdot \left(-c\right)}{{b}^{3}} - \frac{c}{b}
\end{array}
Initial program 15.0%
neg-sub015.0%
associate-+l-15.0%
sub0-neg15.0%
neg-mul-115.0%
associate-*l/15.0%
*-commutative15.0%
associate-/r*15.0%
/-rgt-identity15.0%
metadata-eval15.0%
Simplified15.0%
Taylor expanded in b around inf 96.4%
distribute-lft-out96.4%
mul-1-neg96.4%
+-commutative96.4%
unpow296.4%
associate-*l*96.4%
Simplified96.4%
Final simplification96.4%
(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 15.0%
neg-sub015.0%
associate-+l-15.0%
sub0-neg15.0%
neg-mul-115.0%
associate-*l/15.0%
*-commutative15.0%
associate-/r*15.0%
/-rgt-identity15.0%
metadata-eval15.0%
Simplified15.0%
Taylor expanded in b around inf 92.4%
associate-*r/92.4%
neg-mul-192.4%
Simplified92.4%
Final simplification92.4%
(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 15.0%
add-log-exp8.9%
neg-mul-18.9%
fma-def8.9%
*-commutative8.9%
*-commutative8.9%
Applied egg-rr8.9%
Taylor expanded in c around 0 3.3%
associate-*r/3.3%
distribute-rgt1-in3.3%
metadata-eval3.3%
mul0-lft3.3%
metadata-eval3.3%
Simplified3.3%
Final simplification3.3%
herbie shell --seed 2023240
(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)))