Inspecting Dask objects — Anaconda Enterprise 4.4 documentation

Anaconda Enterprise: Documentation

# Inspecting Dask objects

Dask itself is just a specification on top of normal Python dictionaries. Objects like `dask.Array` are just a thin wrapper around these dictionaries with a little bit of shape metadata.

Users should only have to interact with the higher-level `Array` objects. Developers may want to dive more deeply into the dictionaries/task graphs themselves

## `dask` attribute

The first step is to look at the `.dask` attribute of an array

    >>> import dask.array as da
    >>> x = da.ones((5, 15), chunks=(5, 5))
    >>> x.dask
    {('wrapped_1', 0, 0): (ones, (5, 5)),
     ('wrapped_1', 0, 1): (ones, (5, 5)),
     ('wrapped_1', 0, 2): (ones, (5, 5))}

This attribute becomes more interesting as you perform operations on your Array objects

    >>> (x + 1).dask
    {('wrapped_1', 0, 0): (ones, (5, 5)),
     ('wrapped_1', 0, 1): (ones, (5, 5)),
     ('wrapped_1', 0, 2): (ones, (5, 5))
     ('x_1', 0, 0): (add, ('wrapped_1', 0, 0), 1),
     ('x_1', 0, 1): (add, ('wrapped_1', 0, 1), 1),
     ('x_1', 0, 2): (add, ('wrapped_1', 0, 2), 1)}

## Visualize graphs with DOT

If you have basic graphviz tools like `dot` installed then dask can also generate visual graphs from your task graphs.

    >>> d = (x + 1).dask
    >>> from dask.dot import dot_graph
    >>> dot_graph(d)
    Writing graph to mydask.pdf

The result is shown to the right.