Minutes_2020_09_29

Numba Meeting: 2020-09-29

Attendees: Graham, Guilherme, Hameer, Pearu, Stuart, Todd, Val, Siu

0. Feature Discussion

• Refprune status #6266

  • and potential optimisation

  fanout

  
  digraph {
      node [shape=box]
  
      A [label="A\nincref"]
      B [label="B\ndecref"]
      C [label="C\ndecref"]
      A -> B, C
      B -> D
      C -> E
  
  }
  

  • refops balanced for all outgoing edges

  draft pseudo algorithm (Siu needs to update this):

  • for each children of A as cur-node:

    • find a decref that:
      • node dominates decref
      • decref postdom cur-node
    • if not found:
      • recurse algorithm at this point

  • if decref is found for all children, prune is possible

  • Stats from python runtests.py numba/tests/test_typedlist.py

  Ran 86 tests in 79.457s
  
  refprune stats per-BB 5542 diamond 116 fanout 41 fanout+raise 223
  

  • Turn on sanitzers
  • Where the refprune pass should be inserted in the optimization pipeline?
    • inlining reveals more refops to be pruned
  • Put a level to enable which refprune subpass
    • Stuart thinks this is a good idea

• Type annotation (TA): https://github.com/numba/numba/pull/6222

  • TA doesn't always lead to clean code
  • high verbosity
  • What does TA give us?
  • Goals of TA:
    • easier to contribute
  • Experience of TA:
    • Hameer: Helpful in sparse. Less in code that are highly generic. Depends on the code.
    • Pearu: Helpful on the user side for specifying func sigs instead of custom type system.
    • Pytorch is doing type annotations -> docstrings.
    • Hameer: not all IDEs check type annotations match up with docs etc.
    • Stuart: Can types be compounded more to decrease verbosity?

1. New Issues

• #6274 - Changes to literal behaviour between <=0.49.0 and >=0.50.0
  • used to work for the wrong reason
• #6273 - Numba np.zeros giving incorrect result and wierd behavior
  • weird structued-dtype error
• #6270 - is_serialiable raises TypeError on Python 3.8+
  • Siu to look at
• #6269 - Failed in nopython mode pipeline (step: nopython frontend)
  • very likely another llvmlite version mismatch
• #6268 - Support fortran ordered arrays in parallel accelerator
  • feature request
• #6264 - Caching: functions captured in closure
  • user suggested fix: https://github.com/numba/numba/pull/6284
• #6263 - 'CPUDispatcher' object is not subscriptable
  • user question... answered
• #6259 - Add support for ndarray 'contains'
  • PR: https://github.com/numba/numba/pull/6271
• #6256 - guvectorize in-place operations work only in some cases
  • TODO: check if this is supposed to work

Closed Issues

• #6285 - could I use the numba speed up the np.argsort ?
• #6280 - Issues using the target keyword argument with @vectorize decorator
• #6276 - numba advices to use cross2d but specified path is wrong
• #6260 - Type cannot be determined when using 'if a not in b' in list construction
• #6258 - Support string datatype declaration for numpy array creation
• #6257 - .ptp() not @njit compilable anymore?

2. New PRs

• #6287 - Fix #5713: cache typed dict and list functions
• #6286 - Add np.allclose support ref. issue #4074
  • May be too involved, may not do what Numpy does, needs a closer look.
• #6284 - Prevent cache busting by the UUID of Dispatcher
• #6283 - Add note on how public CI is impl and what users can do to help.
• #6279 - Add support for np.asarray_chkfinite [WIP] [need help]
• #6278 - Improve typed list performance.
• #6275 - Switch on SLP vectorize.
• #6272 - Feature/swapaxes
• #6271 - Support ndarray contains
  • need to guard against a key type mismatch? Numba checks this alreay with casting and can determine what kind of cast it is.
• *** #6266 - Use custom LLVM refcount pruning pass

Closed PRs

• #6282 - Remove docs on Python 2(.7) EOL.
• #6281 - Remove numba.jitclass shim as per deprecation schedule.
• #6277 - fix: cross2d wrong doc. reference (issue #6276)
• #6267 - speed up a couple of really slow unittests
• #6265 - Fix #6260
• #6262 - Support dtype from str literal.
• #6261 - Add np.ndarray.ptp() support.

3. Next Release: Version 0.52.0, RC=7th Oct, Final=RC+=~3weeks?

• Requests for 0.52
  • Fast(er) typed.List/typed.Dict? Doesn't have to be in 0.52, next 3-5 months is fine.

4. Upcoming tasks