
(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 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(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 -1.7e-96)
(/ (- c) b)
(if (<= b 5.4e+73)
(/ (- (- 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 <= -1.7e-96) {
tmp = -c / b;
} else if (b <= 5.4e+73) {
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 <= (-1.7d-96)) then
tmp = -c / b
else if (b <= 5.4d+73) 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 <= -1.7e-96) {
tmp = -c / b;
} else if (b <= 5.4e+73) {
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 <= -1.7e-96: tmp = -c / b elif b <= 5.4e+73: 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 <= -1.7e-96) tmp = Float64(Float64(-c) / b); elseif (b <= 5.4e+73) 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 <= -1.7e-96) tmp = -c / b; elseif (b <= 5.4e+73) 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, -1.7e-96], N[((-c) / b), $MachinePrecision], If[LessEqual[b, 5.4e+73], 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 -1.7 \cdot 10^{-96}:\\
\;\;\;\;\frac{-c}{b}\\
\mathbf{elif}\;b \leq 5.4 \cdot 10^{+73}:\\
\;\;\;\;\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}
if b < -1.7e-96Initial program 14.1%
Simplified14.1%
Taylor expanded in b around -inf 85.9%
associate-*r/85.9%
neg-mul-185.9%
Simplified85.9%
if -1.7e-96 < b < 5.3999999999999998e73Initial program 82.3%
if 5.3999999999999998e73 < b Initial program 64.6%
Simplified64.8%
Taylor expanded in b around inf 99.4%
mul-1-neg99.4%
unsub-neg99.4%
Simplified99.4%
Final simplification88.4%
(FPCore (a b c)
:precision binary64
(if (<= b -2.4e-97)
(/ (- c) b)
(if (<= b 6.8e-52)
(* -0.5 (/ (+ b (sqrt (* c (* a -4.0)))) a))
(- (/ c b) (/ b a)))))
double code(double a, double b, double c) {
double tmp;
if (b <= -2.4e-97) {
tmp = -c / b;
} else if (b <= 6.8e-52) {
tmp = -0.5 * ((b + sqrt((c * (a * -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 <= (-2.4d-97)) then
tmp = -c / b
else if (b <= 6.8d-52) then
tmp = (-0.5d0) * ((b + sqrt((c * (a * (-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 <= -2.4e-97) {
tmp = -c / b;
} else if (b <= 6.8e-52) {
tmp = -0.5 * ((b + Math.sqrt((c * (a * -4.0)))) / a);
} else {
tmp = (c / b) - (b / a);
}
return tmp;
}
def code(a, b, c): tmp = 0 if b <= -2.4e-97: tmp = -c / b elif b <= 6.8e-52: tmp = -0.5 * ((b + math.sqrt((c * (a * -4.0)))) / a) else: tmp = (c / b) - (b / a) return tmp
function code(a, b, c) tmp = 0.0 if (b <= -2.4e-97) tmp = Float64(Float64(-c) / b); elseif (b <= 6.8e-52) tmp = Float64(-0.5 * Float64(Float64(b + sqrt(Float64(c * Float64(a * -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 <= -2.4e-97) tmp = -c / b; elseif (b <= 6.8e-52) tmp = -0.5 * ((b + sqrt((c * (a * -4.0)))) / a); else tmp = (c / b) - (b / a); end tmp_2 = tmp; end
code[a_, b_, c_] := If[LessEqual[b, -2.4e-97], N[((-c) / b), $MachinePrecision], If[LessEqual[b, 6.8e-52], N[(-0.5 * N[(N[(b + N[Sqrt[N[(c * N[(a * -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 -2.4 \cdot 10^{-97}:\\
\;\;\;\;\frac{-c}{b}\\
\mathbf{elif}\;b \leq 6.8 \cdot 10^{-52}:\\
\;\;\;\;-0.5 \cdot \frac{b + \sqrt{c \cdot \left(a \cdot -4\right)}}{a}\\
\mathbf{else}:\\
\;\;\;\;\frac{c}{b} - \frac{b}{a}\\
\end{array}
\end{array}
if b < -2.4e-97Initial program 14.1%
Simplified14.1%
Taylor expanded in b around -inf 85.9%
associate-*r/85.9%
neg-mul-185.9%
Simplified85.9%
if -2.4e-97 < b < 6.80000000000000035e-52Initial program 77.9%
Simplified77.9%
pow1/277.9%
pow-to-exp72.7%
Applied egg-rr72.7%
Taylor expanded in a around inf 36.3%
+-commutative36.3%
mul-1-neg36.3%
log-rec36.3%
remove-double-neg36.3%
log-prod70.1%
associate-*r*70.1%
*-commutative70.1%
*-commutative70.1%
associate-*r*70.1%
Simplified70.1%
expm1-log1p-u48.5%
expm1-udef21.0%
exp-to-pow21.2%
pow1/221.2%
Applied egg-rr21.2%
expm1-def51.0%
expm1-log1p75.0%
*-lft-identity75.0%
*-lft-identity75.0%
associate-*r*75.0%
*-commutative75.0%
rem-square-sqrt0.0%
unpow20.0%
associate-*r*0.0%
unpow20.0%
rem-square-sqrt75.0%
Simplified75.0%
if 6.80000000000000035e-52 < b Initial program 71.8%
Simplified72.0%
Taylor expanded in b around inf 90.6%
mul-1-neg90.6%
unsub-neg90.6%
Simplified90.6%
Final simplification85.3%
(FPCore (a b c) :precision binary64 (if (<= b -5e-311) (/ (- c) b) (- (/ c b) (/ b a))))
double code(double a, double b, double c) {
double tmp;
if (b <= -5e-311) {
