Function map_overlap

dask/array/overlap.py:501–782

Map a function over blocks of arrays with some overlap We share neighboring zones between blocks of the array, map a function, and then trim away the neighboring strips. If depth is larger than any chunk along a particular axis, then the array is rechunked. Note that this funct

(
    func,
    *args,
    depth=None,
    boundary=None,
    trim=True,
    align_arrays=True,
    allow_rechunk=True,
    **kwargs,
)

def map_overlap(
    func,
    *args,
    depth=None,
    boundary=None,
    trim=True,
    align_arrays=True,
    allow_rechunk=True,
    **kwargs,
):
    """Map a function over blocks of arrays with some overlap

    We share neighboring zones between blocks of the array, map a
    function, and then trim away the neighboring strips. If depth is
    larger than any chunk along a particular axis, then the array is
    rechunked.

    Note that this function will attempt to automatically determine the output
    array type before computing it, please refer to the ``meta`` keyword argument
    in ``map_blocks`` if you expect that the function will not succeed when
    operating on 0-d arrays.

    Parameters
    ----------
    func: function
        The function to apply to each extended block.
        If multiple arrays are provided, then the function should expect to
        receive chunks of each array in the same order.
    args : dask arrays
    depth: int, tuple, dict or list, keyword only
        The number of elements that each block should share with its neighbors
        If a tuple or dict then this can be different per axis.
        If a list then each element of that list must be an int, tuple or dict
        defining depth for the corresponding array in `args`.
        Asymmetric depths may be specified using a dict value of (-/+) tuples.
        Note that asymmetric depths are currently only supported when
        ``boundary`` is 'none'.
        The default value is 0.
    boundary: str, tuple, dict or list, keyword only
        How to handle the boundaries.
        Values include 'reflect', 'periodic', 'nearest', 'none',
        or any constant value like 0 or np.nan.
        If a list then each element must be a str, tuple or dict defining the
        boundary for the corresponding array in `args`.
    trim: bool, keyword only
        Whether or not to trim ``depth`` elements from each block after
        calling the map function.
        Set this to False if your mapping function already does this for you
    align_arrays: bool, keyword only
        Whether or not to align chunks along equally sized dimensions when
        multiple arrays are provided.  This allows for larger chunks in some
        arrays to be broken into smaller ones that match chunk sizes in other
        arrays such that they are compatible for block function mapping. If
        this is false, then an error will be thrown if arrays do not already
        have the same number of blocks in each dimension.
    allow_rechunk: bool, keyword only
        Allows rechunking, otherwise chunk sizes need to match and core
        dimensions are to consist only of one chunk.