#9586: Lecture Scheduler
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Reporter: schilly | Owner: jason, jkantor
Type: enhancement | Status: needs_review
Priority: major | Milestone: sage-4.5.2
Component: numerical | Keywords:
Author: | Upstream: N/A
Reviewer: | Merged:
Work_issues: |
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Comment(by schilly):
Thank's for looking into this.
ad 1. I just wish to have it in sage because I spent much time
implementing it and I like it. About part-of-sage-or-not, there is afaik
also a rubic cube solver, even with some visuals, and also a sudoku solver
in sage ... and there are more papers about combinatorial optimization
w.r.t. scheduling than about sudoku! ;)
ad 2. it depends on the solver, i.e. if there is no feasible solution
[that means that all constraints are true] it returns an exception.
handling this in a better way is not part of the scope of this
application, it's part of the mip.pyx file where the solver interfaces
are. also, there are sophisticated methods to deal with infeasible CSP
problems, i.e. solvers like gurobi can generate an IIS set to learn more
about why the problem is infesible. (but we haven't even wrapped gurobi
now). so, for now just an error depending on the selected solver.
ad 3. it doesn't scale with glpk or cbc (you get the later one via a spkg
and the {{{solver='Coin'}}} parameter in {{{solve()}}}. the only open
source csp solver that might be able to scale to real world applications
is scip, but it is currently not able to solve this kind of problem due to
a bug (reported upstream, this bug will be resolved in the next release in
oct 2010). cplex might be the best choice for now. apart from that, i have
a real world example for that model, but it's not meant for the public
(real names and so on).
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/9586#comment:4>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
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