Selecting the right number of cores for a vasp calculation. Pdf introducing k point parallelism into vasp ricardo. Use the different makefiles for different versions of vasp note. Ucl discovery is ucls open access repository, showcasing and providing access to ucl research outputs from all ucl disciplines. May 02, 2014 1 if using pseodupotential, then less k points can be used as compared with allelectron calculations. This script reads in vasps doscar file for a non spinpolarized calculation and plots the dos and the integrateddos using matplotlib. New features and releases, bugfixes, highlighted papers, and more. For vasp and insulator calculation, 444 might be good enough. The simple one is to perform a static nsw0, ibrion1 selfconsistent calculation and to take the doscar file from this calculation. Various k point schemes for bz sampling number of k points should increase with decreasing band gap and smearing t. Edit the kpoints file and add the points for the band structure at the end, using 0 as weight 4. Liion diffusion in lifepo4 for battery applications.
It supports calculations of metallic and insulating solids, molecules, atoms, and some model hamiltonians. Whilst this is common in similar codes, the latest release of vasp when i started o. For many years ab initio electronic structure calculations have been one. One of the best known and widely used software for performing this type of calculation is the vienna ab initio simulation package, vasp, which currently.
Note that the vasp makefiles generally do not support parallel compilation. What can we expect from this new feature in terms of performance. The list of generated gpoints for each k point a double list, which are used with the coefficients for each k point and band to recreate the wavefunction e. Quastion about kpoints and energy cutoff physics forums. Introducing kpoint parallelism into vasp maniopoulou, a. Introducing kpoint parallelism into vasp by asimina maniopoulou, erlend r. Using the stopcar file it is possible to stop vasp during the program execution.
Symmetry is used to map equivalent k points to each other, which can reduce the total number of k points significantly. Introducing kpoint parallelism into vasp the university. Vasp generates a equally spaced k point grid with the coordinates. You can refer to the vasp manual to find more information 2 energy cutoff has nothing to do with k point. A new flag was introduced, to control the behaviour of the mixer. The doscar file can be visualized with drawdos a simple fortran program, which requires erlgraph routines. The gpoints depend on the k point and reciprocal lattice and therefore are identical for each band at the same k point.
Mpi bases parallelization, with excellent scaling on multicore machines nehalemtm, opterontm, intel. In a periodic solid, one can use blochs theorem to show that the wave function for an electron can be expressed as the product of a planewave and a function with the periodicity of the lattice ashcroftmermin. Various k point schemes for bz sampling number of kpoints should increase with decreasing band gap and smearing t. Consequently, a substantial effort has gone into the development and optimization of many of these codes for the specific purpose of running on massively parallel systems. Ut theoretical chemistry code forum university of texas.
Articles describing such developments typically illustrate the scaling performance of the code with an example of strong scaling 9 27, i. Introducing kpoint parallelism into vasp maniopoulou, asimina. The gpoints depend on the kpoint and reciprocal lattice and therefore are identical for each band at the same kpoint. Qmcpack is an open source quantum monte carlo package for ab initio electronic structure calculations. There is a special line mode for generating kpoints for e. During these projects, i hope to introduce them into the modern black. During this 5 th edition, hpc users of the various flemish universities gather together at the belgian royal academy of science kvab to present their stateoftheart work using the flemish tier1 and tier2 supercomputers. Whilst this is common in similar codes, vasp does not currently support it, and we will show that through its use, the scalability of total energy calculations can. Abinit is a package whose main program allows one to find the total energy, charge density, electronic structure and many other properties of systems made of electrons and nuclei, molecules and periodic solids within density functional theory dft, manybody perturbation theory gw approximation and bethesalpeter equation and dynamical mean field theory dmft.
The list of generated gpoints for each kpoint a double list, which are used with the coefficients for each kpoint and band to recreate the wavefunction e. Everybody is welcome to have a look, but posting questions and answers is reserved for licensed user only. Recent developments in the abinit software package. The data is organized in an outfile to be read into some plotting program. One of the best known and widely used software for performing this type of calculation is the vienna ab initio simulation package, vasp, which currently offers a parallelisation strategy based on the distribution of bands and plane wave coefficients over the machine processors. Use of symmetries allows treatment of only symmetry inequivalent k points and reduces computation. The number of k point groups that run in parallel is controlled by the kpar parameter. This script reads in vasps eigenval file and obtains a data set of energy, kpoint pairs for every band calculated. In any plane wave program, the execution time scales like n3 for some parts of the.
Over the course of proling vasp, the underlying software stack on hpcx was updated from sp7 to sp9 where sp stands for service pack. The vacuum comes not quite for free in siesta, but at a generously discounted price. Vasp computational materials physics universitat wien. A bit of surface science university of vienna, faculty of physics and center for computational materials science, vienna, austria. Useful values for the length vary between 10 large gap insulators and 100 dmetals. An effective algorithm for the quasiharmonic calculation of thermoelastic stiffness constants of materials is discussed and implemented into the crystal program for quantummechanical simulations of extended systems. The binary executable file vasp can run in both serial mode e. Calculate band structure using vasp by bin shan, 2003 vasp version. Vasp generates a equally spaced kpoint grid with the coordinates. In order to optimize the lattice parameters, send the lifepo 4 structure from the stash to the scripter to set up a new dft calculation as follows add the new calculator block and modify the following parameters sggapbe exchange correlation potential. Implemented real space quantum monte carlo algorithms include variational, diffusion, and reptation monte carlo.
