awkward vs libheif

Awkward Array releases roughly monthly and has spent the past year rebuilding its compute layer. The CPU kernels were migrated from a parents-based to an offsets-based representation and the GPU kernels moved onto cuda.compute, culminating in 2.10.0's roughly 5x average speedup on list reductions. Since then the work has shifted to numerical robustness — overflow-safe, numerically stable implementations of var, std, mean, covar and corr — and to closing correctness gaps in the Numba lowering path.

The project is converging on one kernel specification with CPU and GPU implementations kept in step, so new operations land on both backends in the same release rather than trailing months apart. The willingness to change internal layouts and accept different floating-point results in a minor release says the maintainers treat the kernel layer as private and are optimizing it accordingly. Recurring fixes for silent data corruption in the Numba and cppyy paths suggest the interop surfaces are where the remaining risk sits.

Expect the parents-to-offsets migration to finish on the GPU side and the cuda.compute backend to keep absorbing operations that are still CPU-only, with the lazy IR scheduling layer added in 2.11.0 as the next thing to gain visible functionality.