Spreadsheet String To Array DBL Performance Improvement

[pauldavey]

While developing and profiling a batch data-analysis program, I found that the "Read From Spreadsheet File.vi" function was where the majority ofthe execution time was spent.  Digging further, I found the time was spent in the "Spreadsheet String To Array" function.  Obviously I cannot look inside this function, but I wondered if I can somehow speed it up.  Attached is a Vi that illustrates what I came up with as an alternative.

Basically using "Spreadsheet String To Array" only to split it up to a 2D String Array, and then "Fract/Exp String to Number" to convert the strings to numbers.

It consistently runs in just over 60% of the time of using Spreadsheet String To Array on it's own to do the conversion.

I am curious as to why using the two functions is quicker than just the one on it's own? Perhaps NI can improve the internals a bit?  Or perhaps it is not a fair comparison?

Labview 8.6f1 Win XP SP2

Message Edited by pauldavey on 03-25-2009 02:55 PM

[Baji]

Nice post paul

[Vivek_N]

Thank you for bringing this to our attention! I will be putting forward this question to our R&D department. If I do find any useful information, I will go ahead and post it here. 

[ASInc]

FYI:  This behavior is still there in LabVIEW 2010.

[Yamaeda]

Adding a couple of other conversions to test against i noticed that:

1. Scan from string through a double loop was the slowest

2. Scan Value was slightly faster

3. Direct conversion through Spreadsheet to array as in OP

4. 2-step convert through Fract/Exp.

Could it be that Spreadsheet to array uses Scan Value internally?

/Y

[Sarci1]

Hello Yamaeda,

Would you be willing to post your code here?  I would like to take a closer look and inform our R&D department if necessary.

Lynn