tfdeploy.py

# -*- coding: utf-8 -*-

"""
Deploy tensorflow graphs for fast evaluation and export to tensorflow-less environments running
numpy.
"""


__author__     = "Marcel Rieger"
__copyright__  = "Copyright 2016-2025, Marcel Rieger"
__credits__    = ["Marcel Rieger"]
__contact__    = "https://github.com/riga/tfdeploy"
__license__    = "BSD-3-Clause"
__status__     = "Development"
__version__    = "0.4.2"

__all__ = ["Model", "Tensor", "Operation", "Ensemble",
           "UnknownOperationException", "OperationMismatchException",
           "InvalidImplementationException", "UnknownImplementationException",
           "EnsembleMismatchException", "ScipyOperationException",
           "reset", "optimize", "print_tensor", "print_op", "print_tf_tensor", "print_tf_op",
           "IMPL_NUMPY", "IMPL_SCIPY", "IMPLS",
           "METHOD_MEAN", "METHOD_MAX", "METHOD_MIN", "METHOD_CUSTOM", "METHODS",
           "HAS_SCIPY"]


# imports for core code
import os
import re
from uuid import uuid4
from functools import reduce

try:
    # python 2
    import cPickle as pickle
except ImportError:
    # python 3
    import pickle

# third-party imports
import numpy as np


# metaclass decorator from six package, credits to Benjamin Peterson
def add_metaclass(metaclass):
    def wrapper(cls):
        orig_vars = cls.__dict__.copy()
        slots = orig_vars.get("__slots__")
        if slots is not None:
            if isinstance(slots, str):
                slots = [slots]
            for slots_var in slots:
                orig_vars.pop(slots_var)
        orig_vars.pop("__dict__", None)
        orig_vars.pop("__weakref__", None)
        return metaclass(cls.__name__, cls.__bases__, orig_vars)
    return wrapper


class Model(object):
    """
    A trained model that contains one or more converted tensorflow graphs. When *path* is set, a
    previously saved model is loaded from that path. Usage:

    .. code-block:: python

       import tensorflow as tf
       import tfdeploy as td

       # build your graph, use names for input and output tensors
       sess = tf.Session()
       x = tf.placeholder("float", shape=[None, 784], name="input")
       W = tf.Variable(tf.truncated_normal([784, 100], stddev=0.05))
       b = tf.Variable(tf.zeros([100]))
       y = tf.nn.softmax(tf.matmul(x, W) + b, name="output")
       sess.run(tf.initialize_all_variables())

       # ... training ...

       # create a model and save it to disk
       model = td.Model()
       model.add(y, sess)
       model.save("/path/to/model.pkl")

    And then in an other file:

    .. code-block:: python

       import tfdeploy as td
       import numpy as np

       model = td.Model("/path/to/model.pkl")
       inp, outp = model.get("input", "output")

       batch = np.random.rand(10000, 784)
       result = outp.eval({inp: batch})

    .. py:attribute:: roots

       Contained root tensors in a dict mapped to a key.
    """

    value_index_cre = re.compile("\:\d+$")
    default_value_index = 0

    def __init__(self, path=None):
        super(Model, self).__init__()

        self.roots = {}

        # load when desired
        if path is not None:
            self.load(path)

    def get(self, *names, **kwargs):
        """ get(*names, key=None)
        Returns one or more :py:class:`Tensor` instances given by *names* using a deep lookup within
        the model. If *key* is not *None*, only the root tensor with that *key* is traversed. *None*
        is returned when no tensor was found. In case a tensor is passed, it's name is used for the
        lookup.
        """
        tensors = tuple(self._get(name, **kwargs) for name in names)
        return tensors[0] if len(names) == 1 else tensors

    def _get(self, name, key=None):
        if isinstance(name, Tensor):
            name = name.name

        # append the default value_index if there's none
        if not self.value_index_cre.search(name):
            name += ":%d" % self.default_value_index

