Dear Forum Users & Developers, I am new in QE Forum - welcome to All & congratulations for excellent information exchange here and software.
Being new in GIPAW calculations I might have missed the answer browsing the Forum but did not found solution yet. The problem is that I am somehow puzzled by GIPAW calculations: - Using QE 5.0 I did compile it with Intel Fortran, MKL, openmp (more details below). No tuning, no tricks etc. just followed installation guide (./configure & make all). - While pw.x performs nicely, gipaw.x gives results that are difficult for interpretation, and I cannot really locate where the problem is. - Both pw.x and gipaw.x pass self-test; examples were no problem too. However, trying to calculate NMR spectra for slightly complex system calculations with GIPAW give results that seems to be machine dependent to the large extend. Input files and part of output are at the end; shortly "Total NMR chemical shifts in ppm:" is either 16.58 or 134.05 for the same system/element (inputs are simply copied) when calculated on two similar machines. Both computers are Intel based, compiler and libraries differ however: a) intel 11.1 (ifort); mkl 10.3 b) intel 11.1 (ifort); mkl 10.2.5.035 Playing with pseudopotentials, k-points make things even worse.., denser fft grid, density cutoff does not seems to improve results either). I use several other numerical codes on both machines - never had similar problems. I would highly appreciate any suggestions/help toward resolving this problem. best regards & thank you in advance, Zibi Zbigniew Lodziana Polish Academy of Sciences, ul.. Radzikowskiego 152, PL-31-342 Krakow ==================================================================== More detailed output & input. ------------------- Machine (a) Program GIPAW v.5.0 starts on 29Aug2012 ... Parallel version (MPI), running on 36 processors K-points division: npool = 6 R & G space division: proc/pool = 6 ... Parallelization info -------------------- sticks: dense smooth PW G-vecs: dense smooth PW Min 985 985 263 35145 35145 4831 Max 986 986 264 35146 35146 4833 Sum 5913 5913 1581 210873 210873 28991 ... Total NMR chemical shifts in ppm: --------------------------------------- (adopting the Simpson convention for anisotropy and asymmetry)----------- Atom 1 Ca pos: ( 0.000000 6.787326 7.322301) Total sigma: 1417.43 ... Atom 3 B pos: ( 2.443074 2.731768 3.272940) Total sigma: 134.05 ... Atom 11 O pos: ( 4.532848 1.133423 1.942424) Total sigma: 102.07 ... ================= pw.x Program PWSCF v.5.0 starts on 29Aug2012 the Fermi energy is 10.5803 ev ! total energy = -642.94342958 Ry Harris-Foulkes estimate = -642.94342958 Ry estimated scf accuracy < 2.6E-11 Ry ======================== ========================================================== machine (b) Program GIPAW v.5.0 starts on 30Aug2012 Parallel version (MPI), running on 36 processors K-points division: npool = 6 R & G space division: proc/pool = 6 ... Parallelization info -------------------- sticks: dense smooth PW G-vecs: dense smooth PW Min 985 985 263 35145 35145 4831 Max 986 986 264 35146 35146 4833 Sum 5913 5913 1581 210873 210873 28991 ... Total NMR chemical shifts in ppm: --------------------------------------- (adopting the Simpson convention for anisotropy and asymmetry)----------- Atom 1 Ca pos: ( 0.000000 6.787326 7.322301) Total sigma: 1001.13 ... Atom 3 B pos: ( 2.443074 2.731768 3.272940) Total sigma: 16.58 ... Atom 11 O pos: ( 4.532848 1.133423 1.942424) Total sigma: 68.51 pw.x Program PWSCF v.5.0 starts on 30Aug2012 the Fermi energy is 10.5803 ev ! total energy = -642.94342958 Ry Harris-Foulkes estimate = -642.94342958 Ry estimated scf accuracy < 2.6E-11 Ry ============================================================= INPUTS: pw.x &control calculation = 'scf' prefix = 'CaB4O7' restart_mode = 'from_scratch' tstress = .true. tprnfor = .true. pseudo_dir = './pseudo/' outdir = './tmp/' / &system ibrav = 0 celldm(1) = 1.0 nat = 24 ntyp = 3 ecutwfc = 110 occupations = 'smearing' smearing = 'mp' degauss = 0.005 / &electrons diagonalization = 'david' diago_thr_init = 1e-4 mixing_mode = 'plain' mixing_beta = 0.1 conv_thr = 1e-10 / ATOMIC_SPECIES Ca 40.078 Ca.pbe-tm-new-dc.UPF B 10.811 B.pbe-tm-new-gipaw-dc.UPF O 15.999 O.pbe-tm-new-gipaw-dc.UPF CELL_PARAMETERS (alat= 1.00000000) 20.248307850 0.000000000 0.000000000 0.000000000 8.343848898 0.000000000 0.000000000 0.000000000 8.006202063 ATOMIC_POSITIONS (crystal) Ca 0.000000000 0.813452700 0.914578653 Ca 0.500000000 0.186731631 0.414667081 B 0.120655733 0.327399041 0.408800535 B 0.379358780 0.672598815 0.908813803 B 0.620641220 0.672598815 0.908813803 B 0.879344267 0.327399041 0.408800535 B 0.250722266 0.822127339 0.383740663 B 0.249297780 0.177848977 0.883744720 B 0.750702220 0.177848977 0.883744720 B 0.749277734 0.822127339 0.383740663 O 0.223863043 0.135839302 0.242614879 O 0.276145474 0.864113231 0.742641343 O 0.723854526 0.864113231 0.742641343 O 0.776136957 0.135839302 0.242614879 O 0.138503036 0.647114168 0.331799880 O 0.361509595 0.352879214 0.831821610 O 0.638490405 0.352879214 0.831821610 O 0.861496964 0.647114168 0.331799880 O 0.133904753 0.274432983 0.747354309 O 0.366136763 0.725573696 0.247375604 O 0.633863237 0.725573696 0.247375604 O 0.866095247 0.274432983 0.747354309 O 0.000000000 0.220447425 0.298885908 O 0.500000000 0.779514715 0.798853668 K_POINTS automatic 2 6 6 1 1 1 ======================================= gipaw.x &inputgipaw job = 'nmr' prefix = 'CaB4O7' tmp_dir = './tmp/' isolve = 0 iverbosity = 1 q_gipaw = 0.01 spline_ps = .true. use_nmr_macroscopic_shape = .true. /