
(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(4.0 * Float64(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[(4.0 * N[(a * c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / N[(2.0 * a), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}{2 \cdot a}
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 8 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(4.0 * Float64(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[(4.0 * N[(a * c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / N[(2.0 * a), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}{2 \cdot a}
\end{array}
(FPCore (a b c)
:precision binary64
(if (<= b -4.3e-39)
(/ (- c) b)
(if (<= b 2e+122)
(* -0.5 (/ (+ b (sqrt (fma a (* c -4.0) (* b b)))) a))
(- (/ c b) (/ b a)))))
double code(double a, double b, double c) {
double tmp;
if (b <= -4.3e-39) {
tmp = -c / b;
} else if (b <= 2e+122) {
tmp = -0.5 * ((b + sqrt(fma(a, (c * -4.0), (b * b)))) / a);
} else {
tmp = (c / b) - (b / a);
}
return tmp;
}
function code(a, b, c) tmp = 0.0 if (b <= -4.3e-39) tmp = Float64(Float64(-c) / b); elseif (b <= 2e+122) tmp = Float64(-0.5 * Float64(Float64(b + sqrt(fma(a, Float64(c * -4.0), Float64(b * b)))) / a)); else tmp = Float64(Float64(c / b) - Float64(b / a)); end return tmp end
code[a_, b_, c_] := If[LessEqual[b, -4.3e-39], N[((-c) / b), $MachinePrecision], If[LessEqual[b, 2e+122], N[(-0.5 * N[(N[(b + N[Sqrt[N[(a * N[(c * -4.0), $MachinePrecision] + N[(b * b), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / a), $MachinePrecision]), $MachinePrecision], N[(N[(c / b), $MachinePrecision] - N[(b / a), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq -4.3 \cdot 10^{-39}:\\
\;\;\;\;\frac{-c}{b}\\
\mathbf{elif}\;b \leq 2 \cdot 10^{+122}:\\
\;\;\;\;-0.5 \cdot \frac{b + \sqrt{\mathsf{fma}\left(a, c \cdot -4, b \cdot b\right)}}{a}\\
\mathbf{else}:\\
\;\;\;\;\frac{c}{b} - \frac{b}{a}\\
\end{array}
\end{array}
(FPCore (a b c)
:precision binary64
(if (<= b -6.9e-40)
(/ (- c) b)
(if (<= b 5e+119)
(/ (- (- b) (sqrt (- (* b b) (* 4.0 (* c a))))) (* a 2.0))
(- (/ c b) (/ b a)))))
double code(double a, double b, double c) {
double tmp;
if (b <= -6.9e-40) {
tmp = -c / b;
} else if (b <= 5e+119) {
tmp = (-b - sqrt(((b * b) - (4.0 * (c * a))))) / (a * 2.0);
} else {
tmp = (c / b) - (b / 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) :: tmp
if (b <= (-6.9d-40)) then
tmp = -c / b
else if (b <= 5d+119) then
tmp = (-b - sqrt(((b * b) - (4.0d0 * (c * a))))) / (a * 2.0d0)
else
tmp = (c / b) - (b / a)
end if
code = tmp
end function
public static double code(double a, double b, double c) {
double tmp;
if (b <= -6.9e-40) {
tmp = -c / b;
} else if (b <= 5e+119) {
tmp = (-b - Math.sqrt(((b * b) - (4.0 * (c * a))))) / (a * 2.0);
} else {
tmp = (c / b) - (b / a);
}
return tmp;
}
def code(a, b, c): tmp = 0 if b <= -6.9e-40: tmp = -c / b elif b <= 5e+119: tmp = (-b - math.sqrt(((b * b) - (4.0 * (c * a))))) / (a * 2.0) else: tmp = (c / b) - (b / a) return tmp
function code(a, b, c) tmp = 0.0 if (b <= -6.9e-40) tmp = Float64(Float64(-c) / b); elseif (b <= 5e+119) tmp = Float64(Float64(Float64(-b) - sqrt(Float64(Float64(b * b) - Float64(4.0 * Float64(c * a))))) / Float64(a * 2.0)); else tmp = Float64(Float64(c / b) - Float64(b / a)); end return tmp end
