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).
121
questions
2
votes
1answer
104 views
Dichotomic search for biobjective linear program, max flow problem for hospital patients
I recently asked this question about formulating a max flow diagram for hospital patients. I am now considering a secondary objective which is to maximize the effetiveness of the scheduled treatment. ...
1
vote
3answers
181 views
optimize days between work shift
For a work shift optimization problem, I've defined a binary variable in PuLP as follows:
pulp.LpVariable.dicts('VAR', (range(D), range(N)), 0, 1, 'Binary')
where
...
6
votes
3answers
1k views
Solving Logic puzzles through optimization
I have the following "logic puzzle" (I think this is considered as a "scheduling problem"):
In this problem, there are 5 basketball players - provided some clues about their ...
-2
votes
0answers
76 views
Linking trainer to first shift of employee
Looking for some guidance on the implementation of restricting the first shift of a set of employees if they take place with someone noted as a trainer. Basically, the first shift must be with someone ...
2
votes
0answers
62 views
Minimizing the number of machine starts
Please, if somebody has another approach to a similar MIP problem...
Assume we have some machines $m$ and their activity could be interpreted by the boolean decision variable $x_{i,j} \ i \in m, j \in ...
1
vote
1answer
46 views
Circuit constraint respecting the order of the next n jobs / jobs on each machine starting at 0
I am working on a scheduling problem in OR-Tools using the CP-SAT solver.
I'm working with
python but I managed to rebuild this solution as starting point:
Optimal way to ensure optional intervals are ...
3
votes
3answers
225 views
Scheduling for the shortest days using ILP
I've tried Or-Tools and MILP solvers a couple of different ways on this, but they take a surprisingly long time to realize that the solution they generated fairly quickly is in fact minimal. Is there ...
6
votes
1answer
166 views
Python "Coffee Shop Scheduling Problem" - Scheduling Lunches/Breaks
I'm working on an employee scheduling program in python. Having never done this before, I've been researching different libraries that can be used to accomplish the task.
Unfortunately, none of the ...
2
votes
1answer
45 views
How to model a cumulative resource constraint with same family condition?
Assume that we have 3 tasks to schedule : $x_{a1}, x_{a2}, x_{b3}$. They all use the same cumulative resource : $r_1$. Each activity increases $r_1$ by $1$ at it starts time and decreases $r_1$ by $1$ ...
1
vote
1answer
82 views
Need help with writing short proof related to Critical-Path-Method in scheduling with variable activity duration
stackexchange community,
I am currently working in the area of operations research / scheduling and am attempting to write a short proof. We are working with a directed acyclic graph of activities (...
4
votes
1answer
182 views
How do constraints become redundant in a Big-M conjunction?
The following Big-M conjunction appears on page 14:3 of The Path&Cycle Formulation for the Hotspot Problem in Air Traffic Management:
\begin{align*}
\text{(i)} \quad t_{(g, \; s)} - t_{(f, \; s+...
7
votes
3answers
218 views
How to model a non-overlap constraint between 2 groups of tasks?
Let $T$ be a set of tasks. Each task $t \in T$ has a duration $d_t$.
Let $T_1 \subset T$ and $T_2 \subset T$ such as $T_1 \cap T_2 = \emptyset $
How can I model the following constraint : all tasks ...
3
votes
1answer
162 views
How to merge tasks or do batching in a quality control lab
Background information:
In the Quality Control labs of pharmaceutical companies, analysts inspect products or raw materials in the units of ‘batches’ (which is essential a physical sample of bill, ...
1
vote
2answers
341 views
How to include material flow in job shop scheduling problem (as constraint?)?
I am reading about https://en.wikipedia.org/wiki/Job-shop_scheduling and https://en.wikipedia.org/wiki/Optimal_job_scheduling. Such scheduling is possible if we know the number (amount) of operations (...
5
votes
3answers
332 views
Minimizing cost of transportation and storage of items
I am looking for an optimization algorithm to minimize the cost of transportation and storage cost in warehouse.
Let's assume the following table gives us the weekly forecast of Demand.
...
6
votes
1answer
190 views
How to cope with the rigidity of solutions?
Consider the following problem of Technician Routing and Scheduling Problem.
We have:
A set of customers where each customer needs the intervention of a technician to do some job. Each customer has a ...
1
vote
0answers
67 views
vehicle routing optimization, Big M method of reformulation of constraints
Please excuse me for the long question, if I dont prrovide this info. my post gets removed!
The following optimization problem is called Mixed-Integer Quadratically Constrained Programming
(MIQCP) ...
10
votes
5answers
569 views
What is the state-of-art (in industry and academy) of this scheduling + routing problem?
I have a startup idea and I am coming from a CS background.
The startup tries to solve the following problem. A company having a set of employees that needs to visit several "customers" each ...
5
votes
0answers
40 views
Constant-factor approximation algorithms for max-min number partitioning
In the k-way number partitioning problem, the input is a set of numbers and the goal is to partition them into $k$ parts in an optimal way. The most well-studied optimization objective is to minimize ...
3
votes
0answers
105 views
Harvest planning problem
I need to model the following problem:
For a planning horizon of $P$ equal periods, one has $N$ harvesting locations and $K$ contractors who can harvest at those locations ($K < N$). Each ...
