# Questions tagged [modeling]

For questions related to the process of converting a real-world problem into a mathematical model. Can include questions related to linearization, logical constraints, tightness of formulations, and so on.

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### In a routing and scheduling problem with break consideration, How can I determine whether a node is met before a break or after it?

I'm working on a routing and scheduling problem in the home care services context. I consider a break as a dummy patient, so routing and scheduling are also implemented for the break node (with some ...
829 views

### Modeling: How to force customers visit their NEAREST facility

Let set $I$ denote the facility location set, $N$ denote the customer set, and $d_{ni}, \forall n\in N, i \in I$ is the distance between customer $n$ and facility $i$. The problem is to locate ...
213 views

### Compute overlapping time

I am trying to solve an optimization problem in which there is a set of tasks, $S$, where $s_i$ and $e_i$ are the starting and ending time of task $i \in S$. Each task $i$ must be done within its ...
1 vote
40 views

### SET game: how to generate decks of 12 cards with 6 hidden sets?

This question was initially the second part of another question and justifies a new post. The context is a game called Set: In the game, certain combinations of three cards are said to make up a &...
• 13.3k
133 views

### How to fill the days in sequence?

I have a scheduling problem. 20 hours of work load should be assigned to different days (max 4 days are available and the capacity of ech day is 8 hours max) $\sum_i h_i = 20$ $0 \leq h_i \leq 8$ The ...
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### SET game: how to generate all sets with a MIP?

I am playing around with the game called Set: In the game, certain combinations of three cards are said to make up a "set". For each one of the four categories of features — color, number, ...
76 views

### Optimize revenue function with log part

I am working on an optimization problem where I aim to maximize revenue. My current model has the following objective function: $$Sales(P_i) * log(P_i - const_i))$$ where $P_i$ represents the price ...
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101 views

### Representing a Multi-Level Categorical Variable using Big-M Method in Linear programming

I'm working with a statistical linear model where I have a variable, ( N ), representing the percentage of charging of a battery. Based on ( N ), I derive another variable, ...
• 133
237 views

### Large Language Models for Translating Natural Language to Mathematical Models - Suitable Venues?

I'm currently working on a paper that investigates the capabilities of Large Language Models (like OpenAI's GPT variants) to understand and write mathematical models based solely on natural language ...
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1 vote
96 views

### Breaking symmetry

Suppose resources r1 and r2 are both able to perform jobs j1 and j2. The duration of the jobs being done is d. I would like to model the following rule: Within a time horizon H, perform j1 on r2 only ...
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738 views

### Binary logical constraint dependent on indices

I don't know if I can ask this here, but I've been pulling my hair out trying to think of how to represent this in constraints. I have two sets of binary variables: $X_t$ and $Y_{it}$. So, I want to ...
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### How do I translate the following constraint for gurobi py?

I successfully worked on the problem with following model in Excel, but I have a problem translating it into Python. This is the proposed way to code the problem form the book: ...
135 views

### Transportation Problem

I want to create a transportation model. I have identified importing and exporting countries with their estimated demand and supply. The cost of transportation per one uni is already calculated for ...
239 views

### LP - How to model binary variable that indicates a switch

I have the following question / concern. I have a modeling problem with the decision variable $d_{ptm}$ which indicates whether product $p$ was serviced by machine $m$ in period $t$. It takes the ...
1 vote
110 views

### Modeling of a special form of the precedence constraint

There exists a scheduling problem in which some tasks should be processed on some resources. Additionally, each task needs to be assigned to a specific position on each resource. Let the decision ...
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### Quantifying a measure of standard deviation in MILP

I am trying to set up a MILP for production scheduling. The specific details I'm not sure are important but in general a plant has M machines running N parts, each part requiring W workers. The model ...
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1 vote