It is also possible to start PATHSAMPLE runs without an existing connection between the end points of interest. See keywords DIJINITSTART and DIJINITCONT. In this example we set up PATHSAMPLE from min.data.info files for the two minima and use DIJINITCONT to continue the run and seek an initial connection using PATHSAMPLE.
First, a minimisation was run for each minimum using OPTIM with the DUMPDATA keyword set. The ENDHESS keyword was used to produce frequencies after a BFGSMIN optimisation. In a clean directory, with no preexisting PATHSAMPLE files, two entries were created in min.data and points.min using the PATHSAMPLE READMIN keyword to read each of the min.data.info files in turn. min.A and min.B files were then created using vi with one entry in each, pointing to minima 1 and 2, respectively. After creating a suitable odata.connect file a single cycle of PATHSAMPLE was then run on one core to populate the database with enough minima to run on multiple cores in subsequent connection attempts. Since there is only one possible connection to try in the first cycle, it is necessary to use a single processor in this case along with the DIJINITCONT keyword in pathdata. A couple of cycles on eight cores then produced a connection for this bulk BLJ60 example.
| NATOMS | 60 |
| COPYFILES | perm.allow |
| BULK | 3.587037905 3.587037905 3.587037905 |
| PERMDIST | |
| SYSTEM | LS |
| TEMPERATURE | 0.71 |
| CONNECTIONS | 1 |
| SEED | 1 |
| PERTURB | 0.40 |
| ETOL | 1.0D-7 |
| ITOL | 1.1D0 |
| GEOMDIFFTOL | 0.1D0 |
| DIRECTION | AB |
| EXEC | /home/wales/bin/OPTIM |
| comment READMIN min.data.info.start | |
| comment READMIN min.data.info.finish | |
| comment CPUS 1 | |
| DIJINITCONT EXP | |
| CYCLES 100 | |
| PAIRLIST 1 |
The commented lines were used to read in the initial min.data.info files. A similar procedure can be used if an initial path.info file is available without a complete connection between the desired end points.