5
votes
1answer
92 views
What are (some of) the best resources for shift scheduling/rostering?
Shift scheduling/rostering is obviously very widely researched, with tons of papers around it. I found the review papers by Van den Bergh et al. [1] and Ernst et al. [2], but am looking for something ...
1
vote
0answers
126 views
Adding sequence constraints to the assignment problem- Python
This is an online assignment problem and yet can be considered as an assignment problem with a sequence. Assume that workers are coming into the system sequentially and I want to assign a task to them ...
7
votes
2answers
169 views
What strategies to use for Scheduling of Connected Sequences?
I'm given a problem in which I need to schedule multiple sequences. The goal is to minimize the makespan. I'm allowed to elongate all tasks, but I cannot reduce their width nor disconnect any of the ...
2
votes
1answer
105 views
A specific case of a resource constrained project scheduling problem with partially renewable resources (RCPSP/$\pi$) - OR-Tools
I've been trying solve a specific case of the resource constrained project scheduling problem with partially renewable resources (RCPSP/$\pi$ in the literature e.g. this paper). These resources are ...
3
votes
2answers
137 views
Scheduling of planned orders while respecting certain stock levels
I am searching for the academic name of the problem of computing a valid schedule for planned order. More precisely, The problem consists of: list of orders O, available vehicle per day K, and the ...
1
vote
1answer
83 views
Formulate a constraint set to identify the number of overlapping operations
Let assume we have operation $r \in R$, machine $n \in N$ and day $t \in T$. $S_{r}$ is the service duration of operation $r$. Note that $S_{r}$ can be defined based on time slot (e.g., $S_{1}$ can be ...
1
vote
0answers
61 views
How to use gurobi to plan production and minimize the times of changeovers
Suppose we have two lines: L1 and L2.
Suppose we have 4 product types: A1, ...
3
votes
0answers
64 views
Resource scheduling problem with synchronization constraints: Weak LP relaxation
I have a resource assignment/scheduling problem which involves assigning jobs to $m$ workers. There are 2 sets of different jobs, $J^1$ and $J^2$, and a set of periods $T$.
Let $d_{jt}$ be the number ...
2
votes
0answers
105 views
Multiple Depot/Crew Office Bus Driver Scheduling Modelling
I'm working on Bus Driver Schedule with multiple add-on constraints that are complex and hence trying to figure out how this can be achieved.
Reference of Bus Driver Scheduling using OR-Tools:-
https:/...
2
votes
0answers
71 views
Maximizing the minimum machine completion time
There are $n$ jobs with different processing times, and they should be scheduled on $m$ identical machines such that the smallest completion time is as large as possible. This problem is NP-hard even ...
-4
votes
2answers
66 views
multiple cranes scheduling optimization [closed]
So i'm working on my school project and The problem is described as follow:
we have 31 baths and 4 cranes '1 axis of movement'.
figure 1: a crane imageimagen_2021-06-01_120450.png
figure 2: baths ...
3
votes
1answer
53 views
How would I model the following problem concerning customer service via FCFS vs Appointment Scheduling
I'm unfamiliar with OR, and would like to get some advice on how to "think" about this scenario:
I work for an organization that primarily has store fronts. Customer's arrive throughout the ...
1
vote
2answers
137 views
What kind of scheduling/packing problem is this?
I have the following problem which seems to be a mixture of a resource constrained scheduling and packing problem.
There is a set of activities $A_1,\ldots,A_n$ and given precedences $P$, where $(A_i,...
5
votes
2answers
463 views
How to minimize the number of breaks in sports scheduling?
I have the following sports scheduling problem.
For $n$ teams and $m$ rounds, I define the binary decision variable
$$
x_{i,j,s} = \text{1 if team $i$ plays at home against team $j$ at round $s$, 0 ...
4
votes
1answer
347 views
Assignment and scheduling problem with resource constraints
I have 10 tasks with 6 workers. Each worker can only serve one task at a time and must complete the task before moving on to the next task. Each worker has a maximum work output value and each task ...
2
votes
2answers
90 views
Relationship aware task scheduling heuristics
I have a task scheduling/assignment on machines problem (like a classic bin packing problem) with a twist in which the placement/assignment of one task affects the placement/assignment of other tasks (...
5
votes
3answers
186 views
Modelling precedence relations
I have two tasks $i$ and $k$ with durations $d_i$ and $d_k$, where $d_i$ and $d_k$ are nonnegative variables.
I would like to model that $i$ may precede $k$ or $k$ may precede $i$ and that they may ...
4
votes
2answers
311 views
Scheduling optimisation constraint on consecutive shifts & consecutive night shifts (`python`)
I am trying to write a program to schedule a team of 8 individuals into shifts.
I want to know how to model that every individual must get at least one night shift break, and must not work two ...
2
votes
1answer
77 views
How does the RCPSP's precedence constraint work?
In [1] the authors define the RCPSP (resource-constrained project scheduling problem) as follows:
minimize
$$
\sum_{t} t x_{n t}
$$
subject to
$$
\begin{array}{c}
\sum_{t} x_{j t}=1, \quad j \in J, \\
...
1
vote
0answers
74 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 ...
8
votes
1answer
66 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
177 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
164 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
58 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
103 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
55 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
54 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
95 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
61 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 ...
5
votes
3answers
737 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, ...
