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Questions tagged [operations-research]

Operations Research is the application of quantitative techniques to decision making, typically involving mathematical optimization. Problems include dynamic programming, linear programming and Integer programming & discrete optimization.

Operations Research is the application of quantitative techniques to decision making, typically involving mathematical optimization. A problem is modeled as a math formulation, and the solution obtained via a solver. Problems in OR include dynamic programming, linear programming and Integer programming and discrete optimization.

The other names for Operations Research (OR) include Decision Science, Management Science, or Operational Research.

The Wikipedia page on Operations Research. INFORMS, the society for OR practitioners has a lot of relevant information.

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Is there a simple way to reduce the value of positive slack variables in MILP?

Recently, I have been learning optimization, and my optimization problem, (minimization), is encoded in a MILP solver which tells me it's infeasible for my model. Hence, I introduced a few positive/negative slack variables. Now, I get a feasible…
GermanShepherd
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getting DOcplexException: cannot convert to expression: at 0x7f59feda16d0>

Im trying this code m.minimize(30sum(x["Product A",j])+28sum(I["Product B",j])+0.9sum(I["Product A",j])+0.75sum(I["Product B",j])for i in Products) and it keeps giving me DOcplexException: cannot convert to expression:
Christine Madanat
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Setting Integrality tolerance in CPLEX and forcing decision variables to take rounded values

I am currently trying to solve a linear program in CPLEX that has three decision variables, one which is binary and the other two are continuous. The problem I have is that instead of giving results for the continuous variables like '10' or '0' it…
Arctic_Skill
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How to bundle pairs of trips?

I have a database of optional real-time trip demands. Each with a load that can to be delivered from a departure point to a…
dank
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How to use PROMETHEE multicriteria method in R

I used TOPSIS multicriteria method to select the best number of clusters out of the 34 options. As weights I used 0.5 for each criterion. The coverage criterion is to minimize and the production criterion is to maximize. With these same conditions,…
Antonio
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IBM CPLEX - Warehouse location CP

I'm trying to run the scalablewarehouse example from IBM, with the CP algorithm, but when I add the using CP; to the mod file, I get an error on this line: dvar float Supply[Stores][Warehouses] in 0..1; And the error: Decision variables of type…
drec4s
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Creating normally distributed Multi-dimensional Knapsack Problem (MKP) data from a basis one

I am trying to solve dynamic MKP for my thesis and I need to do the some calculations mentioned in the following passage of an article to create templates from a basis one: 2.3 The Dynamic MKP In our study, we use a dynamic version of the MKP as…
Med Tosby
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Either or constraint WITH ONE POINT IN COMMON in linear programming operations-research

suppose we have a quantity variable x (which is upperbounded by n), and a logic variable y which is equal to y = 1 if x >= s; where s is a generic number y = 0 otherwise => if x is strictly lesser than s => if x < s Surfing around on the internet I…
Matteo
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Python optimization problem: classifier with restrictions

Is there a function/package in python that as evenly as possible distributes a number of points over groups/teams, but with restrictions for every team (type of points, etc.)? So for example you have red, blue and yellow points. And then 5 teams,…
Ja123
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Job-Shop problem variant: given timespan, maximize how many jobs i can perform

I found many variants of the Job Shop Problem, but not the following one, and it looks like pretty useful in pratical scenarios given a timespan (one year for example) n machines the structure of the job (machine, duration), but NOT the amount of…
Joel
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Is there a way to check feasibilty for given values of decision variables in CPLEX?

right now I am trying to implement a particle swarm optimization algorithm in CPLEX to solve a Vehicle Routing Problem with a large number of customers. Firstly, I wrote an optimization model in OPL that is now able to get solutions for smaller…
Arctic_Skill
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Efficient allocation of limited resources (max profit, all possible combinations list)

I want to find the allocation combinations of resources that are the most profitable through limited resource allocation, and make a list of possible combinations. In other words, I want to find the value that maximizes the profit, find the next…
user17276678
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How to linearize an implication?

Could someone help me linearize this implication? Being x and y integer variables, the implication is the following x >= 1 --> y = 0 y >= 1 --> x = 0 I would really appreciate some help.
Leila Lemos
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Pyomo: FileNotFoundError: [Errno 2] No such file or directory: '/tmp/tmpsau52uq0.pyomo.sol'

I'm using Gurobi solver for a mathematical problem in Ubuntu. I have installed Gurobi through Anaconda and have successfully installed a license for it. However, I'm getting this error after a few minutes. File "Model22.py", line 704, in …
AliRa
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PuLP : What am I wrong in my constraints ? How to fix it?

I try to make minimize cost model by PuLP many times and still have the error. I would like to make decision for 2 variables below. produce = How many unit will produce for each product ? order = How many qty. will order more for each material item…
Kudadas
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