Sparse Waveforms from spikeinterface

[samuelbray32]

Describe the bug spikeinterface.extract_waveforms has an argument sparse. If this is True the waveform extractor will only return the waveforms on a subset of channels that it deems important on a per-unit basis through one of a set of algorithms here. This is an issue for clusterless feature extraction for probes, as all events are a single "unit" and can have features on very different channels.

Problem: The default value for sparse changed from False to True between spikeinterface versions 0.98.2 and 0.99.0

Solution:

• sparse = True needs to be included in the params["waveform_extraction_params"] dictionary from WaveformFeaturesParams table
• The tutorial notebook for waveform extraction needs to highlite this