Is SNode layout mutable at compile/runtime? Any ongoing work on automatic SNode layout optimization?

[YuanSha0]

Hi, I have two high-level questions about Taichi's SNode system:

1. SNode layout mutability

• Before kernels are actually run (but after I define fields and their SNode layout), is the SNode layout considered already fixed for that process?
• After kernels are compiled, is switching to a different SNode layout supported at runtime, or does that require rebuilding/resetting everything?

2. Automatic SNode layout

• Is there any ongoing work or discussion around automatic SNode layout optimization / automatic selection of SNode structures, instead of fully manual tuning?

Thank you!