
(FPCore (x y z) :precision binary64 (+ x (/ (- y x) z)))
double code(double x, double y, double z) {
return x + ((y - x) / z);
}
real(8) function code(x, y, z)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
code = x + ((y - x) / z)
end function
public static double code(double x, double y, double z) {
return x + ((y - x) / z);
}
def code(x, y, z): return x + ((y - x) / z)
function code(x, y, z) return Float64(x + Float64(Float64(y - x) / z)) end
function tmp = code(x, y, z) tmp = x + ((y - x) / z); end
code[x_, y_, z_] := N[(x + N[(N[(y - x), $MachinePrecision] / z), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
x + \frac{y - x}{z}
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 6 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (x y z) :precision binary64 (+ x (/ (- y x) z)))
double code(double x, double y, double z) {
return x + ((y - x) / z);
}
real(8) function code(x, y, z)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
code = x + ((y - x) / z)
end function
public static double code(double x, double y, double z) {
return x + ((y - x) / z);
}
def code(x, y, z): return x + ((y - x) / z)
function code(x, y, z) return Float64(x + Float64(Float64(y - x) / z)) end
function tmp = code(x, y, z) tmp = x + ((y - x) / z); end
code[x_, y_, z_] := N[(x + N[(N[(y - x), $MachinePrecision] / z), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
x + \frac{y - x}{z}
\end{array}
(FPCore (x y z) :precision binary64 (+ x (/ (- y x) z)))
double code(double x, double y, double z) {
return x + ((y - x) / z);
}
real(8) function code(x, y, z)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
code = x + ((y - x) / z)
end function
public static double code(double x, double y, double z) {
return x + ((y - x) / z);
}
def code(x, y, z): return x + ((y - x) / z)
function code(x, y, z) return Float64(x + Float64(Float64(y - x) / z)) end
function tmp = code(x, y, z) tmp = x + ((y - x) / z); end
code[x_, y_, z_] := N[(x + N[(N[(y - x), $MachinePrecision] / z), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
x + \frac{y - x}{z}
\end{array}
Initial program 100.0%
Final simplification100.0%
(FPCore (x y z)
:precision binary64
(let* ((t_0 (/ (- x) z)))
(if (<= z -0.68)
x
(if (<= z -1.1e-31)
(/ y z)
(if (<= z -4.2e-99)
t_0
(if (<= z -2.2e-171)
(/ y z)
(if (<= z 1.45e-229)
t_0
(if (<= z 1.6e-192) (/ y z) (if (<= z 2.95e-10) t_0 x)))))))))
double code(double x, double y, double z) {
double t_0 = -x / z;
double tmp;
if (z <= -0.68) {
tmp = x;
} else if (z <= -1.1e-31) {
tmp = y / z;
} else if (z <= -4.2e-99) {
tmp = t_0;
} else if (z <= -2.2e-171) {
tmp = y / z;
} else if (z <= 1.45e-229) {
tmp = t_0;
} else if (z <= 1.6e-192) {
tmp = y / z;
} else if (z <= 2.95e-10) {
tmp = t_0;
} else {
tmp = x;
}
return tmp;
}
real(8) function code(x, y, z)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
real(8) :: t_0
real(8) :: tmp
