
(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 7 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 (* -1.0 (/ c b))))
(if (<= b -5e+153)
(* -1.0 (+ t_0 (/ b a)))
(if (<= b 5e-112)
(/ (+ (- b) (sqrt (- (* b b) (* (* 4.0 a) c)))) (* 2.0 a))
t_0))))
double code(double a, double b, double c) {
double t_0 = -1.0 * (c / b);
double tmp;
if (b <= -5e+153) {
tmp = -1.0 * (t_0 + (b / a));
} else if (b <= 5e-112) {
tmp = (-b + sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * a);
} else {
tmp = t_0;
}
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 = (-1.0d0) * (c / b)
if (b <= (-5d+153)) then
tmp = (-1.0d0) * (t_0 + (b / a))
else if (b <= 5d-112) then
tmp = (-b + sqrt(((b * b) - ((4.0d0 * a) * c)))) / (2.0d0 * a)
else
tmp = t_0
end if
code = tmp
end function
public static double code(double a, double b, double c) {
double t_0 = -1.0 * (c / b);
double tmp;
if (b <= -5e+153) {
tmp = -1.0 * (t_0 + (b / a));
} else if (b <= 5e-112) {
tmp = (-b + Math.sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * a);
} else {
tmp = t_0;
}
return tmp;
}
def code(a, b, c): t_0 = -1.0 * (c / b) tmp = 0 if b <= -5e+153: tmp = -1.0 * (t_0 + (b / a)) elif b <= 5e-112: tmp = (-b + math.sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * a) else: tmp = t_0 return tmp
function code(a, b, c) t_0 = Float64(-1.0 * Float64(c / b)) tmp = 0.0 if (b <= -5e+153) tmp = Float64(-1.0 * Float64(t_0 + Float64(b / a))); elseif (b <= 5e-112) tmp = Float64(Float64(Float64(-b) + sqrt(Float64(Float64(b * b) - Float64(Float64(4.0 * a) * c)))) / Float64(2.0 * a)); else tmp = t_0; end return tmp end
function tmp_2 = code(a, b, c) t_0 = -1.0 * (c / b); tmp = 0.0; if (b <= -5e+153) tmp = -1.0 * (t_0 + (b / a)); elseif (b <= 5e-112) tmp = (-b + sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * a); else tmp = t_0; end tmp_2 = tmp; end
code[a_, b_, c_] := Block[{t$95$0 = N[(-1.0 * N[(c / b), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[b, -5e+153], N[(-1.0 * N[(t$95$0 + N[(b / a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], If[LessEqual[b, 5e-112], 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], t$95$0]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := -1 \cdot \frac{c}{b}\\
\mathbf{if}\;b \leq -5 \cdot 10^{+153}:\\
\;\;\;\;-1 \cdot \left(t\_0 + \frac{b}{a}\right)\\
\mathbf{elif}\;b \leq 5 \cdot 10^{-112}:\\
\;\;\;\;\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a}\\
\mathbf{else}:\\
\;\;\;\;t\_0\\
\end{array}
\end{array}
if b < -5.00000000000000018e153Initial program 45.8%
*-commutative45.8%
Simplified45.8%
Taylor expanded in b around -inf 98.5%
Taylor expanded in c around 0 99.7%
if -5.00000000000000018e153 < b < 5.00000000000000044e-112Initial program 82.9%
if 5.00000000000000044e-112 < b Initial program 17.9%
*-commutative17.9%
Simplified17.9%
Taylor expanded in b around inf 86.7%
(FPCore (a b c)
:precision binary64
(let* ((t_0 (* -1.0 (/ c b))))
(if (<= b -4.3e-44)
(* -1.0 (+ t_0 (/ b a)))
(if (<= b 1.35e-116) (* (+ b (sqrt (* (* -4.0 a) c))) (/ 0.5 a)) t_0))))
double code(double a, double b, double c) {
double t_0 = -1.0 * (c / b);
double tmp;
if (b <= -4.3e-44) {
tmp = -1.0 * (t_0 + (b / a));
} else if (b <= 1.35e-116) {
tmp = (b + sqrt(((-4.0 * a) * c))) * (0.5 / a);
} else {
tmp = t_0;
}
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 = (-1.0d0) * (c / b)
if (b <= (-4.3d-44)) then
tmp = (-1.0d0) * (t_0 + (b / a))
else if (b <= 1.35d-116) then
tmp = (b + sqrt((((-4.0d0) * a) * c))) * (0.5d0 / a)
