cast __m512 to __m512d

Hey all,

simple question:

How does the cast operation _mm512_castps_pd work?

A __m512 data type holds 16 floats i.e. 16 elements. Contrary to that a __m512d data type can only hold 8 elements -- so what happens if I use the following instructions

__m512   a_ = _mm512_set1_ps( 2.0 );
__m512d b_ = _mm512_castps_pd( a_ );

Is it possible to load data from memory with _mm512_load_ps and then do a "cast operation" from float to double precision into two __m512d registers.

Thanks

Patrick