I have a model where the queue's capacity limit is 2. I also set up a "SelectOutput"-block before the queue, as customers who can't enter the queue are lost. So now I want to find out the mean rate at which customers are lost? How can I do that?
Many thanks!
Create a variable leftLastMin of type int.
In the "on exit (false)" code of the SelectOutput, write leftLastMin ++
Now, create a recurring event that triggers every minute. Here, you can easily do something with the number left last minute (traceln, store into dataset or statistics object...).
Also, reset your counter leftLastMin=0 so it is ready for the next minute.
Related
I have the following problem which I am unable to solve:
I have a situation where a security point (added as delay) holds every half an hour a 15 min break. After the break, the security guards increase their speed till the queue is shorter than 10pp.
I wanted to model this as follows: a state chart with delay.set_capacity(0) after 30 minutes and delay.set_capacity(1) again after the 15 min break. For the increased speed after the break, I added an additional state with condition: queue.size()>10 and now I want to set the action such that the delay function changes the delay time from exponential (1/10) to exponential (1/5) as long as queue.size()>10.
Anyone experience with which function in the action box to use? Or would you suggest a different function?
Since you are using, or at least want to use a statechart I would suggest the following design, where you have composite states inside the working state to indicate if the security agent is working fast or normal and a message transition to let it move from one state to the next.
It is advised to use a message transition and trigger it as needed instead of a conditional state which gets chected for every change inside the agent since this can be a computational expensive exercise.
I assume you already implemented the correct capacity settings for the different on enter actions for working and breaking
Now you simply need to send the message every time an agent enters the queue and every time it exits the delay block, and of course, see the delay time based on the state of the statechart.
Aee screenshot below.
Edited Version:
I'm actually modelling an airport check-in terminal. It works fine so far, but additional I'm still trying to implement a function, that allows my pedestrians not to enter the service-queue if the queue time exceeds a preselected value (e.g. already 15 Passengers in the queue) and therefore walks to some kind of backup Service that opens during this busy times.
Here is my approach:
Variable QueueSize returns permanently the actual Number of Passengers in the Queue.
Every time a ped enters the pedservice block CheckInEco, the function waitingTime() starts:
QueueSize = CheckInEco.size();
if (QueueSize > 15) CheckInEco.cancel(ped)
So, as soon as there are more than 15 Agents in the queue, number 16 should bypass and move to an alternate ServiceBlock, which I would connect to the ccl Port of the CheckInEco Service. But when building the model, I get this message: ped cannot be resolved to a variable?
According to Anylogic Help, it should be possible to use this cancel - call, but I'm not really experienced with it.. Maybe, someone can help me out?
You can simply use a select output block to prevent pedestrians from going into the service block if there are more than 16 pedestrians already in.
Your original question had to do with waiting time, you should follow the exact same approach. But with waiting time it gets more complicated since you don't want to take the average waiting time from the start of the simulation.... so you need to decide if you want to take the last 10 minutes, 1 hour etc and do you want to include the current waiting time of agents in the queue. Since this is the the questions anymore I am not going to add it here, perhaps ask a new question if this is still the case.
I would like to create a database with different arrival times that my forklifts pick the pallets (rack pick) to the certain times. How could I do this? Which process blocks could I use to access to a database with arrival times?
For example at 10am on May 20 45 pallets should pick out of the pallet rack. I tested it with a delay block and it works but only with different hours where the pallets get picked and not an specific date. The important thing is the date which I get from a database.
process
Probably the easiest way is to have your in-rack agents (after your RackStore block) sit in a Wait block, and be freed from there (using the Wait block's free function) --- to then carry on to a RackPick block --- via AnyLogic dynamic events whose timings come from a database table.
(Your model as-is will just have your agents immediately exiting the rack and going to the Sink because the Queue does not stop them leaving.)
Your model startup would loop through the rows in the table and create dynamic event instances with the appropriate timeouts (delays from model start), and with a dynamic event parameter which specified the number of pallets to pick (and thus the number to free from the Wait block).
I'm running a similation where i would lige to know the total amount of time agents spends in a delay block. I can access the data when running single simulations in the Dataset log under flowchart_stats_time_in_state_log
https://imgur.com/R5DG51a
However i would like to to write the data from block 5 (spraying) to an output in order to store the data when running multiple simulations.
https://imgur.com/MwPBvO8
Im guessing that the value reffence should look something like the expression below. It is not working however so i would aprreciate it alot if anybody could help me out or suggest an alternate solution for getting the data.
flowchart_stats_time_in_state_log.total_seconds.spraying;
Btw. Time measures dose not work for this situation since i need to know the total amount of time spend in a block after a 12 hour shift. with time measures i do not get the data from the agents that are still in the block when the simulation ends.
Based on the goal of summing all processing times, you could solve it mathematically. Set the output equal to block.statsUtilization.mean() * capacity * time() calculated on simulation end.
For example, if you have a capacity of 1 and a run length of 100 minutes, then if you had a utilization of 50%; that means you had an agent in the block for 50 minutes. Utilization = time busy / total time. Because of this relationship, we can calculate how long agents were actually in the block.
Another alternative would be to have a variable to track time in block, incrementing when the agents leave. At end of the run, you would need to call a function to iterate over the agents still in the block to add their time. AnyLogic allows you to pretty easily loop over queues, delays, or anything that holds agents:
for( MyAgent agent : delayBlockName ){
variable += time() - agent.enterBlockTime;
}
To implement this solution, you would need to create your own agent (name it something better than MyAgent) with a variable for when the agent enters the block. You would then need to then mark the time each agent enters the block.
I don't understand this question....
Please describe how to use a priority queue to implement a queue.
Do I simply assign the priority as the time of entrance? and since a queue is fifo I would min prioritize so the oldest time comes first?
Using the time as the priority key is one way to do it. Be careful, though, to use a time that doesn't change externally. You wouldn't want to be using local time when it comes time to set your clocks back an hour during the Daylight Saving Time switch.
You could also start an integer counter at 0, and increment it with every item you add to the queue.
In theory, you could just give every item equal priority, but in practice that might end up acting like a stack. It depends on how your priority queue implementation treats equal items. If the implementation is a binary heap, for example, it could insert the equal item as the new smallest item. So you'd end up with LIFO.