        # return the first occurance of a tensor with that name
        if key is not None:
            return self.roots[key].get(name)
        else:
            return reduce(lambda t1, t2: t1 or t2.get(name), self.roots.values(), None)

    def __getitem__(self, name):
        return self.get(name)

    def __contains__(self, name):
        return self.get(name) is not None

    def add(self, tensor, tf_sess=None, key=None, **kwargs):
        """
        Adds a new root *tensor* for a *key* which, if *None*, defaults to a consecutive number.
        When *tensor* is not an instance of :py:class:`Tensor` but an instance of
        ``tensorflow.Tensor``, it is converted first. In that case, *tf_sess* should be a valid
        tensorflow session and *kwargs* are forwarded to the :py:class:`Tensor` constructor.
        """
        if not isinstance(tensor, Tensor):
            tensor = Tensor(tensor, tf_sess, **kwargs)

        if key is None:
            if len(self.roots) == 0:
                key = 0
            else:
                key = max(self.roots.keys()) + 1

        self.roots[key] = tensor

    def load(self, path):
        """
        Loads all tensors from a file defined by *path* and adds them to the root set.
        """
        path = os.path.expandvars(os.path.expanduser(path))
        with open(path, "rb") as f:
            roots = pickle.load(f)

        for key, tensor in roots.items():
            self.add(tensor, key=key)

    def save(self, path):
        """
        Saves all tensors of the root set to a file defined by *path*.
        """
        path = os.path.expandvars(os.path.expanduser(path))
        with open(path, "wb") as f:
            pickle.dump(self.roots, f)


class TensorRegister(type):
    """
    Meta class of :py:class:`Tensor` that performs instance caching indexed by tensorflow tensor
    instances.
    """

    instances = {}

    def __call__(cls, tf_tensor, *args, **kwargs):
        # simple caching
        if tf_tensor not in cls.instances:
            inst = super(TensorRegister, cls).__call__(tf_tensor, *args, **kwargs)
            cls.instances[tf_tensor] = inst
        return cls.instances[tf_tensor]


@add_metaclass(TensorRegister)
class Tensor(object):
    """
    Building block of a model. In *graph* terms, tensors represent connections between nodes (ops)
    of a graph. It contains information on the op it results from. The conversion uses the
    (tensorflow) instances *tf_tensor* and *tf_sess*, *tf_feed_dict* can be set to evaluate the
    tensor's current value.

    .. py:attribute:: name

       The name of the tensor.

    .. py:attribute:: value_index

       The integer value index of this tensor, i.e., the position in the op's output list.

    .. py:attribute:: op

       The op instance that defines the value of this tensor. When created from a
       ``tensorflow.Placeholder`` or a ``tensorflow.Variable/V2``, op will be *None*.

    .. py:attribute:: value

       The value of this tensor. When created from a ``tensorflow.Variable/V2``, this will be the
       value of that variable, or *None* otherwise until it is evaluated the first time.
    """

    def __init__(self, tf_tensor, tf_sess, tf_feed_dict=None):
        super(Tensor, self).__init__()

        if not tf_sess:
            raise ValueError("bad tensorflow session: %s" % tf_sess)

        self.name = tf_tensor.name
        self.value_index = tf_tensor.value_index
        self.op = None
        self.value = None
        self.last_uuid = None

        # guess the value
        # explicitly evaluate variables and constants, use feed_dict for placeholders
        if tf_tensor.op.type in ("Variable", "VariableV2", "Const"):
            self.value = tf_tensor.eval(session=tf_sess, feed_dict=tf_feed_dict)
        elif tf_tensor.op.type == "Placeholder":
            if tf_feed_dict is not None and tf_tensor in tf_feed_dict:
                self.value = tf_feed_dict[tf_tensor]

        # create the op
        # no op for variables, placeholders and constants
        if tf_tensor.op.type not in ("Variable", "VariableV2", "Const", "Placeholder"):
            self.op = Operation.new(tf_tensor.op, tf_sess, tf_feed_dict=tf_feed_dict)

    def get(self, *names):
        """
        Returns one or more tensors given by *names* using a deep lookup within the inputs of the
        op. Note that *this* tensor is returned when the name matches. *None* is returned when no
        tensor was found.
        """
        tensors = tuple(self._get(name) for name in names)
        return tensors[0] if len(names) == 1 else tensors

    def _get(self, name):
        if self.name == name:
            return self
        elif self.op is None:
            return None
        else:
            return self.op.get(name)

    def eval(self, feed_dict=None, _uuid=None):
        """ eval(feed_dict=None)
        Returns the value of this tensor based on the evaluation of all dependent ops and tensors.
        You can overwrite values of dependent tensors using *feed_dict*, a mapping of tensors to
        numpy arrays, which is passed down the evaluation chain.
        """
        # set a cache uuid for this eval call
        if _uuid is None:
            _uuid = uuid4()