t_0 = -x / z
if (z <= (-0.68d0)) then
tmp = x
else if (z <= (-1.1d-31)) then
tmp = y / z
else if (z <= (-4.2d-99)) then
tmp = t_0
else if (z <= (-2.2d-171)) then
tmp = y / z
else if (z <= 1.45d-229) then
tmp = t_0
else if (z <= 1.6d-192) then
tmp = y / z
else if (z <= 2.95d-10) then
tmp = t_0
else
tmp = x
end if
code = tmp
end function
public static double code(double x, double y, double z) {
double t_0 = -x / z;
double tmp;
if (z <= -0.68) {
tmp = x;
} else if (z <= -1.1e-31) {
tmp = y / z;
} else if (z <= -4.2e-99) {
tmp = t_0;
} else if (z <= -2.2e-171) {
tmp = y / z;
} else if (z <= 1.45e-229) {
tmp = t_0;
} else if (z <= 1.6e-192) {
tmp = y / z;
} else if (z <= 2.95e-10) {
tmp = t_0;
} else {
tmp = x;
}
return tmp;
}
def code(x, y, z): t_0 = -x / z tmp = 0 if z <= -0.68: tmp = x elif z <= -1.1e-31: tmp = y / z elif z <= -4.2e-99: tmp = t_0 elif z <= -2.2e-171: tmp = y / z elif z <= 1.45e-229: tmp = t_0 elif z <= 1.6e-192: tmp = y / z elif z <= 2.95e-10: tmp = t_0 else: tmp = x return tmp
function code(x, y, z) t_0 = Float64(Float64(-x) / z) tmp = 0.0 if (z <= -0.68) tmp = x; elseif (z <= -1.1e-31) tmp = Float64(y / z); elseif (z <= -4.2e-99) tmp = t_0; elseif (z <= -2.2e-171) tmp = Float64(y / z); elseif (z <= 1.45e-229) tmp = t_0; elseif (z <= 1.6e-192) tmp = Float64(y / z); elseif (z <= 2.95e-10) tmp = t_0; else tmp = x; end return tmp end
function tmp_2 = code(x, y, z) t_0 = -x / z; tmp = 0.0; if (z <= -0.68) tmp = x; elseif (z <= -1.1e-31) tmp = y / z; elseif (z <= -4.2e-99) tmp = t_0; elseif (z <= -2.2e-171) tmp = y / z; elseif (z <= 1.45e-229) tmp = t_0; elseif (z <= 1.6e-192) tmp = y / z; elseif (z <= 2.95e-10) tmp = t_0; else tmp = x; end tmp_2 = tmp; end
code[x_, y_, z_] := Block[{t$95$0 = N[((-x) / z), $MachinePrecision]}, If[LessEqual[z, -0.68], x, If[LessEqual[z, -1.1e-31], N[(y / z), $MachinePrecision], If[LessEqual[z, -4.2e-99], t$95$0, If[LessEqual[z, -2.2e-171], N[(y / z), $MachinePrecision], If[LessEqual[z, 1.45e-229], t$95$0, If[LessEqual[z, 1.6e-192], N[(y / z), $MachinePrecision], If[LessEqual[z, 2.95e-10], t$95$0, x]]]]]]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{-x}{z}\\
\mathbf{if}\;z \leq -0.68:\\
\;\;\;\;x\\
\mathbf{elif}\;z \leq -1.1 \cdot 10^{-31}:\\
\;\;\;\;\frac{y}{z}\\
\mathbf{elif}\;z \leq -4.2 \cdot 10^{-99}:\\
\;\;\;\;t_0\\
\mathbf{elif}\;z \leq -2.2 \cdot 10^{-171}:\\
\;\;\;\;\frac{y}{z}\\
\mathbf{elif}\;z \leq 1.45 \cdot 10^{-229}:\\
\;\;\;\;t_0\\
\mathbf{elif}\;z \leq 1.6 \cdot 10^{-192}:\\
\;\;\;\;\frac{y}{z}\\
\mathbf{elif}\;z \leq 2.95 \cdot 10^{-10}:\\
\;\;\;\;t_0\\
\mathbf{else}:\\
\;\;\;\;x\\
\end{array}
\end{array}
if z < -0.680000000000000049 or 2.9500000000000002e-10 < z Initial program 100.0%
remove-double-neg100.0%
neg-sub0100.0%
neg-sub0100.0%
remove-double-neg100.0%
--rgt-identity100.0%
associate-+l-100.0%
div0100.0%
div-sub100.0%
associate-+l-100.0%
neg-sub0100.0%
