
(FPCore (x y) :precision binary64 (/ (- x y) (- 2.0 (+ x y))))
double code(double x, double y) {
return (x - y) / (2.0 - (x + y));
}
real(8) function code(x, y)
real(8), intent (in) :: x
real(8), intent (in) :: y
code = (x - y) / (2.0d0 - (x + y))
end function
public static double code(double x, double y) {
return (x - y) / (2.0 - (x + y));
}
def code(x, y): return (x - y) / (2.0 - (x + y))
function code(x, y) return Float64(Float64(x - y) / Float64(2.0 - Float64(x + y))) end
function tmp = code(x, y) tmp = (x - y) / (2.0 - (x + y)); end
code[x_, y_] := N[(N[(x - y), $MachinePrecision] / N[(2.0 - N[(x + y), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{x - y}{2 - \left(x + y\right)}
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 6 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (x y) :precision binary64 (/ (- x y) (- 2.0 (+ x y))))
double code(double x, double y) {
return (x - y) / (2.0 - (x + y));
}
real(8) function code(x, y)
real(8), intent (in) :: x
real(8), intent (in) :: y
code = (x - y) / (2.0d0 - (x + y))
end function
public static double code(double x, double y) {
return (x - y) / (2.0 - (x + y));
}
def code(x, y): return (x - y) / (2.0 - (x + y))
function code(x, y) return Float64(Float64(x - y) / Float64(2.0 - Float64(x + y))) end
function tmp = code(x, y) tmp = (x - y) / (2.0 - (x + y)); end
code[x_, y_] := N[(N[(x - y), $MachinePrecision] / N[(2.0 - N[(x + y), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{x - y}{2 - \left(x + y\right)}
\end{array}
(FPCore (x y) :precision binary64 (/ (- x y) (- 2.0 (+ x y))))
double code(double x, double y) {
return (x - y) / (2.0 - (x + y));
}
real(8) function code(x, y)
real(8), intent (in) :: x
real(8), intent (in) :: y
code = (x - y) / (2.0d0 - (x + y))
end function
public static double code(double x, double y) {
return (x - y) / (2.0 - (x + y));
}
def code(x, y): return (x - y) / (2.0 - (x + y))
function code(x, y) return Float64(Float64(x - y) / Float64(2.0 - Float64(x + y))) end
function tmp = code(x, y) tmp = (x - y) / (2.0 - (x + y)); end
code[x_, y_] := N[(N[(x - y), $MachinePrecision] / N[(2.0 - N[(x + y), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{x - y}{2 - \left(x + y\right)}
\end{array}
Initial program 100.0%
Final simplification100.0%
(FPCore (x y)
:precision binary64
(if (<= x -2.0)
-1.0
(if (<= x -3e-105)
(* x 0.5)
(if (<= x 7.2e-99)
1.0
(if (<= x 4e-8) (* x 0.5) (if (<= x 2.8e+71) 1.0 -1.0))))))
double code(double x, double y) {
double tmp;
if (x <= -2.0) {
tmp = -1.0;
} else if (x <= -3e-105) {
tmp = x * 0.5;
} else if (x <= 7.2e-99) {
tmp = 1.0;
} else if (x <= 4e-8) {
tmp = x * 0.5;
} else if (x <= 2.8e+71) {
tmp = 1.0;
} else {
tmp = -1.0;
}
return tmp;
}
real(8) function code(x, y)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8) :: tmp
if (x <= (-2.0d0)) then
tmp = -1.0d0
else if (x <= (-3d-105)) then
tmp = x * 0.5d0
