Questions tagged [constraint-programming]
For questions on modeling satisfaction or optimization problems in languages designed for expressing (often high-level) constraints on decision variables.
192 questions
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Set cover constraint programming
I am interested in learning how Constraint Programming solvers implement set cover constraints internally. Specifically, I am curious to know how operations like, constraint propagation, domain ...
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Highly Non-convex Function for Algorithm Comparison
I am designing a numerical experiment to compare the performance of various nonconvex optimization algorithms (e.g., SGD with momentum, Adam, BFGS, etc.). To do this properly, I need a challenging ...
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Job Scheduling with Start-to-Start Precedence Constraints — Literature and Modeling Help
I’m studying a job scheduling problem where the precedence constraints are of the start-to-start type — that is, if job (i) precedes job (j), then job (j) can only start after job (i) has started:
$$
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Docplex CP Model Solution Found but Can't Retrieve Decision Variable Values
I'm using Docplex's Constraint Programming model with two 4-dimensional binary decision variables:
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Any x of constraint : CP Solver
I am working on CP approach for a problem with many "Select #x of items" type of constraints. It is like a set cover constraint where the goal is to select $x$ out of $n$ items to satisfy ...
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Job Shop Scheduling Problem: Identifying Problem Type and software for automation of schedule
I am trying to make an automatic schedule generated for the first workstation for the jobs released based on the total processing time taken by each job at all workstations(excluding wait times in ...
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How do I improve as a rookie in the industry?
I am reaching out for help because I feel lost in my current work situation and would like to hear advice from you guys. Currently, as an operations research optimization algorithm engineer at a small ...
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Topological sorting efficiency
Encouraged by this answer I tried formulating my problem in the CP system MiniZinc. When I tried it out on my real problem with ~40k nodes and ~500k edges, it didn't go anywhere, which is not ...
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Effect of nonnegativity constraints on solving ILPs
Consider the integer linear program (ILP)
$$
\max \{ c^T x \mid Ax = b, x \in \mathbb{Z}^n \},
$$
where $A$ is a totally unimodular matrix. It is well known that in this case, the ILP can be solved in ...
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I am working on a Linear Transshipment problem to find for the minimum Utilities required- problem dealing with variables
I have a Linear Transshipment problem, the objective is to find for the Minimum cost of the Utilities and i have formulated a code for the constraints in the problem and the variables which are ...
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Scheduling optimization, adding loop change constraint
I am quite new to constraint programming and cp-sat. By following this blog post and example, I have been able to mostly tailor it to suit my shift scheduling. However there is one constraint I would ...
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Explaining propagation of the global cardinality constraint
I am using the generalized arc consistent algorithm from Regin, J. C. (1996) to propagate the global cardinality constraint. Values are removed from the domain of a variable if the variable node and ...
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Slow performance with simple constraint programming model
Im pretty new in the world of CP. Currently Im trying to solved a single machine scheduling problem with changeovers.
Here is my code and model:
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CPLEX CP Optimizer's search phase doesn't support Restart SearchType
CPLEX CP Optimizer allows users to set search phases to specify the order in which variables are searched and the method for assigning values, thereby accelerating the search process.
However, when ...
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Is it necessary to iterate the simulated annealing algorithm so many times in a production scenario?
I have recently been working on coding a solution for a assembly line balancing problem. My approach is to first use a greedy algorithm to generate an initial feasible solution, and then apply ...
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