        # already cached? this is important for tensors that are used multiple time within the graph
        if _uuid == self.last_uuid:
            return self.value
        else:
            self.last_uuid = _uuid

        if feed_dict is None:
            feed_dict = {}

        # when _this_ tensor is in the feed_dict, return the fed value
        # otherwise, eval the op
        if self in feed_dict:
            self.value = feed_dict[self]
        elif self.op is not None:
            self.value = self.op.eval(feed_dict=feed_dict, _uuid=_uuid)[self.value_index]

        return self.value

    def __call__(self, *args, **kwargs):
        return self.eval(*args, **kwargs)


class OperationRegister(type):
    """
    Meta class of :py:class:`Operation` that performs instance caching indexed by tensorflow op
    instances. Additionaly, all derived classes are registered in a mapping using their type's for
    faster op class lookup.
    """

    classes = {}
    instances = {}

    def __new__(metacls, classname, bases, classdict):
        # when not set explicitly in that class, set type to the class name
        classdict.setdefault("types", (classname,))
        cls = super(OperationRegister, metacls).__new__(metacls, classname, bases, classdict)
        # register the class for each of its types
        for type in cls.types:
            metacls.classes[type] = cls
        return cls

    def __call__(cls, tf_op, *args, **kwargs):
        # simple caching
        if tf_op not in cls.instances:
            inst = super(OperationRegister, cls).__call__(tf_op, *args, **kwargs)
            cls.instances[tf_op] = inst
        return cls.instances[tf_op]


# implementation types
IMPLS = IMPL_NUMPY, IMPL_SCIPY = range(2)
IMPL_NAMES = ["numpy", "scipy"]


@add_metaclass(OperationRegister)
class Operation(object):
    """
    Building block of a model. In *graph* terms, operations (ops) represent nodes that are connected
    via tensors. It contains information on its input tensors. The conversion uses the
    (tensorflow) instance *tf_op*, all *args* and *kwargs* are forwarded to the :py:class:`Tensor`
    constructor for this op's input tensors. Op instances can have multiple implementations, i.e.,
    different methods that lead to equivalent results but might use additional third-party software
    such as *scipy*. To select a specific implementation, invoke :py:func:`use_impl`:

    .. code-block:: python

       # tell SomeOp to use the scipy implementation of its op logic
       SomeOp.use_impl(IMPL_SCIPY)

    See :py:func:`add_impl` for more info about adding new implementations.

    .. py:attribute:: types
       classmember

       A tuple containing the types of tensorflow ops that this op can represent.

    .. py:attribute:: unpack
       classmember

       If *True* (default), the values of evaluated input tensors are forwarded to *func* as single
       arguments, or, otherwise, as a list.

    .. py:attribute:: attrs
       classmember

       Names of the configuration attributes of the original tensorflow op in a tuple.

    .. py:attribute:: name

       The name of the op.

    .. py:attribute:: inputs

       Tuple of tensors that are input to this op. Their order is important as they are forwarded to
       *func* for evaluation.

