What is the correct parameter to give an initial solution to a LP problem in IBM ILOG CPLEX using OPL.
I'm modelling a large scale school timetabling problem and as a way of reducing the total solution time, i'd like to begin the process with an initial solution, i.e last year's timetable.
You have to use IloOplCplexVectors for that purpose. The example shipped in opl/examples/opl/warmstart/warmstart.mod does exactly what you have in mind. It should help to get you going.
Related
I am new to OptPlanner but I have a reasonable understanding of constraint solving alebit somewhat dated.
I have a problem I want to model. On the one hand the National Grid have requirements to save electricity between defined time slots on specific days in specific locations (post codes). On the other individuals with static or mobile batteries charge their batteries at some point during a 24 hour cycle and have a need to get a specific amount of charge into those batteries. I need to model a set of constraints at the top (the grid) and the constraints at the bottom (the individuals) to ensure the individuals get what they need and the grid saves what it requires.
What model should I pick and why?
I am just starting this so I have not tried anything yet. I would prefer a Java/SpringBoot solution.
Many thanks for any help.
Steve T
First read the domain modeling guide in the docs to understand my answer below.
https://www.optaplanner.org/docs/optaplanner/latest/design-patterns/design-patterns.html#domainModelingGuide
I think the maintenance scheduling quickstart might be a good start. Code is here:
https://github.com/kiegroup/optaplanner-quickstarts/tree/stable/use-cases/maintenance-scheduling
Motivation: it sounds like there could be gaps between charging at the charging stations, so a chained through time model does not fit. You're not solving a VRP anyway. So I suspect a timegrain model it is, which is what the maintenance scheduling quickstart actually uses.
Trying to model vehicles' emissions, I used the HBEFA model. There is an issue when the vehicles stop( the first two seconds in my scenario) or decelerate so that no emissions data are recorded during these situations. While I replaced my emission models with PHEMlight, I noticed that getting the license from TU Graz is a must for modeling the buses' emissions which is not possible for me at the moment. Do you have any idea to solve this issue?
regards,
Ali
Essentially this is an open bug in SUMO see https://github.com/eclipse/sumo/issues/2110 and the references therein. There is currently no good workaround except for manually adapting the emission values after the run for those vehicles by using the emissions for a slow moving bus. I will try to resolve this for the next release though
I wanted to solve the following equation in Anylogic:
0=44.00*m^6+7.84*m^4-43.2*m^3+7.84*m^2+1.16
Anylogic have a lot of Numeric tools. Can somebody help me how to use this tools?
Jan
You could use an online calculator to solve it, e.g. Symbolab, which will also detail the steps, which may give you sufficient information to construct a solution in AnyLogic.
It solves it thus.
I'm just starting learning to use OptaPlanner recently. Please pardon me if there is any technically inaccurate description below.
Basically, I have a problem to assign several tasks on a bunch of machines. Tasks have some precedence restrictions such that some task cannot be started before the end of another task. In addition, each task can only be run on certain machines. The target is to minimize the makespan of all these tasks.
I modeled this problem with Chained Through Time Pattern in which each machine is the anchor. But the problem is that tasks on certain machine might not be executed sequentially due to the precedence restriction. For example, Task B can only be started after Task A completes while Tasks A and B are executed on machines I and II respectively. This means during the execution of Task A on machine I, if there is no other task that can be run on machine II, then machine II can only keep idle until Task A completes at which point Task B could be started on it. This kind of gap is not deterministic as it depends on the duration of Task A with respect to this example. According to the tutorial of OptaPlanner, it seems that additional planning variable gaps should be introduced for this kind of problem. But I have difficulty in modeling this gap variable now. In general, how to integrate the gap variable in the model using Chained Through Time Pattern? Some detailed explanation or even a simple example would be highly appreciated.
Moreover, I'm actually not sure whether chained through time pattern is suitable for modeling this kind of task assigning problem or I just used an entirely inappropriate method. Could someone please shed some light on this? Thanks in advance.
I'am using chained through time pattern to solve the same question as yours.And to solve the precedence restriction you can write drools rules.
Is it possible to create a real time workflow optimization using OptaPlanner?
Or is there other open source alternative?
The number of workers that are available to each sub station fluctuates with time. So we will only know the number of maximum worker right before the work start.
The diagram below is the possible situation.