<div dir="ltr">Greetings all,<div><br></div><div>I'm having some problem getting convergence in my DFT +U calculations. My system is anti-ferromagnetic double perovskite Sr2FeWO6. It is experimentally an insulator but there are reports that state one needs Hubbard U on Fe 3d orbital to account for the on site repulsion. However after adding an U value it doesn't converge after 500 iterations and sometimes the job got killed by the batch system (not walltime, something like buffer overflow), typical pbs output looks like this (varies on different platform):</div>
<div><br></div><div><br></div><div>Rank 16 [Wed Nov 9 23:21:11 2011] [c0-0c0s4n1] Fatal error in PMPI_Bcast: Message truncated, error stack:</div><div><div>PMPI_Bcast(1308)......................: MPI_Bcast(buf=0x3e0def0, count=26208, MPI_DOUBLE_PRECISION, root=1, comm=0xc4000000) failed</div>
<div>MPIR_Bcast(998).......................:</div><div>MPIR_Bcast_scatter_ring_allgather(842):</div><div>MPIR_Bcast_binomial(157)..............:</div><div>MPID_nem_gni_lmt_start_recv(920)......: Message from rank 0 and tag 2 truncated; 213408 bytes received but buffer size is 209664</div>
<div>[0] ERROR - nem_gni_error_handler(): a transaction error was detected,error category 0x4 error code 0xb2e</div><div>Rank 0 [Wed Nov 9 23:21:11 2011] [c0-0c0s4n0] GNI transaction error detected</div><div>[NID 00009] 2011-11-09 23:21:11 Apid 1944384: initiated application termination</div>
<div><br></div><div><br></div><div>And the pw.x output ends like this:</div><div><br></div><div><br></div><div><div>atom 24 Tr[ns(na)]= 6.1782057</div><div>atom 24 spin 1</div><div>eigenvalues: 0.9740685 0.9841342 0.9842280 0.9899863 0.9914280</div>
<div> eigenvectors</div><div> 1 0.0332876 0.0801355 -0.2854709 0.9362259 -0.1856276</div><div> 2 0.0172615 0.0589306 0.8879786 0.1822775 -0.4177297</div><div> 3 0.4670136 0.8765271 -0.0107306 -0.0778135 0.0861883</div>
<div> 4 -0.0557289 -0.0272157 0.3597350 0.2894423 0.8848545</div><div> 5 0.8816953 -0.4701756 0.0218145 0.0205958 0.0254629</div><div> occupations</div><div> 0.990 -0.003 0.000 0.000 0.000</div><div>-0.003 0.986 0.000 -0.001 0.000</div>
<div> 0.000 0.000 0.984 0.003 0.001</div><div> 0.000 -0.001 0.003 0.976 0.003</div><div> 0.000 0.000 0.001 0.003 0.988</div><div>atom 24 spin 2</div><div>eigenvalues: 0.0394193 0.0400804 0.1166033 0.1376013 0.9206564</div>
<div> eigenvectors</div><div> 1 -0.0457703 -0.2123040 -0.9448844 -0.2058039 0.1329300</div><div> 2 0.1857246 0.9542619 -0.1868327 -0.1235578 0.0686851</div><div> 3 -0.0675780 -0.0156072 0.1108752 0.1546050 0.9792822</div>
<div> 4 -0.9788987 0.1940608 -0.0050595 -0.0004723 -0.0638113</div><div> 5 -0.0245350 -0.0800506 0.2448840 -0.9583712 0.1206087</div><div> occupations</div><div> 0.134 -0.017 -0.005 0.020 -0.002</div><div>-0.017 0.049 -0.018 0.067 -0.011</div>
<div>-0.005 -0.018 0.093 -0.205 0.034</div><div> 0.020 0.067 -0.205 0.851 -0.090</div><div>-0.002 -0.011 0.034 -0.090 0.127</div><div>nsum = 49.3436516</div><div> exit write_ns</div><div><br></div><div> total cpu time spent up to now is 4234.0 secs</div>
<div><br></div><div> total energy = -5515.60273544 Ry</div><div> Harris-Foulkes estimate = -5515.60272792 Ry</div><div> estimated scf accuracy < 0.00001279 Ry</div><div><br></div>