+-commutative100.0%
sub-neg100.0%
Simplified100.0%
Taylor expanded in x around inf 73.5%
Taylor expanded in z around inf 69.9%
if -0.680000000000000049 < z < -1.10000000000000005e-31 or -4.19999999999999968e-99 < z < -2.2000000000000001e-171 or 1.45e-229 < z < 1.6000000000000001e-192Initial program 100.0%
remove-double-neg100.0%
neg-sub0100.0%
neg-sub0100.0%
remove-double-neg100.0%
--rgt-identity100.0%
associate-+l-100.0%
div0100.0%
div-sub100.0%
associate-+l-100.0%
neg-sub0100.0%
+-commutative100.0%
sub-neg100.0%
Simplified100.0%
Taylor expanded in x around 0 72.2%
neg-mul-172.2%
distribute-neg-frac72.2%
Simplified72.2%
Taylor expanded in x around 0 72.0%
if -1.10000000000000005e-31 < z < -4.19999999999999968e-99 or -2.2000000000000001e-171 < z < 1.45e-229 or 1.6000000000000001e-192 < z < 2.9500000000000002e-10Initial program 100.0%
remove-double-neg100.0%
neg-sub0100.0%
neg-sub0100.0%
remove-double-neg100.0%
--rgt-identity100.0%
associate-+l-100.0%
div0100.0%
div-sub100.0%
associate-+l-100.0%
neg-sub0100.0%
+-commutative100.0%
sub-neg100.0%
Simplified100.0%
Taylor expanded in x around inf 70.9%
Taylor expanded in z around 0 70.7%
mul-1-neg70.7%
distribute-frac-neg70.7%
Simplified70.7%
Final simplification70.5%
(FPCore (x y z)
:precision binary64
(let* ((t_0 (+ x (/ y z))) (t_1 (/ (- x) z)))
(if (<= z -2.9e-47)
t_0
(if (<= z -1.65e-98)
t_1
(if (<= z -1.8e-170)
t_0
(if (<= z 1.6e-229)
t_1
(if (<= z 1.05e-191) (/ y z) (if (<= z 1.8e-15) t_1 t_0))))))))
double code(double x, double y, double z) {
double t_0 = x + (y / z);
double t_1 = -x / z;
double tmp;
if (z <= -2.9e-47) {
tmp = t_0;
} else if (z <= -1.65e-98) {
tmp = t_1;
} else if (z <= -1.8e-170) {
tmp = t_0;
} else if (z <= 1.6e-229) {
tmp = t_1;
} else if (z <= 1.05e-191) {
tmp = y / z;
} else if (z <= 1.8e-15) {
tmp = t_1;
} else {
tmp = t_0;
}
return tmp;
}
real(8) function code(x, y, z)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
real(8) :: t_0
real(8) :: t_1
real(8) :: tmp
t_0 = x + (y / z)
t_1 = -x / z
if (z <= (-2.9d-47)) then
tmp = t_0
else if (z <= (-1.65d-98)) then
tmp = t_1
else if (z <= (-1.8d-170)) then
tmp = t_0
else if (z <= 1.6d-229) then
tmp = t_1
else if (z <= 1.05d-191) then
tmp = y / z
else if (z <= 1.8d-15) then
tmp = t_1
else
tmp = t_0
end if
code = tmp
end function
public static double code(double x, double y, double z) {
double t_0 = x + (y / z);
double t_1 = -x / z;
double tmp;
if (z <= -2.9e-47) {
tmp = t_0;
} else if (z <= -1.65e-98) {
tmp = t_1;
} else if (z <= -1.8e-170) {
tmp = t_0;
} else if (z <= 1.6e-229) {
tmp = t_1;
} else if (z <= 1.05e-191) {
tmp = y / z;
} else if (z <= 1.8e-15) {
tmp = t_1;
} else {
tmp = t_0;
}
return tmp;
}
def code(x, y, z): t_0 = x + (y / z) t_1 = -x / z tmp = 0 if z <= -2.9e-47: tmp = t_0 elif z <= -1.65e-98: tmp = t_1 elif z <= -1.8e-170: tmp = t_0 elif z <= 1.6e-229: tmp = t_1 elif z <= 1.05e-191: tmp = y / z elif z <= 1.8e-15: tmp = t_1 else: tmp = t_0 return tmp
