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).
86
questions
2
votes
2answers
68 views
Modelling precedence relations
I have two tasks $i$ and $k$ with durations $d_i$ and $d_k$, where $d_i$ and $d_k$ are nonnegative variables.
I would like to model that $i$ may precede $k$ or $k$ may precede $i$ and that they may ...
4
votes
1answer
88 views
Scheduling optimisation constraint on consecutive shifts & consecutive night shifts (`python`)
I am trying to write a program to schedule a team of 8 individuals into shifts.
I want to know how to model that every individual must get at least one night shift break, and must not work two ...
2
votes
1answer
57 views
How does the RCPSP's precedence constraint work?
In [1] the authors define the RCPSP (resource-constrained project scheduling problem) as follows:
minimize
$$
\sum_{t} t x_{n t}
$$
subject to
$$
\begin{array}{c}
\sum_{t} x_{j t}=1, \quad j \in J, \\
...
1
vote
0answers
33 views
Modified bus scheduling problem question in ortools
Has been crossposted in stackoverflow. I want to solve the bus scheduling problem using ortools with some minor modifications. In my case, the max number of drivers is known. The modifications I would ...
5
votes
1answer
49 views
Real-life timetabling problems in education
I am looking for papers/resources that deal with timetabling problems in education. I want the resources to cover as much information as possible:
I don't have enough contact with people who are ...
1
vote
1answer
69 views
Job Shop Scheduling Problem: jobs are scheduled on the same machine at the same time
I want to solve a job shop scheduling problem. I got $n$ Jobs that have to be scheduled on $k$ Machines. A Job $i$ has 2 or 3 Tasks $j$, and there is a known sequence of the Tasks of a Job. One ...
4
votes
3answers
123 views
Optimization formulation has slow performance
I am formulating and solving a scheduling problem. The problem consists of scheduling items on a single machine, where the only time element is the transition from item $i$ to item $j$. For example, ...
3
votes
1answer
46 views
How to assign task, resources to trips
In a scheduling problem I want to assign the resources to tasks, each task has earliest start date, latest start date and duration. Also each resource has fixed number of available hours in a day. The ...
2
votes
2answers
82 views
Scheduling: Tasks changing the state of the executing machine
I have a scheduling problem in which machines consume their battery when executing tasks and charge their battery when not executing tasks. A single task has to be executed in one go (no recharging ...
0
votes
1answer
46 views
What is a good approach to deciding which jobs (from a list of HPC jobs) should be ran locally vs. on the cloud given time & cost constraints?
Cloud computing has transformed the landscape of compute operations. Of course, there are still many labs/businesses with local, large-scale compute clusters. For those businesses who keep the ...
3
votes
0answers
51 views
Where I can study some job shop scheduling by course (video )?
I am seeking the help to know where I can study the job shop scheduling Heuristics or using solver
by some course/video as I see some of books and papers hard to understand .
It is hoped that the ...
3
votes
2answers
84 views
Scheduling Problem With Identical Machines
I am working on a nonlinear scheduling problem that minimizes the electricity cost of a facility. This system includes a number of identical machines that consume power and produce a product. When the ...
2
votes
1answer
52 views
MIP for resources to task assignments
I have few tasks t1, t2, t3, t4, t5 which need to be assigned to resources r1, r2, the tasks are located across multiple ...
1
vote
0answers
76 views
Production planning with production regularity over time
I've been studying a problem of the following kind:
$T = 1,\ldots, \max{T}$ is a discrete period of time, and we can use every production unit $i \in I$ at most twice. Every unit has a fixed attribute ...
5
votes
3answers
386 views
Gurobi and CPLEX cannot exploit more than 32 cores of machine
I have some attempts to solve a scheduling problem using the Gurobi and doCPLEX API in python and .NET on Ubuntu-server installed on a hyper-computing cluster with 64 physical cores. Unfortunately, ...
2
votes
2answers
62 views
Parallel scheduling with precedence constraints and variable job length
I have $N$ jobs and $M$ machines and want to minimize the makespan, i.e. the total time to finish all jobs. Some jobs have precedence constraints and can only be started once other jobs are finished. ...
