Class Compose

imperative/python/megengine/data/transform/vision/transform.py:178–283

r"""Composes several transfomations together. Args: transforms: list of :class:`VisionTransform` to compose. batch_compose: whether keep the same transform order in batch data when shuffle. shuffle_indices: indices used for random shuffle, start at 1. order: the

class Compose(VisionTransform):
    r"""Composes several transfomations together.

    Args:
        transforms: list of :class:`VisionTransform` to compose.
        batch_compose: whether keep the same transform order in batch data when shuffle.
        shuffle_indices: indices used for random shuffle, start at 1.
        order: the same with :class:`VisionTransform`

    .. seealso:: Refer to :mod:`~.data.transform` module for vision transform APIs.

    Examples:

        >>> import megengine.data.transform as T
        >>> T.Compose([  # doctest: +SKIP
        ...     T.RandomHorizontalFlip(),  # 1st
        ...     T.RandomVerticalFlip(),    # 2nd
        ...     T.CenterCrop(100),         # 3rd
        ...     T.ToMode("CHW"),           # 4th
        ...     ],
        ...     shuffle_indices=[(1, 2, 3)]
        ... )

        In this case, ``shuffle_indices`` is given so each input data will be transformed
        out of order:

        .. math::

           \begin{array}{cc}
           [{\color{red}1 \quad 2 \quad 3} \quad 4] & [{\color{red}1 \quad 3 \quad 2} \quad 4] \\
           [{\color{red}2 \quad 1 \quad 3} \quad 4] & [{\color{red}2 \quad 3 \quad 1} \quad 4] \\
           [{\color{red}3 \quad 1 \quad 2} \quad 4] & [{\color{red}3 \quad 2 \quad 1} \quad 4]
           \end{array}

        In another case, if ``[(1, 3), (2, 4)]`` is given, then the 1st and 3rd transfomation
        will be random shuffled, the 2nd and 4th transfomation will also be shuffled:

        .. math::

           \begin{array}{cc}
           [{\color{red}1} \quad {\color{blue}2} \quad {\color{red}3} \quad {\color{blue}4}] &
           [{\color{red}1} \quad {\color{blue}4} \quad {\color{red}3} \quad {\color{blue}2}] \\
           [{\color{red}3} \quad {\color{blue}2} \quad {\color{red}1} \quad {\color{blue}4}] &
           [{\color{red}3} \quad {\color{blue}4} \quad {\color{red}1} \quad {\color{blue}2}]
           \end{array}

        Different colors represent different groups that need to be internally shuffled.

        .. warning::

           Different samples within each batch will also use random transfomation orders,
           unless ``batch_compose`` is set to ``True``.

    """

    def __init__(
        self,
        transforms: List[VisionTransform] = [],