How to up-cast array data to a pre-allocated array

[JÞB]

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@skaley wrote:

I'm attaching a screenshot that shows more of the acquisition VI (had to do some cleanup).

For reference, the host code is running on a PXIe-8840, and I am acquiring from an NI 5172 using the recon oscope instrument design library (IDL) template.

When I initialize my class I create the i16 and i32 arrays and put them in DVRs.

The de-interleaver (orange block) is part of the IDL and takes in a pre-allocated 2D i16 array to reshape the data from the FPGA. Because I want to scale the data, I want to put that i16 data into the i32 buffer and then scale.

I hang on to the i16 array because this buffer will need to be used on the next acquisition. Recall I am attempting to stream at 5 FPS (5 FPS for the large images, I can hit 20-60 for smaller images) - so this VI is being call inside of an acquisition loop repeatedly. Because I am using preallocated DVRs, I need to put something back in the DVR; this is where the i16 wire branch comes from.

Additionally, I need to use the data outside of this VI for display/logging purposes (I have 8 cards that I am aggregating data from), so that is why we see the i32 wire branch in this screenshot.

You both make a good point about the fact that there will need to be a copy of the data, I just want to make sure I am doing it in the most efficient way possible because I am working with such large data sets.

I have tried the implicit coercion and did not see a difference in performance and the Profile Buffer Allocations tool reported the same allocation happening.

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Mark the DVR for concurrent Read Only and you can safely NOT put anything back in it it will still be the preallocated array it was.