◆ group()

downgrade_t<Value> boost::simd::group ( Value const &  x,
Value const &  y 

This function object aggregates two boost::simd::pack of basic type T and cardinal N into a single boost::simd::pack of cardinal 2*N and using a type twice smaller than T.

Conversion of values during this operations are made using the C language conversion rules and may induce roll over.

Header <boost/simd/function/group.hpp>
For any type T and integral constant N, consider two value x and y of type boost::simd::pack<T,N>. The following code:
auto r = group(x, y);
is equivalent to:
boost::simd::downgrade_t< boost::simd::pack<T,N> > r{x[0], ..., x[N-1], y[0], ..., y[N-1]};
xFirst pack to aggregate
ySecond pack to aggregate
The aggregation of all values in its arguments, converted to the downgraded type.