Is there any data type equivalent for queue?
显示 更早的评论
Is there any data type which can handle FIFO queue operations?
I am using arrays to handle queues, but it has executional overhead since the size changes on each iteration. Now, I have to handle even array of queues, but it is getting complicated as each queue has different length at the end of each iteration. When I add an element in a row, the columns length of all the rows increases which makes it difficult to handle it.
Is there any efficient way to handle this situation. Even a link which discusses similar topics would be of great help.
回答（3 个）
Guillaume
2020-4-30
2 个投票
The short answer is that no, unfortunately, there's no queue implemented in base matlab (there may be something hidden in one of the toolboxes but it's unlikely you'd be able to use it generically).
I would have a look at the fileexchange, there's probably several implementations of various quality. If there's nothing good enough there, I'd look at implementing it myself. A naive implementation would just grow/shrink an array as the queue fills/empties which indeed would be very innefficient in matlab (and most languages). A better implementation would grow the array in progressively larger chunks.
4 个评论
ROSHITH SEBASTIAN
2020-4-30
Guillaume
2020-5-9
Attached is a simple implementation of a queue in matlab. It is implemented as a class, but it should be fast.
It's not very sophisticated, the storage space of the queue will double in size every time it runs out of space and never decrease. I don't believe it would be a problem unless you have a great number of very long queues. The memory footprint of an empty queue would be |8 bytes * current capacity|.
The queue can store any kind of object, matrices, structures, etc. The type of object should have no impact on performance. Storing 5000 elements in the queue and then dequeuing them all takes around 80 millisecond on my machine.
You can create an array of queues. I'd recommend you use the static method queue.MakeVectorOfQueues unless you know how to create an array of handle objects:
%create an array of 5 queues:
myqueues = queue.MakeVectorOfQueues(5);
%fill queues at random
for i = 1:20
myqueues(randi(5)).enqueue(i);
end
%dequeue all queues:
for q = 1:5
fprintf('queue %d contained: ', q);
while myqueues(q).Depth > 0
fprintf('%d ', myqueues(q).dequeue);
end
fprintf('\n');
end
ROSHITH SEBASTIAN
2020-5-11
编辑：ROSHITH SEBASTIAN
2020-5-11
Anubhav Kumar
2021-3-19
@Guillaume I have attached queue.m file in the same directory where my main.m file is present and I am trying to use queue but in main.m where I have written q = queue; on runnung the script error is thrwoing at q = queue.
please help me so that I can solve my issue.
parallel.pool.PollableDataQueue
As revealed by the package name, it can be shared among parallel workers.
Mahendra
2023-8-9
0 个投票
Instead of resizing arrays during execution, you can initialize them with zeros up to a generous length. This way, you avoid frequent size adjustments and can simply track the relevant data within this pre-allocated space.
I frequently do this and found it to not have any speed penalties. We are wasting RAM but rarely are a problem on modern day PCs.
1 个评论
Melih Furkan SEN
2023-11-3
And how will you pop them ?) or sort?)
类别
在 帮助中心 和 File Exchange 中查找有关 Startup and Shutdown 的更多信息
2020-4-30
2023-11-3
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
Translated by 
