Hi As you described....... This is not a grompp warning, but a warning from one of the analysis tools. grompp will never take masses 'out of the blue', but will always use the force field description (atom type definitions) or the mass specified in the .top/.itp file. It will bail out if no mass is properly defined for a specified atom. As David pointed out, these tools would benefit from reading in a .tpr (run input) file, not a .top file.
1. If I have the correct information in my .top file and .gro file, I could successfully run "GROMPP" command without the warning. And, I could ignore the warning from the analysis tools. right? 2. you described " these tools would benefit from reading in a .tpr (run input) file, not a .top file.......... " how about the .gro file? I see nothing wrong with my .gro file. Thank you Lin _______________________________________________ gmx-users mailing list gmx-users@gromacs.org http://www.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