For non-trivial problems, it is advisable to save a BASIS file at the end of a run, in order to restart the run if necessary, or to provide a good starting point for some closely related problem.
Three formats are available for saving basis descriptions. They are invoked by SPECS lines of the following form:
|
New Basis |
file |
10 |
|
Backup |
file |
11 |
|
Punch |
file |
20 |
|
Dump |
file |
30 |
The file numbers may be whatever is convenient, or zero for files that are not wanted.
NEW BASIS and BACKUP BASIS files are saved in that order every kth iteration, where k is the Save frequency.
NEW BASIS, PUNCH and DUMP files are saved at the end of a run, in that order. They may be re-loaded at the start of a subsequent run by specifying SPECS lines of the following form:
|
Old Basis |
file |
10 |
|
Insert |
file |
20 |
|
Load |
file |
30 |
Only one such file will actually be loaded. If more than one positive file number is specified, the order of precedence is as shown. If no BASIS files are specified, one of the Crash options takes effect.
Figures 1 illustrate the data formats used for BASIS files. 80-character fixed-length records are suitable in all cases. (36-character records would be adequate for PUNCH and DUMP files.) The files shown correspond to the optimal solution for the economic-growth model MANNE. (The problem has 10 nonlinear constraints, 10 linear constraints, and 30 variables.) Selected column numbers are included to define significant data fields.