The CONTROL file is read by the subroutine SIMDEF and defines the control variables for running a DL_POLY_2 or DL_MULTI job.
The only difference in the CONTROL file between DL_MULTI and DL_POLY_2 is
in the definition of the Ewald sum precision. DL_POLY_2 uses the
record
| ewald precision | f |
| whereas DL_MULTI uses the following records | |
| mulp precision | |
| fd0 | |
| fd1 | |
| fd2 | |
| fd3 | |
| fd4 | |
| fr0 | |
| fr1 | |
| fr2 | |
| fr3 | |
| fr4 | |
fd0 is the Ewald precision in direct space for pole order 0, fd1 for pole order 1 and so on. fr0, fr1 are the corresponding terms for reciprocal space.
It is recommended that the user sets a high precision (smaller value of the f parameter) for pole orders greater than 0 in direct space. If this is not done there will be an energy drift due to energy changes when the higher order poles cross the cutoff boundary. Values of 0.001 can be used for pole order 0 and for all the reciprocal space terms, although smaller values will give better energy stability. Values not less than 0.000001 should be used for the higher order terms in direct space.