function code(x, y, z) t_0 = Float64(x + Float64(y / z)) t_1 = Float64(Float64(-x) / z) tmp = 0.0 if (z <= -2.9e-47) tmp = t_0; elseif (z <= -1.65e-98) tmp = t_1; elseif (z <= -1.8e-170) tmp = t_0; elseif (z <= 1.6e-229) tmp = t_1; elseif (z <= 1.05e-191) tmp = Float64(y / z); elseif (z <= 1.8e-15) tmp = t_1; else tmp = t_0; end return tmp end
function tmp_2 = code(x, y, z) t_0 = x + (y / z); t_1 = -x / z; tmp = 0.0; if (z <= -2.9e-47) tmp = t_0; elseif (z <= -1.65e-98) tmp = t_1; elseif (z <= -1.8e-170) tmp = t_0; elseif (z <= 1.6e-229) tmp = t_1; elseif (z <= 1.05e-191) tmp = y / z; elseif (z <= 1.8e-15) tmp = t_1; else tmp = t_0; end tmp_2 = tmp; end
code[x_, y_, z_] := Block[{t$95$0 = N[(x + N[(y / z), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[((-x) / z), $MachinePrecision]}, If[LessEqual[z, -2.9e-47], t$95$0, If[LessEqual[z, -1.65e-98], t$95$1, If[LessEqual[z, -1.8e-170], t$95$0, If[LessEqual[z, 1.6e-229], t$95$1, If[LessEqual[z, 1.05e-191], N[(y / z), $MachinePrecision], If[LessEqual[z, 1.8e-15], t$95$1, t$95$0]]]]]]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := x + \frac{y}{z}\\
t_1 := \frac{-x}{z}\\
\mathbf{if}\;z \leq -2.9 \cdot 10^{-47}:\\
\;\;\;\;t_0\\
\mathbf{elif}\;z \leq -1.65 \cdot 10^{-98}:\\
\;\;\;\;t_1\\
\mathbf{elif}\;z \leq -1.8 \cdot 10^{-170}:\\
\;\;\;\;t_0\\
\mathbf{elif}\;z \leq 1.6 \cdot 10^{-229}:\\
\;\;\;\;t_1\\
\mathbf{elif}\;z \leq 1.05 \cdot 10^{-191}:\\
\;\;\;\;\frac{y}{z}\\
\mathbf{elif}\;z \leq 1.8 \cdot 10^{-15}:\\
\;\;\;\;t_1\\
\mathbf{else}:\\
\;\;\;\;t_0\\
\end{array}
\end{array}
if z < -2.9e-47 or -1.6500000000000001e-98 < z < -1.8000000000000002e-170 or 1.8000000000000001e-15 < z Initial program 100.0%
remove-double-neg100.0%
neg-sub0100.0%
neg-sub0100.0%
remove-double-neg100.0%
--rgt-identity100.0%
associate-+l-100.0%
div0100.0%
div-sub100.0%
associate-+l-100.0%
neg-sub0100.0%
+-commutative100.0%
sub-neg100.0%
Simplified100.0%
Taylor expanded in x around 0 92.0%
neg-mul-192.0%
distribute-neg-frac92.0%
Simplified92.0%
sub-neg92.0%
distribute-frac-neg92.0%
remove-double-neg92.0%
+-commutative92.0%
Applied egg-rr92.0%
if -2.9e-47 < z < -1.6500000000000001e-98 or -1.8000000000000002e-170 < z < 1.60000000000000007e-229 or 1.04999999999999993e-191 < z < 1.8000000000000001e-15Initial program 100.0%
remove-double-neg100.0%
neg-sub0100.0%
neg-sub0100.0%
remove-double-neg100.0%
--rgt-identity100.0%
associate-+l-100.0%
div0100.0%
div-sub100.0%
associate-+l-100.0%
neg-sub0100.0%
+-commutative100.0%
sub-neg100.0%
Simplified100.0%
Taylor expanded in x around inf 71.6%
Taylor expanded in z around 0 71.6%
mul-1-neg71.6%
distribute-frac-neg71.6%
Simplified71.6%
if 1.60000000000000007e-229 < z < 1.04999999999999993e-191Initial program 99.9%
remove-double-neg99.9%
neg-sub099.9%
neg-sub099.9%
remove-double-neg99.9%