    .. py:attribute:: kwargs

       Keyword arguments containing configuration values that will be passed to *func*.
    """

    impl = None
    impls = []

    types = ()
    unpack = True
    attrs = ()
    output_dtypes = False

    def __init__(self, tf_op, *args, **kwargs):
        super(Operation, self).__init__()

        # compare types as a cross check
        if tf_op.type not in self.types:
            raise OperationMismatchException("operation types do not match: %s, %s" \
                                             % (self.types, tf_op.type))

        self.name = tf_op.name
        self.inputs = tuple(Tensor(tf_tensor, *args, **kwargs) for tf_tensor in tf_op.inputs)

        self.value = None
        self.last_uuid = None

        # store attributes as kwargs for calls to eval
        self.kwargs = []
        for attr in self.attrs:
            try:
                value = tf_op.get_attr(attr)
            except ValueError:
                value = None
            self.kwargs.append(value)

        # store output dtypes for calls to eval when x is True
        self.output_dtypes = [dtype_map[dtype] for dtype in tf_op._output_types]

    @classmethod
    def new(cls, tf_op, *args, **kwargs):
        """
        Factory function that takes a tensorflow op *tf_op* and returns an instance of the
        appropriate op class. *args* and *kwargs* are forwarded to the op constructor. Raises an
        exception of type :py:exc:`UnknownOperationException` in case the requested op type is not
        known.
        """
        if tf_op.type not in cls.classes:
            raise UnknownOperationException("unknown operation: %s" % tf_op.type)

        return cls.classes[tf_op.type](tf_op, *args, **kwargs)

    def set_attr(self, attr, value):
        """
        Overwrites the value of an attribute *attr* with a new *value*.
        """
        if attr not in self.attrs:
            raise AttributeError("no attribute '%s' in op '%s'" % (attr, self.name))

        self.kwargs[self.attrs.index(attr)] = value

    def get(self, *names):
        """
        Returns one or more tensors given by *names* using a deep lookup within this op. *None* is
        returned when no tensor was found.
        """
        tensors = tuple(self._get(name) for name in names)
        return tensors[0] if len(names) == 1 else tensors

    def _get(self, name):
        return reduce(lambda t1,t2: t1 or t2.get(name), self.inputs, None)

    def eval(self, feed_dict=None, _uuid=None):
        """ eval(feed_dict=None)
        Returns the value of all output tensors in a tuple. See :py:meth:`Tensor.eval` for more
        info.
        """
        # set a cache uuid for this eval call
        if _uuid is None:
            _uuid = uuid4()

        # already cached?
        if _uuid == self.last_uuid:
            return self.value
        else:
            self.last_uuid = _uuid

        args = [t.eval(feed_dict=feed_dict, _uuid=_uuid) for t in self.inputs]
        if self.unpack:
            args.extend(self.kwargs)
        else:
            args = [args] + self.kwargs
        if self.__class__.output_dtypes:
            args.append(self.output_dtypes)

        self.value = self.func(*args)

        return self.value

    @classmethod
    def func(cls, *args):
        """
        The actual op logic. By default, the method call is forwareded to the
        implementation-specific version which is determined using *impl*. Overwrite this method in
        inheriting classes to disable this feature. Must return a tuple.
        """
        if cls.impl == IMPL_NUMPY:
            return cls.func_numpy(*args)
        elif cls.impl == IMPL_SCIPY:
            return cls.func_scipy(*args)
        else:
            raise InvalidImplementationException(cls.impl)

    @staticmethod
    def func_numpy(*args):
        """
        Numpy implementation of the op logic. Returns a tuple.
        """
        raise NotImplementedError

    @staticmethod
    def func_scipy(*args):
        """
        Scipy implementation of the op logic. Returns a tuple.
        """
        raise NotImplementedError

    @classmethod
    def factory(cls, func=None, impl=IMPL_NUMPY, **kwargs):
        """ factory(func=None, impl=IMPL_NUMPY, **kwargs)
        Returns a new op class whose static function will be set to *func*. The name of *func* will
        also be the op class name. *impl* is the default implementation type of the op. *kwargs* are
        used to update the class dict of the newly created op class.
        """
        if impl not in IMPLS:
            raise InvalidImplementationException(impl)

        def wrapper(func):
            classdict = {"impls": [], "func_" + IMPL_NAMES[impl]: staticmethod(func)}
            classdict.update(kwargs)

            cls = Operation.__class__(func.__name__, (Operation,), classdict)
            cls.__doc__ = func.__doc__
            cls.impls.append(impl)
            cls.use_impl(impl)

            return cls

        return wrapper if func is None else wrapper(func)

    @classmethod
    def use_impl(cls, impl):
        """
        Switches the implementation type to *impl*. Returns the previous type.
        """
        if impl not in cls.impls:
            raise UnknownImplementationException(impl)

        prev = cls.impl
        cls.impl = impl
        return prev

    @classmethod
    def add_impl(cls, impl):
        """
        Decorator to add an additional implementation to this op. Example:

        .. code-block:: python

           # initial implementation using factory, defaults to numpy
           @Operation.factory
           def MyOp(a, b):
               # use numpy only
               return ...