else if (x <= 7.2d-99) then
tmp = 1.0d0
else if (x <= 4d-8) then
tmp = x * 0.5d0
else if (x <= 2.8d+71) then
tmp = 1.0d0
else
tmp = -1.0d0
end if
code = tmp
end function
public static double code(double x, double y) {
double tmp;
if (x <= -2.0) {
tmp = -1.0;
} else if (x <= -3e-105) {
tmp = x * 0.5;
} else if (x <= 7.2e-99) {
tmp = 1.0;
} else if (x <= 4e-8) {
tmp = x * 0.5;
} else if (x <= 2.8e+71) {
tmp = 1.0;
} else {
tmp = -1.0;
}
return tmp;
}
def code(x, y): tmp = 0 if x <= -2.0: tmp = -1.0 elif x <= -3e-105: tmp = x * 0.5 elif x <= 7.2e-99: tmp = 1.0 elif x <= 4e-8: tmp = x * 0.5 elif x <= 2.8e+71: tmp = 1.0 else: tmp = -1.0 return tmp
function code(x, y) tmp = 0.0 if (x <= -2.0) tmp = -1.0; elseif (x <= -3e-105) tmp = Float64(x * 0.5); elseif (x <= 7.2e-99) tmp = 1.0; elseif (x <= 4e-8) tmp = Float64(x * 0.5); elseif (x <= 2.8e+71) tmp = 1.0; else tmp = -1.0; end return tmp end
function tmp_2 = code(x, y) tmp = 0.0; if (x <= -2.0) tmp = -1.0; elseif (x <= -3e-105) tmp = x * 0.5; elseif (x <= 7.2e-99) tmp = 1.0; elseif (x <= 4e-8) tmp = x * 0.5; elseif (x <= 2.8e+71) tmp = 1.0; else tmp = -1.0; end tmp_2 = tmp; end
code[x_, y_] := If[LessEqual[x, -2.0], -1.0, If[LessEqual[x, -3e-105], N[(x * 0.5), $MachinePrecision], If[LessEqual[x, 7.2e-99], 1.0, If[LessEqual[x, 4e-8], N[(x * 0.5), $MachinePrecision], If[LessEqual[x, 2.8e+71], 1.0, -1.0]]]]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;x \leq -2:\\
\;\;\;\;-1\\
\mathbf{elif}\;x \leq -3 \cdot 10^{-105}:\\
\;\;\;\;x \cdot 0.5\\
\mathbf{elif}\;x \leq 7.2 \cdot 10^{-99}:\\
\;\;\;\;1\\
\mathbf{elif}\;x \leq 4 \cdot 10^{-8}:\\
\;\;\;\;x \cdot 0.5\\
\mathbf{elif}\;x \leq 2.8 \cdot 10^{+71}:\\
\;\;\;\;1\\
\mathbf{else}:\\
\;\;\;\;-1\\
\end{array}
\end{array}
if x < -2 or 2.80000000000000002e71 < x Initial program 100.0%
remove-double-neg100.0%
+-commutative100.0%
distribute-neg-frac2100.0%
distribute-frac-neg100.0%
sub-neg100.0%
distribute-neg-in100.0%
remove-double-neg100.0%
+-commutative100.0%
sub-neg100.0%
neg-sub0100.0%
associate--r-100.0%
metadata-eval100.0%
metadata-eval100.0%
+-commutative100.0%
+-commutative100.0%
associate-+r+100.0%
metadata-eval100.0%
Simplified100.0%
Taylor expanded in x around inf 79.6%
if -2 < x < -3.0000000000000001e-105 or 7.2000000000000001e-99 < x < 4.0000000000000001e-8Initial program 99.9%
remove-double-neg99.9%
+-commutative99.9%
distribute-neg-frac299.9%
distribute-frac-neg99.9%
sub-neg99.9%
distribute-neg-in99.9%
remove-double-neg99.9%
+-commutative99.9%
sub-neg99.9%
neg-sub099.9%
associate--r-99.9%
metadata-eval99.9%
metadata-eval99.9%
+-commutative99.9%
+-commutative99.9%
associate-+r+99.9%
metadata-eval99.9%
Simplified99.9%
Taylor expanded in y around 0 69.9%
mul-1-neg69.9%
distribute-neg-frac269.9%
neg-sub069.9%
associate-+l-69.9%
neg-sub069.9%
+-commutative69.9%
unsub-neg69.9%
Simplified69.9%
Taylor expanded in x around 0 66.5%