--rgt-identity99.9%
associate-+l-99.9%
div099.9%
div-sub99.9%
associate-+l-99.9%
neg-sub099.9%
+-commutative99.9%
sub-neg99.9%
Simplified99.9%
Taylor expanded in x around 0 67.1%
neg-mul-167.1%
distribute-neg-frac67.1%
Simplified67.1%
Taylor expanded in x around 0 67.1%
Final simplification82.6%
(FPCore (x y z) :precision binary64 (if (or (<= x -1.1e-43) (not (<= x 5.4e+26))) (- x (/ x z)) (+ x (/ y z))))
double code(double x, double y, double z) {
double tmp;
if ((x <= -1.1e-43) || !(x <= 5.4e+26)) {
tmp = x - (x / z);
} else {
tmp = x + (y / z);
}
return tmp;
}
real(8) function code(x, y, z)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
real(8) :: tmp
if ((x <= (-1.1d-43)) .or. (.not. (x <= 5.4d+26))) then
tmp = x - (x / z)
else
tmp = x + (y / z)
end if
code = tmp
end function
public static double code(double x, double y, double z) {
double tmp;
if ((x <= -1.1e-43) || !(x <= 5.4e+26)) {
tmp = x - (x / z);
} else {
tmp = x + (y / z);
}
return tmp;
}
def code(x, y, z): tmp = 0 if (x <= -1.1e-43) or not (x <= 5.4e+26): tmp = x - (x / z) else: tmp = x + (y / z) return tmp
function code(x, y, z) tmp = 0.0 if ((x <= -1.1e-43) || !(x <= 5.4e+26)) tmp = Float64(x - Float64(x / z)); else tmp = Float64(x + Float64(y / z)); end return tmp end
function tmp_2 = code(x, y, z) tmp = 0.0; if ((x <= -1.1e-43) || ~((x <= 5.4e+26))) tmp = x - (x / z); else tmp = x + (y / z); end tmp_2 = tmp; end
code[x_, y_, z_] := If[Or[LessEqual[x, -1.1e-43], N[Not[LessEqual[x, 5.4e+26]], $MachinePrecision]], N[(x - N[(x / z), $MachinePrecision]), $MachinePrecision], N[(x + N[(y / z), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;x \leq -1.1 \cdot 10^{-43} \lor \neg \left(x \leq 5.4 \cdot 10^{+26}\right):\\
\;\;\;\;x - \frac{x}{z}\\
\mathbf{else}:\\
\;\;\;\;x + \frac{y}{z}\\
\end{array}
\end{array}
if x < -1.09999999999999999e-43 or 5.4e26 < x Initial program 100.0%
remove-double-neg100.0%
neg-sub0100.0%
neg-sub0100.0%
remove-double-neg100.0%
--rgt-identity100.0%
associate-+l-100.0%
div0100.0%
div-sub100.0%
associate-+l-100.0%
neg-sub0100.0%
+-commutative100.0%
sub-neg100.0%
Simplified100.0%
Taylor expanded in x around inf 88.7%
if -1.09999999999999999e-43 < x < 5.4e26Initial program 100.0%
remove-double-neg100.0%
neg-sub0100.0%
neg-sub0100.0%
remove-double-neg100.0%
--rgt-identity100.0%
associate-+l-100.0%
div0100.0%
div-sub100.0%
associate-+l-100.0%
neg-sub0100.0%
+-commutative100.0%
sub-neg100.0%
Simplified100.0%
Taylor expanded in x around 0 83.5%
neg-mul-183.5%
distribute-neg-frac83.5%
Simplified83.5%
sub-neg83.5%
distribute-frac-neg83.5%
remove-double-neg83.5%
+-commutative83.5%
Applied egg-rr83.5%
Final simplification86.6%
(FPCore (x y z) :precision binary64 (if (<= z -0.68) x (if (<= z 2.2e+70) (/ y z) x)))
double code(double x, double y, double z) {
double tmp;
if (z <= -0.68) {
tmp = x;
} else if (z <= 2.2e+70) {
tmp = y / z;
} else {
tmp = x;
