NTEMPER
NTEMPER = [integer]
Default: NTEMPER = 200
Description: NTEMPER specifies how often temperature swaps are attempted during parallel tempering. The flag must be used in combination with IMAGES and LTEMPER.
NTEMPER must be a positive integer. Swaps are on average attempted after NTEMPER molecular dynamics steps. Specifically, a random number between [0,1[ is drawn. The next temperature swaps are attempted after NTEMPER steps. Obviously, for NTEMPER=1 swaps are attempted at every MD step. In the present code version, temperature swaps are alternatively performed between images 1,2 and 3,4 and 5,6 etc. Upon the next swap attempts, the swaps are attempted between imaged 2,3 and 4,5 and 6,7 etc. This implies that many swaps are attempted at the same time.
Furthermore, for NTEMPER=0 no temperature swaps are attempted. This can be useful to perform many independent calculations in the directories 01, 02, 03, ... .
A final note is in place. The tag NTEMPER must be set in the INCAR files of the subdirectories 01, 02, 03, and NTEMPER must be identical in all subdirectories. Failure to observe this rule can lead to unexpected behavior.