As reported on the user forum in https://gromacs.bioexcel.eu/t/segmentation-fault-with-pairdist/1006 Hi all, I want to compute the min/max distance between each oxygen atoms in a group and the COM of the system with pairdist, but I get a Segmentation fault error. The command and the output are: ``` $ gmx_mpi pairdist -s system.tpr -f system.xtc -n system_index.ndx Available static index groups: Group 0 "System" (20523 atoms) Group 1 "Other" (20523 atoms) Group 2 "TIP3" (20523 atoms) Group 3 "OH2_around_10_of_COM" (137 atoms) Specify a selection for option 'ref' (Reference positions to calculate distances from): (one per line, <enter> for status/groups, 'help' for help) > [2.194, 2.368, 0.150] Selection '[2.194, 2.368, 0.150]' parsed Available static index groups: Group 0 "System" (20523 atoms) Group 1 "Other" (20523 atoms) Group 2 "TIP3" (20523 atoms) Group 3 "OH2_around_10_of_COM" (137 atoms) Specify any number of selections for option 'sel' (Positions to calculate distances for): (one per line, <enter> for status/groups, 'help' for help, Ctrl-D to end) > 3 Selection '3' parsed > Reading file md_1ns_equil_10A_sphere_restrained_10000.tpr, VERSION 2020.1 (single precision) Reading file md_1ns_equil_10A_sphere_restrained_10000.tpr, VERSION 2020.1 (single precision) [login:13575] *** Process received signal *** [login:13575] Signal: Segmentation fault (11) [login:13575] Signal code: Address not mapped (1) [login:13575] Failing at address: (nil) [login:13575] [ 0] /lib64/libpthread.so.0(+0xf630)[0x7f3e81962630] [login:13575] [ 1] /home/adi865j/Softwares/gromacs-2020.1/gromacs-2020.1_built/lib64/libgromacs_mpi.so.5(_Z33gmx_ana_indexmap_init_orgid_groupP18gmx_ana_indexmap_tPK10gmx_mtop_t9e_index_t+0x224)[0x7f3e82d8c6c4] [login:13575] [ 2] /home/adi865j/Softwares/gromacs-2020.1/gromacs-2020.1_built/lib64/libgromacs_mpi.so.5(_ZN3gmx9Selection22initOriginalIdsToGroupEPK10gmx_mtop_t9e_index_t+0x22)[0x7f3e82dbea02] [login:13575] [ 3] /home/adi865j/Softwares/gromacs-2020.1/gromacs-2020.1_built/lib64/libgromacs_mpi.so.5(+0x965977)[0x7f3e82a0d977] [login:13575] [ 4] /home/adi865j/Softwares/gromacs-2020.1/gromacs-2020.1_built/lib64/libgromacs_mpi.so.5(+0x9525d1)[0x7f3e829fa5d1] [login:13575] [ 5] /home/adi865j/Softwares/gromacs-2020.1/gromacs-2020.1_built/lib64/libgromacs_mpi.so.5(+0x43dc24)[0x7f3e824e5c24] [login:13575] [ 6] /home/adi865j/Softwares/gromacs-2020.1/gromacs-2020.1_built/lib64/libgromacs_mpi.so.5(_ZN3gmx24CommandLineModuleManager3runEiPPc+0x20f)[0x7f3e824dff7f] [login:13575] [ 7] gmx_mpi[0x404d4c] [login:13575] [ 8] /lib64/libc.so.6(__libc_start_main+0xf5)[0x7f3e80d88555] [login:13575] [ 9] gmx_mpi[0x404e11] [login:13575] *** End of error message *** Segmentation fault (core dumped) ``` Attached are the .tpr and .xtc files. Best[system.tpr](/uploads/2a24ea1f52989ad1edb786666b895faa/system.tpr) [system.xtc](/uploads/48c351db65461739c2a91fa155c37db4/system.xtc)