String concatenation and vi speed

[Crawling]

I am trying to convert waveform data in .tdms into ASCII file in a particular format in order to be read by another software. The vi which I have written (attached) is able to do the job but at a very slow pace. In takes the vi approximately 20 minutes to complete a one second data (22050 samples). This us too slow as I am planning to work with waveform data at 1.5 million samples (takes 16 hours). I think the problem is attributed to the string concatination. Does anyone has any suggestion as how I can improve on this vi performance in terms of its speed. Thanks. 

Running Labview 2011 on a window 7 laptop (i5 2.50GHz with 8G RAM)

[Crawling · Accepted solution]

Sorry about this question.  I had it solved after removing the 'wait until the next ms multiple' vi from the loop iteration. 

[JÞB]

For some additional optomizations you can get a boost by using autoindexing tunnels and do your string concatinizations in one fell swoop (Yes, Concatinate String works just fine on arrays)

[altenbach]

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@Crawling wrote:

I had it solved after removing the 'wait until the next ms multiple' vi from the loop iteration. 

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Jeff already pointed out some more optimizations, but here are a few more things that are wrong with your VI:

• Your shift register is uninitialized, meaning that its contents grow with each run and eventually you will run out of memory.
• Even with 1.5M samples, it will only a few seconds, so the progress bar is not really needed.
• If you like simpler code, you could do something as follows (it is very slightly slower that Jeff's but probably worth it for easier code maintenance and diagram real estate.) 🙂

 

(I left the CR at the beginning like in your code, jeff move ot to the end of each segment. Not sure what you really want)

[JÞB]

That is scary. does parallelism effect speed?

My code slightly faster than Christians? That has to be a compiler optimization bug. But, I'll cherish the moment.

[Crawling]

Dear Jeff,

Thanks for the input.  By the way what is the vi connecting between the interleave 1-D array and concatenated string.  I do not recongize the symbol.  I believe it is to convert the 1D string array to string. The closest I could get in my search is byte array to string which is incorrect.

[RavensFan]

It is Concatenate, on the string palette.  It works on arrays.

Jeff posted a snippet, so you can drag that image to a block diagram.  Then use context help to hover over the functions you are not familiar with.

[JÞB]

Actually Bill, that's "Interleave arrays". One of those resizable array functions that need a bit more press in core 1.

[RavensFan]

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He was asking between Interleave Arrays and Concatenated string which I assumed he meant was the indicator terminal snce that is what the indicator was labelled.

Concatenate is between the Interleave Arrays and the terminal.

[JÞB]

Silly mobile version.... Needs an inline viewer for images.   I appologize Bill, you are correct.