[Pw_forum] QE 5.1 version

[Paolo Giannozzi]

Version 5.1 of the Quantum ESPRESSO distribution is
available for download from www.quantum-espresso.org
and from qe-forge.org. See the attached relase-notes.txt
files for a list of changes, bugs fixed, incompatibilities
with previous versions or previous behavior.

Everybody who is using the Quantum ESPRESSO distribution is 
encouraged to upgrade and to report problems to the mailing 
list.

PG
-- 
Paolo Giannozzi, Dept. Chemistry&Physics&Environment, 
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222 
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New in 5.1 version:

   * "Cold restart" for Car-Parrinello dynamics
   * Calling QE from external codes made easier: see new subdirectory COUPLE
   * PW: Hybrid functionals for USPP and PAW (experimental)
   * PW: partial support to the use of k-point labels in the Brillouin zone
   * PW: Langevin dynamics with Smart Monte Carlo
   * CP and PW: Tkatchenko-Scheffler vdW correction (experimental)
   * GWW replaced by GWL (using Lanczos chains)
   * turboTDDFT: pseudo_Hermitian Lanczos algorithm and 
     Davidson-like diagonalization added
   * PWCOND with DFT+U
   * New functionals: gau-pbe, PW86 (unrevised), B86B, XDM (exchange-hole 
     dipole moment) model of dispersions, vdW-DF3, vdW-DF4 (Klimes et al),
     rVV10, optB86b-vdW, rev-vdW-DF2 
   * PHonon: Calculation of phonon dispersions using the finite displacements 
     supercell approach. See subdirectory FD/ in PHonon.
   * dynmat.x can calculate phonon contribution to dielectric tensor
   * turboTDDFT now supports hybrid functionals (only with norm-conserving
     pseudopotentials)
   * "image" parallelization re-introduced in pw.x: see code "manypw.x"

Incompatible changes in 5.1 version:

   * Initialization of MPI modified in order to simplify usage of QE routines
     from external codes. It is now possible to run an instance of QE into a
     mpi communicator passed by the external routine. Changes affect a few MPI
     initialization routines (e.g. mp_start) and some MPI related modules;
     the communicator must be explicitly specified when calling mp_* interfaces
     to low-level MPI libraries.
   * Input variable "london" should be replaced by " vdw_corr='Grimme-D2' "
   * Routine "electrons" doesn't deal any longer with non-scf cases;
     use routine "non_scf" instead. For hybrid functionals, the loops over
     the charge density and over the exchange potential have been separated.
   * Restart mechanism of pw.x changed a lot. It works ONLY if you stop
     the code cleanly with the prefix.EXIT file, or by setting "max_seconds";
     disk_io='high' no longer needed (use it ONLY if tight with memory)
     Restarting from hard crashes is no longer supported.
   * Major restructuring of DFT+U and related modules in PW: related variables
     moved to module ldaU, "swfcatom" moved to module "basis"
   * Definition of "nwordwfc" in PP/ follows the same logic as in PW/
   * Calls to "find_equiv_sites" and "writemodes" changed (fixed dimension
     "nax" removed)
   * Call to "open_buffer" changed: unit must be a valid fortran unit > 0;
     max number of records is no longer specified; a new flag explicitly
     specifies if writing to RAM buffer is required. Functionalities of 
     Modules/buffers.f90 have been considerably modified and extended.

Fixed in 5.1 version:

   * PHonon: G=0 component of the deformation potential at q=0 was incorrect
     (the contribution from the average coulomb potential, i.e. the integral 
      of the Coulomb contribution on the unit cell, was missing). For more 
     details, see M. Calandra et al. Phys. Rev. B 82 165111 , section III B.
   * PWscf: spin-polarized HSE for PAW was incorrectly implemented
   * PHonon: Gamma-specific code wasn't properly restarting in parallel
   * PHonon: epsil + paw was not working with k-point parallelization.
   * PHonon: problem with the symmetry analysis in D_6h. The problem appeared
     in special cases after the symmetry reshuffling made by the phonon code.
   * PWscf: starting with uniform charge worked only for non-spin-polarized
     calculations. Not a big deal unless one used HGH or other pseudopotentials
     without atomic charge information
   * PWscf: Forces with finite electric field (lelfield=.true.) and US PP
     were incorrect in parallel execution
   * D3: bug when the crystal has symmetry but the small group of the 
     q-point has no symmetry.
   * Bogus "file not found" error in pp.x when extracting quantities not
     requiring wave functions if these were "collected" - v.5.0.2 only
   * Some quantities calculated in real space (including the charge itself
     when tqr=.true.) were not always accurately computed in parallel
     execution if the number of planes wasn't the same for all processors
   * Bogus symmetry error in NEB due to missing re-initialization
     of fractional translations