*-commutative66.5%
Simplified66.5%
if -3.0000000000000001e-105 < x < 7.2000000000000001e-99 or 4.0000000000000001e-8 < x < 2.80000000000000002e71Initial program 100.0%
remove-double-neg100.0%
+-commutative100.0%
distribute-neg-frac2100.0%
distribute-frac-neg100.0%
sub-neg100.0%
distribute-neg-in100.0%
remove-double-neg100.0%
+-commutative100.0%
sub-neg100.0%
neg-sub0100.0%
associate--r-100.0%
metadata-eval100.0%
metadata-eval100.0%
+-commutative100.0%
+-commutative100.0%
associate-+r+100.0%
metadata-eval100.0%
Simplified100.0%
Taylor expanded in y around inf 61.2%
Final simplification70.1%
(FPCore (x y)
:precision binary64
(let* ((t_0 (/ x (- 2.0 x))))
(if (<= y -3.6e+56)
1.0
(if (<= y 1.08e-27)
t_0
(if (<= y 1.05e+20) (/ y (- y 2.0)) (if (<= y 7.5e+73) t_0 1.0))))))
double code(double x, double y) {
double t_0 = x / (2.0 - x);
double tmp;
if (y <= -3.6e+56) {
tmp = 1.0;
} else if (y <= 1.08e-27) {
tmp = t_0;
} else if (y <= 1.05e+20) {
tmp = y / (y - 2.0);
} else if (y <= 7.5e+73) {
tmp = t_0;
} else {
tmp = 1.0;
}
return tmp;
}
real(8) function code(x, y)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8) :: t_0
real(8) :: tmp
t_0 = x / (2.0d0 - x)
if (y <= (-3.6d+56)) then
tmp = 1.0d0
else if (y <= 1.08d-27) then
tmp = t_0
else if (y <= 1.05d+20) then
tmp = y / (y - 2.0d0)
else if (y <= 7.5d+73) then
tmp = t_0
else
tmp = 1.0d0
end if
code = tmp
end function
public static double code(double x, double y) {
double t_0 = x / (2.0 - x);
double tmp;
if (y <= -3.6e+56) {
tmp = 1.0;
} else if (y <= 1.08e-27) {
tmp = t_0;
} else if (y <= 1.05e+20) {
tmp = y / (y - 2.0);
} else if (y <= 7.5e+73) {
tmp = t_0;
} else {
tmp = 1.0;
}
return tmp;
}
def code(x, y): t_0 = x / (2.0 - x) tmp = 0 if y <= -3.6e+56: tmp = 1.0 elif y <= 1.08e-27: tmp = t_0 elif y <= 1.05e+20: tmp = y / (y - 2.0) elif y <= 7.5e+73: tmp = t_0 else: tmp = 1.0 return tmp
function code(x, y) t_0 = Float64(x / Float64(2.0 - x)) tmp = 0.0 if (y <= -3.6e+56) tmp = 1.0; elseif (y <= 1.08e-27) tmp = t_0; elseif (y <= 1.05e+20) tmp = Float64(y / Float64(y - 2.0)); elseif (y <= 7.5e+73) tmp = t_0; else tmp = 1.0; end return tmp end
function tmp_2 = code(x, y) t_0 = x / (2.0 - x); tmp = 0.0; if (y <= -3.6e+56) tmp = 1.0; elseif (y <= 1.08e-27) tmp = t_0; elseif (y <= 1.05e+20) tmp = y / (y - 2.0); elseif (y <= 7.5e+73) tmp = t_0; else tmp = 1.0; end tmp_2 = tmp; end
code[x_, y_] := Block[{t$95$0 = N[(x / N[(2.0 - x), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[y, -3.6e+56], 1.0, If[LessEqual[y, 1.08e-27], t$95$0, If[LessEqual[y, 1.05e+20], N[(y / N[(y - 2.0), $MachinePrecision]), $MachinePrecision], If[LessEqual[y, 7.5e+73], t$95$0, 1.0]]]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{x}{2 - x}\\
\mathbf{if}\;y \leq -3.6 \cdot 10^{+56}:\\
\;\;\;\;1\\
\mathbf{elif}\;y \leq 1.08 \cdot 10^{-27}:\\
\;\;\;\;t\_0\\
\mathbf{elif}\;y \leq 1.05 \cdot 10^{+20}:\\