else
tmp = t_0
end if
code = tmp
end function
public static double code(double a, double b, double c) {
double t_0 = -1.0 * (c / b);
double tmp;
if (b <= -4.3e-44) {
tmp = -1.0 * (t_0 + (b / a));
} else if (b <= 1.35e-116) {
tmp = (b + Math.sqrt(((-4.0 * a) * c))) * (0.5 / a);
} else {
tmp = t_0;
}
return tmp;
}
def code(a, b, c): t_0 = -1.0 * (c / b) tmp = 0 if b <= -4.3e-44: tmp = -1.0 * (t_0 + (b / a)) elif b <= 1.35e-116: tmp = (b + math.sqrt(((-4.0 * a) * c))) * (0.5 / a) else: tmp = t_0 return tmp
function code(a, b, c) t_0 = Float64(-1.0 * Float64(c / b)) tmp = 0.0 if (b <= -4.3e-44) tmp = Float64(-1.0 * Float64(t_0 + Float64(b / a))); elseif (b <= 1.35e-116) tmp = Float64(Float64(b + sqrt(Float64(Float64(-4.0 * a) * c))) * Float64(0.5 / a)); else tmp = t_0; end return tmp end
function tmp_2 = code(a, b, c) t_0 = -1.0 * (c / b); tmp = 0.0; if (b <= -4.3e-44) tmp = -1.0 * (t_0 + (b / a)); elseif (b <= 1.35e-116) tmp = (b + sqrt(((-4.0 * a) * c))) * (0.5 / a); else tmp = t_0; end tmp_2 = tmp; end
code[a_, b_, c_] := Block[{t$95$0 = N[(-1.0 * N[(c / b), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[b, -4.3e-44], N[(-1.0 * N[(t$95$0 + N[(b / a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], If[LessEqual[b, 1.35e-116], N[(N[(b + N[Sqrt[N[(N[(-4.0 * a), $MachinePrecision] * c), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * N[(0.5 / a), $MachinePrecision]), $MachinePrecision], t$95$0]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := -1 \cdot \frac{c}{b}\\
\mathbf{if}\;b \leq -4.3 \cdot 10^{-44}:\\
\;\;\;\;-1 \cdot \left(t\_0 + \frac{b}{a}\right)\\
\mathbf{elif}\;b \leq 1.35 \cdot 10^{-116}:\\
\;\;\;\;\left(b + \sqrt{\left(-4 \cdot a\right) \cdot c}\right) \cdot \frac{0.5}{a}\\
\mathbf{else}:\\
\;\;\;\;t\_0\\
\end{array}
\end{array}
if b < -4.30000000000000013e-44Initial program 67.9%
*-commutative67.9%
Simplified67.9%
Taylor expanded in b around -inf 89.1%
Taylor expanded in c around 0 89.8%
if -4.30000000000000013e-44 < b < 1.35e-116Initial program 78.2%
*-commutative78.2%
Simplified78.2%
Taylor expanded in b around 0 70.5%
div-inv70.4%
add-sqr-sqrt45.6%
sqrt-unprod69.2%
sqr-neg69.2%
sqrt-prod25.1%
add-sqr-sqrt68.3%
associate-*r*68.4%
metadata-eval68.4%
div-inv68.4%
clear-num68.4%
Applied egg-rr68.4%
if 1.35e-116 < b Initial program 17.9%
*-commutative17.9%
Simplified17.9%
Taylor expanded in b around inf 86.7%
(FPCore (a b c)
:precision binary64
(let* ((t_0 (* -1.0 (/ c b))))
(if (<= b -7.2e-42)
(* -1.0 (+ t_0 (/ b a)))
(if (<= b 6.2e-112) (/ (- (sqrt (* (* -4.0 a) c)) b) (* a 2.0)) t_0))))
double code(double a, double b, double c) {
double t_0 = -1.0 * (c / b);
double tmp;
if (b <= -7.2e-42) {
tmp = -1.0 * (t_0 + (b / a));
} else if (b <= 6.2e-112) {
tmp = (sqrt(((-4.0 * a) * c)) - b) / (a * 2.0);
} else {
tmp = t_0;
}
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 = (-1.0d0) * (c / b)
if (b <= (-7.2d-42)) then
tmp = (-1.0d0) * (t_0 + (b / a))
else if (b <= 6.2d-112) then
tmp = (sqrt((((-4.0d0) * a) * c)) - b) / (a * 2.0d0)
else
tmp = t_0
end if
code = tmp
end function
public static double code(double a, double b, double c) {
double t_0 = -1.0 * (c / b);
double tmp;
if (b <= -7.2e-42) {
tmp = -1.0 * (t_0 + (b / a));
} else if (b <= 6.2e-112) {
tmp = (Math.sqrt(((-4.0 * a) * c)) - b) / (a * 2.0);
} else {
tmp = t_0;
}
return tmp;
}
def code(a, b, c): t_0 = -1.0 * (c / b) tmp = 0 if b <= -7.2e-42: tmp = -1.0 * (t_0 + (b / a)) elif b <= 6.2e-112: tmp = (math.sqrt(((-4.0 * a) * c)) - b) / (a * 2.0) else: tmp = t_0 return tmp