           # also add a scipy implementation
           @MyOp.add_impl(IMPL_SCIPY)
           def MyOp(a, b):
               # also use scipy
               return ...
        """
        if impl not in IMPLS:
            raise InvalidImplementationException(impl)

        def wrapper(func):
            setattr(cls, "func_" + IMPL_NAMES[impl], staticmethod(func))
            if impl not in cls.impls:
                cls.impls.append(impl)
            return cls

        return wrapper


# ensemble method types
METHODS = METHOD_MEAN, METHOD_MAX, METHOD_MIN, METHOD_CUSTOM = range(4)
METHOD_NAMES = ["mean", "max", "min", "custom"]


class Ensemble(object):
    """
    An ensemble is a wrapper around multiple models to compute ensemble values. It can initialized
    with a list of model paths and an ensembling method that decides how to compute the merged
    value.

    .. code-block:: python

       # create the ensemble
       ensemble = Ensemble(["model1.pkl", "model2.pkl", ...], METHOD_MEAN)

       # get input and output tensors (which actually are TensorEnsemble instances)
       input, output = ensemble.get("input", "output")

       # evaluate the ensemble just like a normal model
       batch = ...
       value = output.eval({input: batch})

    If you want to use another method than ``METHOD_MEAN``, ``METHOD_MAX`` or ``METHOD_MAX``, use
    ``METHOD_CUSTOM`` and overwrite the ``func_custom`` method of the :py:class:`TensorEnsemble`
    instance.

    .. py:attribute:: models

       A list that contains all read models.

    .. py:attribute:: method

       The ensembling method.
    """

    def __init__(self, paths=None, method=METHOD_MEAN):
        """ __init__(paths=None, method=METHOD_MEAN)
        """
        super(Ensemble, self).__init__()

        # check method
        if method not in METHODS:
            raise UnknownEnsembleMethodException(method)
        self.method = method

        # loaded models
        self.models = []

        # load when desired
        if paths is not None:
            self.load(paths)

    def get(self, *names, **kwargs):
        """ get(*names, key=None)
        Returns one or more :py:class:`TensorEnsemble` instances given by *names* using a deep
        lookup within all read models. Each returned tensor ensemble will have ``len(models)``
        tensors. If a model does not contain a specific tensor defined by a specific *name*, the
        associated ensemble tensor will contain a *None* for that model in its tensors. If *key* is
        not *None*, only the root tensors with that *key* are traversed.
        """
        # create empty tensor ensembles with our method
        tensor_ensembles = [TensorEnsemble([], self.method) for name in names]

        # loop over models, collect and add tensors
        for model in self.models:
            tensors = model.get(*names, **kwargs)
            if not isinstance(tensors, tuple):
                tensors = (tensors,)
            for i, t in enumerate(tensors if isinstance(tensors, tuple) else (tensors,)):
                tensor_ensembles[i].tensors.append(t)

        return tensor_ensembles[0] if len(names) == 1 else tuple(tensor_ensembles)

    def load(self, paths):
        """
        Loads models from a list of *paths*.
        """
        for path in paths:
            self.models.append(Model(path))


class TensorEnsemble(object):
    """
    A tensor ensemble basically contains a list of tensors that correspond to models of an
    :py:class:`Ensemble` instance.

    .. py:attribute: tensors

       The list of contained tensors. Tensor *i* corresponds to model *i*.

