The HISTORY file is the dump file of atomic coordinates, velocities and forces. Its principal use is for off-line analysis. The file is written by the subroutines TRAJECT or TRAJECT/SMALL>_U. The control variables for this file are ltraj, nstraj, istraj and keytrj which are created internally, based on information read from the traj directive in the CONTROL file (see above). The HISTORY file will be created only if the directive traj appears in the CONTROL file. Note that the HISTORY file can be written in either a formatted or unformatted version. We describe each of these separately below.
The HISTORY file can become very large, especially if it is formatted. For serious simulation work it is recommended that the file be written to a scratch disk capable of accommodating a large data file. Alternatively the file may be written as unformatted (below), which has the additional advantage of speed. However, writing an unformatted file has the disadvantage that the file may not be readily readable except by the machine on which it was created. This is particularly important if graphical processing of the data is required.