ABINIT Discussion Forums

Dear Joe, ABINIT can handle only periodic systems in the X,Y, and Z directions, so you can only calculate for a rope of nanotubes. The values of acell are the periods in each of these directions ( = dimensions of unit cell). So acell_1 and acell_2 must definitely be larger than the diameter of the C...

It turns out that its in absolute units, not relative to the Fermi energy.

Hello,

Are the values of energy in the _DOS file measured in "absolute" units or relative to the Fermi level?

Thank you,
Mamikon

Hello, I notice that when I start a calculation that progresses slowly, for the first few SCF cycles, with each SCF cycle the amount of memory used increases. Is this due to the iteration history for the Pulay mixer getting longer (until it has 7 datasets)? Will decreasing npulayit lessen the memory...

Xavier,

Thanks! I will try it out.

-Mamikon

Hello,

I see that ABINIT has the ability to calculate crystals in a constant
electric field. I am wondering whether it can calculate in an
arbitrary non-homogeneous (coordinate dependent) electric field. Does
anyone know if this is possible or how it could be implemented?

Thanks
Mamikon

David, Actually, your second answer answers my first question as well. I didn't know that a non-SCF calculation must iterate for wavefunctions even after a converged SCF density: scprqt: WARNING - nstep= 1 was not enough non-SCF iterations to converge; maximum residual= 5.477E-01 exceeds tolwfr= 1.0...

David, Thanks for the reply; below are my SCF and non-SCF input files in that order. They are for a CNT. My questions are rather general. SCF: # DENSITY CALCULATION # ACCURACY & CONVERGENCE ecut 36 # must be converged ngkpt 1 1 54 # must be converged - Fermi point must be well captured! kptopt 1...

Hello, I am making non-scf Band Structure calculations which reads a well converged self consistent _DEN file from a previous run (from a separate input file). The program reads the _DEN file and says it is OK for calculation, but it begins its own self consistent loop (even though iscf = -2) and mo...

Hello, I am working on converging unit cell sizes for a CNT (i.e., converging the vacuum volume to approach a "single" CNT system). If anyone has an experience with this, what kind of cross-convergence effects should I expect between the vacuum padding, ecut, and the k-point sampling? Many...

Hello, I am exploring BigDFT capabilities within ABINIT. I get the error: STOP ml1 < nl1 - Is this in the psp file? How should I fix it? [ EDITED: It was in the psp file. I found in the BigDFT manual that " BigDFT supports the GTH and HGH pseudopotentials... " ]. Also, I have these questio...

Hello,

I don't know much about it, but maybe using MPI I/O for wavefunction files will help decrease the dramatic memory utilization by one processor. See the documentation for the variable accesswff:

http://www.abinit.org/documentation/hel ... #accesswff

-Mamikon

Hello, As I understand it, ABINIT comes with its own internal LAPACK and BLAS libraries. Recently I have learned about parallel versions of LAPACK (ScaLAPACK), BLAS (PBLAS) and parallel-netcdf. My question is: does ABINIT have any support for these, and if yes, how should I connect them? Also, would...

Dear Matteo, Thank you for the notification! Unfortunately, while the calculation is now very fast with kssform = 3, it is not very useful, because I cannot take enough bands with the CG Algorithm. Although I am calculating for a metallic CNT, it becomes an insulator to DP, probably because the cond...

Just an update: I increased the convergence parameters and that made the warnings vanish, but as it turned out, this caused no difference in results- that is, the previous settings were already well converged despite the warnings. I guess the warnings were not essential.

Hello, I am using ABINIT 5.8.4 on SUSE. I have recently made the parallel compilation of ABINIT and am using Open MPI 1.4.1 . It seems to work fine: when I turn on a KSS file calculation in sequential mode and in parallel mode (11 cores in the latter for efficient distribution) for comparison, the p...

Matteo, Fabien,

Thanks for your replies. I did feel that the warnings were not very dangerous, but wanted to take care of them anyway. I'll try out your suggestions next time I calculate a KSS file and post the results.

-Mamikon Gulian

Hello, When calculating a KSS file I periodically get this warning every few k-points: outkss.F90:1403:WARNING The diagonalized eigenvalues differ by more than 10^-3 Hartree with respect to the conjugated gradient values. My questions: (1) If its calculating both the Conjugated Gradient values and D...

Using "iprcel 45" fixed the SCF convergence issues, and it turns out that the major problem was just a mix-up on my part of PSP file names... With better k-point sampling (and the correct PSP file), as you suggested, it relaxes to the value in the literature. Thanks for the help and your r...

Dear Matthieu, Thanks for your reply. I apologize it took me so long to acknowledge it, but we've had 1 meter of snow here in D.C (power issues...). I did mean SFC cycles, not datasets, and I am using a norm-conserving PSP of the Troullier-Martins type (.pspnc) I appreciate for your notifications ab...