the difference of FFT analysis with large data in labview

[hhtnwpu]

do FFT analysis with large data , I found there are more than one choice in the function panel in labview ,in signal process or signal express,S&V tool box. the function in signal process can process more data than others,how can i process more data (more than 10000000 rows)?

[JamesMc86]

Do you need an FFT that large? The reason I ask is that the figures you discuss are very large for an FFT, normally for a long time period we break it down into smaller chunks to FFT to see things change over time over the data set.

I would avoid the express VI, on these data sizes you need to avoid any data conversions which the express VI will cause. Between the other two I'm not sure of different advantages. If you are doing sound and vibration type analysis then I would use this as the results should easily feed into the other functions. To avoid the licensing of the toolkit though you could use the built in function.

There is another option but it is another toolkit which has some high performance functions to perform the FFT in GPU or multicore optimised to improve the performance if it becomes necessary (it can also perform the FFT on SGL data as opposed to DBL)

[mje]

I'm also curious about this. Such large arrays could pose problems. A 10 M element DBL array is 80 MB, and 160 MB for the resulting complex data type. Do you actually expect to reliably be able to pull continuous chunks of memory larger than that, even on a 64-bit environment? I've done my share of working with large data sets and through experience learned never try to float around arrays like that. LabVIEW does not fail gracefully if it fails to allocate memory...