Objective sense, name, and offset in MPS files
The CPLEX extension of MPS files supports name and sense of an objective function.
CPLEX extends
the MPS standard by allowing two additional sections: OBJSEN
and OBJNAME
.
They may be specified after the NAME
section. OBJSEN
sets
the objective function sense, and OBJNAME
selects
an objective function from among the free rows within the file. If
neither of these sections appears in the MPS file, CPLEX assumes that the problem
is a minimization and that the objective function is the first free
row encountered in the ROWS
section. If
these options are used, they must appear in order and as the first
and second sections after the NAME
section.
The values for OBJSENSE
can be MAX
or MIN
.
Here is an example of these optional sections:
NAME example.mps
OBJSENSE
MAX
OBJNAME
rowname
CPLEX has also extended the MPS file format to support an objective offset
as the negative value of the right hand side (RHS) of the objective function
in the
RHS
section of an MPS file. For example, the following
line in the RHS
section declares an offset of the
objective function as -25. (Notice the change of sign.)
rhs obj 25