So I would assume you never wrote any forces in your trr file. The mdp file option nstfout=0 is most probably set, isn't it ? If you use -pforce you realize, that forces arise in your simulation, but you donot tell gromacs to write them to a file.
/Flo
* Shuangxing Dai <[email protected]> [2009-06-27 12:19:09 -0600]:
Hi, all, I was wondering about the force given by Gromacs. One is in the .trr and .tpr file. When I read then with gmxdump, they are all zeros: traj.trr frame 0: natoms= 24000 step= 0 time=0.0000000e+00 lambda= 0 box (3x3): box[ 0]={ 3.24900e+00, 0.00000e+00, 0.00000e+00} box[ 1]={ 0.00000e+00, 5.62743e+00, 0.00000e+00} box[ 2]={ 0.00000e+00, 0.00000e+00, 1.04120e+01} f (24000x3): f[ 0]={ 0.00000e+00, 0.00000e+00, 0.00000e+00} f[ 1]={ 0.00000e+00, 0.00000e+00, 0.00000e+00} f[ 2]={ 0.00000e+00, 0.00000e+00, 0.00000e+00} f[ 3]={ 0.00000e+00, 0.00000e+00, 0.00000e+00} .... When I use mdrun -pforce 0 to get all the non-zero force, I get: step 0 atom 4687 x 0.975 3.189 0.781 force 3.58158e+02 step 0 atom 4688 x 0.975 3.189 0.586 force 7.16316e+00 step 0 atom 4689 x 0.975 3.189 0.586 force 3.65324e+02 step 0 atom 4690 x 0.812 3.095 1.041 force 3.58167e+02 step 0 atom 4691 x 0.812 3.095 0.846 force 7.16314e+00 .... Why this happens? Thanks in advance. Shuangxing Dai _______________________________________________ gmx-users mailing list [email protected] http://lists.gromacs.org/mailman/listinfo/gmx-users Please search the archive at http://www.gromacs.org/search before posting!Please don't post (un)subscribe requests to the list. Use the www interface or send it to [email protected].Can't post? Read http://www.gromacs.org/mailing_lists/users.php
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