Questions tagged [scheduling]

For questions about methods that assign resources to work requests (e.g. processor time to tasks) usually minimizing some cost measure (e.g. makespan).

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Workforce scheduling problem difficulty

I am working on a workforce scheduling MIP -- given a set of shift candidates (different shapes and sizes of shifts created out of labor demand) and a set of workers, optimally assign the shifts under ...
SDC's user avatar
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2 answers
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Problem 8.17 of Korte and Vygen

An airline wants to conduct a given set of scheduled flights with as few airplanes as possible. All available airplanes are of the same type. For each flight we know the departure time and the flight ...
Nico Konrad's user avatar
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Scheduling: Connecting the end and the beginning of the planning horizon

I would like to create a rota that repeats every 28 days and adheres to the usual rules. These include the minimum/maximum number of consecutive working days and the break days. I have created a model ...
lukdooxb1's user avatar
1 vote
0 answers
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Execution time of sequential asynchronous process and division of labour

I wasn't sure if I should put this question here, but I guess is as good as any. When we have a sequential process that has a number of tasks, were each task requires the previous one to be completed, ...
gabriel's user avatar
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2 votes
1 answer
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Replace the constraint using ==> by a linear formulation

I would like to know how to express the continuity constraint without using a decision variable in the conditional form. My challenge is to stay with a linear formulation. I will start to explain my ...
Basma Ben Mahmoud's user avatar
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1 answer
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Circular queue modeling

Let $P$ be a set of discretely interruptible processes/tasks; $T_i \in \mathbb{N}$ be the running time of process $i \in P$; And $\tau \in \mathbb{N}$ be the maximum amount of time a process can use ...
Matheus Diógenes Andrade's user avatar
2 votes
0 answers
50 views

Implement a rolling horizon approach into a schedulig problem

I have just come across the topic of 'Rolling Horizon' in my literature research and would now like to apply it myself, but unfortunately I don't know where to start. This is my model, which is ...
lukdooxb1's user avatar
2 votes
1 answer
231 views

How to modify a model to be cyclic?

I have the following question. I have the following physician problem with the indices $I$ (doctor), $T$ (days) and $J$ (shifts). $x_{itj}$ is the decision variable, $d_{tj}$ is the demand and $g$ is ...
manofthousandnames's user avatar
2 votes
2 answers
318 views

How to model weekend constraints in a nurse rostering problem?

I have the following problem. I have a Nurse rostering problem and want to model the following. I have the indices $D$ (days), $I$ (nurse), $S$ (shift). My planning period $D$ is 28 days. Now I want ...
Uni ewr's user avatar
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Workforce scheduling optimization using ML model output

I am working on a workforce scheduling problem where we want to come up with an intelligent way to identify a set of shift candidates that is just enough to cover all labor demand but also flexible ...
SDC's user avatar
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5 votes
2 answers
198 views

How to combine MIP solver with a CP one?

I am working on the scheduling problem in the class of parallel resource scheduling models. When I have studied some papers regarding that, I see the method that combines an MIP with a CP. The ...
A.Omidi's user avatar
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Job Scheduling with Energy Consumption using Linear Programming

I'm looking for some advice for an optimization problem regarding scheduling jobs in a datacenter. So I have a list of jobs and each job has a required time for finishing and a number of cores it has ...
wind.leon's user avatar
1 vote
2 answers
157 views

Workforce scheduling problem

I am working on a employee scheduling problems (assigning shifts to temporary workers) by modeling it as a MIP. There is a one shift per day constraint for the employees. There are overnight shifts ...
SDC's user avatar
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2 votes
1 answer
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Compute time between tasks

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 own ...
Christopher Expósito Izquierdo's user avatar
1 vote
1 answer
109 views

Scheduling & Routing Problem

Looking for some advice on how to approach this combo scheduling + routing problem. I am a supply chain OR consultant, and was recently approached by a potential client. Without giving too much away, ...
Ralph Asher's user avatar
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Pyomo + Gurobi Scheduling Tasks within Working Hours

I initially posted this on stackoverflow and got redirected here. You can view the old post with formatted tables here: StackOverflow Post I have a python schedule optimization script using pyomo and ...
Phil Franjo's user avatar
2 votes
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28 views