function tmp_2 = code(a, b, c) tmp = 0.0; if (b <= -6.9e-40) tmp = -c / b; elseif (b <= 5e+119) tmp = (-b - sqrt(((b * b) - (4.0 * (c * a))))) / (a * 2.0); else tmp = (c / b) - (b / a); end tmp_2 = tmp; end
code[a_, b_, c_] := If[LessEqual[b, -6.9e-40], N[((-c) / b), $MachinePrecision], If[LessEqual[b, 5e+119], N[(N[((-b) - N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(4.0 * N[(c * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / N[(a * 2.0), $MachinePrecision]), $MachinePrecision], N[(N[(c / b), $MachinePrecision] - N[(b / a), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq -6.9 \cdot 10^{-40}:\\
\;\;\;\;\frac{-c}{b}\\
\mathbf{elif}\;b \leq 5 \cdot 10^{+119}:\\
\;\;\;\;\frac{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(c \cdot a\right)}}{a \cdot 2}\\
\mathbf{else}:\\
\;\;\;\;\frac{c}{b} - \frac{b}{a}\\
\end{array}
\end{array}
(FPCore (a b c)
:precision binary64
(if (<= b -3.3e-37)
(/ (- c) b)
(if (<= b 6.8e-7)
(* -0.5 (/ (+ b (pow (* a (* c -4.0)) 0.5)) a))
(- (/ c b) (/ b a)))))
double code(double a, double b, double c) {
double tmp;
if (b <= -3.3e-37) {
tmp = -c / b;
} else if (b <= 6.8e-7) {
tmp = -0.5 * ((b + pow((a * (c * -4.0)), 0.5)) / a);
} else {
tmp = (c / b) - (b / 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) :: tmp
if (b <= (-3.3d-37)) then
tmp = -c / b
else if (b <= 6.8d-7) then
tmp = (-0.5d0) * ((b + ((a * (c * (-4.0d0))) ** 0.5d0)) / a)
else
tmp = (c / b) - (b / a)
end if
code = tmp
end function
public static double code(double a, double b, double c) {
double tmp;
if (b <= -3.3e-37) {
tmp = -c / b;
} else if (b <= 6.8e-7) {
tmp = -0.5 * ((b + Math.pow((a * (c * -4.0)), 0.5)) / a);
} else {
tmp = (c / b) - (b / a);
}
return tmp;
}
def code(a, b, c): tmp = 0 if b <= -3.3e-37: tmp = -c / b elif b <= 6.8e-7: tmp = -0.5 * ((b + math.pow((a * (c * -4.0)), 0.5)) / a) else: tmp = (c / b) - (b / a) return tmp
function code(a, b, c) tmp = 0.0 if (b <= -3.3e-37) tmp = Float64(Float64(-c) / b); elseif (b <= 6.8e-7) tmp = Float64(-0.5 * Float64(Float64(b + (Float64(a * Float64(c * -4.0)) ^ 0.5)) / a)); else tmp = Float64(Float64(c / b) - Float64(b / a)); end return tmp end
function tmp_2 = code(a, b, c) tmp = 0.0; if (b <= -3.3e-37) tmp = -c / b; elseif (b <= 6.8e-7) tmp = -0.5 * ((b + ((a * (c * -4.0)) ^ 0.5)) / a); else tmp = (c / b) - (b / a); end tmp_2 = tmp; end
code[a_, b_, c_] := If[LessEqual[b, -3.3e-37], N[((-c) / b), $MachinePrecision], If[LessEqual[b, 6.8e-7], N[(-0.5 * N[(N[(b + N[Power[N[(a * N[(c * -4.0), $MachinePrecision]), $MachinePrecision], 0.5], $MachinePrecision]), $MachinePrecision] / a), $MachinePrecision]), $MachinePrecision], N[(N[(c / b), $MachinePrecision] - N[(b / a), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq -3.3 \cdot 10^{-37}:\\
\;\;\;\;\frac{-c}{b}\\
\mathbf{elif}\;b \leq 6.8 \cdot 10^{-7}:\\
\;\;\;\;-0.5 \cdot \frac{b + {\left(a \cdot \left(c \cdot -4\right)\right)}^{0.5}}{a}\\
\mathbf{else}:\\
\;\;\;\;\frac{c}{b} - \frac{b}{a}\\
\end{array}
\end{array}
(FPCore (a b c)
