GAMS — The Solver Manuals - Available Software

CPLEX 11 201
The solution pool relative gap parameter can also be used as a stopping criterion for the populate procedure:
if populate cannot enumerate any more solutions that satisfy this objective quality, then it will stop. In
the presence of both an absolute and a relative solution pool gap parameter, populate will stop when the
smaller of the two is reached.
(default = 1e+075)
solnpoolintensity (integer)
Controls the trade-off between the number of solutions generated for the solution pool and the amount
of time or memory consumed. This parameter applies both to MIP optimization and to the populate
procedure.
Values from 1 to 4 invoke increasing effort to find larger numbers of solutions.
expensive in terms of time and memory but are likely to yield more solutions.
(default = 0)
0 Automatic. Its default value, 0 , lets Cplex choose which intensity to apply.
Higher values are more
1 Mild: generate few solutions quickly. For value 1, the performance of MIP optimization is not affected.
There is no slowdown and no additional consumption of memory due to this setting. However, populate
will quickly generate only a small number of solutions. Generating more than a few solutions with this
setting will be slow. When you are looking for a larger number of solutions, use a higher value of this
parameter.
2 Moderate: generate a larger number of solutions. For value 2, some information is stored in the branch
and cut tree so that it is easier to generate a larger number of solutions. This storage has an impact
on memory used but does not lead to a slowdown in the performance of MIP optimization. With this
value, calling populate is likely to yield a number of solutions large enough for most purposes. This
value is a good choice for most models.
3 Aggressive: generate many solutions and expect performance penalty. For value 3, the algorithm is
more aggressive in computing and storing information in order to generate a large number of solutions.
Compared to values 1 and 2, this value will generate a larger number of solutions, but it will slow
MIP optimization and increase memory consumption. Use this value only if setting this parameter to
2 does not generate enough solutions.
4 Very aggressive: enumerate all practical solutions. For value 4, the algorithm generates all solutions
to your model. Even for small models, the number of possible solutions is likely to be huge; thus
enumerating all of them will take time and consume a large quantity of memory.
solnpoolpop (integer)
Regular MIP optimization automatically adds incumbents to the solution pool as they are discovered. Cplex
also provides a procedure known as populate specifically to generate multiple solutions. You can invoke this
procedure either as an alternative to the usual MIP optimizer or as a successor to the MIP optimizer. You
can also invoke this procedure many times in a row in order to explore the solution space differently (see
option solnpoolpoprepeat). In particular, you may invoke this procedure multiple times to find additional
solutions, especially if the first solutions found are not satisfactory.
(default = 1)
1 Just collect the incumbents found during regular optimization
2 Calls the populate procedure
solnpoolpopdel (string)
After the GAMS program specified in solnpoolpoprepeat determined to continue the search for alternative
solutions, the file specified by this option is read in. The solution numbers present in this file will be delete
from the solution pool before the populate routine is called again. The file is automatically deleted by the
GAMS/Cplex link after processing.
solnpoolpoprepeat (string)
After the termination of the populate procedure (see option solnpoolpop). The GAMS program specified
in this option will be called which can examine the solutions in the solution pool and can decide to run the