Posts by Hendryk Bockelmann
YAXT (Yet Another eXchange Tool)
- 23 May 2024
YAXT is a communication layer on top of the MPI library. At starting, the library generates a mapping table between source and target decomposition (communication pattern) and a specific redistribution objects, based on MPI derived datatypes, to perform the exchanges. YAXT is used by YAC for both interpolation weight generation and the coupling field exchange. To calculate the communication patterns of exchanges, more efficient than a simple MPI “all to all”, the libraries rely on a rendezvous algorithm based on a distributed directory of global indices. YAXT not only optimises the exchange pattern but also reduces the communication number, grouping the exchanged arrays on MPI derived datatypes, supposed to reduce the array copies and pack-unpack operations.
CDI-PIO (Climate Data Interface with parallel writing )
- 23 May 2024
CDI-PIO is currently used for parallelized GRIB1/GRIB2 and NetCDF output in ECHAM and ICON models. CDI-PIO is the parallel I/O component of the Climate Data Interface (CDI) that is developed and maintained by the Max-Planck-Institute for Meteorology and DKRZ. It is used by ICON, MPIOM, ECHAM, and the Climate Data Operator (CDO) toolkit. The two main I/O paths for output data are writing GRIB files using MPI-IO, and writing NetCDF4 files using HDF5 (which may then also use MPI-IO,or other VOL plugins).