I am using a priority based queue to pick agents from a pallet rack. Priority of agents can be 0 or 1. If there are 10 agents in palletRack, I want to pick all the agents having priority=1 first. My problem in the current flowchart is: Agents with priority=0 are pickup up before agents with priority=1. May be because the agents enter & leave the Queue block one by one, multiple agents aren't present in the Queue block at the same time so that they can be sorted. How to resolve this?
put a hold block between queueStorage2 and pickFromStorage1 and on the on enter action of queueStorage2, you check if all your agents are there, and if they are (with whatever condition you need to check to be sure everything is there) you unblock the hold with hold.unblock();
Related
I used seize-move-release in order to move the agent with the resource. shown in the figure below.
Problem
Now the only problem is, how agents will wait in the queue (capacity 2) for there turn to go to the Delay section using resource. Explanation is in the image below.
What i am trying to achieve:
I mean agents wait in the queue (capacity 2). Once the delay(machine) gets empty, only then resource transfer the agent from the queue to the delay.
Note:
I try to use service because Service block have queue too but I need the queue before the resource pool.
I hope I explain my problem well let me know if I miss some thing.
I used Wait Block for the agents to Wait but when wait capacity equals to 2 . Agents stop moving forward.
Use a "Wait" object ahead of moveTo.
Whenever the delay capacity decreases to zero ("on exit" code box of delay you can check it using delay.size()==0?), you can tell an agent in the "Wait" object to advance now, using wait.free(agentToFree).
If you want to free the oldest agent, use wait.free(wait.get(wait.size()-1))
I am trying to work out how to use the "Population of agents" radio button functionality in the Advanced section of the "Queue" block from the process library.
I am able to successfully select the "Population of agents" option and specify the number of queues to be in the population however I am then unable to direct agents to any of the queues in the population. Ultimately, I need to send agents to specific queues in the collection (population) but I can't seem to work out how to do that.
The screenshot shows a bit more of what I am trying to achieve:
Even though you have the option to create a population of queues, there's no possible use for it since you can't add an agent to the queue without a flow (for insteance enter block)
In order to make a good population of queues, you need to create a population of agents called for instance QueueAgent
And in this queue agent you will have
enter->queue->exit
Then you can choose to what queue to send your agent to send it by using queueAgents.get(index).enter.take(agent) where index is the queue index to which your agent needs to be sent
the exit block will send your agent back to an enter block that will be connected to speacialtyProcesses
The only blocks in which it makes sense to create a population are the blocks that create agents such as source or enter blocks.
in my model I have a queue were multiple agents from different sources come together to seize an transporter ( see picture). But now they leave immediately after they enter the queue to the seize transporter block. But I want to keep them in to queue until a transporter is free and then the first one in the queue should seize a transporter and so should move to the seize transporter block. How should I fix this?
There are several ways:
After the queue, add a RestrictedArea elements to limit the number of agents in the Seize seizeTransporter4 element. In the queue, you can sort the agents.
Instead of a queue element, use a Wait element, in which case you need to write the logic for extracting agents and sending them to seizeTransporter4 element.
The second way is more flexible in terms of writing logic.
seizeTransporter has its own embedded queue. You can access that value with seizeTransporter4.size(). If you insist on having them separately, instead of queue, use delay block, with stopDelay option. Whenever the seizeTransporter4.size() drops below number of available transporters, run the stop delay function. Like
if (seizeTransporter4.size()<=3){
myDelay.stopDelay(myDelay.get(0));
}
I have a not so typical scenario for which I am not sure how to proceed:
There are two stations located at two different locations.
Both stations require the same resource.
The resource moves from station to station once released. So it keeps going from station 1 to station 2 to station 1, etc. until it is seized again. This is modeled by adding a link from the resource process port of the release block. So it is not completely released unless a condition applies. The condition is that there are agents waiting in the queue of the seize block of that same resource. So it should keep moving until it is needed again. The tricky part is that there are two seize blocks for that resource, one for each station. It is possible that agents are ready and waiting in the resource's seize element at both stations. I am adding an image of the resource's process at release. So at "selectOuput4" it checks whether station 1's seize element has agents waiting, if so, the resource is released and can be seized. Otherwise, it moves to station 2 and checks the same but for station 2.
My concern is that there might be a situation where both stations have agents waiting in their respective seize blocks. How can I make sure the resource will be seized by station 1's seize element and not station 2's, and vice versa. Is there a way to control where the resource is going in a case where two seize elements are waiting for it? Or is it always random?
I apologize for the long post, and I hope I managed to deliver my idea properly.
First, I think your design is a bit weird because you keep the resource always seized.
What I would do is first have a statechart in the resource that controls the resource movement from one place to the next so you have more control over it. The statechart would be used to move your resource ONLY when it's not seized. This will allow a case in which your resource is moving from station 1 to station 2 but something comes to station 1 queue and the resource can immediately react and come back to station 1 before it reaches station 2 (if you think it would be a good idea to do that)
The second is that the seize block defines the priority for a task when the agent arrives to the seize block, and your situation requires changing that priority dynamically, which can't be done as far as I know, so the wait block before the seize block is unfortunately a good option.
I'm trying to emulate what QUEST does when a buffer is queried for a certain Part. In there if the part is not in the buffer the request is left pending and if a Part arrives to the buffer it's released to the machine requesting it. I have also seen this behavior in SimPy which is another DES engine.
I can't seem to find a simple way to do this in AL. The queue block has the following methods:
release(agent): Will return false and forget about the request if there's not an agent as the one specified
remove(agent): Will return null if there's no agent in the queue
So those methods won't do what I want...
It gets a little more complicated as the queue contains agents with parameters and I want to request a specific set of parameters (let's say the agents have a number parameter that can go from 1 to 3 and I'm only interested in agents in the queue if this parameter has the value 2).
Also there's a series of agents pulling this agents from the queue simultaneously and I'd like a priority to be set (let's say FIFO)
so there's a couple things that I've tried and have lead me nowhere:
Using a seize block instead of queue and adding the agents to the embedded queue in the seize block. -> I can't find the proper method to seize from the buffer in a different way from a buffer block (so I moved to option 2) but seize does have a promising customize resource choice that could help with the parameter down-selection
Using a seize block and storing the agents in a pool as resources. issues with dynamic creation of resources, seizing the appropriate one etc...
Creating a queue of requests that have returned null from a queue. This sounds like an overkill but I'll look into it
All of those appear to be a bit complex for such a simple thing in other softwares for simulation so I'm wondering if I'm missing something or if someone has come across this issue before
Suggestion 1: may it helps you to store the agents in the queue in a collection (or different collections, according to the parameter settings). Events: "on enter" and "on exit"
Suggestion 2: may the Wait - block helps you here?