I am trying to simulate a customer by using agents. In the statechart I built, I would like to apply to each individual agent the waiting time spent in the system by defining different variables:
WatingTimeStart, WaitingTimeEnd and WaitingTime
In order to assign the waiting time to each agent I am using the following command in the transition prior to the state I would like to apply the condition:
this.WaitingTimeStart=time();
In the next State I am then using the following:
this.WaitingTimeEnd=time();
this.WaitingTime=this.WaitingTimeEnd-this.WaitingTimeStart;
Followed by the next transition with the condition (TolerarableWaitingTime is a pre-defined Variable)
this.WaitingTime>TolerarableWaitingTime;
My Problem is the transition does not accept the condition and is not processing the agents to the next state.
I probably make a mistake in:
assinging the variable WaitingTime to each agent
applying the condition correcly
Thanks a lot for any thoughts.
Bastian
It was difficult to understand your question, but here it goes: first, you don't need to use "this", you can just do in the transition previous to the state in question:
WaitingTimeStart=time();
also by convention your variables should start with a low case letter, so it should be waitingTimeStart.
But you don't really even need that code and you are overcomplicating yourself... if you want to apply a waiting time (or a delay) you don't need a conditional transition, you can just use a timeout transition instead, where the timeout time is equal to TolerarableWaitingTime
Related
I know that you can turn on a vehicle signal (for example, the left indicator) in traci using:
traci.vehicle.setSignals(vehID, int)
where the integer related to the specific signal can be found using the following link (https://sumo.dlr.de/docs/TraCI/Vehicle_Signalling.html#signaling), but is there a way of turning off a specific signal that would be otherwise turned on by the program (i.e., a setSignalOff)?
I think that there is a function in the underlying C++ code (switchOffSignal() in MSVehicle.h) but there doesn't appear to be a traci command that turns off a specific signal.
I appreciate that it is (generally) a pleasant visual aesthetic and has no impact on vehicle behaviour, but it would be very useful for what I am trying to do!
Switching off signals should work from traci. By using sometihng like traci.vehicle.setSignals("ego", 0), I can switch them off. Be aware that this will be reset after the step, so you may have to do that in every timestep.
So, Michael is right in that:
traci.vehicle.setSignals("ego", 0)
should turn off all signals (although the signals still appeared on for me visually, which confused me initially).
To turn off individual signals but keep the others on you need to:
For all the "on" signals find the value of 2^n, where n is the bit integer (which can be found using the following link: https://sumo.dlr.de/docs/TraCI/Vehicle_Signalling.html)
Sum all these 2^n values (let's call this variable x) and use this value in the setSignals function: traci.vehicle.setSignals("ego", x).
So for example, if we want the brake light, the right indicator and the high beam on (but all the other signals off) we would do:
RightIndicatorValue = pow(2,0)
BrakeLightValue = pow(2,3)
HighBeamValue = (2,6)
SignalValue = RightIndicatorValue + BrakeLightValue + HighBeamValue
traci.vehicle.setSignals(("ego", SignalValue)
I have a requirement like this.
Flux<Integer> s1 = .....;
s1.flatMap(value -> anotherSource.find(value));
I need a way to stop this s1 when anotherSource.find gives me first empty. how to do that?
Note:
One possible solution is to throw error then capture it to stop.
anotherSource.find(value).switchIfempty(Mono.error(..))
I am looking for better solution than this.
You won't find a specific operator for this, you'll have to combine operators to achieve it. (Note that doesn't make it a "hack" per-se, reactive frameworks are generally intended to be used in a way where you combine basic operators together to achieve your use-case.)
I would agree that using an error to achieve is far from ideal though as it potentially disrupts the flow of real errors in the reactive chain - so that should really be a last resort.
The approach I've generally taken in cases where I want the stream to stop based on an inner publisher is to materialise the inner stream, filter out the onComplete() signals and then re-add the onComplete() wherever appropriate (in this case, if it's empty.) You can then dematerialise the outer stream and it'll respond to the completed signal wherever you've injected it, stopping the stream:
s1.flatMap(
value ->
anotherSource
.find(value)
.materialize()
.filter(s -> !s.isOnComplete())
.defaultIfEmpty(Signal.complete()))
.dematerialize()
This has the advantage of preserving any error signals, while also not requiring another object or special value.
I am building a work-logging app which starts by showing a list of projects that I can select, and then when one is selected you get a collection of other buttons, to log data related to that selected project.
I decided to have a selected_project : Maybe Int in my model (projects are keyed off an integer id), which gets filled with Just 2 if you select project 2, for example.
