Element Connectivity integer type I4/I8

[MicK7]

The MLL is enforcing the Zone_t data (meaning number of vertices and cells) to use the same integer type as Element_t section data (ie ElementConnectivity and ElementStartOffset). Thus they can be switched as a whole between I4 or I8 representation.

However, the SIDS and Mapping do not seem to specify such a constraint of coherence. We could imagine to mix I4 and I8 in the same Zone_t to minimize disk or memory footprint of Element_t nodes. Or even better use I4 in Zone_t that do not need more while using I8 in other Zone_t.

The questions are:

• What are the current practices ?
• What about adding a constraint to tell that Zone_t should be coherent within but can be different from one another in the CGNS standard ?