    .. py:attribute: method

       The ensembling method.
    """

    def __init__(self, tensors, method=METHOD_MEAN):
        super(TensorEnsemble, self).__init__()

        # check method
        if method not in METHODS:
            raise UnknownEnsembleMethodException(method)
        self.method = method

        self.tensors = list(tensors)

    def eval(self, feed_dict=None):
        """
        Evaluates all contained tensors using a *feed_dict* and returns the ensemble value. The keys
        of *feed_dict* must be tensor ensembles. Its values can be batches, i.e., numpy arrays, or
        lists or tuples of batches. In the latter case, these lists or tuples must have the same
        length as the list of stored tensors as they will be mapped.
        """
        # first, check that the length of all feed_dict keys match our own length
        for tensor_ensemble in feed_dict:
            if len(tensor_ensemble.tensors) != len(self.tensors):
                raise EnsembleMismatchException("incompatible lengths of tensors: %d, %d" \
                                                % (len(self.tensors), len(tensor_ensemble.tensors)))

        # create a joined uuid
        _uuid = uuid4()

        # prepare feed_dicts
        feed_dicts = [{} for _ in range(len(self.tensors))]
        for tensor_ensemble, value in feed_dict.items():
            for i, tensor in enumerate(tensor_ensemble.tensors):
                if tensor is not None:
                    feed_dicts[i][tensor] = value[i] if isinstance(value, (list, tuple)) else value

        # eval all tensors
        values = [t.eval(feed_dict=d, _uuid=_uuid) for t, d in zip(self.tensors, feed_dicts)]

        # return the computed ensemble value
        return self.func(values)

    def __call__(self, *args, **kwargs):
        return self.eval(*args, **kwargs)

    def func(self, values):
        """
        The actual ensembling logic that combines multiple *values*. The method call is forwareded
        tothe ensemble method-specific variant which is determined using *method*.
        """
        if self.method == METHOD_MEAN:
            return self.func_mean(values)
        elif self.method == METHOD_MAX:
            return self.func_max(values)
        elif self.method == METHOD_MIN:
            return self.func_min(values)
        elif self.method == METHOD_CUSTOM:
            return self.func_custom(values)
        else:
            raise UnknownEnsembleMethodException(self.method)

    @staticmethod
    def func_mean(values):
        return np.mean(np.stack(values), axis=0)

    @staticmethod
    def func_max(values):
        return np.amax(np.stack(values), axis=0)

    @staticmethod
    def func_min(values):
        return np.amin(np.stack(values), axis=0)

    @staticmethod
    def func_custom(values):
        raise NotImplementedError


class UnknownOperationException(Exception):
    """
    An exception which is raised when trying to convert an unknown tensorflow.
    """


class OperationMismatchException(Exception):
    """
    An exception which is raised during instantiation of an op whose type does not match the
    underlying tensorflow op.
    """


class InvalidImplementationException(Exception):
    """
    An exception which is raised when an implementation of an unknown type is registered for an
    :py:class:`Operation` class.
    """


class UnknownImplementationException(Exception):
    """
    An exception which is raised when an :py:class:`Operation` instance is requested to use an
    implementation type that was not yet added.
    """


class UnknownEnsembleMethodException(Exception):
    """
    An exception which is raised when an :py:class:`Ensemble` instance is initialised with an
    unknown ensemle method.
    """


class EnsembleMismatchException(Exception):
    """
    An exception which is raised when a :py:class:`TensorEnsemble` instance is evaluated with a
    *feed_dict* whose keys, i.e. also :py:class:`TensorEnsemble` instances, do not match the tensor
    to evaluate. An example would be that a tensor ensemble with *n* tensors is evaluated with a
    tensor ensemble it its *feed_dict* that contains *m* tensors.
    """


class ScipyOperationException(Exception):
    """
    An exception which is raised when trying to evaluate an op that uses scipy internally and scipy
    is not available.
    """
    def __init__(self, attr):
        msg = "trying to access 'scipy.%s', but scipy is not installed on your system, " \
              "install scipy to use this operation or use an other implementation" % attr
        super(ScipyOperationException, self).__init__(msg)


# parses the tf version and returns a tuple, e.g. "0.12.0-rc1" => (0, 12, 0, "rc1")
def _parse_tf_version(v):
    parts = v.split(".", 2)
    if "-" in parts[2]:
        parts.extend(parts.pop().split("-", 1))
    return tuple([int(p) for p in parts[:3]] + parts[3:])


