
(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
(if (<= b -5.2e+47)
(- (/ c b) (/ b a))
(if (<= b 4.5e-26)
(/ (- (sqrt (- (* b b) (* c (* 4.0 a)))) b) (* a 2.0))
(/ (- c) b))))
double code(double a, double b, double c) {
double tmp;
if (b <= -5.2e+47) {
tmp = (c / b) - (b / a);
} else if (b <= 4.5e-26) {
tmp = (sqrt(((b * b) - (c * (4.0 * a)))) - b) / (a * 2.0);
} else {
tmp = -c / b;
}
return tmp;
}
real(8) function code(a, b, c)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: c
real(8) :: tmp
if (b <= (-5.2d+47)) then
tmp = (c / b) - (b / a)
else if (b <= 4.5d-26) then
tmp = (sqrt(((b * b) - (c * (4.0d0 * a)))) - b) / (a * 2.0d0)
else
tmp = -c / b
end if
code = tmp
end function
public static double code(double a, double b, double c) {
double tmp;
if (b <= -5.2e+47) {
tmp = (c / b) - (b / a);
} else if (b <= 4.5e-26) {
tmp = (Math.sqrt(((b * b) - (c * (4.0 * a)))) - b) / (a * 2.0);
} else {
tmp = -c / b;
}
return tmp;
}
def code(a, b, c): tmp = 0 if b <= -5.2e+47: tmp = (c / b) - (b / a) elif b <= 4.5e-26: tmp = (math.sqrt(((b * b) - (c * (4.0 * a)))) - b) / (a * 2.0) else: tmp = -c / b return tmp
function code(a, b, c) tmp = 0.0 if (b <= -5.2e+47) tmp = Float64(Float64(c / b) - Float64(b / a)); elseif (b <= 4.5e-26) tmp = Float64(Float64(sqrt(Float64(Float64(b * b) - Float64(c * Float64(4.0 * a)))) - b) / Float64(a * 2.0)); else tmp = Float64(Float64(-c) / b); end return tmp end
function tmp_2 = code(a, b, c) tmp = 0.0; if (b <= -5.2e+47) tmp = (c / b) - (b / a); elseif (b <= 4.5e-26) tmp = (sqrt(((b * b) - (c * (4.0 * a)))) - b) / (a * 2.0); else tmp = -c / b; end tmp_2 = tmp; end
code[a_, b_, c_] := If[LessEqual[b, -5.2e+47], N[(N[(c / b), $MachinePrecision] - N[(b / a), $MachinePrecision]), $MachinePrecision], If[LessEqual[b, 4.5e-26], N[(N[(N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(c * N[(4.0 * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] / N[(a * 2.0), $MachinePrecision]), $MachinePrecision], N[((-c) / b), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq -5.2 \cdot 10^{+47}:\\
\;\;\;\;\frac{c}{b} - \frac{b}{a}\\
\mathbf{elif}\;b \leq 4.5 \cdot 10^{-26}:\\
\;\;\;\;\frac{\sqrt{b \cdot b - c \cdot \left(4 \cdot a\right)} - b}{a \cdot 2}\\
\mathbf{else}:\\
\;\;\;\;\frac{-c}{b}\\
\end{array}
\end{array}
if b < -5.20000000000000007e47Initial program 71.1%
Taylor expanded in b around -inf
mul-1-negN/A
distribute-rgt-inN/A
distribute-neg-inN/A
associate-*l/N/A
*-lft-identityN/A
*-commutativeN/A
mul-1-negN/A
distribute-rgt-neg-outN/A
remove-double-negN/A
lower-fma.f64N/A
lower-/.f64N/A
unpow2N/A
lower-*.f64N/A
distribute-neg-frac2N/A
mul-1-negN/A
lower-/.f64N/A
mul-1-negN/A
lower-neg.f6498.8
Applied rewrites98.8%
Applied rewrites98.8%
if -5.20000000000000007e47 < b < 4.4999999999999999e-26Initial program 79.8%
if 4.4999999999999999e-26 < b Initial program 13.4%
Taylor expanded in b around inf
mul-1-negN/A
distribute-neg-frac2N/A
lower-/.f64N/A
lower-neg.f6490.5
Applied rewrites90.5%
Final simplification88.5%
(FPCore (a b c)
:precision binary64
(if (<= b -5.2e+47)
(- (/ c b) (/ b a))
(if (<= b 4.5e-26)
(* (/ -0.5 a) (- b (sqrt (fma a (* c -4.0) (* b b)))))
(/ (- c) b))))
double code(double a, double b, double c) {
double tmp;
if (b <= -5.2e+47) {
tmp = (c / b) - (b / a);
} else if (b <= 4.5e-26) {
tmp = (-0.5 / a) * (b - sqrt(fma(a, (c * -4.0), (b * b))));
} else {
tmp = -c / b;
}
return tmp;
}
function code(a, b, c) tmp = 0.0 if (b <= -5.2e+47) tmp = Float64(Float64(c / b) - Float64(b / a)); elseif (b <= 4.5e-26) tmp = Float64(Float64(-0.5 / a) * Float64(b - sqrt(fma(a, Float64(c * -4.0), Float64(b * b))))); else tmp = Float64(Float64(-c) / b); end return tmp end
