Scippx

Experimentation with implementation of Scipp features based on Xarray or duck arrays in general. This mainly demonstrates a possible model of interaction between multiple duck-array implementations in a "stack" of duck array layers.

Duck arrays

This prototype currently uses or provides the following "duck arrays". A central goal is to evaluate if the current duck-array mechanism is capable of combining all these in a coherent and user-friendly manner:

Duck array	scope
dask.array.Array	array for parallel computing
pint.Quantity	array withunits
xarray.Variable	array with dims
xarray.DataArray	array with coords dict
MultiMaskArray	array with masks dict
BinEdgeArray	array wrapping N+1 edges
VectorArray	array of vectors

Demonstrated concepts

The tests in test/array_property_test.py demonstrate the main idea. Central parts of the implementation are found in src/scippx/array_property.py and src/scippx/array_attr.py. The following concepts are demonstrated:

• Mechanism for letting duck-array implementations expose properties or methods on all wrapping levels. The mechanism ensures that important properties from higher levels in the duck array stack are not dropped. For example, accessing the magnitude property of a pint.Quantity layer does not lose information about dimension labels of the wrapping xr.Variable.
• Mechanism for modifying or removing duck-array layers. As above this keep (and validates) information from wrapping layers, such as dimension labels.
• Use with dask, without involvement of wrapping layers, i.e., duck arrays do not require special handling to support wrapping dask arrays.