Hi everyone, I have asked about the settings in GROMACS that would do the same job as *kspace_style* and *kspace_modify* in LAMMPS, and got reply from Mark a few days ago, but there are some points I'm still not very clear. Please help me with this again.
In details, these 2 commands in LAMMPS are: * - kspace_style pppm 1e-5 *(kspace_style defines a long-range solver, pppm is P3M algorithm, 1.0e-5 means that the RMS error will be a factor of 100,000 smaller than the reference force) * - kspace_modify diff ad *(kspace_modify sets the parameters used by the kspace solvers, *diff* keyword specifies the differentiation scheme used by the PPPM method to compute forces on particles, *ad* keyword means approach uses only 1 FFT to transfer information back to real space for a total of 2 FFTs per timestep). I know that coulombtype *= *P3M-AD can set the pppm algorithm for long range interaction. However, I'm not sure about the *1e-5 *part in* 'kspace_style pppm 1e-5'. *Would the command 'ewald-rtol = 1e-05' do the same job? I'm not sure because the 1e-5 in 'kspace_style pppm 1e-5' defines how much the RMS error is smaller than the reference force, while 1e-05 in 'ewald-rtol = 1e-05' defines the relative strength of the Ewald-shifted direct potential. What values should I set for ewald-rtol to get the same meaning as ' *kspace_style **1e-5'* ? Also, would there be much difference (e.g. in the energy of the molecules, in the output pressure, etc.) when PME is used instead of P3M? (I have tried with some simple systems and got similar results when PME is used instead of P3M-AD) Thank you very much for your help. I really appreciate it. Best regards, Anh Vo -- Gromacs Users mailing list * Please search the archive at http://www.gromacs.org/Support/Mailing_Lists/GMX-Users_List before posting! * Can't post? Read http://www.gromacs.org/Support/Mailing_Lists * For (un)subscribe requests visit https://maillist.sys.kth.se/mailman/listinfo/gromacs.org_gmx-users or send a mail to gmx-users-requ...@gromacs.org.