[petsc-dev] Man pages usage of "Collective on XXX"

[Hapla Vaclav]

On 6 Feb 2019, at 21:08, Matthew Knepley via petsc-dev <petsc-dev at mcs.anl.gov<mailto:petsc-dev at mcs.anl.gov>> wrote:

On Wed, Feb 6, 2019 at 3:03 PM Dave May via petsc-dev <petsc-dev at mcs.anl.gov<mailto:petsc-dev at mcs.anl.gov>> wrote:
* I notice that most man pages will say
  Collective on <type>
e.g.
https://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/DMDA/DMDACreate.html

* Some others say
  Collective on <implementation-name>

e.g.
https://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/DMDA/DMDACreateNaturalVector.html

or

https://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/DM/DMCompositeAddDM.html

In the former, at least the word "DMDA" gets linked back to the implementation, whilst in the latter "DMComposite" does not.

Should "Collective on <implementation-name>" be avoided?
It is potentially somewhat unclear given that the name of the implementation does not appear anywhere in the arg  list (type or variable name).

That said, "collective on <type>" could be similarly criticized if a method existed with two args of the same type.

* Many of the methods in this file

  www.mcs.anl.gov/petsc/petsc-current/src/dm/impls/shell/dmshell.c.html<http://www.mcs.anl.gov/petsc/petsc-current/src/dm/impls/shell/dmshell.c.html>

simply say "Collective" (without a type or implementation name), or they say "Logically Collective on XXX"

I do realize that there is a pattern that the statement "collective on xxx" or "not collective" applies (implicitly) to the first argument of any PETSc function call (at least that I've come across) so possibly just indicating the method as "Collective" might suffice (assuming (i) there is a pattern and (ii) everyone knows about the pattern).

Q: Should I make a PR to unify these man pages (and any others I spot) to just say "Collective on <type>"?

This has always bugged me. It should say, I think, 'Collective on <arg name>", or "Logically collective on <arg name>".

+1

I also think it's a property of the concrete argument and not the class. But it would be an epic task to rewrite it everywhere.

Vaclav


  Thanks,

     Matt

Thanks,
  Dave




--
What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.
-- Norbert Wiener

https://www.cse.buffalo.edu/~knepley/<http://www.cse.buffalo.edu/~knepley/>

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