Dear QE community, I recently tried to run a simple calculation using a large supercell with ibrav=1. The cell contains 13 atoms. pw.x runs, but consumes a huge amount of memory (in the example below more than 400 Mb of ram for each pw.x process). If I set A = 50.0 it consumes more than 1Gb of RAM for each process, and of course having 8 cPU and 8 Gb of RAM the calculation continously swap with the disk... Perhaps I'm doing something wrong, but I cannot find the reason.
The data are derived from an analogue calculation where 104 atoms were present in the cell for a real periodic calculation. This optimization runs without any problem. I'm using QE 4.1.2. I would appreciate any suggestion. Thanks, Carlo --------- &CONTROL title = 'Barb_gas2' , calculation = 'relax' , restart_mode = 'from_scratch' , outdir = './' , pseudo_dir = '../PP/' , prefix = 'Barb_gas2' , disk_io = 'default' , verbosity = 'default' , etot_conv_thr = 1e-4 , forc_conv_thr = 1e-3 , nstep = 256 , iprint = 1, tstress = .true. , tprnfor = .true. , / &SYSTEM ibrav = 1, A = 10.0 , B = 10.0 , C = 10.0 , cosAB = 0.0d0 , cosAC = 0.0 , cosBC = 0.0d0 , nat = 13, ntyp = 4, ecutwfc = 120 , nosym = .true. , / &ELECTRONS electron_maxstep = 256, conv_thr = 1.0D-6 , startingpot = 'atomic' , startingwfc = 'atomic' , mixing_mode = 'plain' , mixing_beta = 0.7D0 , mixing_ndim = 8, diagonalization = 'david' , / &IONS ion_dynamics = 'bfgs' , / ATOMIC_SPECIES H 1.00794 H.pbe-tm-gipaw.UPF O 15.99940 O.pbe-tm-gipaw.UPF C 12.01070 C.pbe-tm-gipaw.UPF N 14.00674 N.pbe-tm-gipaw.UPF ATOMIC_POSITIONS (angstrom) O 4.54996963 4.16012233 3.24841463 O 4.27040451 8.61116200 3.94060959 O 1.70010607 5.59594564 6.44124884 N 3.13203364 4.88891811 4.86017069 N 4.41614536 6.39243688 3.61722930 C 4.06455509 5.08156078 3.87216675 C 3.99019119 7.48412061 4.31476378 C 3.26108613 7.19962350 5.59032474 C 2.60656705 5.86093941 5.67109699 H 2.86290309 4.11746664 4.98744525 H 4.99506469 6.53336424 2.97784697 H 3.91898313 7.20780232 6.28834462 H 2.63762500 7.85329996 5.80293441 K_POINTS automatic 1 1 1 1 1 1 -- ------------------------------------------------------ Carlo Nervi carlo.nervi at unito.it Tel:+39 011 6707507/8 Fax: +39 011 6707855 - Dipartimento di Chimica IFM via P. Giuria 7, 10125 Torino, Italy http://lem.ch.unito.it/