A new release candidate of MPICH, 4.1rc4, is now available for download. This release contains fixes for shared memory initialization and MPI_Allgatherv calls on intracommunicators of size=1. As a reminder, only critical bugs will be fixed before the 4.1 GA release. Please give it a try and report any issues! You can find the release on our downloads page (https://www.mpich.org/downloads/) Regards, The MPICH team =============================================================================== Changes in 4.1 =============================================================================== # Thread-cs in ch4 changed to per-vci. # Testsuite (test/mpi) is configured separately from mpich configure. # Added options in autogen to accelerate CI builds, including using pre-built sub-modules. Added -yaksa-depth option to generate shallower yaksa pup code for faster build and smaller binaries. # Support singleton init using hydra. # On OSX, link option flat_namespace is no longer turned on by default. # Generate mpi.mod Fortran interfaces using Python 3. For many compilers, including gfortran, flags such as -fallow-mismatched-args is no longer necessary. # Fixed message queue debugger interface in ch4. # PMI (src/pmi) is refactored as a subdir and can be separately distributed. # Added MPIX_Comm_get_failed. # Experimental MPIX stream API to enable explicit thread contexts. # Experimental MPIX gpu enqueue API. It currently only supports CUDA streams. # Delays GPU resource allocation in yaksa. # CH3 nemesis ofi netmod is removed. # New collective algorithms. All collective algorithms are listed in src/mpi/coll/coll_algorithms.txt # Removed hydra2. We will port unique features of hydra2, including tree-launching, to hydra in the future release. # Added in-repository wiki documentation. # Added stream workq to support optimizations for enqueue operations. # Better support for large count APIs by eliminating type conversion issues. # Hydra now uses libpmi (src/pmi) for handling PMI messages. # Many bug fixes and enhancements. A full list of changes since 4.0.3 can be found here: https://github.com/pmodels/mpich/compare/v4.0.3...v4.1rc4