[QE-users] Monitoring the ion velocities in pw.x

Dear quantum espresso community, We would like to monitor the ion velocities during an MD run of pw.x and cannot find appropriate key words for that in the documentation. Would we need to modify the code in order to output the velocities at each time step or is there another way?

Re: [QE-users] SIGSEGV fault in phonon calculation

Dear Ruochen Shi, A segmentation fault generally does not occur because of lack of available memory. In that case, you would see an error like "out of memory, killed", or "killed (signal 9)" - the details of which depend on your OS, MPI library, and possibly scheduler. Segmentation faults

Re: [QE-users] TB09, TPSS

Dear Paolo, I changed io_rho_xml.f90 so that if the kinetic energy density file isn't found, the array is set to 0: 155d144 < LOGICAL :: ekin_density_exists 172,180c161,164 < INQUIRE( FILE=TRIM(dirname) // "ekin-density", EXIST=ekin_density_exists) < IF (

Re: [QE-users] k-points selection for Band Structure calculation

Hello, You can find the k vectors for hexagonal Si here: https://www.cryst.ehu.es/cgi-bin/cryst/programs/nph-kv-list I have chosen the "simplest" hexagonal system (n°168), but you can change it if necessary here:

[QE-users] k-points selection for Band Structure calculation

Hey everyone, I am trying to study the effect of pressure on the band structure of *'Si - simple hexagonal (Phase V)*', which is stable between 17 to 30 GPa (approx.) Here is a paper published in Nature ( https://www.nature.com/articles/s41586-020-2150-y), which has a figure with the band

[QE-users] SIGSEGV fault in phonon calculation

Dear all, I'm a new user to quantum-espresso, and recently i've encontered a problem when calculating phonon frequency in a heterojunction structure containing 24 atoms in an unit cell. A "forrtl: severe (174): SIGSEGV, segmentation fault occurred" error happens, which is frequently asked by

Re: [QE-users] Issues in restart_mode = 'restart'

If I remember correctly in older version of QE you could restarted crashed calculation but it would lead to more issues than it would actually solve. Keep in mind that if you specify max_seconds, it will still run a bit to finish the current scf iteration and to make a clean exit. If you run

Re: [QE-users] Issues in restart_mode = 'restart'

Restarting from an interrupted calculations works only if the calculation is cleanly stopped. This happens either when the specified maximum execution time is reached (variable max_seconds) or when the running code receives a signal to stop, typically via a "prefix".EXIT file. Restarting from a

Re: [QE-users] Difference between Geometry Optimization and a SCF calculation

Dear Chaman, When I say final geometry, I mean a,b,c,alpha,beta,gamma and all of the fractional coordinates of the atoms: enough to specify the structure in it's entirety. These can all change with pressure, as well as the unit cell shrinking, atoms sometimes move around when the crystal is

Re: [QE-users] Difference between Geometry Optimization and a SCF calculation

Thank you for the clarification. Regards, *Chaman Gupta* Graduate Research Student, *Novosselov Research Group , UW* Graduate Research Student, *Pauzauskie Research Group , UW* University of Washington Seattle,

Re: [QE-users] Difference between Geometry Optimization and a SCF calculation

Also, the BURAI GUI gives the option to enter in either kbar or GPa. Regards, *Chaman Gupta* Graduate Research Student, *Novosselov Research Group , UW* Graduate Research Student, *Pauzauskie Research Group , UW*

Re: [QE-users] Difference between Geometry Optimization and a SCF calculation

Great explanation. That clears up so many of my questions, and the in-general how to approach my problem. When you say feed the final geometry, you are referring to the a,b,c and alpha,beta,gamma values right? A fundamental question: When I say that I have a structure and I apply external

Re: [QE-users] Difference between Geometry Optimization and a SCF calculation

Dear Chaman, Firstly, the pressures in QE are in kbar, not GPa (I don't know if this is different in the GUI version), see https://www.quantum-espresso.org/Doc/INPUT_PW.html. Because the cell changes shrinks (and possibly the atoms move) as you increase the pressure, you should do a geometry

Re: [QE-users] Difference between Geometry Optimization and a SCF calculation

Thanks a lot Michael for the explanation. Diving a bit more into my specific situation, here's my problem statement: I have a 'Si simple hexagonal phase (Phase V)' which is stable in the pressure range of 17 to 30 GPa (approx.). I want to generate the band structure for this Si at different

Re: [QE-users] Difference between Geometry Optimization and a SCF calculation

Dear Chapman Gupta The three calculations are all reliable, but they have different purposes; you should know what you need. scf: single point calculations (possibly with calculation of forces and stresses at the end). It gives you the total energy and eigenvalues @ k-points of the

Re: [QE-users] Difference between Geometry Optimization and a SCF calculation

Dear Chaman, Essentially, a geometry optimisation moves the atoms around to reduce the energy of the system. The energy of the system is calculated using an scf calculation. The geometry optimisation is therefore a bunch of scf calculations strung together, with a succession of atomic positions

[QE-users] Difference between Geometry Optimization and a SCF calculation

Hey everyone, Might be a very naive question, but I have been very confused with this recently. I have a 'Si - simple hexagonal' cif file. I want to see the band structure and/or the band gap (HOMO - LUMO). 1. I ran a 'scf' calculation on BURAI (a GUI for QE). It generated an output file which

Re: [QE-users] DFPT getting stuck [MPI_ERR_TRUNCATE]

Yes, I changed it recently: https://gitlab.com/QEF/q-e/-/commit/334e70c7c6c61f5a16fc5d9027fed52bcf0ffdcf I was fed up with automated tests crashing if k-point parallelization was used. Paolo On Wed, May 20, 2020 at 10:54 AM Lorenzo Paulatto wrote: > You are right, in the sense that now the

Re: [QE-users] DFPT getting stuck [MPI_ERR_TRUNCATE]

You are right, in the sense that now the code just writes "suboptimal parallelization: some nodes have no k-points" I'm quite sure I remember the code stopping because it was run with more pools than k-points, was this changed recently, Paolo? On 5/20/20 10:34 AM, M.J. Hutcheon wrote: Dear 

Re: [QE-users] DFPT getting stuck [MPI_ERR_TRUNCATE]

Dear Lorenzo, I'm quite sure that the pw code stops if you try to run with more pools than k-points ! This doesn't seem to be the case? I ran a vc-relax and an scf (attached output) with these (terrible) parallelism settings, and they ran just fine. Best, Michael On 2020-05-20 09:25,

Re: [QE-users] DFPT getting stuck [MPI_ERR_TRUNCATE]

While I am quite sure that such a wasteful parallelization works anyway for the self-consistent code, I'm quite sure that the pw code stops if you try to run with more pools than k-points ! I am not equally sure it will for the phonon code. If the ph code does not stop in this case, I'm

Re: [QE-users] DFPT getting stuck [MPI_ERR_TRUNCATE]

Dear Paolo, Thank you very much for your response, that was indeed what was causing the error. During my investigation, I noticed that an error check in PHonon/PH/solve_linter.f90 should have been firing, but wasn't; I've submitted a fix on GitLab