Plexon2RawIO's implementation of _get_analogsignal_chunks can be improved

[nikhilchandra]

Is your feature request related to a problem? Please describe.
The latest version of the PL2FileReader API includes a function capable of retrieving subsets of data from an analog channel. Switching _get_analogsignal_chunks to this function should (hopefully) remove the need to load entire channels into self._analogsignal_cache (this takes up a LOT of memory) and might also speed things up.

Describe the solution you'd like
I want to do the following:

• Add content to the currently empty pypl2lib function "pl2_get_analog_data_subset"
• Replace the underlying DLL to the latest version
• In plexon2rawio.py, add code to retrieve fragment (i.e., segment) information for each stream to the _parse_header function
• Rewrite _get_analogsignal_chunks to use the subset function in conjunction with fragment information in lieu of the present cached solution
• Run tests to check whether the new method is faster

Describe alternatives you've considered
There are none that I can think of.

Related Question
What is the proper way to handle requests that exceed the limits of a recording's segments? For example, suppose I have a multi-trial recording in which 2 recording segments run from [0, 10] and [50, 60] (units in seconds). Suppose the user requests data from [5, 15] seconds -- obviously we have data from [5, 10] from the first segment. But for the interval [10, 15] -- do we just return zeros?

[zm711]

Sounds cool to me. I'm sure @h-mayorquin is also interested.

[h-mayorquin]

That sounds great. Concerning the question of what to do when asking for out of bound data. That is not clear to me, is this something that you have made a made a decision about @zm711 ?

[samuelgarcia]

Hi. On spikeinterface side we decided to raise an error.
On neo side this have never been clear.
I think the most often case is to clip not to zero pad.

[zm711]

I'm looking right now and a bunch of the memmap ones just do slicing [start:stop, :] so that would just follow whatever the numpy memmap convention allows, no. Where is the clipping machinery?

[nikhilchandra]

@samuelgarcia Please, could you clarify what you mean by "clipping"?

[samuelgarcia]

Hi sorry just reading this.
I am a bit fuzzy.
cliping was for : if stop in [start:stop, :] si greater than the shape[0] then stop is is "clip" to shape[0].
In short very often neo behave like numpy for upper boudary.
but spikeinterface do not, it is more strick.