CHARMM Development Project Forums User Discussion & Questions Setup, I/O, and Basic questions Reading DCD trajectory using MPI CHARMM

Note that the coor dyna command computes the average structure over the number of frames processed. It will be very slow if you try to a read a large number of single frames from a long trajectory since it starts over reading the trajectory from the beginning at each invocation. You can use "coor read file ifile .... CONT" (io.info):
READ COOR FILE IFILE 10 UNIT 51
READ COOR FILE CONT IFILE 10 UNIT 51
will first read frame 10 and then frame 20 from unit 51.