Function optimize_blockwise

dask/blockwise.py:1077–1106

High level optimization of stacked Blockwise layers For operations that have multiple Blockwise operations one after the other, like ``x.T + 123`` we can fuse these into a single Blockwise operation. This happens before any actual tasks are generated, and so can reduce overhead. T

(graph, keys=())

def optimize_blockwise(graph, keys=()):
    """High level optimization of stacked Blockwise layers

    For operations that have multiple Blockwise operations one after the other, like
    ``x.T + 123`` we can fuse these into a single Blockwise operation.  This happens
    before any actual tasks are generated, and so can reduce overhead.

    This finds groups of Blockwise operations that can be safely fused, and then
    passes them to ``rewrite_blockwise`` for rewriting.

    Parameters
    ----------
    graph : HighLevelGraph
    keys : Iterable
        The keys of all outputs of all collections.
        Used to make sure that we don't fuse a layer needed by an output

    Returns
    -------
    HighLevelGraph

    See Also
    --------
    rewrite_blockwise
    """
    out = _optimize_blockwise(graph, keys=keys)
    while out.dependencies != graph.dependencies:
        graph = out
        out = _optimize_blockwise(graph, keys=keys)
    return out


def _optimize_blockwise(full_graph, keys=()):