[QST] why have Int<2>{} in coalesce_x function when last shape value equal to constant one.

[Shan19900305]

In function coalesce_x, shape value is using default Int<2>{} when last shape value equal to constant one. Why need to do this?

`
template <class Shape, class Stride>
CUTE_HOST_DEVICE constexpr
auto
coalesce_x(Layout<Shape,Stride> const& layout)
{
auto flat_shape = flatten(layout.shape());
auto flat_stride = flatten(layout.stride());

constexpr int R = decltype(rank(flat_shape))::value;
if constexpr (is_constant<1, decltype(get(flat_shape))>::value) {
return detail::bw_coalesce(flat_shape, flat_stride, Int<2>{}, get(flat_stride));
} else {
return detail::bw_coalesce(flat_shape, flat_stride, get(flat_shape), get(flat_stride));
}
}
`

[ccecka]

It is an implementation detail that fixes cases like

(4,1):(1,42) o 12:1 => (4,3):(1,42)

to obey the composition definition

(A o B)(c) = A(B(c))

even when B(c) is "out-of-bounds" of A while also wanting to coalesce A before computing the result.