Environment Variable

Below a list of variables that can be exported on your environment to activate specific features of BerkeleyGW.

• export BGW_NUM_THREADS_SORT=4
  Set the number of OpenMP threads to be used in the sorting algorithm.

• export BGW_HDF5_WRITE_REDIST=1
  In Full-Frequency calculations perform a data redistribution of the frequency epsilon over contiguous chunks of memory to improve HDF5 I/O performance paying an extra communication cost.

  • Activate using: 1, T, t, Y, y
  • Deactivate using: 0, F, f, N, n
  • Default: non active

• export BGW_WFN_HDF5_INDEPENDENT=1
  Use MPIO independent instead of collective, depending on the HDF5 implementation and architecture can improve performance.

  • Activate using: 1, T, t, Y, y
  • Deactivate using: 0, F, f, N, n
  • Default: non active (H5FD_MPIO_COLLECTIVE)

• export BGW_HDF5_BANDS_COMM_STYLE=1
  Allows to change the communication style when reading in blocks of bands from WFN files.

  • 0 Native HDF5 all ranks read from file
  • 1 Using MPI collectives (BCast) (default)
  • 2 Using MPI point-to-point (Send/Recv)

• export BGW_SCALAPACK_MEM_RESCALE=0.5
  Rescale the workspace memory in ScalaPACK diagonalization calls by the provided factor.

• export BGW_SCALAPACK_ALGO=1
  Allows to select which diagonalization algorithm to use.

  • -1 or 0 PDSYEVX
  • 1 PDSYEVR
  • 2 PZHEEVD

• export BGW_ELPA_NO_GPU=1
  If ELPA is compiled with GPU support enable to switch to the CPU implementation.

  • Activate using: 1, T, t, Y, y
  • Deactivate using: 0, F, f, N, n
  • Default: non active (GPU version)