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Questions tagged [cp-sat-solver]

Questions relating to the Google CP-SAT solver, available through OR-Tools.

105 questions
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Or-Tools CP-SAT solver export/import: how to access vars after loading a model?

Using the Python interface to the OR-Tools CP-CAT solver (reference), I would like to be able to save a cp_model, load it at a later time or from a different process, and continue interacting with it. I'm able to serialize a model into a Protubuf,…
etov
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Seeding the CP-SAT solver

In googles OR-tools library, the "Original" CP-Solver (discussed here: https://developers.google.com/optimization/cp/original_cp_solver) can be reseeded using .ReSeed(). However, the newer version, CP-SAT cannot. My assumption is that CP-SAT will…
Andrew
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ORTools / Python : How to keep track of the amount of some variables in the solve process?

First, I want to precise I'm not a pro dev. I have some really basics knowledge, and this is my first real coding Project. ( and i guess i didnt choose the easiest one ) This is a Python(3) project. I wanted to create a tool for a famous football…
Bastien_F
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When resulting in an infeasible model, what tips are there to break down the nexus of the issue

I am new to using or-tools and I have been tasked with minimizing a quadratic objective function with lots of IntVar variables. I don't know where to start breaking down what the problem could be concerning an infeasable model and welcome any tips…
Tejas
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Python ortools | Add Exactly 2 instead if AddExactlyOne

I'm using AddExactlyOne from Python or-tools CP-SAT for the nurses scheduling problem. (Using the from ortools.sat.python import cp_model code at the bottom of the link) However, this code used AddExactlyOne to assign exact only one nurse in a…
MG G
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OR-Tools CP-Sat: Efficiently optimize toward an average value

I'm new to OR-Tools and CP-Sat I'm looking for guidance on how to most efficiently optimize sums of variables toward a common average value. Here's a very simplified example to help explain: from ortools.sat.python import cp_model from random import…
schwartz721
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Spreading out shift assignments in constraint solver (ortools)

I used the Google OR-Tools Employee Scheduling script (thanks by the way) to make a on-call scheduler. Everything works fine and it is doing what it is supposed to. It makes sure each person works about the same amount of "shifts" (two week…
D.Wills
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ortools - CP-SAT : how to fetch the feasible solution if the best incumbent solution does not change after 'x' seconds

I am solving integer programming problem leveraging CP-SAT solver (ortools). Looking at the logs, I notice that the solver finds the solution that actually is optimal (proven later), but spends a lot of time in proving optimality. Essentially, the…
Bhartendu Awasthi
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CP-SAT MODEL_INVALID The divisor cannot span across zero in constraint

Dears, I need your help on that CP-SAT implementation. Here a simplified version of what I'm doing: assume that I have 3 boolean decision variables: x1, x2, x3 and boolean coefficents a1 a2 a3 model.Add(num == a1*x1+a2*x2+a3*x3) model.Add(denom ==…
stefano guerrieri
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Does the Google OR-Tools CP-SAT support relaxation method to sovle MIQP?

I applied the CP-SAT sovler to sovle a MIQP problem, and it found a optimat result successfully. Do I need to further consider the relaxation method for the problem? Does the CP-SAT sovler support relaxation?
user19508782
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Google OR Tools OnlyEnforceIf

I got a problem for using onlyenforceif to set up constraint. work[employee , shift , day] is the BoolVar indicating the scheduling status for each staff each day. I would like to set a limit that for staff who worked on shift A on day 1 and shift B…
Carson
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Constraint on uniqueness for Assignement Optimization Problem using OR-Tools CP-SAT Solver

The problem I am trying to solve is pretty similar to the one described in the OR-tools documentation: https://developers.google.com/optimization/assignment/assignment_example#cp_sat_solution. I have 15 workers that I need to assign to 5 tasks. The…
Oli
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Google OR-Tools library: Type Error GetOrMakeIndex

I'm studying the google OR-Tools library and I came across this problem that I can't understand. First of all, I get the same error if I copy and paste the code from the nqueens example in the official guide. I propose as an example the classic…
pofferbacco
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Using NewBoolVar in Google OR-Tools

I am wondering the syntax for logical constraints in Google OR-Tools. I have a nurse scheduling project I have done in CPLEX that I am translating over to Google OR-Tools. I have come across the documentation for channeling constraints in Google…
Steve White
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Find the right Google OR-Tools algorithm

I have to find the set of integers that minimize this objective function: The costraints are: every x must be a non-negative integer T, A and B are double known numbers. I have been looking at the OR-Tools C++ library in order to solve this…
AathakA
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