:precision binary64
(if (<= b -3.1e-38)
(/ (- c) b)
(if (<= b 1.7e-6)
(* -0.5 (/ (+ b (sqrt (* a (* c -4.0)))) a))
(- (/ c b) (/ b a)))))
double code(double a, double b, double c) {
double tmp;
if (b <= -3.1e-38) {
tmp = -c / b;
} else if (b <= 1.7e-6) {
tmp = -0.5 * ((b + sqrt((a * (c * -4.0)))) / a);
} else {
tmp = (c / b) - (b / 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) :: tmp
if (b <= (-3.1d-38)) then
tmp = -c / b
else if (b <= 1.7d-6) then
tmp = (-0.5d0) * ((b + sqrt((a * (c * (-4.0d0))))) / a)
else
tmp = (c / b) - (b / a)
end if
code = tmp
end function
public static double code(double a, double b, double c) {
double tmp;
if (b <= -3.1e-38) {
tmp = -c / b;
} else if (b <= 1.7e-6) {
tmp = -0.5 * ((b + Math.sqrt((a * (c * -4.0)))) / a);
} else {
tmp = (c / b) - (b / a);
}
return tmp;
}
def code(a, b, c): tmp = 0 if b <= -3.1e-38: tmp = -c / b elif b <= 1.7e-6: tmp = -0.5 * ((b + math.sqrt((a * (c * -4.0)))) / a) else: tmp = (c / b) - (b / a) return tmp
function code(a, b, c) tmp = 0.0 if (b <= -3.1e-38) tmp = Float64(Float64(-c) / b); elseif (b <= 1.7e-6) tmp = Float64(-0.5 * Float64(Float64(b + sqrt(Float64(a * Float64(c * -4.0)))) / a)); else tmp = Float64(Float64(c / b) - Float64(b / a)); end return tmp end
function tmp_2 = code(a, b, c) tmp = 0.0; if (b <= -3.1e-38) tmp = -c / b; elseif (b <= 1.7e-6) tmp = -0.5 * ((b + sqrt((a * (c * -4.0)))) / a); else tmp = (c / b) - (b / a); end tmp_2 = tmp; end
code[a_, b_, c_] := If[LessEqual[b, -3.1e-38], N[((-c) / b), $MachinePrecision], If[LessEqual[b, 1.7e-6], N[(-0.5 * N[(N[(b + N[Sqrt[N[(a * N[(c * -4.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / a), $MachinePrecision]), $MachinePrecision], N[(N[(c / b), $MachinePrecision] - N[(b / a), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq -3.1 \cdot 10^{-38}:\\
\;\;\;\;\frac{-c}{b}\\
\mathbf{elif}\;b \leq 1.7 \cdot 10^{-6}:\\
\;\;\;\;-0.5 \cdot \frac{b + \sqrt{a \cdot \left(c \cdot -4\right)}}{a}\\
\mathbf{else}:\\
\;\;\;\;\frac{c}{b} - \frac{b}{a}\\
\end{array}
\end{array}
(FPCore (a b c) :precision binary64 (if (<= b -5e-310) (/ (- c) b) (- (/ c b) (/ b a))))
double code(double a, double b, double c) {
double tmp;
if (b <= -5e-310) {
tmp = -c / b;
} else {
tmp = (c / b) - (b / 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) :: tmp
if (b <= (-5d-310)) then
tmp = -c / b
else
tmp = (c / b) - (b / a)
end if
code = tmp
end function
public static double code(double a, double b, double c) {
double tmp;
if (b <= -5e-310) {
tmp = -c / b;
} else {
tmp = (c / b) - (b / a);
}
return tmp;
}
def code(a, b, c): tmp = 0 if b <= -5e-310: tmp = -c / b else: tmp = (c / b) - (b / a) return tmp
function code(a, b, c) tmp = 0.0 if (b <= -5e-310) tmp = Float64(Float64(-c) / b); else tmp = Float64(Float64(c / b) - Float64(b / a)); end return tmp end
function tmp_2 = code(a, b, c) tmp = 0.0; if (b <= -5e-310) tmp = -c / b; else tmp = (c / b) - (b / a); end tmp_2 = tmp; end
code[a_, b_, c_] := If[LessEqual[b, -5e-310], N[((-c) / b), $MachinePrecision], N[(N[(c / b), $MachinePrecision] - N[(b / a), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq -5 \cdot 10^{-310}:\\
\;\;\;\;\frac{-c}{b}\\