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-311)) 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-311) {
tmp = -c / b;
} else {
tmp = (c / b) - (b / a);
}
return tmp;
}
def code(a, b, c): tmp = 0 if b <= -5e-311: tmp = -c / b else: tmp = (c / b) - (b / a) return tmp
function code(a, b, c) tmp = 0.0 if (b <= -5e-311) 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-311) tmp = -c / b; else tmp = (c / b) - (b / a); end tmp_2 = tmp; end
code[a_, b_, c_] := If[LessEqual[b, -5e-311], 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^{-311}:\\
\;\;\;\;\frac{-c}{b}\\
\mathbf{else}:\\
\;\;\;\;\frac{c}{b} - \frac{b}{a}\\
\end{array}
\end{array}
if b < -5.00000000000023e-311Initial program 27.0%
Simplified27.0%
Taylor expanded in b around -inf 70.9%
associate-*r/70.9%
neg-mul-170.9%
Simplified70.9%
if -5.00000000000023e-311 < b Initial program 73.8%
Simplified73.9%
Taylor expanded in b around inf 75.0%
mul-1-neg75.0%
unsub-neg75.0%
Simplified75.0%
Final simplification72.9%
(FPCore (a b c) :precision binary64 (if (<= b -7.5e-10) (/ c b) (- (/ b a))))
double code(double a, double b, double c) {
double tmp;
if (b <= -7.5e-10) {
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 <= (-7.5d-10)) 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 <= -7.5e-10) {
tmp = c / b;
} else {
tmp = -(b / a);
}
return tmp;
}
def code(a, b, c): tmp = 0 if b <= -7.5e-10: tmp = c / b else: tmp = -(b / a) return tmp
function code(a, b, c) tmp = 0.0 if (b <= -7.5e-10) tmp = 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 <= -7.5e-10) tmp = c / b; else tmp = -(b / a); end tmp_2 = tmp; end
code[a_, b_, c_] := If[LessEqual[b, -7.5e-10], N[(c / b), $MachinePrecision], (-N[(b / a), $MachinePrecision])]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq -7.5 \cdot 10^{-10}:\\
\;\;\;\;\frac{c}{b}\\
\mathbf{else}:\\
\;\;\;\;-\frac{b}{a}\\
\end{array}
\end{array}
if b < -7.49999999999999995e-10Initial program 8.5%
clear-num8.5%
associate-/r/8.5%
associate-/r*8.5%
metadata-eval8.5%
add-sqr-sqrt6.1%
sqrt-unprod7.5%
sqr-neg7.5%
sqrt-prod0.0%
add-sqr-sqrt5.4%
fma-neg5.4%
*-commutative5.4%
distribute-rgt-neg-in5.4%
metadata-eval5.4%
associate-*r*5.4%
Applied egg-rr5.4%
Taylor expanded in a around 0 27.0%
if -7.49999999999999995e-10 < b Initial program 70.6%
Simplified70.6%
Taylor expanded in b around inf 55.2%
associate-*r/55.2%
mul-1-neg55.2%
Simplified55.2%
Final simplification45.6%
(FPCore (a b c) :precision binary64 (if (<= b -1.45e-307) (/ (- c) b) (- (/ b a))))
double code(double a, double b, double c) {
double tmp;
if (b <= -1.45e-307) {
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 <= (-1.45d-307)) 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 <= -1.45e-307) {
tmp = -c / b;
} else {
tmp = -(b / a);
}
return tmp;
}
def code(a, b, c): tmp = 0 if b <= -1.45e-307: tmp = -c / b else: tmp = -(b / a) return tmp
function code(a, b, c) tmp = 0.0 if (b <= -1.45e-307) 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 <= -1.45e-307) tmp = -c / b; else tmp = -(b / a); end tmp_2 = tmp; end
code[a_, b_, c_] := If[LessEqual[b, -1.45e-307], N[((-c) / b), $MachinePrecision], (-N[(b / a), $MachinePrecision])]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq -1.45 \cdot 10^{-307}:\\
\;\;\;\;\frac{-c}{b}\\
\mathbf{else}:\\
\;\;\;\;-\frac{b}{a}\\
\end{array}
\end{array}
if b < -1.45e-307Initial program 26.4%
Simplified26.5%
Taylor expanded in b around -inf 71.4%
associate-*r/71.4%
neg-mul-171.4%
Simplified71.4%
if -1.45e-307 < b Initial program 74.0%
Simplified74.1%
Taylor expanded in b around inf 74.3%
associate-*r/74.3%
mul-1-neg74.3%
Simplified74.3%
Final simplification72.8%
(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 49.5%
Simplified49.5%
clear-num49.5%
un-div-inv49.5%
Applied egg-rr49.5%
Taylor expanded in b around -inf 37.7%
Taylor expanded in b around 0 2.5%
Final simplification2.5%
(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}
Initial program 49.5%
clear-num49.4%
associate-/r/49.4%
associate-/r*49.4%
metadata-eval49.4%
add-sqr-sqrt13.2%
sqrt-unprod24.7%
sqr-neg24.7%
sqrt-prod19.6%
add-sqr-sqrt30.5%
fma-neg30.5%
*-commutative30.5%
distribute-rgt-neg-in30.5%
metadata-eval30.5%
associate-*r*30.5%
Applied egg-rr30.5%
Taylor expanded in a around 0 11.2%
Final simplification11.2%
(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 2023194
(FPCore (a b c)
:name "quadm (p42, negative)"
: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)))