# Source code for dask.array.blockwise

    from __future__ import annotations

    import numbers
    import warnings

    import tlz as toolz

    from dask import base, utils
    from dask.blockwise import _blockwise_unpack_collections_task_spec
    from dask.blockwise import blockwise as core_blockwise
    from dask.highlevelgraph import HighLevelGraph
    from dask.layers import ArrayBlockwiseDep

    def blockwise(
        func,
        out_ind,
        *args,
        name=None,
        token=None,
        dtype=None,
        adjust_chunks=None,
        new_axes=None,
        align_arrays=True,
        concatenate=None,
        meta=None,
        **kwargs,
    ):
        """Tensor operation: Generalized inner and outer products

        A broad class of blocked algorithms and patterns can be specified with a
        concise multi-index notation.  The ``blockwise`` function applies an in-memory
        function across multiple blocks of multiple inputs in a variety of ways.
        Many dask.array operations are special cases of blockwise including
        elementwise, broadcasting, reductions, tensordot, and transpose.

        Parameters
        ----------
        func : callable
            Function to apply to individual tuples of blocks
        out_ind : iterable
            Block pattern of the output, something like 'ijk' or (1, 2, 3)
        *args : sequence of Array, index pairs
            You may also pass literal arguments, accompanied by None index
            e.g. (x, 'ij', y, 'jk', z, 'i', some_literal, None)
        **kwargs : dict
            Extra keyword arguments to pass to function
        dtype : np.dtype
            Datatype of resulting array.
        concatenate : bool, keyword only
            If true concatenate arrays along dummy indices, else provide lists
        adjust_chunks : dict
            Dictionary mapping index to function to be applied to chunk sizes
        new_axes : dict, keyword only
            New indexes and their dimension lengths
        align_arrays: bool
            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.

        Examples
        --------
        2D embarrassingly parallel operation from two arrays, x, and y.

        >>> import operator, numpy as np, dask.array as da
        >>> x = da.from_array([[1, 2],
        ...                    [3, 4]], chunks=(1, 2))
        >>> y = da.from_array([[10, 20],
        ...                    [0, 0]])
        >>> z = blockwise(operator.add, 'ij', x, 'ij', y, 'ij', dtype='f8')
        >>> z.compute()
        array([[11, 22],
               [ 3,  4]])

        Outer product multiplying a by b, two 1-d vectors

        >>> a = da.from_array([0, 1, 2], chunks=1)
        >>> b = da.from_array([10, 50, 100], chunks=1)
        >>> z = blockwise(np.outer, 'ij', a, 'i', b, 'j', dtype='f8')
        >>> z.compute()
        array([[  0,   0,   0],
               [ 10,  50, 100],
               [ 20, 100, 200]])

        z = x.T

        >>> z = blockwise(np.transpose, 'ji', x, 'ij', dtype=x.dtype)
        >>> z.compute()
        array([[1, 3],
               [2, 4]])

        The transpose case above is illustrative because it does transposition
        both on each in-memory block by calling ``np.transpose`` and on the order
        of the blocks themselves, by switching the order of the index ``ij -> ji``.

        We can compose these same patterns with more variables and more complex
        in-memory functions

        z = X + Y.T

        >>> z = blockwise(lambda x, y: x + y.T, 'ij', x, 'ij', y, 'ji', dtype='f8')
        >>> z.compute()
        array([[11,  2],
               [23,  4]])

        Any index, like ``i`` missing from the output index is interpreted as a
        contraction (note that this differs from Einstein convention; repeated
        indices do not imply contraction.)  In the case of a contraction the passed
        function should expect an iterable of blocks on any array that holds that
        index.  To receive arrays concatenated along contracted dimensions instead
        pass ``concatenate=True``.

        Inner product multiplying a by b, two 1-d vectors

        >>> def sequence_dot(a_blocks, b_blocks):
        ...     result = 0
        ...     for a, b in zip(a_blocks, b_blocks):
        ...         result += a.dot(b)
        ...     return result

        >>> z = blockwise(sequence_dot, '', a, 'i', b, 'i', dtype='f8')
        >>> z.compute()
        np.int64(250)

        Add new single-chunk dimensions with the ``new_axes=`` keyword, including
        the length of the new dimension.  New dimensions will always be in a single
        chunk.

        >>> def f(a):
        ...     return a[:, None] * np.ones((1, 5))

        >>> z = blockwise(f, 'az', a, 'a', new_axes={'z': 5}, dtype=a.dtype)

        New dimensions can also be multi-chunk by specifying a tuple of chunk
        sizes.  This has limited utility as is (because the chunks are all the
        same), but the resulting graph can be modified to achieve more useful
        results (see ``da.map_blocks``).

        >>> z = blockwise(f, 'az', a, 'a', new_axes={'z': (5, 5)}, dtype=x.dtype)
        >>> z.chunks
        ((1, 1, 1), (5, 5))

        If the applied function changes the size of each chunk you can specify this
        with a ``adjust_chunks={...}`` dictionary holding a function for each index
        that modifies the dimension size in that index.

