I am trying to model the parking lot using road traffic library. However, the example mostly gas station is only give me an idea on queue problems not a parking lot.
Can anyone guide me on the idea of how I can set the parking lot problem in any logic tools?? i.e. vehicles are coming in the parking lot and randomly select the space and holding in the space in some period before exit.
I am really confusing on how to set the parking lot spaces in the model.
Thank you in advances
I don't think you'll find an object that directly does that.
I'll probably start by looking at defining the lot with nodes and paths and model the lots as a resource. when a car comes in it requests a resource from the lot-pool.
To release it again you have different options. The easy way is just a random delay before it is released, if you want to specify a specific car to release you'll need to have a function to pick those out.
Related
I have a problem where I have several events that are occurring in a project, the events happen semi-concurrently, where they do not start at the same time but multiple can still be occurring at once.
Each event is a team of people working on a linear task, starting at the beginning and then working their way to the end. Their progress is based on a physical distance.
I essentially need to figure out each events start time in order for no teams to be at the same location, nor passing eachother, at any point.
I am trying to program this in MATLAB so that the output would be the start and end time for each event. The idea would be to optimize the total time taken for the project.
I am not sure where to begin with something like this so any advice would be greatly appreciated.
If I understand correct, you just want to optimize the "calendar" of events with limited resources (aka space/teams).
This kind of problems are those called NP and there is no "easy" way to search for the best solution.
You here have two options:
Greedy like algorithm: You will have your solution in a resonable time but it won't be the best one.
Brute force like algorithm: You will find the best solution but maybe not in the time you need it.
Usually if the amount of events is low you can go for 2nd option but if don't you may need to go for the first one.
No mather which one you choose first thing you will need to do is to compute if a solution is valid. What does this mean? It means to check for every event wheter if it collisions whith others in time, space and teams.
So lets imagine the problem of making the calendar on a University. There you have to think about:
Students
Teacher
Classroom
So for each event I have to check if another event have same students, teacher or classroom at the same time. First of all I will check the events that match in time with the actual event. Then I will compare the actual event with all the others.
Once you have this done you could just write a greedy algorithm that starts placing events on time just checking if it collides with some other.
Hello all!
I have a question about where should the seats be assigned to keep track if it's booked for a showtime.
There is currently two way i thought of.
1) Assign the seats to the showtime instead of cinema. However this means that for each showtime it may have a different number of seats( which should not be true).
2) Check if the seat is assigned by accessing moviergoer->booking-> movieticket->seat number.
This method is tedious and uses more processing time. But i feel it's the right way as it will mean that the seats will be fixed.
I'm sorry if any other part of my diagram is wrongly drawn. However please guide me through this main question! I will be glad to get feedback for other part of my diagram too.
I really hope to learn more from this scenario.
Your design seems ok so far. Just a few observations:
you should remove the navigation in general since it does not add much value
the association from Booking to ShowTime seems superfluous as the Ticket already holds the needed information
re-think about duplicating cinema/movie:string in ShowTime as it adds unwanted redundancy
why do you have a <<use>> iso. an association in Review?
A seat is related to the cinema and the cinema offers show times. So 1) is ok.
Edit: You would map the ticket like this:
The both ID roles would map the ids in ShowTime and Seat. I would use an artificial integer for the seatID and likely some HHMM format for the showTimeID.
While studying for Interviews, this question came to my mind.
I am planning to design a parking lot and I am assuming the following things:
It has multiple levels. Each Level has 2 rows.
The vehicle type could be small, compact and large.
Each row at a certain level has multiple parking spots.
Each parking spot has red/green light indicator( Red- No space, Green- Free space)
Also each parking spot will have size small, compact and large.
6(optional). Also want to add handicapped person situation.
These are some of the assumptions that I could come up with(Not sure if they are enough or I need more).
I was thinking of designing the system in such a way that as soon as the Vehicle enters the Parking entrance.
He should be given information that where is the nearest vacant spot available(For example- Level 3, Row 2, Spot # 10)
I would like to know how to go about designing such a system? I have seen many other designs but none achieves this i guess.
Not sure what you want to achieve through point 6, but the rest are pretty simple to achieve with an OO design, through the usual abstraction, inheritance and polymorphism principles.
You can have an interface called AvailabilityIndicator which has a boolean method isAvailable(), which represents the light indicator (the bulb will show red if isAvailable() is false, and green if true).
You can have an abstract class called ParkingSlot, which implements AvailabilityIndicator.
This could have the level, row and spot number in it.
You can have 3 classes LargeParkingSlot, CompactParkingSlot and SmallParkingSlot which extend ParkingSlot. (Not that your functionality actually needs this, unless the different parking slots have different behaviours or data you want to model, but since you mentioned you wanted an OO approach I mentioned it, otherwise a simple slotType parameter in ParkingSlot would do.)