\mathbf{else}:\\
\;\;\;\;\frac{c}{b} - \frac{b}{a}\\
\end{array}
\end{array}
(FPCore (a b c) :precision binary64 (if (<= b -2.25e-291) (/ (- c) b) (/ (- b) a)))
double code(double a, double b, double c) {
double tmp;
if (b <= -2.25e-291) {
tmp = -c / b;
} else {
tmp = -b / 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) :: tmp
if (b <= (-2.25d-291)) then
tmp = -c / b
else
tmp = -b / a
end if
code = tmp
end function
public static double code(double a, double b, double c) {
double tmp;
if (b <= -2.25e-291) {
tmp = -c / b;
} else {
tmp = -b / a;
}
return tmp;
}
def code(a, b, c): tmp = 0 if b <= -2.25e-291: tmp = -c / b else: tmp = -b / a return tmp
function code(a, b, c) tmp = 0.0 if (b <= -2.25e-291) tmp = Float64(Float64(-c) / b); else tmp = Float64(Float64(-b) / a); end return tmp end
function tmp_2 = code(a, b, c) tmp = 0.0; if (b <= -2.25e-291) tmp = -c / b; else tmp = -b / a; end tmp_2 = tmp; end
code[a_, b_, c_] := If[LessEqual[b, -2.25e-291], N[((-c) / b), $MachinePrecision], N[((-b) / a), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq -2.25 \cdot 10^{-291}:\\
\;\;\;\;\frac{-c}{b}\\
\mathbf{else}:\\
\;\;\;\;\frac{-b}{a}\\
\end{array}
\end{array}
(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}
(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 / 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}
(FPCore (a b c)
:precision binary64
(let* ((t_0 (sqrt (- (* b b) (* 4.0 (* a c))))))
(if (< b 0.0)
(/ c (* a (/ (+ (- b) t_0) (* 2.0 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 = c / (a * ((-b + t_0) / (2.0 * a)));
} else {
tmp = (-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 = c / (a * ((-b + t_0) / (2.0d0 * a)))
else
tmp = (-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 = c / (a * ((-b + t_0) / (2.0 * a)));
} else {
tmp = (-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 = c / (a * ((-b + t_0) / (2.0 * a))) else: tmp = (-b - t_0) / (2.0 * a) return tmp
function code(a, b, c) t_0 = sqrt(Float64(Float64(b * b) - Float64(4.0 * Float64(a * c)))) tmp = 0.0 if (b < 0.0) tmp = Float64(c / Float64(a * Float64(Float64(Float64(-b) + t_0) / Float64(2.0 * a)))); else tmp = 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 = c / (a * ((-b + t_0) / (2.0 * a))); else tmp = (-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[(4.0 * N[(a * c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]}, If[Less[b, 0.0], N[(c / N[(a * N[(N[((-b) + t$95$0), $MachinePrecision] / N[(2.0 * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[((-b) - t$95$0), $MachinePrecision] / N[(2.0 * a), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}\\
\mathbf{if}\;b < 0:\\
\;\;\;\;\frac{c}{a \cdot \frac{\left(-b\right) + t_0}{2 \cdot a}}\\
\mathbf{else}:\\
\;\;\;\;\frac{\left(-b\right) - t_0}{2 \cdot a}\\
\end{array}
\end{array}
herbie shell --seed 2023347
(FPCore (a b c)
:name "The quadratic formula (r2)"
:precision binary64
:herbie-target
(if (< b 0.0) (/ c (* a (/ (+ (- b) (sqrt (- (* b b) (* 4.0 (* a c))))) (* 2.0 a)))) (/ (- (- b) (sqrt (- (* b b) (* 4.0 (* a c))))) (* 2.0 a)))
(/ (- (- b) (sqrt (- (* b b) (* 4.0 (* a c))))) (* 2.0 a)))