3
votes
1answer
94 views
What are the flow based formulations?
What are the flow-based formulations? For what optimization problems are they applied, and in which form? Which are the specificities of such a formulation?
Also, the same question for the time staged ...
3
votes
0answers
101 views
Production planning for a video game economy
I'm a software developer who likes to play a video game that has a complex economy. I realized that the type of problem I'm trying to solve mimics real life operations research problems, and I am ...
2
votes
0answers
45 views
Heuristic to compute upper bound for the simple assembly line balancing problem type 2?
I am currently working on SALBP-2 described as:
Given the number m of assembly stations, minimize the cicle time c.
I have done a bit of research and found the following approach to solve it:
The ...
3
votes
0answers
50 views
Flexible Job Shop with Preemption
I'm trying to solve a flexible job shop problem variant that has precedence constraints on jobs along with a few other issues. We have a MIP formulation and also a simulated annealing algorithm to ...
5
votes
3answers
625 views
How to determine if this problem is NP-HARD or NP-COMPLETE?
Suppose that I have a pool with N nodes and I have to move the nodes one by one to another pool. For each move, consider a value on the edge linking the two pools. The goal is to find a order of nodes ...
3
votes
2answers
105 views
Relaxation and complexity of two formulations
I have two different MILP formulations for the same scheduling problem with the same complexity but with different running times. Why it is recommended to compare the relaxed versions of each ...
1
vote
1answer
80 views
What kind of job shop scheduling problem is this and how do I solve it?
I have a production planning / scheduling problem, which I believe is a kind of job shop scheduling problem.
But I would like to get some input on what kind of job shop scheduling problem it is and ...
1
vote
1answer
106 views
Constraint programming and scheduling issues
I have a constraint problem that I need to resolve, but I did not how know to model the problem:
I have 11 employees, I will name them from $a$ to $k$: $\{a,b,c,d,e,f,g,h,i,j,k\}$.
I have a small ...
6
votes
1answer
239 views
Multi-period linear dynamic programming with differing in-period dependencies and changes
I’m not sure if I’m wording this right but in a nutshell, my problem is:
I’m modelling potential actions a boat owner can do to their boat. Let’s say he wants to know over the 50 year lifespan of the ...
2
votes
1answer
67 views
MIP for assigning tasks with prerequisite tasks
I have a modified assignment problem for which I'm having difficulty formulating the constraints mathematically.
I have a set of workers and a set of tasks which should be completed in the minimum ...
4
votes
0answers
74 views
Best known results on the flexible jobshop benchmarks
Is there a website that compiles the best known results on the flexible jobshop problem ?
I know there was a blog post/article by Quintiq, a (deleted) blog post on CP Optimizer, some more recent ...
1
vote
2answers
89 views
How this problem can be defined as MultiObjective optimisation
I need to optimize the end-to-end latency of a multi-component application.
Assuming that the application has 10 components, component 1-5 is hosted by device 1, and device 2 is hosting the other 5 ...
3
votes
2answers
100 views
How is this problem called in literature?
I have a scheduling problem but rather than having a fixed duration of each task, we have another "concept" that verifies the following property.
Let's say task A requires a default 200 ...
5
votes
0answers
79 views
Quantifying Feasibility
I have a scheduling model formulation ( experimental setup) that takes in product states as input (sample points) and checks the model status (response) and returns feasible or infeasible.
My plan is ...
-2
votes
1answer
171 views
Optimized Production Planning & Scheduling
I want to create an optimized schedule and production to meet demand of four different buyers. I am starting with Pulp but not able to account for continuous production variable and discrete dispatch ...
2
votes
2answers
172 views
How to correct this scheduling algorithm?
I have a scheduling problem to solve. It's a resource-constrained project scheduling problem with time-varying resource availabilities. The objective is minimizing tardiness. The full detailed model ...
2
votes
1answer
105 views
Is a convex or MILP (without big-M) formulation possible for this problem
Assume we are given a directed acyclic graph (DAG) $G(V, A)$, where $|V| = n, |A| = m$, and the graph contains a source node $\mathbf{s}$ (i.e. every node in $V \backslash \mathbf{s}$ is connected by ...