\;\;\;\;\frac{y}{y - 2}\\
\mathbf{elif}\;y \leq 7.5 \cdot 10^{+73}:\\
\;\;\;\;t\_0\\
\mathbf{else}:\\
\;\;\;\;1\\
\end{array}
\end{array}
if y < -3.59999999999999998e56 or 7.5e73 < y Initial program 100.0%
remove-double-neg100.0%
+-commutative100.0%
distribute-neg-frac2100.0%
distribute-frac-neg100.0%
sub-neg100.0%
distribute-neg-in100.0%
remove-double-neg100.0%
+-commutative100.0%
sub-neg100.0%
neg-sub0100.0%
associate--r-100.0%
metadata-eval100.0%
metadata-eval100.0%
+-commutative100.0%
+-commutative100.0%
associate-+r+100.0%
metadata-eval100.0%
Simplified100.0%
Taylor expanded in y around inf 88.5%
if -3.59999999999999998e56 < y < 1.08e-27 or 1.05e20 < y < 7.5e73Initial program 100.0%
remove-double-neg100.0%
+-commutative100.0%
distribute-neg-frac2100.0%
distribute-frac-neg100.0%
sub-neg100.0%
distribute-neg-in100.0%
remove-double-neg100.0%
+-commutative100.0%
sub-neg100.0%
neg-sub0100.0%
associate--r-100.0%
metadata-eval100.0%
metadata-eval100.0%
+-commutative100.0%
+-commutative100.0%
associate-+r+100.0%
metadata-eval100.0%
Simplified100.0%
Taylor expanded in y around 0 79.0%
mul-1-neg79.0%
distribute-neg-frac279.0%
neg-sub079.0%
associate-+l-79.0%
neg-sub079.0%
+-commutative79.0%
unsub-neg79.0%
Simplified79.0%
if 1.08e-27 < y < 1.05e20Initial program 100.0%
remove-double-neg100.0%
+-commutative100.0%
distribute-neg-frac2100.0%
distribute-frac-neg100.0%
sub-neg100.0%
distribute-neg-in100.0%
remove-double-neg100.0%
+-commutative100.0%
sub-neg100.0%
neg-sub0100.0%
associate--r-100.0%
metadata-eval100.0%
metadata-eval100.0%
+-commutative100.0%
+-commutative100.0%
associate-+r+100.0%
metadata-eval100.0%
Simplified100.0%
Taylor expanded in x around 0 81.3%
Final simplification82.5%
(FPCore (x y) :precision binary64 (if (<= y -3.7e+55) 1.0 (if (<= y 6.5e+74) (/ x (- 2.0 x)) 1.0)))
double code(double x, double y) {
double tmp;
if (y <= -3.7e+55) {
tmp = 1.0;
} else if (y <= 6.5e+74) {
tmp = x / (2.0 - x);
} else {
tmp = 1.0;
}
return tmp;
}
real(8) function code(x, y)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8) :: tmp
if (y <= (-3.7d+55)) then
tmp = 1.0d0
else if (y <= 6.5d+74) then
tmp = x / (2.0d0 - x)
else
tmp = 1.0d0
end if
code = tmp
end function
public static double code(double x, double y) {
double tmp;
if (y <= -3.7e+55) {
tmp = 1.0;
} else if (y <= 6.5e+74) {
tmp = x / (2.0 - x);
} else {
tmp = 1.0;
}
return tmp;
}
def code(x, y): tmp = 0 if y <= -3.7e+55: tmp = 1.0 elif y <= 6.5e+74: tmp = x / (2.0 - x) else: tmp = 1.0 return tmp
function code(x, y) tmp = 0.0 if (y <= -3.7e+55) tmp = 1.0; elseif (y <= 6.5e+74) tmp = Float64(x / Float64(2.0 - x)); else tmp = 1.0; end return tmp end
function tmp_2 = code(x, y) tmp = 0.0; if (y <= -3.7e+55) tmp = 1.0; elseif (y <= 6.5e+74) tmp = x / (2.0 - x); else tmp = 1.0; end tmp_2 = tmp; end