# default (last) tf version
_tf_version_string = "0.12.0-rc1"
_tf_version = _parse_tf_version(_tf_version_string)


def setup(tf, order=None):
    """
    Sets up global variables (currently only the tensorflow version) to adapt to peculiarities of
    different tensorflow versions. This function should only be called before :py:class:`Model`
    creation, not for evaluation. Therefore, the tensorflow module *tf* must be passed:

    .. code-block:: python

       import tensorflow as tf
       import tfdeploy as td

       td.setup(tf)

       # ...

    Also, when *order* is not *None*, it is forwarded to :py:func:`optimize` for convenience.
    """
    global _tf_version_string, _tf_version
    _tf_version_string = tf.__version__
    _tf_version = _parse_tf_version(_tf_version_string)

    if order is not None:
        optimize(order)


def reset():
    """
    Resets the instance caches of :py:class:`TensorRegister` and :py:class:`OperationRegister`.
    """
    TensorRegister.instances.clear()
    OperationRegister.instances.clear()


def optimize(order):
    """ optimize(impl)
    Tries to set the implementation type of all registered :py:class:`Operation` classes to *impl*.
    This has no effect when an op does not implement that type.

    The behavior is equivalent to:

    .. code-block:: python

       for op in Operation.__subclasses__():
           if impl in op.impls:
               op.use_impl(impl)

    *impl* can also be a list or tuple of valid implementation types representing a preferred order.
    """
    if not isinstance(order, (list, tuple)):
        order = [order]

    for op in Operation.__subclasses__():
        for impl in order:
            if impl in op.impls:
                op.use_impl(impl)
                break


def print_tensor(td_tensor, indent="|   ", max_depth=-1, depth=0):
    """ print_tensor(td_tensor, indent="    ", max_depth=-1)
    Prints the dependency graph of a :py:class:`Tensor` *td_tensor*, where each new level is
    indented by *indent*. When *max_depth* is positive, the graph is truncated at that depth, where
    each tensor and each op count as a level.
    """
    offset = depth * indent
    line = "td tensor: %s" % td_tensor.name
    if td_tensor.value is not None:
        line += " (%s)" % (",".join(str(i) for i in td_tensor.value.shape),)

    print(offset + line)

    if td_tensor.op and (max_depth < 0 or max_depth > depth):
        print_op(td_tensor.op, indent=indent, max_depth=max_depth, depth=depth+1)


def print_op(td_op, indent="|   ", max_depth=-1, depth=0):
    """ print_op(td_op, indent="    ", max_depth=-1)
    Prints the dependency graph of a :py:class:`Operation` *td_op*, where each new level is indented
    by *indent*. When *max_depth* is positive, the graph is truncated at that depth, where each
    tensor and each op count as a level.
    """
    offset = depth * indent
    line = "td op: %s (%s)" % (td_op.name, ",".join(td_op.types))

    print(offset + line)

    if max_depth < 0 or max_depth > depth:
        for td_tensor in td_op.inputs:
            print_tensor(td_tensor, indent=indent, max_depth=max_depth, depth=depth+1)


def print_tf_tensor(tf_tensor, indent="|   ", max_depth=-1, depth=0):
    """ print_tf_tensor(tf_tensor, indent="    ", max_depth=-1)
    Prints the dependency graph of a tensorflow tensor *tf_tensor*, where each new level is indented
    by *indent*. When *max_depth* is positive, the graph is truncated at that depth, where each
    tensor and each op count as a level.
    """
    offset = depth * indent
    shape = tuple(int(i) for i in tf_tensor.get_shape())
    line = "tf tensor: %s (%s)" % (tf_tensor.name, ",".join(str(i) for i in shape))

    print(offset + line)

    if tf_tensor.op and (max_depth < 0 or max_depth > depth):
        print_tf_op(tf_tensor.op, indent=indent, max_depth=max_depth, depth=depth+1)


def print_tf_op(tf_op, indent="|   ", max_depth=-1, depth=0):
    """ print_tf_op(tf_tensor, indent="    ", max_depth=-1)
    Prints the dependency graph of a tensorflow operation *tf_op*, where each new level is indented
    by *indent*. When *max_depth* is positive, the graph is truncated at that depth, where each
    tensor and each op count as a level.
    """
    offset = depth * indent
    line = "tf op: %s (%s)" % (tf_op.name, tf_op.type)

    print(offset + line)

    if max_depth < 0 or max_depth > depth:
        for tf_tensor in tf_op.inputs:
            print_tf_tensor(tf_tensor, indent=indent, max_depth=max_depth, depth=depth+1)


