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faq:cholesky_decomp_failed

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]                                                                     *
*  \___/                             CPASSERT failed                          *
*    |                                                                        *
*  O/|                                                                        *
* /| |                                                                        *
* / \                                                  fm/cp_fm_cholesky.F:94 *
*******************************************************************************

===== Routine Calling Stack =====

10 cp_fm_cholesky_decompose
9 make_full_inverse_cholesky
8 make_preconditioner
7 prepare_preconditioner
6 init_scf_loop
5 scf_env_do_scf
4 qs_energies
3 qs_forces
2 qs_mol_dyn_low
1 CP2K

This says that CP2K failed to compute a Cholesky decomposition during the construction of the preconditioner for OT. Most likely, the overlap matrix (S) has become singular (or at least numerically close to singular). Here are some causes / possible solutions:

• Try some of the other PRECONDITIONER options, which may prove to be more stable for your system.
• Decrease the value of EPS_DEFAULT or EPS_PGF_ORB, to reduce the amount of numerical noise in the construction of S.
• Check carefully that the Basis Set(s) chosen for your calculation are appropriate for the system. If the basis set is over-complete this could result in a singular overlap matrix - try switching to a smaller basis set.
faq/cholesky_decomp_failed.txt · Last modified: 2015/12/14 21:04 by oschuett