Tools
For a model in LINLib we have collected points which
represent some solution to a problem. The points are part of the library
and are in GAMS data exchange (GDX) format. They are
identified by the model name plus the extension _p1.gdx, _p2.gdx,
etc. For example, the model
10teams
has a solution point
10teams_p1.gdx.
The header of the point file contains details
of the point, for example objective function value at that point and
solver used to obtain the solution. The file page also contains
model statistics such as number of variables, discrete variables, constraints,
etc. For details the user is referred to a point page such as
10teams_p1.
Running MIP models from specific points
In order to start a MIP model from a certain point users can run GAMS in the
following way:
>> gams (modelname) --point=(point number) optfile=1
where
--point=p1 (p2, p3, etc.)
The option --point=(point number) tells GAMS to use a feasible point, where
the --point value is the point number (p1, p2, p3, etc.).
For MIP models, users will also have to
create an option file for the specific solver used in order to tell
it to use the restart point. For example, for CPLEX one would create
an option file cplex.opt with the entry
mipstart 1
Furthermore, users need to include the optfile=1 option to
specify that a solver option file is used.
Running LP models from specific points
If users with to make use of a starting point for LPs, the syntax is similar
as for MIP models.
>> gams (modelname) --point=(point number)
No solver option file is necessary to tell GAMS to use the point.
