Calculate atomic fluctuations (RMSF) for atoms over time blocks.
[crdset <crd set>] [<mask>] [out <filename>] [window <size>] [bfactor]
Calculate atomic positional fluctuations for atoms in <mask> over windows of size <size>. If bfactor is specified, the fluctuations are weighted by (similar but not necessarily equivalent to crystallographic B-factor calculation).
Units are , or if bfactor specified.