code[x_, y_] := If[LessEqual[y, -3.7e+55], 1.0, If[LessEqual[y, 6.5e+74], N[(x / N[(2.0 - x), $MachinePrecision]), $MachinePrecision], 1.0]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;y \leq -3.7 \cdot 10^{+55}:\\
\;\;\;\;1\\
\mathbf{elif}\;y \leq 6.5 \cdot 10^{+74}:\\
\;\;\;\;\frac{x}{2 - x}\\
\mathbf{else}:\\
\;\;\;\;1\\
\end{array}
\end{array}
if y < -3.7000000000000002e55 or 6.49999999999999962e74 < y Initial program 100.0%
remove-double-neg100.0%
+-commutative100.0%
distribute-neg-frac2100.0%
distribute-frac-neg100.0%
sub-neg100.0%
distribute-neg-in100.0%
remove-double-neg100.0%
+-commutative100.0%
sub-neg100.0%
neg-sub0100.0%
associate--r-100.0%
metadata-eval100.0%
metadata-eval100.0%
+-commutative100.0%
+-commutative100.0%
associate-+r+100.0%
metadata-eval100.0%
Simplified100.0%
Taylor expanded in y around inf 88.5%
if -3.7000000000000002e55 < y < 6.49999999999999962e74Initial program 100.0%
remove-double-neg100.0%
+-commutative100.0%
distribute-neg-frac2100.0%
distribute-frac-neg100.0%
sub-neg100.0%
distribute-neg-in100.0%
remove-double-neg100.0%
+-commutative100.0%
sub-neg100.0%
neg-sub0100.0%
associate--r-100.0%
metadata-eval100.0%
metadata-eval100.0%
+-commutative100.0%
+-commutative100.0%
associate-+r+100.0%
metadata-eval100.0%
Simplified100.0%
Taylor expanded in y around 0 75.6%
mul-1-neg75.6%
distribute-neg-frac275.6%
neg-sub075.6%
associate-+l-75.6%
neg-sub075.6%
+-commutative75.6%
unsub-neg75.6%
Simplified75.6%
Final simplification80.2%
(FPCore (x y) :precision binary64 (if (<= x -4e+32) -1.0 (if (<= x 3.65e+71) 1.0 -1.0)))
double code(double x, double y) {
double tmp;
if (x <= -4e+32) {
tmp = -1.0;
} else if (x <= 3.65e+71) {
tmp = 1.0;
} else {
tmp = -1.0;
}
return tmp;
}
real(8) function code(x, y)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8) :: tmp
if (x <= (-4d+32)) then
tmp = -1.0d0
else if (x <= 3.65d+71) then
tmp = 1.0d0
else
tmp = -1.0d0
end if
code = tmp
end function
public static double code(double x, double y) {
double tmp;
if (x <= -4e+32) {
tmp = -1.0;
} else if (x <= 3.65e+71) {
tmp = 1.0;
} else {
tmp = -1.0;
}
return tmp;
}
def code(x, y): tmp = 0 if x <= -4e+32: tmp = -1.0 elif x <= 3.65e+71: tmp = 1.0 else: tmp = -1.0 return tmp
function code(x, y) tmp = 0.0 if (x <= -4e+32) tmp = -1.0; elseif (x <= 3.65e+71) tmp = 1.0; else tmp = -1.0; end return tmp end
function tmp_2 = code(x, y) tmp = 0.0; if (x <= -4e+32) tmp = -1.0; elseif (x <= 3.65e+71) tmp = 1.0; else tmp = -1.0; end tmp_2 = tmp; end
code[x_, y_] := If[LessEqual[x, -4e+32], -1.0, If[LessEqual[x, 3.65e+71], 1.0, -1.0]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;x \leq -4 \cdot 10^{+32}:\\
\;\;\;\;-1\\
\mathbf{elif}\;x \leq 3.65 \cdot 10^{+71}:\\
\;\;\;\;1\\
\mathbf{else}:\\
\;\;\;\;-1\\
\end{array}
\end{array}
if x < -4.00000000000000021e32 or 3.64999999999999998e71 < x Initial program 100.0%
remove-double-neg100.0%
+-commutative100.0%
distribute-neg-frac2100.0%
distribute-frac-neg100.0%