The buttons that appear when a project is selected send messages like AddMinutes 10 (i.e. log 10 minutes of work to the selected project).
Obviously the update function will receive one of these types of messages only if a project has been selected but I still have to keep checking that selected_project is a Just p.
Is there any way to avoid this?
One idea I had was to have the buttons send a message which contains the project id, such as AddMinutes 2 10 (i.e. log 10 minutes of work to project 2). To some extent this works, but I now get a duplication -- the Just 2 in the model.selected_project and the AddMinutes 2 ... message that the button emits.
Update
As Simon notes, the repeated check that model.selected_project is a Just p has its upside: the model stays relatively more decoupled from the UI. For example, there might be other UI ways to update the projects and you might not need to have first selected a project.
To avoid having to check the Maybe each time you need a function which puts you into a context wherein the value "wrapped" by the Maybe is available. That function is Maybe.map.
In your case, to handle the AddMinutes Int message you can simply call: Maybe.map (functionWhichAddsMinutes minutes) model.selected_project.
Clearly, there's a little bit more to it since you have to produce a model, but the point is you can use Maybe.map to perform an operation if the value is available in the Maybe. And to handle the Maybe.Nothing case, you can use Maybe.withDefault.
At the end of the day is this any better than using a case expression? Maybe, maybe not (pun intended).
Personally, I have used the technique of providing the ID along with the message and I was satisfied with the result.
I have a situation here in my code where all tasks are running with same priority based on round robin (with fixed time slice of 50ms) scheduling algorithm. Now I want to run one particular task say Task A, exactly within a time period of 10ms to update some communication db. Since,current scheduling is based on round robin with fixed time slice of 50ms due to that the Task A is not able to get called exactly in 10ms. I am not getting any solution to cope up with the current problem.
Please do provide your valuable suggestion & advice.
Thanks in advance,
Vijay Khaitan
Not exactly sure what you are asking here. If you do not want Task A to run longer than 10ms, and you know that you will return from your communication functions in less than that, you can take a time reading at the beginning of Task A, and call osThreadYield() from Task A after you hit 10ms (busy loop).
If you are somewhere in Task B, and need to call Task A in exactly 10ms, it becomes a bit more complicated, since you don't know what thread can preempt your Task B at that time. What you can try, is in Task B, keep a handle to Task A. Then when you are ready to wait 10ms, do the following:
osThreadId id;
id = osThreadGetId (); // id for the currently running thread
osThreadSetPriority(id, osPriorityRealtime); // Make sure we get back here quickly
osWait(10); // Wait 10ms
osThreadSetPriority(id, osPriorityNormal); // Go back to normal
// If you need to create Task A, do so here, otherwise you can
// use osSignalSet here and osSignalWait in Task A
You can also call directly create Task A, set its priority to osPriorityRealtime, yield from Task B, and have the first method in Task A be osWait(10). As soon as you return, set its priority back to normal.
I am currently reading the Programming Erlang Second Edition Writing Software for a concurrent world written by Joe Armstrong and I have the following assignment :
Write a function start(AnAtom, Fun) to register AnAtom as spawn(Fun). Make sure your program works correctly in the case when two parallel processes simultaneously evaluate start/2. In this case you must guarantee that one succeeds and the other fails.
I understand the first bit. I need to register the process of Fun to the AnAtom. However what does the second part want me to do?
If two processes call start/2 at the same time then one of them must fail? Why? Given that the AnAtom is different to any others (which will be done inside the body of start/2 why would I want to fail one of the processes?
From what I can understand so far we have:
a = spawn(process1).
b = spawn(process2).
a ! {self(), registerProcess} //which should call the start/2
b ! {self(), registerProcess} //which should call the start/2
What is the problem here? Two processes will evaluate start/2. Why fail one of them? I'm probably missing the logic here or what I understood so far is completely wrong. Can anybody explain this in easier terms so I can get my head around it?
I believe the exercise is asking you to think about what happens when two parallel process evaluate start/2 using the SAME atom as the first parameter. When start(a, MyFunction) completes, there should be a spawned function (running MyFunction) associated with the name (atom) a.... what happens if
start(cool, MyFun1) and
start(cool, MyFun2)
are both executed simultaneously? How do you guarantee that one succeeds and the other fails.... does this help?
EDIT: I think you are not understanding the register process part of the assignment. When you get done with start(name, MyFun), doing a whereis(name) from the repl should return the process identifier of the process that got created.
This is not about sending the process a message to give it a name, it is about registering the process your created under the name passed in as the first parameter to start/2