        >>> def double(x):
        ...     return np.concatenate([x, x])

        >>> y = blockwise(double, 'ij', x, 'ij',
        ...               adjust_chunks={'i': lambda n: 2 * n}, dtype=x.dtype)
        >>> y.chunks
        ((2, 2), (2,))

        Include literals by indexing with None

        >>> z = blockwise(operator.add, 'ij', x, 'ij', 1234, None, dtype=x.dtype)
        >>> z.compute()
        array([[1235, 1236],
               [1237, 1238]])
        """
        out = name
        new_axes = new_axes or {}

        # Input Validation
        if len(set(out_ind)) != len(out_ind):
            raise ValueError(
                "Repeated elements not allowed in output index",
                [k for k, v in toolz.frequencies(out_ind).items() if v > 1],
            )
        new = (
            set(out_ind)
            - {a for arg in args[1::2] if arg is not None for a in arg}
            - set(new_axes or ())
        )
        if new:
            raise ValueError("Unknown dimension", new)

        from dask.array.core import normalize_arg, unify_chunks

        if align_arrays:
            chunkss, arrays = unify_chunks(*args)
        else:
            arginds = [(a, i) for (a, i) in toolz.partition(2, args) if i is not None]
            chunkss = {}
            # For each dimension, use the input chunking that has the most blocks;
            # this will ensure that broadcasting works as expected, and in
            # particular the number of blocks should be correct if the inputs are
            # consistent.
            for arg, ind in arginds:
                for c, i in zip(arg.chunks, ind):
                    if i not in chunkss or len(c) > len(chunkss[i]):
                        chunkss[i] = c
            arrays = args[::2]

        for k, v in new_axes.items():
            if not isinstance(v, tuple):
                v = (v,)
            chunkss[k] = v

        arginds = list(zip(arrays, args[1::2]))
        numblocks = {}

        dependencies = []
        arrays = []

        # Normalize arguments
        argindsstr = []

        for arg, ind in arginds:
            if ind is None:
                arg = normalize_arg(arg)
                arg, collections = _blockwise_unpack_collections_task_spec(arg)

                dependencies.extend(collections)
            else:
                if (
                    hasattr(arg, "ndim")
                    and hasattr(ind, "__len__")
                    and arg.ndim != len(ind)
                ):
                    raise ValueError(
                        "Index string %s does not match array dimension %d"
                        % (ind, arg.ndim)
                    )
                if not isinstance(arg, ArrayBlockwiseDep):
                    numblocks[arg.name] = arg.numblocks
                    arrays.append(arg)
                    arg = arg.name
            argindsstr.extend((arg, ind))

        # Normalize keyword arguments
        kwargs2 = {}
        for k, v in kwargs.items():
            v = normalize_arg(v)
            v, collections = _blockwise_unpack_collections_task_spec(v)
            dependencies.extend(collections)
            kwargs2[k] = v

        # Finish up the name
        if not out:
            out = "{}-{}".format(
                token or utils.funcname(func).strip("_"),
                base.tokenize(func, out_ind, argindsstr, dtype, **kwargs),
            )

        graph = core_blockwise(
            func,
            out,
            out_ind,
            *argindsstr,
            numblocks=numblocks,
            dependencies=dependencies,
            new_axes=new_axes,
            concatenate=concatenate,
            **kwargs2,
        )
        graph = HighLevelGraph.from_collections(
            out, graph, dependencies=arrays + dependencies
        )

        chunks = [chunkss[i] for i in out_ind]
        if adjust_chunks:
            for i, ind in enumerate(out_ind):
                if ind in adjust_chunks:
                    if callable(adjust_chunks[ind]):
                        chunks[i] = tuple(map(adjust_chunks[ind], chunks[i]))
                    elif isinstance(adjust_chunks[ind], numbers.Integral):
                        chunks[i] = tuple(adjust_chunks[ind] for _ in chunks[i])
                    elif isinstance(adjust_chunks[ind], (tuple, list)):
                        if len(adjust_chunks[ind]) != len(chunks[i]):
                            raise ValueError(
                                f"Dimension {i} has {len(chunks[i])} blocks, adjust_chunks "
                                f"specified with {len(adjust_chunks[ind])} blocks"
                            )
                        chunks[i] = tuple(adjust_chunks[ind])
                    else:
                        raise NotImplementedError(
                            "adjust_chunks values must be callable, int, or tuple"
                        )
        chunks = tuple(chunks)

        if meta is None:
            from dask.array.utils import compute_meta

            meta = compute_meta(func, dtype, *args[::2], **kwargs)
        return new_da_object(graph, out, chunks, meta=meta, dtype=dtype)

    def atop(*args, **kwargs):
        warnings.warn("The da.atop function has moved to da.blockwise")
        return blockwise(*args, **kwargs)

    from dask.array.core import new_da_object