sub-neg100.0%
distribute-neg-in100.0%
remove-double-neg100.0%
+-commutative100.0%
sub-neg100.0%
neg-sub0100.0%
associate--r-100.0%
metadata-eval100.0%
metadata-eval100.0%
+-commutative100.0%
+-commutative100.0%
associate-+r+100.0%
metadata-eval100.0%
Simplified100.0%
Taylor expanded in x around inf 84.3%
if -4.00000000000000021e32 < x < 3.64999999999999998e71Initial program 100.0%
remove-double-neg100.0%
+-commutative100.0%
distribute-neg-frac2100.0%
distribute-frac-neg100.0%
sub-neg100.0%
distribute-neg-in100.0%
remove-double-neg100.0%
+-commutative100.0%
sub-neg100.0%
neg-sub0100.0%
associate--r-100.0%
metadata-eval100.0%
metadata-eval100.0%
+-commutative100.0%
+-commutative100.0%
associate-+r+100.0%
metadata-eval100.0%
Simplified100.0%
Taylor expanded in y around inf 50.3%
Final simplification63.6%
(FPCore (x y) :precision binary64 -1.0)
double code(double x, double y) {
return -1.0;
}
real(8) function code(x, y)
real(8), intent (in) :: x
real(8), intent (in) :: y
code = -1.0d0
end function
public static double code(double x, double y) {
return -1.0;
}
def code(x, y): return -1.0
function code(x, y) return -1.0 end
function tmp = code(x, y) tmp = -1.0; end
code[x_, y_] := -1.0
\begin{array}{l}
\\
-1
\end{array}
Initial program 100.0%
remove-double-neg100.0%
+-commutative100.0%
distribute-neg-frac2100.0%
distribute-frac-neg100.0%
sub-neg100.0%
distribute-neg-in100.0%
remove-double-neg100.0%
+-commutative100.0%
sub-neg100.0%
neg-sub0100.0%
associate--r-100.0%
metadata-eval100.0%
metadata-eval100.0%
+-commutative100.0%
+-commutative100.0%
associate-+r+100.0%
metadata-eval100.0%
Simplified100.0%
Taylor expanded in x around inf 37.7%
Final simplification37.7%
(FPCore (x y) :precision binary64 (let* ((t_0 (- 2.0 (+ x y)))) (- (/ x t_0) (/ y t_0))))
double code(double x, double y) {
double t_0 = 2.0 - (x + y);
return (x / t_0) - (y / t_0);
}
real(8) function code(x, y)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8) :: t_0
t_0 = 2.0d0 - (x + y)
code = (x / t_0) - (y / t_0)
end function
public static double code(double x, double y) {
double t_0 = 2.0 - (x + y);
return (x / t_0) - (y / t_0);
}
def code(x, y): t_0 = 2.0 - (x + y) return (x / t_0) - (y / t_0)
function code(x, y) t_0 = Float64(2.0 - Float64(x + y)) return Float64(Float64(x / t_0) - Float64(y / t_0)) end
function tmp = code(x, y) t_0 = 2.0 - (x + y); tmp = (x / t_0) - (y / t_0); end
code[x_, y_] := Block[{t$95$0 = N[(2.0 - N[(x + y), $MachinePrecision]), $MachinePrecision]}, N[(N[(x / t$95$0), $MachinePrecision] - N[(y / t$95$0), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := 2 - \left(x + y\right)\\
\frac{x}{t\_0} - \frac{y}{t\_0}
\end{array}
\end{array}
herbie shell --seed 2024095
(FPCore (x y)
:name "Data.Colour.RGB:hslsv from colour-2.3.3, C"
:precision binary64
:alt
(- (/ x (- 2.0 (+ x y))) (/ y (- 2.0 (+ x y))))
(/ (- x y) (- 2.0 (+ x y))))