VASP interactive
To run VASP interactively, make sure the corresponding modules has been loaded, the change to the working directory containing all the input files and execute the command, i.e. vasp. So, basically you execute swsetup vasp and then vasp. After starting VASP, you will get a output similar to the following:
running on 1 nodes: distr: one band on 1 nodes, 1 groups vasp.4.6.36 17Feb09 complex POSCAR found : 1 types and 4 ions LDA part: xc-table for Ceperly-Alder, standard interpolation POSCAR, INCAR and KPOINTS ok, starting setup WARNING: wrap around errors must be expected FFT: planning ... 1 reading WAVECAR entering main loop N E dE d eps ncg rms rms(c) DAV: 1 0.171904832619E+03 0.17190E+03 -0.12785E+04 2688 0.132E+03 DAV: 2 -0.139486735106E+02 -0.18585E+03 -0.18195E+03 2816 0.297E+02 DAV: 3 -0.219597939772E+02 -0.80111E+01 -0.77212E+01 3120 0.754E+01 DAV: 4 -0.221560634061E+02 -0.19627E+00 -0.19475E+00 2816 0.106E+01 DAV: 5 -0.221585319930E+02 -0.24686E-02 -0.24677E-02 2888 0.931E-01 0.148E+01 DAV: 6 -0.220787802645E+02 0.79752E-01 -0.60216E+01 2792 0.935E+01 0.138E+01 DAV: 7 -0.188888548414E+02 0.31899E+01 -0.16576E+01 2800 0.455E+01 0.929E-01 DAV: 8 -0.188797520710E+02 0.91028E-02 -0.11630E-01 2720 0.260E+00 0.476E-01 DAV: 9 -0.188758089926E+02 0.39431E-02 -0.86160E-03 3208 0.981E-01 0.651E-02 DAV: 10 -0.188757571416E+02 0.51851E-04 -0.38206E-04 2496 0.180E-01 1 F= -.18875757E+02 E0= -.18853669E+02 d E =-.662648E-01
VASP uses a self-consistency cycle with a Pulay mixer and an iterative matrix diagonalisation scheme to calculate the Kohn Sham (KS) ground-state. Each line corresponds to one electronic step, and in each step the wavefunctions are iteratively improved a little bit, and the charge density is refined once. A copy of stdout (that's what you see on the screen) is also written to the file OSZICAR. The columns have the following meaning: Column N is counter for the electronic iteration step, E is the current free energy, dE the change of the free energy between two steps, and d eps the change of the band-structure energy. The column ncg indicates how often the Hamilton operator is applied to the wavefunctions. The column rms gives the initial norm of the residual vector that is summed over all occupied bands, and is an indication how well the wave-functions are converged. Finally the column rms(c) indicates the difference between the input and output charge density. During the first four steps, the density and the potentials are not updated to pre-converge the wavefunctions (therefore rms(c) is not shown). After the first four iterations, the update of the charge density starts. The final line shows the free electronic energy F after convergence has been reached. More information (for instance the forces and the stress tensor) can be found in the OUTCAR file. Please check this file in order to get an impression which information can be found on the OUTCAR file. Another important file is the WAVECAR file which stores the final wave functions. To speed up calculations, VASP usually tries to read this file upon startup. At the end of calculations, the file is written (or if it exists, overwritten).
