cf.Index.rechunk

Index.rechunk(*args, **kwargs)

Change the chunk structure of the data.

New in version 3.14.0.

See also

cf.Data.rechunk

Parameters

chunks: int, tuple, dict or str, optional

Specify the chunking of the underlying dask array.

Any value accepted by the chunks parameter of the dask.array.from_array function is allowed.

By default, "auto" is used to specify the array chunking, which uses a chunk size in bytes defined by the cf.chunksize function, preferring square-like chunk shapes.

Parameter example:

A blocksize like 1000.

Parameter example:

A blockshape like (1000, 1000).

Parameter example:

Explicit sizes of all blocks along all dimensions like ((1000, 1000, 500), (400, 400)).

Parameter example:

A size in bytes, like "100MiB" which will choose a uniform block-like shape, preferring square-like chunk shapes.

Parameter example:

A blocksize of -1 or None in a tuple or dictionary indicates the size of the corresponding dimension.

Parameter example:

Blocksizes of some or all dimensions mapped to dimension positions, like {1: 200}, or {0: -1, 1: (400, 400)}.

threshold: int, optional

The graph growth factor under which we don’t bother introducing an intermediate step. See dask.array.rechunk for details.

block_size_limit: int, optional

The maximum block size (in bytes) we want to produce, as defined by the cf.chunksize function.

balance: bool, optional

If True, try to make each chunk the same size. By default this is not attempted.

This means balance=True will remove any small leftover chunks, so using d.rechunk(chunks=len(d) // N, balance=True) will almost certainly result in N chunks.

Returns

Index or None

The construct with rechunked data, or None if the operation was in-place.

Examples

See cf.Data.rechunk for examples.