Increase your k point set in the file kpoints to e. The above file instructs vasp to calculate the energy at each k point between gamma point and x point, gamma point and l point. Pdf introducing kpoint parallelism into vasp researchgate. On the hector phase 2b system, using a standard compilation of vasp 5. Kpar is the number of points that are to be treated in parallel available as of vasp. For many years ab initio electronic structure calculations based upon density functional theory have been one of the main application areas in high performance computing hpc. Home services we offer high performance computing research hpc publication list hpc publication list. The following table compares the time to run a simple benchmark case one au atom, lda, encut400, ismear1, sigma0. Testing the kpoint parallelization in vasp peter larsson nsc.
Two different approaches of increasing complexity and accuracy are presented. An introduction to the new vasp build system as introduced with release version 5. The symmetries of the brillouin zone are now taken into account for the k point sampling in the mobility and electronphononcoupling calculations. Accurate dos and bandstructure calculations calculating a dos can be done in two ways. For some software packages this is an important remark, for other packages this. This means that a number of compute cores together work on an individual point choose kpar such that it is an integer divisor of the total number of cores. Whilst this is common in similar codes, vasp does not currently support it, and we will show that through its use, the scalability of total energy calculations can be markedly improved. Briefly, vasp utilizes planewaves as the basis set to expand the kohnsham orbitals. Exploiting k point parallelism 50 100 150 200 250 300 0 2000 4000 6000 8000 0 12000 vasp 5.
The first one is a quasistatic approximation where the thermal dependence of elastic constants is. Introducing kpoint parallelism into vasp ucl discovery. Minerals free fulltext thermoelasticity of materials. How to use vasp on an hpc cluster hkhlr hpc hessen. We have achieved substantial improvements by introducing a new level of parallelism based upon the use of k point sampling within vasp. Kpoint generation scheme grid size x y z mesh shift you can also specify each kpoint manually. A vasp license must be purchased from the vasp software gmbh. This update provides more advanced compilers and communication libraries from ibm. The upper limit of kpar is obviously the number of k points in your calculation.
Speedup obtained on hector before blue squares and after red diamonds implementation of kpoint parallelisation within vasp 5. The meanfree path can either be assumed or computed. One of the software packages that uses dft to solve the quantum problem for materials uses periodic boundary conditions. However,when i use it to calculated the ir vibration, it doesnot work if i dont set npar1. One of the best known and widely used software for performing this type of calculation is the vienna ab initio simulation package, vasp, which currently offers a parallelisation strategy based on the distribution of bands and plane wave coefficients. One of the best known and widely used software for performing this type of calculation is the vienna ab initio simulation package, vasp, which currently offers a. If i use it for geometric optimization, it works well.
Symmetry is used to map equivalent kpoints to each other, which can reduce the total number of kpoints significantly. Siesta is very forgiving in introducing, if necessary, a lot of vacuum around a molecule, a slab or an atomic chain, much more forgiving than planewave methods are. In theory, the maximum number of cores you can run on using combined k point and bandparallelization is nbands kpar. Introducing kpoint parallelism into vasp asimina maniopoulou numerical algorithms group ltd, hector cse. Of course you can always use more k points to test k point convergence. How to compile vasp micro and nano mechanics group. Vasp is a package for performing abinitio quantummechanical molecular dynamics md using pseudopotentials and a plane wave basis set.
We have achieved substantial improvements by introducing a new level of parallelism based upon the use of kpoint sampling within vasp. One of the best known and widely used software for performing this type of calculation is the vienna ab initio simulation package, vasp, which. One of the best known and widely used software for performing this type of. Introducing k point parallelism into vasp by asimina maniopoulou, erlend r.
December 2016 the delocalized physicist danny vanpoucke. It is now possible to compute metal resistivity using a constant meanfree path. Typically, the kohnsham equations are solved by minimisation of the. Atomistic simulation of surface selectivity on carbonate formation at calcium and magnesium oxide.
I have achieved this by introducing a new level of parallelism based upon the use of kpoint sampling within vasp. First of all, switching on a parallelization parameter does not. This script reads in vasp s doscar file for a non spinpolarized calculation and plots the dos and the integrateddos using matplotlib. This script reads in vasp s eigenval file and obtains a data set of energy, k point pairs for every band calculated. Performance analysis of electronic structure codes on hpc. The set of points is distributed over kpar groups of compute cores, in a roundrobin fashion. The file kpoints must contain the kpoint coordinates and weights or the mesh size for creating the kpoint grid. A collection of examples for running different types of vasp calculations. Introducing kpoint parallelism into vasp sciencedirect. Maniopoulou a, davidson er, graucrespo r, walsh a, bush ij, et al. Converge wave function, with hse and a standard kpoint grid 2. Fulltext available article may 2008 acm transactions on mathematical software.
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