<div> total magnetization = 0.00 Bohr mag/cell</div><div> absolute magnetization = 32.50 Bohr mag/cell</div><div><br></div><div> iteration #102 ecut= 50.00 Ry beta=0.20</div><div> Davidson diagonalization with overlap</div>
<div>Application 1944384 exit codes: 1</div><div>Application 1944384 exit signals: Killed</div><div>Application 1944384 resources: utime ~4162s, stime ~88s</div></div><div><br></div><div><br></div><div>My input file is:</div>
<div><br></div><div><br></div><div><div>&control</div><div> calculation = 'scf'</div><div> title = 'Sr2FeWO6'</div><div> verbosity = 'high'</div><div> restart_mode = 'from_scratch'</div>
<div> pseudo_dir = '/workdir/jianglai/psp/gga'</div><div> etot_conv_thr = 1.D-6</div><div> forc_conv_thr = 2.D-4</div><div> disk_io = 'low'</div><div> tstress = .true.</div>
<div> tprnfor = .true.</div><div> wf_collect = .true.</div><div> nstep = 5000</div><div>/</div><div>&system</div><div> ibrav = -12</div><div> A = 11.301600</div>
<div> B = 5.613600</div><div> C = 15.885000</div><div> cosAC = -0.000366588948</div><div> nat = 80</div><div> ntyp = 5</div>
<div> nbnd = 351</div><div> ecutwfc = 50</div><div> occupations = 'smearing'</div><div> degauss = 2.D-3</div><div> nspin = 2</div><div>
starting_magnetization(2) =0.5</div><div> starting_magnetization(3) =-0.5</div><div> lda_plus_u = .true.</div><div> hubbard_U(2) = 4</div><div> hubbard_U(3) = 4</div><div>/</div>
<div>&electrons</div><div> electron_maxstep = 500</div><div> startingwfc = 'random'</div><div> diagonalization = 'david'</div><div> mixing_mode = 'plain'</div>
<div> mixing_beta = 2.D-1</div><div> mixing_ndim = 8</div><div> conv_thr = 1.0D-8</div><div> /</div><div>&IONS</div><div> bfgs_ndim = 4</div><div> upscale = 25</div>
<div> pot_extrapolation = 'second_order'</div><div> wfc_extrapolation = 'second_order'</div><div>/</div><div>&CELL</div><div> cell_dynamics = 'bfgs'</div><div> press_conv_thr = 5.D-1</div>
<div>/</div><div>ATOMIC_SPECIES</div><div> Sr 87.62 Sr.upf</div><div> Fe1 55.847 Fe.semi.upf</div><div> Fe2 55.847 Fe.semi.upf</div><div> W 183.85 W.fhi.UPF</div><div> O 15.999 O.upf</div>
<div><br></div><div>ATOMIC_POSITIONS {crystal}</div><div>Sr 0.499500 0.012900 0.124550</div><div>Sr 0.500500 0.987100 0.875450</div><div>Sr 0.750500 0.512900 0.125450</div><div>Sr 0.749500 0.487100 0.374550</div>
<div>Sr 0.499500 0.012900 0.624550</div><div>Sr 0.500500 0.987100 0.375450</div><div>Sr 0.750500 0.512900 0.625450</div><div>Sr 0.749500 0.487100 0.874550</div><div>
Sr 0.999500 0.012900 0.124550</div><div>Sr 0.000500 0.987100 0.875450</div><div>Sr 0.250500 0.512900 0.125450</div><div>Sr 0.249500 0.487100 0.374550</div></div><div>
<div>Sr 0.250500 0.512900 0.625450</div><div>Sr 0.249500 0.487100 0.874550</div><div>Fe1 0.250000 -0.000000 0.250000</div><div>Fe1 0.750000 -0.000000 0.750000</div><div>
Fe2 0.000000 0.500000 0.000000</div><div>Fe2 0.500000 0.500000 0.500000</div><div>Fe2 0.250000 -0.000000 0.750000</div><div>Fe2 0.750000 -0.000000 0.250000</div><div>
Fe1 -0.000000 0.500000 0.500000</div>
<div>Fe1 0.500000 0.500000 0.000000</div><div>W 0.250000 0.000000 0.000000</div><div>W 0.750000 0.000000 0.000000</div><div>W -0.000000 0.500000 0.250000</div><div>
