https://www.cp2k.org/ 2026-05-06T18:08:20+00:00 https://www.cp2k.org/ https://www.cp2k.org/_media/wiki:logo.png text/html 2020-08-21T10:15:13+00:00 Anonymous (anonymous@undisclosed.example.com) https://www.cp2k.org/faq:cholesky_decomp_failed?rev=1598004913&do=diff How do I solve "CPASSERT failed" in cp_fm_cholesky.F? If you see the following error message (line number correct as of CP2K 2.7, Dec 2015), with a routine calling stack that includes prepare_preconditioner, for example: ******************************************************************************* * ___ * * / \ * * [ABORT] … text/html 2020-08-21T10:15:13+00:00 Anonymous (anonymous@undisclosed.example.com) https://www.cp2k.org/faq:cite?rev=1598004913&do=diff How to cite CP2K When performing calculations with CP2K, you will find a “R E F E R E N C E S” section in the output. This section lists the scientific articles that describe the specific modules and methods used in the calculation. “” Sometimes, you may need to cite CP2K in contexts where a detailed list of references is not appropriate (for example, as part of a list of quantum chemistry or solid state physics software packages). In this case, we recommend citing the latest relevant CP2K rev… text/html 2020-08-21T10:15:13+00:00 Anonymous (anonymous@undisclosed.example.com) https://www.cp2k.org/faq:common_mistakes?rev=1598004913&do=diff My simulation fails. Any ideas? Common mistakes are: * CUTOFF not converged. Anything below 200 is almost certainly too low. Test the convergence explicitly. * SCF cycle not converged. * Cell too small. Keep in mind that CP2K does not have k-point sampling. * atoms missing / wrong coordinates : visualize your geometry, including periodic images text/html 2020-08-21T10:15:13+00:00 Anonymous (anonymous@undisclosed.example.com) https://www.cp2k.org/faq:contribute?rev=1598004913&do=diff How can one contribute to CP2K? Use CP2K ! * Enabling great science is the main purpose of CP2K. Use CP2K for high quality work, and show others how to use CP2K correctly and efficiently. * In publications, give credit to the program used, and cite text/html 2022-03-09T13:17:16+00:00 Anonymous (anonymous@undisclosed.example.com) https://www.cp2k.org/faq:cuda_support?rev=1646831836&do=diff Which parts of CP2K are CUDA-accelerated? Have a look at our GPU page as well as this howto . text/html 2020-08-21T10:15:13+00:00 Anonymous (anonymous@undisclosed.example.com) https://www.cp2k.org/faq:cutoff?rev=1598004913&do=diff How can one guess a reasonable cutoff value? This is for the impatient CP2K user: As a rule of thumb one can multiply the largest exponent of the Gaussian basis sets employed by 40 to obtain a reasonable guess for the cutoff value in Rydberg. The first column of the CP2K basis set format contains the Gaussian exponents, e.g. for the oxygen DZVP-MOLOPT-SR- text/html 2020-08-21T10:15:13+00:00 Anonymous (anonymous@undisclosed.example.com) https://www.cp2k.org/faq:doing_io?rev=1598004913&do=diff What is the correct way to write information to the screen? When writing output in cp2k, to the screen or a file, one should use a printkey. text/html 2023-09-26T12:50:10+00:00 Anonymous (anonymous@undisclosed.example.com) https://www.cp2k.org/faq:hfx_eps_warning?rev=1695732610&do=diff I received a warning message about the Kohn Sham matrix not 100% occupied when doing Hartree-Fock or hybrid calculations, what is going on, and what should I do? Since version 2023.2EPS_PFG_ORBKSMIN_PAIR_LIST_RADIUSKSEPS_PFG_ORB When you do a calculation that involves the calculation of the Hartree-Fock exchange (e.g. calculations with hybrid functionals, including using the text/html 2020-08-21T10:15:13+00:00 Anonymous (anonymous@undisclosed.example.com) https://www.cp2k.org/faq:hint_insufficiently_exploiting_cpu_extensions?rev=1598004913&do=diff HINT: Compiler target flags insufficiently exploiting the extensions of this CPU model. When running CP2K you may get the following HINT in the output: HINT in environment.F:804 The compiler target flags used to build this binary are insufficiently exploiting the extensions which are available for this CPU model. text/html 2020-08-21T10:15:13+00:00 Anonymous (anonymous@undisclosed.example.com) https://www.cp2k.org/faq:kpoints?rev=1598004913&do=diff Which features are working