> On Oct 16, 2019, at 2:50 AM, Pierre Jolivet via petsc-dev > <petsc-dev@mcs.anl.gov> wrote: > > Hello, > I’m trying to understand what is the rationale for naming a function > ISBlockGetIndices and another ISLocalToGlobalMappingGetBlockIndices (BlockGet > vs. GetBlock).
ISBlockGetIndices returns the indices for each block; it is method that only applies too the ISBlock subclass. Given its purpose its name is perfect. ISLocalToGlobalMapping is a class that has direct support for a block size (unlike IS which has no concept of a block size, it is an abstraction of any collection of integers). ISLocalToGlobalMappingGetBlockIndices is then a method on ISLocalToGlobalMapping that gives you the block indices (one index per block). Given its purpose its name is also perfect; the method is getblockindices() Note there is also ISLocalToGlobalMappingGetIndices(). Though IS and ISLocalToGlobalMapping both begin with IS they are really not closely related. > Also, it looks to me like the implementation of ISBlockGetIndices is somehow > less versatile than ISLocalToGlobalMappingGetBlockIndices. > Indeed, I may call ISLocalToGlobalMappingGetBlockIndices with an underlying > non-block IS, while I can’t for ISBlockGetIndices, so a check must be > performed by the user, e.g., > https://www.mcs.anl.gov/petsc/petsc-current/src/vec/is/is/examples/tutorials/ex3.c.html#line58 > or this (IMHO) ugly code duplication > https://www.mcs.anl.gov/petsc/petsc-dev/src/vec/is/utils/isltog.c.html#line322. > > Thoughts and/or comments? Would it make sense to add an > ISGetBlockIndices/ISRestoreBlockIndices or would that be too confusing for > the user? For non ISBlock subclass of IS I don't know what ISGetBlockIndices is suppose to even mean. > > Thanks, > Pierre
