# Tag Info

4

I could be wrong, but I am fairly certain that line of the CONTCAR technically doesn't matter. If you put a O instead of H, but put the potentials in the right order, you will get the right result even though the element is wrong. For visualization, it will definitely be wrong but I don't think the calculated result is wrong. In tools such as ASE the ...

4

If by "standard", you mean an "official" VASP-supported program, then the answer is no. VASP gives you the raw text output for you to deal with on your own. That being said, the vasprun.xml file produced at the end of a run contains many of the important calculation results, so any parser than can read an XML file can also parse this data ...

5

Here are a few things you could try: ./configure --with-hdf5-libs=<options> --with-hdf5-include=<path> (note the double dashes) export HDF5_LIBS='-L/path/to/your/lib -lhdf5 -lhdf5fortran' before you ./configure Use the new cmake route to install QE (see example instructions here) which should be more robust and will likely replace the configure ...

4

# # To run VASP this script calls $vasp_std # (or posibly$vasp_gam and/or $vasp_ncl). # These variables can be defined by sourcing vaspcmd . vaspcmd 2> /dev/null As mentioned in the comments, the answer is actually in your question. vaspcmd is just any script you provide that defines the$vasp_std, $vasp_gam and$vasp_ncl variables which give the full ...

7

The community wiki by Tyberius is a bit misleading here, you are not doing molecular dynamics calculations (IBRION=0) but likely a geometry optimization (IBRION=1,2,3). In the case of geometry optimization, the CHGCAR is not the predicted charge density, but is instead the charge density of the last completed step. For this reason, you should find no ...

5

In the passage just above what you quoted, it says: For dynamic simulation (IBRION=0), the charge density on the file is the predicted charge density for the next step: i.e. it is compatible with the CONTCAR file, but incompatible with the last positions in the OUTCAR file. This means while the density in the CHGCAR file is a density for the position given ...

1

This is related to your other question, you are correct VASP only supports fixing atoms along the X, Y, and Z axis. You can use ASE optimizers with the FixLine or FixPlane constraints to do this. You just specify which atoms are constrained and which direction they are constrained to move in. Just be aware, ASE running VASP is slower than VASP running its ...

0

The FixAtoms constraint will be turned into the selective dynamics tags as "F F F". ASE will also convert selective dynamics to this constraint when reading. I think the FixedPlane and FixedLine could in theory also work, but I am not sure they do since they support directions not aligned with the X, Y, and Z axis. If you need this and it doesn't ...

5

I don't know any VASP-specific details, but the basic answer is that the three versions are almost identical, and solve the same equations in the same way. If we take vasp_std as the reference, then the differences are: vasp_gam If your system has time-reversal symmetry (true for most simulations), then $+k$ and $-k$ are symmetry-related and we can restrict ...

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