The facet-defining inequalities for a single resource scheduling problem

Suppose, there exists a scheduling problem $S$, in this case a single resource, with the following descriptions: $$ \text{conv(S)} = \{x \in \mathbb{R}^n \ | \ \forall \lambda_{i} \in \mathbb{R}^{n+}, ...
A.Omidi's user avatar
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Can dynamic programming find globally optimal solutions for scheduling problems

I want to know if dynamic programming can generally find globaly optimal solutions for scheduling problems? I think this might be difficult as dynamic makes one at a time decisions without calculating ...
PeterBe's user avatar
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1 vote
1 answer
117 views

Mixed-Integer Programming Model for Scheduling with Dynamic Jobs

I have an optimization problem for deliveries between production lines and a warehouse in a small facility. I need to know how many vehicles and utilities to buy, such that cost and downtime are ...
user18463824's user avatar
1 vote
1 answer
151 views

Is this classed as a version of jobshop? How should it be approached?

I'm looking at a problem that seems quite like flexible jobshop, but as I understand it jobshop is basically all about finding the order/sequence of tasks (across multiple machines potentially), ...
Faolian's user avatar
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2 votes
1 answer
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How to define the sequence depending setup time based on a time index formulation

I am working on a scheduling problem in which I have used two different MIP formulations and also based on the time index variable. My problem is in the class $ P_{j} | \ r_{j}, SDST \ | C_{Max} $. ...
A.Omidi's user avatar
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1 vote
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Optimize cherry picking runs

I am trying to optimize a cherry picking procedure on 96-well microplates. The plates are 12X8 (12 columns, 8 rows). We pass a command file that has many lines like this to a robot: ...
Ryan's user avatar
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2 votes
1 answer
99 views

Formulation for choosing how many items to manufacture

I am working on a scheduler for a manufacturing plant. I have currently set it up so the decision variables are set up as binary variables: $x_{m,p,s}$ = 1 if machine m is running part p on shift s ...
Dano's user avatar
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1 vote
1 answer
97 views

Scheduling repeated tasks with minimum duty cycles

Several tasks need to run repeatedly in a channel, one at a time, over a repeating time frame of length $T$. Associated to each task $i$ is the duration $L_i$ the task will take to run, and a maximum ...
Mark's user avatar
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1 vote
2 answers
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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 ...
Hani Jamshidian's user avatar
1 vote
0 answers
81 views

Linearization of Conditional Constraints for MIP using Cplex

I'm currently working on a mixed-integer programming (MIP) problem and I'm trying to implement a set of conditional constraints in CPlex. These constraints involve decision variables that are indexed ...
B.Kim's user avatar
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2 votes
1 answer
212 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 ...
Christopher Expósito Izquierdo's user avatar
2 votes
4 answers
131 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 ...
Optimization team's user avatar
2 votes
2 answers
378 views

Scheduling to minimize total "wait to start" time

I have a scheduling problem I am trying to work through. As I was outlining the problem, I realized it is probably of a known problem type, but I am unsure of what keywords to search for or what ...
Ike348's user avatar
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3 votes
1 answer
135 views

Meaning of the domain propagation in the context of mixed-integer programming

In the literature, domain propagation defines the process of inferring sequences of local domain reductions at the current node of the branch-and-bound tree. The goal is to shrink the size of the ...
A.Omidi's user avatar
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1 vote
2 answers
232 views

Best algorithm for scheduling interviews

I posted the same question on stackoverflow and immediately referred to post it here. I want to think about the best algorithm which let the interviewer meet maximum number of candidates. Suppose that ...
iyui's user avatar
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0 votes
2 answers
109 views

Assignment problem with multiple precedence constraints

Objective and short problem description The objective is to load as many passenger vehicles as possible on an auto-train. The train consists of multiple wagons with two levels each. The wagons are ...
Christian's user avatar
1 vote
2 answers
102 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 ...
A.Omidi's user avatar
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0 votes
1 answer
56 views

Help finding linear constraint - LP

I have the following question. I have two variables $w_{nds}$ and $m_{nd}$. The first variable indicates whether a nurse $n$ works shift $s$ on day $d$. The second one indicates the motivation of ...
nflgreaternba's user avatar
4 votes
1 answer
92 views