}
return tmp;
}
real(8) function code(x, y, z)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
real(8) :: tmp
if (z <= (-0.68d0)) then
tmp = x
else if (z <= 2.2d+70) then
tmp = y / z
else
tmp = x
end if
code = tmp
end function
public static double code(double x, double y, double z) {
double tmp;
if (z <= -0.68) {
tmp = x;
} else if (z <= 2.2e+70) {
tmp = y / z;
} else {
tmp = x;
}
return tmp;
}
def code(x, y, z): tmp = 0 if z <= -0.68: tmp = x elif z <= 2.2e+70: tmp = y / z else: tmp = x return tmp
function code(x, y, z) tmp = 0.0 if (z <= -0.68) tmp = x; elseif (z <= 2.2e+70) tmp = Float64(y / z); else tmp = x; end return tmp end
function tmp_2 = code(x, y, z) tmp = 0.0; if (z <= -0.68) tmp = x; elseif (z <= 2.2e+70) tmp = y / z; else tmp = x; end tmp_2 = tmp; end
code[x_, y_, z_] := If[LessEqual[z, -0.68], x, If[LessEqual[z, 2.2e+70], N[(y / z), $MachinePrecision], x]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;z \leq -0.68:\\
\;\;\;\;x\\
\mathbf{elif}\;z \leq 2.2 \cdot 10^{+70}:\\
\;\;\;\;\frac{y}{z}\\
\mathbf{else}:\\
\;\;\;\;x\\
\end{array}
\end{array}
if z < -0.680000000000000049 or 2.20000000000000001e70 < z Initial program 100.0%
remove-double-neg100.0%
neg-sub0100.0%
neg-sub0100.0%
remove-double-neg100.0%
--rgt-identity100.0%
associate-+l-100.0%
div0100.0%
div-sub100.0%
associate-+l-100.0%
neg-sub0100.0%
+-commutative100.0%
sub-neg100.0%
Simplified100.0%
Taylor expanded in x around inf 78.7%
Taylor expanded in z around inf 77.2%
if -0.680000000000000049 < z < 2.20000000000000001e70Initial program 100.0%
remove-double-neg100.0%
neg-sub0100.0%
neg-sub0100.0%
remove-double-neg100.0%
--rgt-identity100.0%
associate-+l-100.0%
div0100.0%
div-sub100.0%
associate-+l-100.0%
neg-sub0100.0%
+-commutative100.0%
sub-neg100.0%
Simplified100.0%
Taylor expanded in x around 0 52.2%
neg-mul-152.2%
distribute-neg-frac52.2%
Simplified52.2%
Taylor expanded in x around 0 46.3%
Final simplification57.6%
(FPCore (x y z) :precision binary64 x)
double code(double x, double y, double z) {
return x;
}
real(8) function code(x, y, z)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
code = x
end function
public static double code(double x, double y, double z) {
return x;
}
def code(x, y, z): return x
function code(x, y, z) return x end
function tmp = code(x, y, z) tmp = x; end
code[x_, y_, z_] := x
\begin{array}{l}
\\
x
\end{array}
Initial program 100.0%
remove-double-neg100.0%
neg-sub0100.0%
neg-sub0100.0%
remove-double-neg100.0%
--rgt-identity100.0%
associate-+l-100.0%
div0100.0%
div-sub100.0%
associate-+l-100.0%
neg-sub0100.0%
+-commutative100.0%
sub-neg100.0%
Simplified100.0%
Taylor expanded in x around inf 66.7%
Taylor expanded in z around inf 33.6%
Final simplification33.6%
herbie shell --seed 2023318
(FPCore (x y z)
:name "Statistics.Sample:$swelfordMean from math-functions-0.1.5.2"
:precision binary64
(+ x (/ (- y x) z)))