W 0.500000 0.500000 0.250000</div><div>W 0.250000 -0.000000 0.500000</div><div>W 0.750000 -0.000000 0.500000</div><div>W 0.000000 0.500000 0.750000</div><div>W 0.500000 0.500000 0.750000</div>
<div>O 0.023650 0.496000 0.129500</div><div>O 0.976350 0.504000 0.870500</div><div>O 0.226350 0.996000 0.120500</div><div>O 0.273650 0.004000 0.379500</div><div>
O 0.023650 0.496000 0.629500</div><div>O 0.976350 0.504000 0.370500</div><div>O 0.226350 0.996000 0.620500</div><div>O 0.273650 0.004000 0.879500</div><div>O 0.523650 0.496000 0.129500</div>
<div>O 0.476350 0.504000 0.870500</div><div>O 0.726350 0.996000 0.120500</div><div>O 0.773650 0.004000 0.379500</div><div>O 0.523650 0.496000 0.629500</div><div>
O 0.476350 0.504000 0.370500</div><div>O 0.726350 0.996000 0.620500</div><div>O 0.773650 0.004000 0.879500</div><div>O 0.359500 0.261000 0.012500</div><div>O 0.640500 0.739000 0.987500</div>
<div>O 0.890500 0.761000 0.237500</div><div>O 0.609500 0.239000 0.262500</div><div>O 0.359500 0.261000 0.512500</div><div>O 0.640500 0.739000 0.487500</div><div>
O 0.890500 0.761000 0.737500</div><div>O 0.609500 0.239000 0.762500</div><div>O 0.859500 0.261000 0.012500</div><div>O 0.140500 0.739000 0.987500</div><div>O 0.390500 0.761000 0.237500</div>
<div>O 0.109500 0.239000 0.262500</div><div>O 0.859500 0.261000 0.512500</div><div>O 0.140500 0.739000 0.487500</div><div>O 0.390500 0.761000 0.737500</div><div>
O 0.109500 0.239000 0.762500</div><div>O 0.121000 0.224000 0.488000</div><div>O 0.879000 0.776000 0.512000</div><div>O 0.129000 0.724000 0.762000</div><div>O 0.371000 0.276000 0.738000</div>
<div>O 0.121000 0.224000 0.988000</div><div>O 0.879000 0.776000 0.012000</div><div>O 0.129000 0.724000 0.262000</div><div>O 0.371000 0.276000 0.238000</div><div>
O 0.621000 0.224000 0.488000</div><div>O 0.379000 0.776000 0.512000</div><div>O 0.629000 0.724000 0.762000</div><div>O 0.871000 0.276000 0.738000</div><div>O 0.621000 0.224000 0.988000</div>
<div>O 0.379000 0.776000 0.012000</div><div>O 0.629000 0.724000 0.262000</div><div>O 0.871000 0.276000 0.238000</div><div><br></div><div>K_POINTS (automatic)</div><div>2 4 1 1 1 1</div>
</div><div><br></div><div>I checked quantum espresso example files 25 and in README it says one needs to set starting_ns_eigenvalues sometimes. I'm not sure whether it's the case here but I'm gonna try. Still I don't quite understand the eigenvalues and eigenvectors in write_ns routine. Are eigenvalues the energy of each of the five d orbitals? The what are the eigenvectors?</div>
<div><br></div><div>That all said, if someone has experienced problems like this or knows why convergence is so slow here, please let me know.</div><div><br></div><div>Thanks!</div><div> </div><div>Lai Jiang</div>*********************************<br>
Department of Chemistry<br>School of Arts and Sciences<br>University of Pennsylvania<br>*********************************<br>231 South 34th Street, Box 46<br>Philadelphia, PA 19104<br>Tel: 215-573-4241<br>Fax: 215-573-2112<br>
Email: <a href="mailto:jianglai@sas.upenn.edu" target="_blank">jianglai@sas.upenn.edu</a><br><br>
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