Minutes_2022_12_13

Numba Meeting: 2022-12-13

Attendees: Val, Andre Masella, Graham Markall, Ianna Osborne, Luk, Matthew Murray, Guilherme, stuart, Todd A. Anderson, Siu, brandon willard, Kaustubh Chaudhari FPOC (last week): Val FPOC (incoming): Andre

NOTE: All communication is subject to the Numba Code of Conduct.

Please refer to this calendar for the next meeting date.

0. Discussion

• 3.11 support via numba-hatchery (val)
  • In progress, should be done this week.
  • Issue tracking is #8667
• Move C code to use heap types instead of static types? From #8669.
  • we have values initialized statically, but that makes assumptions about the Python interpeter's internal structures that wrong
  • could provide a function that creates them, but potentially wasteful and may break some C code that assumes pointer for type equal
  • could use g_once_init strategy from Gtk+ that uses a horrible macro to only initialize a value once, dynamically, and then hand out copies
• 0.57 RC date?
  • Probably first or second week of February (pending package availability).
  • LLVM 14 issues are not a blocker
• RNG Generator fma issues (stuart), xref #8232:
  • Background... on some architectures (e.g. M1) NumPy compiled binaries use fma instructions in the RNG module, Numba by default does not generate these instructions (need fp-contract enabled).
  • It seems like large (1000s of ULP) mistmatches can occur in some distributions, particularly those where there's a cumulative effect.
  • Is it likely/possible that use fma instructions could "alter" programs/properties of programs (should be no!? programs should be designed against this).
  • Should users be warned that on some architectures NumPy/Numba RNG "sequences" could be quite different (1000s of ULPs). Docs warning vs. runtime?
  • possible to have a distribution that would be affected, but unclear if that is very unlikely or not
  • we should notify NumPy about this
  • change the test for the ULP level on the M1
  • Clang 14 set fp-contract=on according to https://discourse.llvm.org/t/fp-contraction-fma-on-by-default/64975
• Removal of mk_unique_var #8323 (stuart)
  • desire to use scopes to generate unique variable names, but parfors scopes are tricky
  • no contract for how scopes work when generating new code and this can lead to collisions in names

New "Ready for Review" PRs

1. New Issues

• #8646 - cannot infer type of empty numpy array in local scope of jitclass, although explicitly given.
  • low priority; not actually a jitclass issue
• #8647 - [ANN] Winter break 2023---reduced availability from Dec 17 - Jan 8
• #8652 - Segfault in @njit(parallel=True)-decorated function
  • probably mostly(?) a parfors problem and incorrect assumptions about integer domains
• #8653 - Multidimensional arrays made with np.array(dtype=complex128) are broken
  • related to a reflected list problem that may not be fixable
  • assertion in generated code should be improved to help users undertand problem
• #8654 - literal_unroll with empty iterables
  • not critical given there exists a path to avoid
• #8657 - Check test shards do not accidentally overlap
  • test_azure_config covers this with new tests?
• #8658 - [FEA] Add Support for linking C/C++ with @numba.jit functions
• #8664 - Caching fails when default argument value is nan
  • NaN inequality strikes again
• #8665 - Lowering Error
• #8667 - Create Dockerfile to allow easy access/testing of Numba with Python 3.11 support

Closed Issues

2. New PRs

• #8650 - Split up parfor pass
  • to be abandoned; will close
• #8655 - Support Optional(...) in Typed List
  • could be done, but performance is a problem?
• #8656 - Testhound/fp16 cpu operators
  • waiting for more implementation
• #8659 - Preserve module name of jitted class
  • Siu to review
• #8661 - Make external compiler discovery lazy in the test suite.
  • not required since not the root problem
• #8662 - Add support for .nbytes accessor for numpy arrays
  • old API
• #8663 - Add .tobytes() method for Numpy arrays
  • old API; should be fixed
• #8666 - Updates for Python 3.8 baseline/Python 3.11 migration
  • helping to reduce diff for 3.11
• llvmlite#896 - drop upper limit on Python for conda recipe

Closed PRs

• #8648 - Add overload to handle int(s: str)
• merged - #8649 - Remove numba.core.overload_glue module.
• #8651 - Try re-enabling involved inlining test on Python 3.8+
• #8660 - Preserve PR #8319 commit history

3. Next Release: Version 0.57.0/0.40.0, RC Jan 2023