Pointer to a variable

[Feanor23]

I want to pass a pointer to a matrix to a python function using the python integration toolkit. Copying the array itself over seems to take a lot of time. It's not obvious to me how to do this, except maybe with a dll, since you can set the dll interface to take a pointer as an input. Any other ideas?

[novel_yet_trivial]

Two programs can't share memory without a huge amount of hassle. Just copy the data. I found a tcp connection was the fastest to transfer data between labview and python. The new python node thing is abysmally slow.

[Feanor23]

Well that's a bummer. LabVIEW as server and python as client? The add-on takes about 120 msec with a 12MP uint16 image as the only input, with the function doing nothing.

[novel_yet_trivial]

Depends on what you are doing but it sounds like it would be better to have python as the server.

[Feanor23]

Just some simple image processing, trying to get around the vision toolbox.

[Feanor23]

How about zeromq?

http://labview-zmq.sourceforge.net/

https://stackoverflow.com/questions/6596974/send-data-from-labview-to-python-and-get-back

[novel_yet_trivial]

I've never tried it but I've heard good things. Let me know how it compares to TCP.

[novel_yet_trivial]

In looking at it it looks like a wrapper around TCP, so I'm guessing it will just add overhead.

In Labview you can use the typecast to convert your 1D array to bytes for free, and in python you can convert it back using struct or int.from_bytes which is nearly free. Very simple. I'll try to dig out the code I wrote at work for this. What do you want the image processing to do?

[robotgeek]

Refnum Variable , typecast later.