CFA Array Wrapper Classes

class cfapyx.wrappers.CFAPartition(filename, address, aggregated_units=None, aggregated_calendar=None, global_extent=None, **kwargs)

Bases: ArrayPartition

Wrapper object for a CFA Partition, extends the basic ArrayPartition with CFA-specific methods.

__init__(filename, address, aggregated_units=None, aggregated_calendar=None, global_extent=None, **kwargs)

Wrapper object for the ‘array’ section of a fragment. Contains some metadata to ensure the correct fragment is selected, but generally just serves the fragment array to dask when required.

Parameters:

• filename – (str) The path to a Fragment file from which this partition object will access data from. The partition may represent all or a subset of the data from the Fragment file.

• address – (str) The address of the data variable within the Fragment file, may include a group hierarchy structure.

• aggregated_units – (obj) The expected units for the received data. If the units of the received data are not equal to the aggregated_units then the data is ‘post-processed’ using the cfunits conform function.

• aggregated_calendar – None

copy(extent=None)

Create a new instance of this class from its own methods and attributes, and apply a new extent to the copy if required.

get_kwargs()

Return all the initial kwargs from instantiation, to support .copy() mechanisms by higher classes.

class cfapyx.wrappers.FragmentArrayWrapper(fragment_info, fragment_space, shape, units, dtype, cfa_options={}, named_dims=None)

Bases: ArrayLike

FragmentArrayWrapper behaves like an Array that can be indexed or referenced to return a Dask-like array object. This class is essentially a constructor for the partitions that feed into the returned Dask-like array into Xarray.

partition

alias of CFAPartition

__init__(fragment_info, fragment_space, shape, units, dtype, cfa_options={}, named_dims=None)

Initialisation method for the FragmentArrayWrapper class

Parameters:

• fragment_info – (dict) The information relating to each fragment with the fragment coordinates in fragment space as the key. Each fragment is described by the following: - shape - The shape of the fragment in array space. - location - The file from which this fragment originates. - address - The variable and group name relating to this variable. - extent - The slice object to apply to the fragment on retrieval (usually get the whole array) - global_extent - The slice object that equates to a particular fragment out of the whole array (in array space).

• fragment_space – (tuple) The coordinate system that refers to individual fragments. Each coordinate eg. i, j, k refers to the number of fragments in each of the associated dimensions.

• shape – (tuple) The total shape of the array in array space

• units – (obj) The units of the values represented in this Array-like class.

• dtype – (obj) The datatype of the values represented in this Array-like class.

• cfa_options – (dict) The set of options defining some specific decoding behaviour.

• named_dims – (list) The set of dimension names that apply to this Array object.

Returns:

None

__getitem__(selection)

Non-lazy retrieval of the dask array when this object is indexed.

__array__()

Non-lazy array construction, this will occur as soon as the instance is indexed or any other array behaviour is attempted. Construction of a Dask-like array occurs here based on the decoded fragment info and any other specified settings.

property cfa_options

Relates private option variables to the cfa_options parameter of the backend.