pycroscopy / pycroscopy/sidpy

Handling dask array with unknown dimensions

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Description

When the output shape of an operation is unknown, the output is still a dask array whose shape is treated as nan (not a number). When we try to convert this array of unknown shape into a sidpy dataset, it raises an error.

For example,
dset = sid.Dataset.from_array(np.random.rand(4,5))
new_dset = dset[dset<0.5] # The shape of new_dset is unknown until we use .compute() on it.

The shape of new_dset is (nan,) and dset.like_data(new_dset) does not work. This is important when modifying getitem() to always return a sidpy dataset instead of a dask array.

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Research direction

Start by reproducing the example with Dataset.from_array, boolean indexing through getitem(), and like_data() on the resulting unknown-shape array. Trace how the (nan,) shape is handled before conversion, then verify that the dataset conversion succeeds without computing the array and remains compatible with the planned getitem() behavior.

Written by the indexing model from the issue text.

Assessment

Tech stack
numpy, python
Domain
data
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
45/100

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