Sage Reference Manual: Numerical Optimization - Mirrors

Sage Reference Manual: Numerical Optimization, Release 6.1.1
sage: p = MixedIntegerLinearProgram(solver = "GLPK")
sage: p.solver_parameter("timelimit", 60)
sage: p.solver_parameter("timelimit")
60.0
sum(L)
Efficiently computes the sum of a sequence of LinearFunction elements
INPUT:
•mip – the MixedIntegerLinearProgram parent.
•L – list of LinearFunction instances.
Note: The use of the regular sum function is not recommended as it is much less efficient than this one
EXAMPLES:
sage: p = MixedIntegerLinearProgram()
sage: v = p.new_variable()
The following command:
sage: s = p.sum([v[i] for i in xrange(90)])
is much more efficient than:
sage: s = sum([v[i] for i in xrange(90)])
write_lp(filename)
Write the linear program as a LP file.
This function export the problem as a LP file.
INPUT:
•filename – The file in which you want the problem to be written.
EXAMPLE:
sage: p = MixedIntegerLinearProgram(solver="GLPK")
sage: x = p.new_variable()
sage: p.set_objective(x[1] + x[2])
sage: p.add_constraint(-3*x[1] + 2*x[2], max=2)
sage: p.write_lp(os.path.join(SAGE_TMP, "lp_problem.lp"))
Writing problem data to ...
9 lines were written
For more information about the LP file format : http://lpsolve.sourceforge.net/5.5/lp-format.htm
write_mps(filename, modern=True)
Write the linear program as a MPS file.
This function export the problem as a MPS file.
INPUT:
•filename – The file in which you want the problem to be written.
•modern – Lets you choose between Fixed MPS and Free MPS
–True – Outputs the problem in Free MPS
–False – Outputs the problem in Fixed MPS
30 Chapter 2. Mixed integer linear programming