Hello,
As a new QE user, I do some tests with the HSE Functional for BCC ferromagnetic Fe with a cell containing 2 atoms (because a want to go to CoFe after that). My input file is : &control title='Fe CC HSE', calculation = 'scf', prefix = 'Fe_CC_HSE', pseudo_dir='./', verbosity = 'high' / &system ibrav = 6, celldm(1) = 5.45, celldm(3) = 1.0, nat = 2, ntyp = 1, nspin = 2, occupations='smearing', smearing='gauss', degauss=0.01, starting_magnetization(1) = 1.0, ecutwfc = 33, input_dft='HSE', report = 5 / &electrons mixing_beta = 0.7 / ATOMIC_SPECIES Fe 55.845 Fe.pbe-sp-van.UPF ATOMIC_POSITIONS (crystal) Fe 0.000 0.000 0.000 Fe 0.500 0.500 0.500 K_POINTS (automatic) 7 7 7 0 0 0 Surprisingly, the computation time is huge as writen into the output file : =============================== iteration # 9 ecut= 33.00 Ry beta=0.70 Davidson diagonalization with overlap ethr = 5.49E-08, avg # of iterations = 2.3 Magnetic moment per site: atom: 1 charge: 14.4350 magn: 2.6346 constr: 0.0000 atom: 2 charge: 14.4351 magn: 2.6343 constr: 0.0000 total cpu time spent up to now is 7.2 secs End of self-consistent calculation convergence has been achieved in 9 iterations EXX: now go back to refine exchange calculation total cpu time spent up to now is 4239.4 secs Self-consistent Calculation iteration # 1 ecut= 33.00 Ry beta=0.70 Davidson diagonalization with overlap ethr = 5.49E-08, avg # of iterations = 4.9 total cpu time spent up to now is 52490.2 secs iteration # 2 ecut= 33.00 Ry beta=0.70 Davidson diagonalization with overlap =============================== So, the calculation takes 7 seconds for converging with PBE, 1h10min for calculating the EXX term and 14h35min for the first HSE iteration. Is this correct ? And if so, please, could you try to explain me how to reduce the computation time. Thanks in advance. Best wishes, Daniel
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