code[a_, b_, c_] := If[LessEqual[b, -5.2e+47], N[(N[(c / b), $MachinePrecision] - N[(b / a), $MachinePrecision]), $MachinePrecision], If[LessEqual[b, 4.5e-26], N[(N[(-0.5 / a), $MachinePrecision] * N[(b - N[Sqrt[N[(a * N[(c * -4.0), $MachinePrecision] + N[(b * b), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[((-c) / b), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq -5.2 \cdot 10^{+47}:\\
\;\;\;\;\frac{c}{b} - \frac{b}{a}\\
\mathbf{elif}\;b \leq 4.5 \cdot 10^{-26}:\\
\;\;\;\;\frac{-0.5}{a} \cdot \left(b - \sqrt{\mathsf{fma}\left(a, c \cdot -4, b \cdot b\right)}\right)\\
\mathbf{else}:\\
\;\;\;\;\frac{-c}{b}\\
\end{array}
\end{array}
if b < -5.20000000000000007e47Initial program 62.6%
Taylor expanded in b around -inf
mul-1-negN/A
distribute-rgt-inN/A
distribute-neg-inN/A
associate-*l/N/A
*-lft-identityN/A
*-commutativeN/A
mul-1-negN/A
distribute-rgt-neg-outN/A
remove-double-negN/A
lower-fma.f64N/A
lower-/.f64N/A
unpow2N/A
lower-*.f64N/A
distribute-neg-frac2N/A
mul-1-negN/A
lower-/.f64N/A
mul-1-negN/A
lower-neg.f6493.3
Applied rewrites93.3%
Applied rewrites93.5%
if -5.20000000000000007e47 < b < 4.4999999999999999e-26Initial program 76.6%
Applied rewrites76.4%
if 4.4999999999999999e-26 < b Initial program 14.7%
Taylor expanded in b around inf
mul-1-negN/A
distribute-neg-frac2N/A
lower-/.f64N/A
lower-neg.f6489.4
Applied rewrites89.4%
Final simplification85.1%
(FPCore (a b c)
:precision binary64
(let* ((t_0 (sqrt (- (* b b) (* (* 4.0 a) c)))))
(if (< b 0.0)
(/ (+ (- b) t_0) (* 2.0 a))
(/ c (* a (/ (- (- b) t_0) (* 2.0 a)))))))
double code(double a, double b, double c) {
double t_0 = sqrt(((b * b) - ((4.0 * a) * c)));
double tmp;
if (b < 0.0) {
tmp = (-b + t_0) / (2.0 * a);
} else {
tmp = c / (a * ((-b - t_0) / (2.0 * a)));
}
return tmp;
}
real(8) function code(a, b, c)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: c
real(8) :: t_0
real(8) :: tmp
t_0 = sqrt(((b * b) - ((4.0d0 * a) * c)))
if (b < 0.0d0) then
tmp = (-b + t_0) / (2.0d0 * a)
else
tmp = c / (a * ((-b - t_0) / (2.0d0 * a)))
end if
code = tmp
end function
public static double code(double a, double b, double c) {
double t_0 = Math.sqrt(((b * b) - ((4.0 * a) * c)));
double tmp;
if (b < 0.0) {
tmp = (-b + t_0) / (2.0 * a);
} else {
tmp = c / (a * ((-b - t_0) / (2.0 * a)));
}
return tmp;
}
def code(a, b, c): t_0 = math.sqrt(((b * b) - ((4.0 * a) * c))) tmp = 0 if b < 0.0: tmp = (-b + t_0) / (2.0 * a) else: tmp = c / (a * ((-b - t_0) / (2.0 * a))) return tmp
function code(a, b, c) t_0 = sqrt(Float64(Float64(b * b) - Float64(Float64(4.0 * a) * c))) tmp = 0.0 if (b < 0.0) tmp = Float64(Float64(Float64(-b) + t_0) / Float64(2.0 * a)); else tmp = Float64(c / Float64(a * Float64(Float64(Float64(-b) - t_0) / Float64(2.0 * a)))); end return tmp end
function tmp_2 = code(a, b, c) t_0 = sqrt(((b * b) - ((4.0 * a) * c))); tmp = 0.0; if (b < 0.0) tmp = (-b + t_0) / (2.0 * a); else tmp = c / (a * ((-b - t_0) / (2.0 * a))); end tmp_2 = tmp; end
code[a_, b_, c_] := Block[{t$95$0 = N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(N[(4.0 * a), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]}, If[Less[b, 0.0], N[(N[((-b) + t$95$0), $MachinePrecision] / N[(2.0 * a), $MachinePrecision]), $MachinePrecision], N[(c / N[(a * N[(N[((-b) - t$95$0), $MachinePrecision] / N[(2.0 * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}\\
\mathbf{if}\;b < 0:\\
\;\;\;\;\frac{\left(-b\right) + t\_0}{2 \cdot a}\\
\mathbf{else}:\\
\;\;\;\;\frac{c}{a \cdot \frac{\left(-b\right) - t\_0}{2 \cdot a}}\\
\end{array}
\end{array}
herbie shell --seed 2024219
(FPCore (a b c)
:name "The quadratic formula (r1)"
:precision binary64
:alt
(! :herbie-platform default (let ((d (- (* b b) (* (* 4 a) c)))) (let ((r1 (/ (+ (- b) (sqrt d)) (* 2 a)))) (let ((r2 (/ (- (- b) (sqrt d)) (* 2 a)))) (if (< b 0) r1 (/ c (* a r2)))))))
(/ (+ (- b) (sqrt (- (* b b) (* (* 4.0 a) c)))) (* 2.0 a)))