pre-allocation

Can you preallocate an array of random size?

由 纵然是瞬间 提交于 2021-02-10 05:00:32
问题 The essential part of the code in question can be distilled into: list=rand(1,x); % where x is some arbitrarily large integer hitlist=[]; for n=1:1:x if rand(1) < list(n) hitlist=[hitlist n]; end end list(hitlist)=[]; This program is running quite slowly and I suspect this is why, however I'm unaware how to fix it. The length of the hitlist will necessarily vary in a random way, so I can't simply preallocate a 'zeros' of the proper size. I contemplated making the hitlist a zeros the length of

Can you preallocate an array of random size?

由 时间秒杀一切 提交于 2021-02-10 04:59:08
问题 The essential part of the code in question can be distilled into: list=rand(1,x); % where x is some arbitrarily large integer hitlist=[]; for n=1:1:x if rand(1) < list(n) hitlist=[hitlist n]; end end list(hitlist)=[]; This program is running quite slowly and I suspect this is why, however I'm unaware how to fix it. The length of the hitlist will necessarily vary in a random way, so I can't simply preallocate a 'zeros' of the proper size. I contemplated making the hitlist a zeros the length of

Can you preallocate an array of random size?

由 纵饮孤独 提交于 2021-02-10 04:58:09
问题 The essential part of the code in question can be distilled into: list=rand(1,x); % where x is some arbitrarily large integer hitlist=[]; for n=1:1:x if rand(1) < list(n) hitlist=[hitlist n]; end end list(hitlist)=[]; This program is running quite slowly and I suspect this is why, however I'm unaware how to fix it. The length of the hitlist will necessarily vary in a random way, so I can't simply preallocate a 'zeros' of the proper size. I contemplated making the hitlist a zeros the length of

Preallocating arrays in Matlab?

由 狂风中的少年 提交于 2019-12-17 14:47:57
问题 I am using a simple for loop to crop a large amount of images and then storing them in a cell array. I keep getting the message: The variable croppedSag appears to change size on every loop iteration. Consider preallocating for speed. I have seen this several times before while coding in MATLAB. I have always ignored it and am curious how much preallocating will increase the runtime if I have, say, 10,000 images or a larger number? Also, I have read about preallocating in the documentation

Preallocating arrays in Matlab?

由 与世无争的帅哥 提交于 2019-12-17 14:45:10
问题 I am using a simple for loop to crop a large amount of images and then storing them in a cell array. I keep getting the message: The variable croppedSag appears to change size on every loop iteration. Consider preallocating for speed. I have seen this several times before while coding in MATLAB. I have always ignored it and am curious how much preallocating will increase the runtime if I have, say, 10,000 images or a larger number? Also, I have read about preallocating in the documentation

Queued Message Handler VIs in parent SubVI which execution type is set to be as preallocated (?)

由 怎甘沉沦 提交于 2019-12-11 10:09:09
问题 I am creating an sample of a communication server through LabVIEW. In the main VI I have a server and clients: Execution of the last is set as preallocated clone reentrant. I use Queued Message Handler to transfer messages and commands between server and clients. The picture below is the client VI (preallocated clone reentrant execution) with highlighted Queued Message SubVIs. In my previous question I asked about execution type of SubVIs in the Client VIs (preallocated) and got answer that

Preallocating a Matrix of .NET Arrays

由 别来无恙 提交于 2019-12-10 12:06:51
问题 I'm using Matlab to setup the data acquisition process for an experiment, the function ain.DAQbufferGet is what reads the data from our hardware. It holds a series of data points such as [-200,-160,10,50,-20,40,170,160,-200... etc] . The problem is that the output of DAQbufferGet is a 1x1 System.Int16[] Such an output can also be created by using `NET.createArray('System.Int16', 50000)` Here 50000 is just an example number I want to store the output of DAQbufferGet in a matrix without having

How can I preallocate a non-numeric vector in MATLAB?

由 て烟熏妆下的殇ゞ 提交于 2019-11-28 04:38:03
问题 I've often found myself doing something like this: unprocessedData = fetchData(); % returns a vector of structs or objects processedData = []; % will be full of structs or objects for dataIdx = 1 : length(unprocessedData) processedDatum = process(unprocessedData(dataIdx)); processedData = [processedData; processedDatum]; end Which, whilst functional, isn't optimal - the processedData vector is growing inside the loop. Even mlint warns me that I should consider preallocating for speed. Were

Preallocating arrays in Matlab?

由 ╄→尐↘猪︶ㄣ 提交于 2019-11-27 16:07:52
I am using a simple for loop to crop a large amount of images and then storing them in a cell array. I keep getting the message: The variable croppedSag appears to change size on every loop iteration. Consider preallocating for speed. I have seen this several times before while coding in MATLAB. I have always ignored it and am curious how much preallocating will increase the runtime if I have, say, 10,000 images or a larger number? Also, I have read about preallocating in the documentation and it says to use zeros() for that purpose. How would I use that for the code below? croppedSag = {};
订阅 pre-allocation