function code(a, b, c) t_0 = Float64(-1.0 * Float64(c / b)) tmp = 0.0 if (b <= -7.2e-42) tmp = Float64(-1.0 * Float64(t_0 + Float64(b / a))); elseif (b <= 6.2e-112) tmp = Float64(Float64(sqrt(Float64(Float64(-4.0 * a) * c)) - b) / Float64(a * 2.0)); else tmp = t_0; end return tmp end
function tmp_2 = code(a, b, c) t_0 = -1.0 * (c / b); tmp = 0.0; if (b <= -7.2e-42) tmp = -1.0 * (t_0 + (b / a)); elseif (b <= 6.2e-112) tmp = (sqrt(((-4.0 * a) * c)) - b) / (a * 2.0); else tmp = t_0; end tmp_2 = tmp; end
code[a_, b_, c_] := Block[{t$95$0 = N[(-1.0 * N[(c / b), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[b, -7.2e-42], N[(-1.0 * N[(t$95$0 + N[(b / a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], If[LessEqual[b, 6.2e-112], N[(N[(N[Sqrt[N[(N[(-4.0 * a), $MachinePrecision] * c), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] / N[(a * 2.0), $MachinePrecision]), $MachinePrecision], t$95$0]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := -1 \cdot \frac{c}{b}\\
\mathbf{if}\;b \leq -7.2 \cdot 10^{-42}:\\
\;\;\;\;-1 \cdot \left(t\_0 + \frac{b}{a}\right)\\
\mathbf{elif}\;b \leq 6.2 \cdot 10^{-112}:\\
\;\;\;\;\frac{\sqrt{\left(-4 \cdot a\right) \cdot c} - b}{a \cdot 2}\\
\mathbf{else}:\\
\;\;\;\;t\_0\\
\end{array}
\end{array}
if b < -7.2000000000000004e-42Initial program 67.9%
*-commutative67.9%
Simplified67.9%
Taylor expanded in b around -inf 89.1%
Taylor expanded in c around 0 89.8%
if -7.2000000000000004e-42 < b < 6.1999999999999995e-112Initial program 78.2%
*-commutative78.2%
Simplified78.2%
Taylor expanded in b around 0 70.5%
+-commutative70.5%
unsub-neg70.5%
associate-*r*70.5%
Applied egg-rr70.5%
if 6.1999999999999995e-112 < b Initial program 17.9%
*-commutative17.9%
Simplified17.9%
Taylor expanded in b around inf 86.7%
(FPCore (a b c) :precision binary64 (let* ((t_0 (* -1.0 (/ c b)))) (if (<= b -5e-311) (* -1.0 (+ t_0 (/ b a))) t_0)))
double code(double a, double b, double c) {
double t_0 = -1.0 * (c / b);
double tmp;
if (b <= -5e-311) {
tmp = -1.0 * (t_0 + (b / a));
} else {
tmp = t_0;
}
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 = (-1.0d0) * (c / b)
if (b <= (-5d-311)) then
tmp = (-1.0d0) * (t_0 + (b / a))
else
tmp = t_0
end if
code = tmp
end function
public static double code(double a, double b, double c) {
double t_0 = -1.0 * (c / b);
double tmp;
if (b <= -5e-311) {
tmp = -1.0 * (t_0 + (b / a));
} else {
tmp = t_0;
}
return tmp;
}
def code(a, b, c): t_0 = -1.0 * (c / b) tmp = 0 if b <= -5e-311: tmp = -1.0 * (t_0 + (b / a)) else: tmp = t_0 return tmp
function code(a, b, c) t_0 = Float64(-1.0 * Float64(c / b)) tmp = 0.0 if (b <= -5e-311) tmp = Float64(-1.0 * Float64(t_0 + Float64(b / a))); else tmp = t_0; end return tmp end
function tmp_2 = code(a, b, c) t_0 = -1.0 * (c / b); tmp = 0.0; if (b <= -5e-311) tmp = -1.0 * (t_0 + (b / a)); else tmp = t_0; end tmp_2 = tmp; end
code[a_, b_, c_] := Block[{t$95$0 = N[(-1.0 * N[(c / b), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[b, -5e-311], N[(-1.0 * N[(t$95$0 + N[(b / a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], t$95$0]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := -1 \cdot \frac{c}{b}\\
\mathbf{if}\;b \leq -5 \cdot 10^{-311}:\\
\;\;\;\;-1 \cdot \left(t\_0 + \frac{b}{a}\right)\\
\mathbf{else}:\\
\;\;\;\;t\_0\\
\end{array}
\end{array}
if b < -5.00000000000023e-311Initial program 73.3%
*-commutative73.3%
Simplified73.3%
Taylor expanded in b around -inf 64.7%
