Memory/Speed of Split 1D array vs Delete from array

Just wondering how Split 1D array works - does it create two new arrays in a new section of memory or does it just split the existing array in two, reusing the memory in place. (assuming that the original array is not needed elsewhere). If the latter is the case then presumably it is more efficient to use split array than delete from array if I want to remove element(s) from the beginning or end of the array. Is there a speed advantage as well?
If I use split array but don't then use one of the output arrays is that memory deallocated or does the array remain in memory?
Thanks
Dave

Ok please ignore the results I posted earlier, they are rubbish - not least because I got the column headings mixed up but also because my code was full of bugs
So, here is a revised table, and the code - which hopefully only contains a few bugs... I'm not clued into benchmarking yet so please feel free to rip the code apart.
I still get different results depending on where in the array I split it, most noticeably with subset and reshape. There is no effect with split. I'm guessing this is to do with the memory allocation. (I have not preallocated memory in my code, but I did wire the output arrays to Index Array)
Message Edited by DavidU on 08-12-2008 04:49 PM
Attachments:
Benchmarks 2.png ‏13 KB
split array test.vi ‏25 KB

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Attachments:
help.vi ‏57 KB

It is very difficult to make sense of your diagram, because all the control references are missing, so it is not possible to tell the various data sources apart.
Where is the data coming from? How do you prevent race conditions between the acquisition and analysis parts?
Overall, the diagram is overly complicated and very hard to read. For example clearing the array does not require reading the old array, measuring it's length, followed by "delete from array", followed by writing back to the array. Why don't you just wire an empty array to it? Same result! :-)
You go to tremedous lenght calculating a simple array average, using numerous property reads and indexing arrays inside FOR loops. There is "mean.vi" that does it in one step. (If you only
have base LabVIEW, it might not be available (?), so use "Sum" and divide by n. No loop needed). To find the largest element in an array, use "Array Max & Min" from the array palette, again in one simple step.
I would highly recommend going over some LabVIEW tutorials or look at some of the shipped examples. Make yourself familiar with basic programming concepts such as auto-indexing at loop boundaries. An "index array" wired to the loop counter is never needed.
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Remove Entry from Array

Hi,just another question. Is it possible to remove an entry inside an Array without splitting up by using SubSet und with a combine after that? I found no function for that way...RegardsHenrik

Henrik Skupin wrote:
> Hi,
>
> just another question. Is it possible to remove an entry inside an
> Array without splitting up by using SubSet und with a combine after
> that? I found no function for that way...
The new LabVIEW 6i has a "Delete from Array" VI that will do this more
elegantly.
Regards,
John Lum

What can I delete from what folders to A) get more space and B) speed up machine. 2009 Imac Intel based Leopard

What can I delete from what folders to A) get more space and B) speed up machine. 2009 Imac Intel based Leopard

If you start deleting things in hidden system folders, or in an /Library folder you may very well mess up something.
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There are in fact many places in the system areas that will appear to be redundant, but they are not so just because they have similar path or file names.
Also, how much free space do you have with just a freshly rebooted system? If your system does not have much RAM (given the apps your normally run on it), it may be creating quite a bit of swap space. That will be flushed out with a reboot, but if your system is RAM limited, then it will just grow back. In such a case, more RAM would help.
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My iPad is double downloading iTunes TV series shows and when I delete, the extra show does not delete from the available memory. I have lost almost 30GB of my 64 to this phantom shows.

I am losing available memory on my iPad (64 GB 3rd gen) and it appears to lose memory because some TV shows that I have downloaded from iTunes are appearing twice in my downloads. Both download, but when Only appear as 1 show on my "videos". After viewing the show, I delete, but the duplicate show appears to be still there somewhere (not visible anywhere) taking up the same amount of memory that showed before downloading. It reduces my available memory to download other shows. The general settings do not show any of these phantom shows taking any memory, but the total available is much, much less than what is showing for all usage such as music, videos, photos, apps, etc
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Apologies, wrong thread, please ignore.
Message was edited by: Rhys Bethell

Hi Rhys,
i think what you are talking about is mixing memory size, not speed. You can not mix memory speeds, especially in Macs.
You can mix memory size in most Macs. Very few Macs use memory interleaving that requires exactly the same size memory modules to work best. The iMacs allow mixing size with no impact on performance.
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Memory/Speed of Split 1D array vs Delete from array

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