I am using Anylogic for a simulation-modeling class, and I am not anylogic or coding smart. My last and only coding class was MatLab based about 16 yrs ago. I have a few questions about how to implement modeling concepts in a discrete model with anylogic.
How can I add/inject agents directly into a queue downstream from a source? I have tried adding an additional source to use the “Calls of inject() function,” but I am not sure how to implement it after selecting it ( example: what do I do after selecting the Calls of inject() function). I have the new source feeding directly into the queue where I want the inject.
How can I set the release of an agent to a defined schedule instead of a rate? Currently, I have my working model set to interarrival time. But I would like to set the agent release to a defined schedule. (example: agent-1 released at 120 seconds, agent-2 released at 150 seconds, agent-3 released at 270 seconds)
Any help would be greatly appreciated, especially if it can be written in a “explain to me like I am 5yrs old” format.
Question 1:
If you have a source connected directly to a queue, then when you call source.inject() an agent will be created at the source block and go to the queue. If you have 1 source with multiple possible destinations, then you will have to use select output blocks and some criteria to go from the source to the desired queue.
Since you mentioned not being a strong programmer, this probably wouldn't be for you, but I often find myself creating agents via add_population and then just adding them to an ArrayList until I am ready to pull them into the DES flow. Really, there are near infinite ways to control agent flow within AnyLogic.
Question 2:
Option a: Arrivals by "Arrival Table in Database" You can link an AnyLogic database table to Excel, and then the source block will just have an agent arrive based on that table.
Option b: Arrival Schedule - you could set this up manually within the development environment or load your schedule from a database. I prefer option a over option b given your brief description.
Option c: Read in data to variable and then write code to release based on next arrival time. 1,000s of ways to do this, but one example could be a list of doubles (your arrival times), set an event to delay until next arrival, call inject function, remove that arrival from the list. I think option a would be best for you, but given that AnyLogic allows you to add java code, there are no limits to how sophisticated you could make your arrival logic.
For 2) You could also use an event or a dynamic event. The action could be source.inject(1); and you can schedule them to your preferences with variables. Just be vigilant that you re-start the events if necessary.
There is a demo-model from AnyLogic for dynamic events.
Related
I am creating a model where I require agents from a population to be removed at a certain rate after a certain moment in time. This rate should be similar and have the same variability as a "Rate" in a source block. My current method runs, but I would like to know whether this method is accurate and if there exists a more elegant solution.
To begin the removal, I set up a Timeout Event that creates a Dynamic Event.
create_dynamicEvent(exponential(rate));
My dynamic event then removes the agent by sending it through an enter block to a sink block, and sets up another instance of itself.
enter_sink.take(population.get(0));
create_dynamicEvent(exponential(rate));
Thank you for your help
I would also use Dynamic Events. You may want to create the DE in the Source block, though, i.e. each created agent already "schedules" its destruction. May be more appropriate, but it depends on the real system.
Apart from that: all good
In my source block I want to be the amount of agents based on two different factors namely the amount of beds and visitors per bed. The visitors per bed is just a variable (e.g. visitors=3) and the amount of beds is loaded from the database table which is an excel file (see first image). Now I want to code this in the code block as shown in the example in image 2, but I do not know the correct code and do not know if it is even possible.
Simplest solution is just to do the pre-calcs in the input file and have in the dbase.
The more complex solution is to set the Source arrivals as:
Now, you read your dbase code at the start of the model using SQL (i.e. the query constructor). Make the necessary computations and create a Dynamic Event for each arrival when you want it to happen, relative to the model start. Each dynamic event then calls the source.inject(1) method.
Better still is to not use Source at all but a simple Enter block. The dynamic event creates the agent with all relevant properties from your dbase and pushes it into the Enter block using enter.take(myNewAgent)
But as I said: this is not trivial
I am modeling ticket system with various SLA. The model must contain several service blocks with different reaction time ( from 2 to 32 hours). In the service block only working hours should be taken into account. So in the service block timeout should stop when non-workong hours and on the weekend. Could you please kindly tell me how i can realize it?
Thank you very much in advance!
I can think of two answers, one simplified but works in many cases, the other more advanced and probably more accurate:
Simplified approach: I would set the model in hours and keep everything running as is without any stop. So, at the end of the simulation, if the total time is 100 hours and you know that you have 8 hours/day with 5 days/week, then you'd know the total duration is 2.5 weeks. Of course, this might have limitations or might become more complex later on if you want day-specific actions (e.g. you want to differentiate between Monday, Tuesday, etc.)
Advanced more accurate approach: Create resources whose capacities are defined by schedule and assigned them to your services. Create a schedule and specify the working hours in that schedule. Check the below link to learn more about schedules. I call this the more advanced approach because you need to make sure the schedule is defined correctly and make sure all elements in the model are properly controlled (e.g. non-service blocks such as source, delays, etc.).
https://help.anylogic.com/topic/com.anylogic.help/html/data/schedule.html?resultof=%22%73%63%68%65%64%75%6c%65%73%22%20%22%73%63%68%65%64%75%6c%22%20
I personally would use the first approach if the model is rather simple and modeling working hours is enough for analysis. Otherwise, I'd go for option 2.
Finally, another option I'd like to highlight is the "suspend/resume" functions. I am only adding this because you asked "how to stop timeout". So these functions specifically stop and resume timeout. But you'll need to define the times at which they are executed (through an event for example).
Good day
I'm a new user trying to find my with Anylogic.
Any help with the following question will be appreciated.
Is it possible to start a model with initial values/quantities given to certain blocks/sections in a model? In other words not have the model start from 0 but from the values given.
You can run a "warmup" period manually and save that as a model snapshot. In future runs, you can start off from that snapshot by loading it. See the help on model snapshots
This is the general problem of model initialisation (e.g., if you're modelling a manufacturing facility, you may want the run to start with the facility at the state it would be at on 9am next Monday morning). There is no generic answer: what initialisation you need is 100% model-dependent (as is how easy/hard this is).
In particular, process models make this difficult because entities (agents) are expected to have flowed through the process up to the point they 'start' in. You can use things like extra initialisation-only Source/Enter blocks to 'inject' agents into the appropriate process points, but in most models it's not this easy: you will have all kinds of model state that needs to be made consistent with this (e.g., the agents flowing through the process might have attributes which have changed based on what's happened to them so far, so this would have to be made consistent).
That's why warm-up periods (letting the model run 'from empty' for a period until its state is qualitatively what you want as your starting point) is a common approach. Model snapshots can help you here (see Ben's answer) but they're not the only way of doing it. (You can also just 'reset' all your metrics/output gathering at the point when you determine the warm-up period has ended --- i.e., you are effectively establishing a new 'time zero' --- but, again, exactly what you need to do is 100% model dependent.)
I am simulating a hospital stay with anylogic, on multiple levels. Each level has its own staff, represented by different ResourcePool (doctor, nurses, OSS) I created the flowchart of the actions concerning the patient. Now I would like, at a specific time (lunch and dinner), the OSS do tour the patients.
How do I set up that all OSS of a ResourcePool go to the rooms?
I would like to create a very small parallel flowchart, with sieze, moveTo, delay and release.
TNX
Easiest way is to use the "Downtime" element to prescribe your resources to do some action, see image below:
Under the "task type" selection, you can send them to a separate flow chart using a "ResourceTaskStart" element and they will do what you put downstream of that (moveto, delay...). Make sure to finish that with a ResourceTaskEnd block.
PS: The "Downtime" block can easily be triggered via a schedule. Make sure to read the help on that block (and the ResourceTaskStart/End blocks) and study the example models that use those.