Taylor expanded in c around 0 68.8%
if -5.00000000000023e-311 < b Initial program 26.9%
*-commutative26.9%
Simplified26.9%
Taylor expanded in b around inf 73.9%
(FPCore (a b c) :precision binary64 (if (<= b -5e-311) (* -1.0 (/ b a)) (* -1.0 (/ c b))))
double code(double a, double b, double c) {
double tmp;
if (b <= -5e-311) {
tmp = -1.0 * (b / a);
} else {
tmp = -1.0 * (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 <= (-5d-311)) then
tmp = (-1.0d0) * (b / a)
else
tmp = (-1.0d0) * (c / b)
end if
code = tmp
end function
public static double code(double a, double b, double c) {
double tmp;
if (b <= -5e-311) {
tmp = -1.0 * (b / a);
} else {
tmp = -1.0 * (c / b);
}
return tmp;
}
def code(a, b, c): tmp = 0 if b <= -5e-311: tmp = -1.0 * (b / a) else: tmp = -1.0 * (c / b) return tmp
function code(a, b, c) tmp = 0.0 if (b <= -5e-311) tmp = Float64(-1.0 * Float64(b / a)); else tmp = Float64(-1.0 * Float64(c / b)); end return tmp end
function tmp_2 = code(a, b, c) tmp = 0.0; if (b <= -5e-311) tmp = -1.0 * (b / a); else tmp = -1.0 * (c / b); end tmp_2 = tmp; end
code[a_, b_, c_] := If[LessEqual[b, -5e-311], N[(-1.0 * N[(b / a), $MachinePrecision]), $MachinePrecision], N[(-1.0 * N[(c / b), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq -5 \cdot 10^{-311}:\\
\;\;\;\;-1 \cdot \frac{b}{a}\\
\mathbf{else}:\\
\;\;\;\;-1 \cdot \frac{c}{b}\\
\end{array}
\end{array}
if b < -5.00000000000023e-311Initial program 73.3%
*-commutative73.3%
Simplified73.3%
Taylor expanded in b around -inf 68.1%
if -5.00000000000023e-311 < b Initial program 26.9%
*-commutative26.9%
Simplified26.9%
Taylor expanded in b around inf 73.9%
(FPCore (a b c) :precision binary64 (* -1.0 (/ b a)))
double code(double a, double b, double c) {
return -1.0 * (b / a);
}
real(8) function code(a, b, c)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: c
code = (-1.0d0) * (b / a)
end function
public static double code(double a, double b, double c) {
return -1.0 * (b / a);
}
def code(a, b, c): return -1.0 * (b / a)
function code(a, b, c) return Float64(-1.0 * Float64(b / a)) end
function tmp = code(a, b, c) tmp = -1.0 * (b / a); end
code[a_, b_, c_] := N[(-1.0 * N[(b / a), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
-1 \cdot \frac{b}{a}
\end{array}
Initial program 49.4%
*-commutative49.4%
Simplified49.4%
Taylor expanded in b around -inf 34.5%
(FPCore (a b c) :precision binary64 (/ b a))
double code(double a, double b, double c) {
return b / 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 / a
end function
public static double code(double a, double b, double c) {
return b / a;
}
def code(a, b, c): return b / a
function code(a, b, c) return Float64(b / a) end
function tmp = code(a, b, c) tmp = b / a; end
code[a_, b_, c_] := N[(b / a), $MachinePrecision]
\begin{array}{l}
\\
\frac{b}{a}
\end{array}
Initial program 49.4%
*-commutative49.4%
Simplified49.4%
*-un-lft-identity49.4%
*-un-lft-identity49.4%
prod-diff49.4%
*-commutative49.4%
*-un-lft-identity49.4%
fma-define49.4%
*-un-lft-identity49.4%
+-commutative49.4%
add-sqr-sqrt35.5%
sqrt-unprod46.4%
sqr-neg46.4%
sqrt-prod11.2%
add-sqr-sqrt31.5%
pow231.5%
add-sqr-sqrt21.7%
sqrt-unprod31.5%
sqr-neg31.5%
sqrt-prod11.2%
add-sqr-sqrt31.2%
*-commutative31.2%
*-un-lft-identity31.2%
Applied egg-rr31.2%
Taylor expanded in b around -inf 2.4%
herbie shell --seed 2024050 -o generate:simplify
(FPCore (a b c)
:name "Quadratic roots, full range"
:precision binary64
(/ (+ (- b) (sqrt (- (* b b) (* (* 4.0 a) c)))) (* 2.0 a)))