# Tag Info

9

You don't give any real details on the system, but I can make a guess from your scaling that either the code doesn't properly support openmp (which is unlikely) or your system is way too small to see a benefit. I suspect if you use a bigger system (that can't finish in about 10 seconds on a single core) you will see an improvement. Also keep in mind a ...

7

I think that there should be three considerations (and of course I could be wrong). If you have not compiled the software to work in parallel, specifying multiple (N number of) threads sometimes is said to cause the same job to run in serial mode but N times. Even though you have a multi-core calculation, the actual work being done may not really need more ...

6

This error has been resolved now. Though I am not an expert but here are few thoughts. There may be several reasons for this error: This error might appear due to numerical instability from overlapping atoms. As mentioned by @Phil Hasnip, if the S-matrix eigenvalues are really small. Some pseudopotential may not fit with calculation, USPP giving non-...

6

Have you already tried the Pw_forum? I do not use QE and so cannot directly answer your question. However, I'd say that this is one of those things where you are better off finding either a tutorial (in places such as YouTube) or someone you know with experience in compiling software for linux (just to make sure that your compilation is successful). That ...

4

The source of mistake is assuming one atom in the primitive cell of the hexagonal system. Actually there are two atoms, the atomic positions are ATOMIC_POSITIONS {alat} Hf 0.000000000 0.000000000 0.000000000 Hf 0.666666667 0.333333333 0.790000000

4

Executables are soft-linked in ./bin folder of the parent directory. If you did not compile, please follow these steps. make hp cd bin After that, run the command, ./hp.x If you are accessing the executable from QE input file folder, then you have to specify the whole path of the executable /path-to-qe-folder/bin/hp.x The best practice is to export the ...

4

ibrav = 2 in Quantum Espresso gives an fcc Bravis lattice, as mentioned in the answer by Tyberius, with the lattice vectors: a(1) = ( -0.500000 0.000000 0.500000 ) a(2) = ( 0.000000 0.500000 0.500000 ) a(3) = ( -0.500000 0.500000 0.000000 ) Using an fcc Bravis lattice, which the primitive cell for fcc structures contains one atom. The cubic, ...

3

Please go through the userguide. At the bottom, it has some nice suggestions. Check this mail thread also. Does the program stops because too many errors have not converged or, the calculation keeps going on ? If the calculation did not stop and keeps going on, then you can ignore these warnings. Please do some convergence tests before you proceed for vc-...

2

The energy should be variational with regard to encut, but this is not something to expect for kpoints. However, normally this results in the opposite of what you are observing with the kpoints showing some sort of oscillation. The result you see is due to numerical noise in the encut convergence calculations. Try to tighten the electronic cutoff and you ...

1

With the help of @Tyberius and @BrandonBocklund, I did the calculation of Cu in FCC lattice. Calculated lattice constant $a = 3.62613952 \, A^\circ$, where as experimental value is $a = 3.6149 \, A^\circ$. The major source of confusion is, I interpreted the question as FCC primitive cell has 4 Atoms. &CONTROL calculation = 'vc-relax' , ...

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