Nurse Rostering constraints - LP

I am fairly new to linear programming since I came across this topic at university this semester. We mainly focus on nurse rostering. In the lecture, we created a very basic rostering model with an ...
nflgreaternba's user avatar
0 votes
2 answers
136 views

Linear Programming - Model understaffing

I am reading up a bit on Linear Programming and have taken a lot from "Scheduling Emergency Room Physicians" (by Michael W. Carter & Sophie D. LaPierre, Health Care Management Science 4, ...
mingabua's user avatar
0 votes
1 answer
100 views

How to linearize the waiting time

My question is this: I want to express the time it takes for multiple servers to complete tasks for multiple users. I divide the time into $t$ time slots, and each task may occupy multiple time slots. ...
Yunqi Li's user avatar
2 votes
1 answer
64 views

Machine Scheduling with simultaneous processing of jobs

I am searching for a keyword that describes a machine scheduling problem in which machines are allowed to process multiple jobs at a time. Each job requires a given capacity on the machine. At any ...
yolothan's user avatar
1 vote
1 answer
90 views

Workforce scheduling MIP formulation

I am working on a large scale workforce scheduling problem with a large number of hard and soft constraints. The soft constraints are modeled as objectives with penalties for violating them. So my ...
ORProfessional's user avatar
1 vote
1 answer
572 views

About circuit constraints in OR - tools

I am trying to implement a scheduling problem to solve with CP-SAT from OR-tools. There, in particular, for every machine I want to add a time transition constraint from every task that is performed ...
John D's user avatar
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3 votes
3 answers
253 views

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 ...
Dano's user avatar
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1 vote
2 answers
82 views

How to tackle online scheduling problems?

In scheduling problems, one usually has different options as objective functions (makespan, tardiness, etc). However, for any such type of scheduling problem one can consider an online version of it ...
John D's user avatar
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1 vote
1 answer
153 views

Solver for Flexible Job Shop Scheduling Problem

I have a FJSSP that I would like to solve. However, the jobs in this problem have deadlines and in addition there are setup times between two jobs. Because of this, my objective function is not just ...
John D's user avatar
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2 votes
3 answers
2k views

Identifying the minimum number of required machines to schedule jobs

I am relatively new to the topic of optimization. I am currently trying to address the following problem: We are given a set of jobs, say $J$ with release times, deadlines and duration. Jobs can be ...
Pia MiA's user avatar
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1 vote
1 answer
91 views

Scheduling tasks to minimize the total number of utilized cores

I currently have a scheduling algorithm which computes an approximate solution, say S, for the nominal scenario of a given problem instance, say N. Given that N changes in a way and becomes infeasible,...
Pia MiA's user avatar
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0 votes
0 answers
64 views

Creating a simple class in python for doing simulation of MDP

I am currently learning Python and doing object-oriented programming. I am trying to create a simulation for MDP. My problem statement is: "I have four stages of process. Each stage has two ...
Margi Shah's user avatar
2 votes
3 answers
143 views

Definition of a modified scheduling problem where jobs are halted based on the shifts of employees

I am looking for the name of a scheduling problem in literature with some references. Here is the variant that I have in mind. Given a set of jobs, employees have certain shifts that they can work on ...
whitepanda's user avatar
2 votes
2 answers
116 views

constraint set for a scheduling problem with machine availability

I have a set of tasks $I$ with processing times $p_i, \forall i \in I$. There exists a set of machines $M$ and each machine has availability time ranges in a given time horizon. For instance, given a ...
ball_jan's user avatar
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4 votes
2 answers
559 views

Alternative way to restrict an employee to work on multiple jobs

Suppose I have a set of employee $E$ and set of jobs $J$ in a given time horizon $T$. I would like to make sure that no employee works on multiple jobs where each job $e\in E$ takes a certain amount ...
ball_jan's user avatar
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6 votes
1 answer
648 views

Doubles Round Robin Sorting Algorithm

Background: I have a group of 6 guys that get together and play pickleball every week. We play 2v2 and 2 players sit each game. We play 2 sets of 6 games each week (12 total games) - in each set, ...
WoodGuyPurdue's user avatar