2
votes
0answers
44 views
Scheduling with setup cost
I have a single worker that can work on N different tasks, but his total time T is limited. Let's assume time is in steps of 10 minutes (1 step = 1 mn). The payoff from a single job is 0 for the first ...
1
vote
0answers
63 views
How to identify an MVP for house building?
I am trying to find a minimal viable product for house building company.
I don't know what are the commonly used constraints. Intuitively, I would say that:
There is a set of tasks. Each task has a ...
3
votes
1answer
100 views
Can Deep RL be used to find optimal division point in an application?
I need to optimise the end-to-end latency for a multi-service application while distributing it on multiple devices. The application is a series of services interconnected to each other. The goal is ...
2
votes
0answers
148 views
Operation hours optimization for circular schedule
Here is my problem. A store has X = 15 electical devices with the ability to work non-stop, fully charged, up to 8 hours. Their battery charge lasts 2 hours and the operating hours of the store differ ...
3
votes
2answers
137 views
Limit number of switches in employee scheduling problem
Here is a scheduling problem I need to solve. Given the demand for 2 positions in 1 week with 3 shifts per position, I need to allocate the employees accordingly with some extra operational ...
6
votes
1answer
96 views
CVRP with vehicles blocking each other
I have a standard CVRPTW (capacitated vehicle routing problem with time windows). The instance is given by a (not complete) graph $G$ with weighted $w$ directed edges $e \in E$, and I have a limited ...
4
votes
1answer
135 views
Is it possible to solve VRP using OR-Tools CpModel, instead of RoutingModel?
Is it possible to solve VRP using OR-Tools CpModel, instead of RoutingModel? I want to do synchronized VRP, which is combining vehicle routing and scheduling constraints
1
vote
1answer
249 views
Can I apply decomposition methods for this scheduling problem
I have a centralized optimization problem for a residential area in the context of a smart grid and load flexibility. So let's say I have 10 buildings and each of them has an electric heating device. ...
3
votes
1answer
130 views
Resource constraint with MIP model
My question is how to model a resource constraint with MIP model
(how should I modify it?)
A factory is making blocks. If there is space left at that time, the block can be assembled.
(If the factory ...
3
votes
0answers
67 views
Combining Machine learning and Operations research on a scheduling problem
I am wondering if there is any attempts of combining OR and ML in the following way. Priority-based rules are widely used in Resource Constrained Project Scheduling Problems.
Is there a way to train ...
3
votes
2answers
486 views
How to add logical OR constraint in OR-Tools?
Let's say nurses normally do 1 shift
for d in all_days:
for s in all_shifts:
model.Add(sum(shifts[(n, d, s)] for n in all_nurses) == 1)
But I want to ...
4
votes
1answer
60 views
Business/industrial applications of the single machine scheduling problem
There is a lot of resources talking about the applications of scheduling in business in general.
I would like to know about the applications of the particular case of single machine scheduling.
Any ...
3
votes
1answer
117 views
Space constraint in scheduling problem
I'm studying an MIP model with a scheduling problem and I'm wondering if the space constraint is correct.
If there is space in the factory at that time, the block can be processed, where
$i$ is the ...
3
votes
1answer
100 views
What kind of scheduling problem is this?
I am trying to develop algorithm to solve following basic version of the problem.
1) I would like to know what this problem is called in literature so that I can look it up
2) What are efficient ...
7
votes
1answer
1k views
How to use the least number of colours to colour different routes of a bus route such that no two intersecting routes will have the same colour
I would like to know of a method in which if provided say 10 routes with details regarding which route intersects with which another route, we can use the least number of colours to colour the routes, ...
3
votes
1answer
130 views
What type of scheduling problem is this?
I'm trying to develop a heuristic to solve a scheduling problem. The difficult for me is to treat the time as a variable.
There are 2 variables related to time, $b_{ij}$ and $f_{ij}$, being the time ...
2
votes
1answer
159 views
Nested set in OPL/CPLEX
I'm trying to solve a scheduling problem using OPL/CPLEX. In the model, there are nine tasks in which each task has its specific precedence. the precedence relationship is as follows:
...