with k-point sampling in CP2K? Since CP2K 3.0 (Dec 2015) it is possible to carry out DFT calculations with multiple k-points in CP2K. However, there are several features / combinations that are not yet implemented. This page summarises what is known to work and what is not text/html 2020-08-21T10:15:13+00:00 Anonymous (anonymous@undisclosed.example.com) https://www.cp2k.org/faq:libsmm_arguments_too_long?rev=1598004913&do=diff How do I solve the "Argument list too long" error when building libsmm? The libsmm build process involves compiling many small (versions of) matrix multiplication kernels and testing them. For some shells / settings, the makefile may generate lists of arguments that are too long, and you will see errors like: text/html 2020-08-21T10:15:13+00:00 Anonymous (anonymous@undisclosed.example.com) https://www.cp2k.org/faq:mpi_vs_openmp?rev=1598004913&do=diff Should I use MPI or OpenMP or both? The entire CP2K code is MPI parallelized. Some additional loops are also OpenMP parallelized. You should therefore first take advantage of the MPI parallelization. However, running one MPI-rank per CPU-core will probably lead to memory shortage. text/html 2020-08-21T10:15:13+00:00 Anonymous (anonymous@undisclosed.example.com) https://www.cp2k.org/faq:name?rev=1598004913&do=diff What does the name CP2K stand for? The name is derived from the CPMD code and the original meaning was the CP (Car-Parrinello = ab initio MD) code for the new Millenium. Never mind that we didn't implement the CP method. text/html 2020-08-21T10:15:13+00:00 Anonymous (anonymous@undisclosed.example.com) https://www.cp2k.org/faq:new_basis_set?rev=1598004913&do=diff How can I generate a new basis set? We have different options available to generate basis sets within CP2K. However, all of them also require a large part of manual invention. There are no black box schemes. Method 1: Optimize the exponents of a Gaussian basis with the atomic code for a given reference state (see $l$ text/html 2020-08-21T10:15:13+00:00 Anonymous (anonymous@undisclosed.example.com) https://www.cp2k.org/faq:ngrids?rev=1598004913&do=diff How to choose the NGRIDS in &MGRID The three inputs “CUTOFF”, “NGRIDS”, and “REL_CUTOFF” are important for accuracy and efficiency. The problem is that both, “accuracy and efficiency” depend on the combination of chosen values. See also the text/html 2020-08-21T10:15:13+00:00 Anonymous (anonymous@undisclosed.example.com) https://www.cp2k.org/faq:speedup?rev=1598004913&do=diff How can I speedup my calculations? There are a couple of areas to consider when you are interested in performance, firstly the physics, and secondly, computational. Physical parameters * choosing the cheapest representation of your system that gives correct results e.g. choosing an appropriate basis set (Gaussian), and also an appropriately sized plane-wave expansion (see $n_\text{procs} \approx n_\text{atoms}$ text/html 2020-08-21T10:15:13+00:00 Anonymous (anonymous@undisclosed.example.com) https://www.cp2k.org/faq:toolchain_non_zero_exit_code_detected?rev=1598004913&do=diff Non-zero exit code detected when using the CP2K toolchain script When using the script tools/toolchain/install_cp2k_toolchain.sh for building dependencies of CP2K you may encounter the following message (here for the binutils package, but it may occur at any stage of the installation): text/html 2020-08-21T10:15:13+00:00 Anonymous (anonymous@undisclosed.example.com) https://www.cp2k.org/faq:uks_convention?rev=1598004913&do=diff Into which spin channel do excess electrons go? If you do unrestricted DFT calculations with CP2K for charged systems, you may wonder which spin channel the electron is taken from or added to. Moreover, the sign convention for any output (Hirshfeld or Mulliken spin charge, cube files) may be of interest to you. text/html 2020-08-21T10:15:13+00:00 Anonymous (anonymous@undisclosed.example.com) https://www.cp2k.org/faq:usagestats?rev=1598004913&do=diff How large is CP2K's user base? There is no requirement to register for using CP2K, and the code is freely available in various ways. This makes it difficult to gather accurate usage stats. To provide feedback to funding agencies we therefor look at citations of method papers, or look at website access. The latter info can be found here: