What would be the best way to incorporate changing tide times into an AnyLogic model? I would like to use the times to effectively block and unblock a port. I have looked at the schedule option and the format (Start: Day1, Time) doesn't seem the best way to do it.
You can model the tide by a reoccuring timed trigger.
AnyLogic offers the Dynamic Event for this, an event that can reschedule itself.
Depending on how you have the time data for the tides (list of DateTimes, fixed periods, database), you can retrieve that value for each new rescheduling of the dynamic event.
I attached a screenshot of a simple sample model. Here I assume you have got a list with the interval in minutes between each port-affecting tide moment (Low Tide/Port Blocked - High Tide/Port Open - Low Tide/Port Blocked - and so on....) . The dynamic event then sets a boolean variable portBlocked, but depending on your needs you could also trigger a Statechart Transition, block flowchart modules, or trigger a function.
The Action code of the Dynamic Event:
portBlocked=!portBlocked;
create_MyDynamicEvent(tideIntervalsInMinutes.get(tideCounter),MINUTE);
tideCounter++;
Explanation of the code:
Trigger your needed actions (here simple boolean variable)
Reschedule the event for the next tide change
Update the tide counter (used to retrieve the corresponding tide interval time from the list)
In the startup code of the model you will have to trigger the Dynamic Event once initially, for this just use the same code as point 2 above.
Related
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.
I'm working with code that uses a tumbling window of one day, and would like to send early results to a different DataStream on an hourly basis.
I understand that triggers are a way to go here, but don't really see how it would work.
The current code is as follows:
myStream
.keyBy(..)
.window(TumblingEventTimeWindows.of(Time.days(1)))
.aggregate(new MyAggregateFunction(), new MyProcessWindowFunction())
In my understanding, I should register a trigger, and then on its onEventTime method get a hold of a TriggerContext and I can send data to the labeled output from there. But how do I get the current state of MyAggregateFunction from there? Or would I need to my own computation here inside of onEventTime()?
Also, the documentation states that "By specifying a trigger using trigger() you are overwriting the default trigger of a WindowAssigner.". Would my one day window then still fire correctly, or do I need to trigger it somehow differently?
Another way of doing this is creating two different operators - one that windows by 1 hour, and another that windows by 1 day. Would triggers be a preferred approach to that?
Rather than using a custom Trigger, it would be simpler to have two layers of windowing, where the hourly results are further aggregated into daily results. Something like this:
hourlyResults = myStream
.keyBy(...)
.window(TumblingEventTimeWindows.of(Time.hours(1)))
.aggregate(new MyAggregateFunction(), new MyProcessWindowFunction())
dailyResults = hourlyResults
.keyBy(...)
.window(TumblingEventTimeWindows.of(Time.days(1)))
.aggregate(new MyAggregateFunction(), new MyProcessWindowFunction())
hourlyResults.addSink(...)
dailyResults.addSink(...)
Note that the result of a window is not a KeyedStream, so you will need to use keyBy again, unless you can arrange to leverage reinterpretAsKeyedStream (docs).
Normally when I get to more complex behavior like this, I use a KeyedProcessFunction. You can aggregate (and save in state) hourly and daily results, set timers as needed, and use a side output for the hourly results versus the regular output for the daily results.
There are quite a few questions here. I will try to ask all of them. First of all, if You specify Your own trigger using trigger() this means You are going to effectively override the default trigger and thus the window may not work the way it would by default. So, if You for example if You create the 1 day event time tumbling window, but override a trigger so that it fires for every 20th element, it will never fire based on event time.
Now, after Your custom trigger fires, the output from MyAggregateFunction will be passed to MyProcessWindowFunction, so It will work the same as for the default trigger, you don't need to access the MyAggregateFunction from inside the trigger.
Finally, while it may be technically possible to implement trigger to trigger partial results every hour, my personal opinion is that You should probably go with the two separate windows. While this solution may create a slightly larger overhead and may result in a larger state, it should be much clearer, easier to implement, and finally much more error resistant.
I would like to use my custom flowchart for different process flows and the delay time of my process is coming from a database. I tried to use the parameter but doesn't work. How can I get access to my database and connect it with my delay block in my custom flowchart to get my delay from the dbase. My target is to pick my pallets from the racks to the certain times.
delaytime =timearrival_minutes
Use a DynamicEvent.
Create a function at the model start that loops across all dbase entries. Create a dynamic event for each entry that is triggered by "the dbase-entry date" minus "your current model start date".
In the Dynamic Event, trigger rawMaterialStorage.free(some agent), obviously it is up to you to free from the correct custom block.
Check example models and the help on looping dbase entries and Dynamic Events :)
so my model works fine, but since I introduced conditional events (= an event that triggers once a specified condition is met), I find that the computational performance is decreased.
This is especially annoying when I run experiments with many iterations...
Is there an alternative way to trigger an event at a specified condition?
Thank you :)
The answer to this will be triggering events directly by the mechanism that are influencing the conditions you are monitoring. So instead of having the "permanent" condition check, make sure that each time the condition changes you are triggering a check. If that is not possible, because there are too many influencing factors, or it is continuosly changing, consider a cyclic check in discrete timesteps at an interval that suits you. Even this will be much more performant (depending on your choosen time check interval) then the current continous monitoring.
Example on how to do an event trigger monitoring instead of continous monitoring:
In your main, add global counter variable of type int (here: nrAgentsState1) and create a function to update that variable (here: updateStateCounter). Also in the function: a check that triggers a function whenever your threeshold is reached.
In your transition leading into the state you want to monitor (here: state1), call the function in main that updates the global counter. For the transition leading out of the monitored state, add the same action, but with a -1 as parameter.
I am currently doing a simulation model in AnyLogic of a Distribution Center where from Monday to Saturday I use an event to trigger the loading of a truck. I wish to program this loading every day at the same time, but how can I do it so it happens everyday EXCEPT Sundays. I currently have it as triggered: timeout and mode: cyclic, using calendar dates...
sure, the easy way is to just add a manual exception to the schedule as below:
And the more advanced way is to use a Dynamic Event that executes your daily action.
In the model start code, call create_MyDynamicEvent(7, DAY) to make it trigger after the first 7 days of the sim.
Then in the Dynamic Event action code, add whatever should happen every day. And also add a line that re-creates the same Dynamic event in 1 day, like
create_MyDynamicEvent(1, DAY)
This would then trigger every day, even Sunday. To avoid that, you can add an if-clause in the dynamic event action code to only execute your code if it is not Sunday.