Then its a question of when the vehicle arrives, checking what type of slot it needs and looking up which are the available ones that match. You might want to put them in a Map data structure which maps each slot type to the list of available ones, so that when one is taken it is removed and put in a separate unavailable list, for fast lookup of available slots when a vehicle arrives.
I noticed that for problems such as Cloudbalancing, move factories exist to generate moves and swaps. A "move move" transfers a cloud process from one computer to another. A "swap move" swaps any two processes from their respective computers.
I am developing a timetabling application.
A subjectTeacherHour (a combination of subject and teacher) have
only a subset of Periods to which they may be assigned. If Jane teaches 6 hours at a class, there are 6 subjectTeacherHours each which have to be allocated a Period, from a possible 30 Periods of that class ;unlike the cloudbalance example, where a process can move to any computer.
Only one subjectTeacherHour may be allocated a Period (naturally).
It tries to place subjectTeacherHour to eligible Periods , till an optimal combination is found.
Pros
The manual seems to recommend it.
...However, as the traveling tournament example proves, if you can remove
a hard constraint by using a certain set of big moves, you can win
performance and scalability...
...The `[version with big moves] evaluates a lot less unfeasible
solutions, which enables it to outperform and outscale the simple
version....
...It's generally a good idea to use several selectors, mixing fine
grained moves and course grained moves:...
While only one subjectTeacher may be allocated to Period, the solver must temporarily break such a constraint to discover that swapping two certain Period allocations lead to a better solution. A swap move "removes this brick wall" between those two states.
So a swap move can help lead to better solutions much faster.
Cons
A subjectTeacher have only a subset of Periods to which they may be assigned. So finding intersecting (common) hours between any two subjectTeachers is a bit tough (but doable in an elegant way: Good algorithm/technique to find overlapping values from objects' properties? ) .
Will it only give me only small gains in time and optimality?
I am also worried about crazy interactions having two kinds of moves may cause, leading to getting stuck at a bad solution.
Swap moves are crucial.
Consider 2 courses assigned to a room which is fully booked. Without swapping, it would have to break a hard constraint to move 1 course to a conflicted room and chose that move as the step (which is unlikely).
You can use the build-in generic swap MoveFactory. If you write your own, you can say the swap move isDoable() false when your moving either sides to an ineligible period.
I enjoy making games and now for the first time try myself out on mobile devices. There, performance is of course a much bigger issue than on a nice PC and I find myself particularly struggling with weapon (or rather projectile) class design.
They need to be updated a lot, get destroyed/created a lot and generally require much updating.
At the moment I do it the obvious way, I create a projectile object each time I fire and destroy it on impact. Every frame all active projectiles get checked for collision with other objects.
Both steps seem like they could definitely need improvement. Are there common ways on how to handle such objects effectively?
In general I am looking for advice on how to do clean and performant class design, my googling skills were weak on this one so far.
I will gladly take any advice on this subject.
When you have lots of objects being created and destroyed in a short timespan, a common approach is to have a pool of instances already allocated that you simply reinitialise. Only if the pool is empty do you allocate new instances. Apple do this with MapKit and table views, among others. Studying those interfaces will probably serve you well.
I don't think this is about class design. Your classes are fine; it's the algorithms that need work.
They need to be updated a lot, get destroyed/created a lot and generally require much updating.
Instead of destroying every projectile, consider putting it into a dead projectile list. Then, when you need to create a new one, instead of allocating a fresh object, pull one from the the dead-list and reinitialise it. This is often quicker as you save on memory management calls.
As for updating, you need to update everything that changes - there's no way around that really.
Every frame all active projectiles get checked for collision with other objects.
Firstly - if you check every object against every other then each pair of objects gets compared twice. You can get away with half that number of checks by only comparing the objects that come later in the update list.
#Bad
for obj1 in all_objects:
for obj2 in all_objects:
if obj1 hit obj2:
resolve_collision
#Good
for obj1 in all_objects:
for obj2 in all_objects_after_obj1:
if obj1 hit obj2:
resolve_collision
How to implement 'all_objects_after_obj1' is language specific, but if you have an array or other random access structure holding your objects, you can just start the indexing from 1 after obj1.
Secondly, the hit check itself can be slow. Make sure you're not performing complex mathematics to check the collision when a simpler option would do. And if the world is big, a spatial database scheme can help, eg. a grid map or quadtree, to cut down the number of objects to check potential collisions against. But that is often awkward and a lot of work for little gain in a small game.
Both steps seem like they could definitely need improvement.
They only 'seem'? Profile the app and see where the slow parts are. It's rarely a good idea to guess at performance, because modern languages and hardware can be surprising.
As Jim wrote you can create a pool of objects and manage them. If you looking a specific design pattern there is Flyweight .Hope it will help you.