Hi Michael, I think that this is an issue with the gromacs version I am using (4.6.1). I switched to 4.5.7 and now, I get the error:
Fatal error: The properties of the ... systems are all the same, there is nothing to exchange I don't understand what I am missing here. I suppose if I have 3 replicas to fix a molecule at positions 1.0 and 2.0 and 3.0 while the force constant is being exchanged between them in a range of 300 to 200, I can define 3 mdp files as below: For replica 1 at position 1.0: pull_group0 = POPC pull_weights0 = pull_pbcatom0 = 0 pull_group1 = DNA pull_weights1 = pull_pbcatom1 = 0 pull_vec1 = 0.0 0.0 0.0 pull_init1 = 0.0 0.0 1.0 pull_rate1 = 0 pull_k1 = 300 pull_kB1 = 200 free_energy = yes restraint-lambdas = 1.0 0.5 0.0 init-lambda-state = 0 nstdhdl = 10 For replica 2 at position 2.0: pull_group0 = POPC pull_weights0 = pull_pbcatom0 = 0 pull_group1 = DNA pull_weights1 = pull_pbcatom1 = 0 pull_vec1 = 0.0 0.0 0.0 pull_init1 = 0.0 0.0 2.0 pull_rate1 = 0 pull_k1 = 300 pull_kB1 = 200 free_energy = yes restraint-lambdas = 1.0 0.5 0.0 init-lambda-state = 1 nstdhdl = 10 For replica 3 at position 3.0: pull_group0 = POPC pull_weights0 = pull_pbcatom0 = 0 pull_group1 = DNA pull_weights1 = pull_pbcatom1 = 0 pull_vec1 = 0.0 0.0 0.0 pull_init1 = 0.0 0.0 3.0 pull_rate1 = 0 pull_k1 = 300 pull_kB1 = 200 free_energy = yes restraint-lambdas = 1.0 0.5 0.0 init-lambda-state = 2 nstdhdl = 10 Could you please comment if I am missing something here? Unfortunately, there is not much about this posted before. Many thanks, Parisa -- View this message in context: http://gromacs.5086.x6.nabble.com/window-exchange-umbrella-sampling-tp5009894p5009947.html Sent from the GROMACS Users Forum mailing list archive at Nabble.com. -- gmx-users mailing list gmx-users@gromacs.org http://lists.gromacs.org/mailman/listinfo/gmx-users * Please search the archive at http://www.gromacs.org/Support/Mailing_Lists/Search before posting! * Please don't post (un)subscribe requests to the list. Use the www interface or send it to gmx-users-requ...@gromacs.org. * Can't post? Read http://www.gromacs.org/Support/Mailing_Lists