# imports exclusively for ops
from operator import mul
from itertools import product
from collections import defaultdict

# optional import of scipy
try:
    if os.environ.get("TD_REFUSE_SCIPY", "").lower() in ("1", "true", "yes"):
        raise ImportError

    import scipy as sp
    import scipy.special
    HAS_SCIPY = True
except ImportError:
    class ScipyDummy(object):
        def __getattr__(self, attr):
            raise ScipyOperationException(attr)
    sp = ScipyDummy()
    HAS_SCIPY = False


# mapping of tf dtypes to np dtypes
dtype_map = {
    1: np.float32,
    2: np.float64,
    3: np.int32,
    4: np.uint8,
    5: np.int16,
    6: np.int8,
    7: np.object,
    8: np.complex64,
    9: np.int64,
    10: np.bool,
    14: np.uint16,
    17: np.uint16,
    18: np.complex128,
    19: np.float16,
    101: np.float32,
    102: np.float64,
    103: np.int32,
    104: np.uint8,
    105: np.int16,
    106: np.int8,
    107: np.object,
    108: np.complex64,
    109: np.int64,
    110: np.bool,
    114: np.uint16,
    117: np.uint16,
    118: np.complex128,
    119: np.float16
}


lgamma_vec = np.vectorize(np.math.lgamma)
erf_vec = np.vectorize(np.math.erf)
erfc_vec = np.vectorize(np.math.erfc)

def _transpose(a, dim=2):
    if dim <= 0:
        axes = None
    else:
        axes = list(range(a.ndim))
        axes.append(axes.pop(-1 * dim))
    return np.transpose(a, axes=axes)

def _adjoint(a, dim=2):
    return np.conj(_transpose(a, dim=dim))


#
# sequences
#

@Operation.factory
def LinSpace(start, stop, num):
    """
    Linspace op.
    """
    return np.linspace(start, stop, num=num, dtype=np.float32),


@Operation.factory
def Range(start, limit, delta):
    """
    Range op.
    """
    return np.arange(start, limit, delta, dtype=np.int32),


#
# random tensors
#

@Operation.factory(attrs=("dtype", "seed"))
def RandomStandardNormal(shape, dtype, seed):
    """
    Standard (mu=0, sigma=1) gaussian op.
    """
    if seed:
        np.random.seed(seed)
    return np.random.normal(size=reduce(mul, shape)).reshape(shape).astype(dtype_map[dtype]),


@Operation.factory(attrs=("dtype", "seed"))
def TruncatedNormal(shape, dtype, seed):
    """
    Standard (mu=0, sigma=1) gaussian op with truncation above 2 sigma.
    """
    if seed:
        np.random.seed(seed)
    n = reduce(mul, shape)
    r = np.empty(n, dtype=dtype_map[dtype])
    idxs = np.ones(n, dtype=np.bool)
    while n:
        r[idxs] = np.random.normal(size=n)
        idxs = np.abs(r) > 2
        n = np.sum(idxs)
    return r.reshape(shape),


@Operation.factory(attrs=("dtype", "seed"))
def RandomUniform(shape, dtype, seed):
    """
    Random uniform op.
    """
    if seed:
        np.random.seed(seed)
    return np.random.uniform(size=shape).astype(dtype_map[dtype]),


@Operation.factory(attrs=("seed",))
def RandomUniformInt(shape, minval, maxval, seed):
    """
    Random uniform int op.
    """
    if seed:
        np.random.seed(seed)
    return np.random.randint(minval, maxval, size=shape),


@Operation.factory(attrs=("seed",))
def RandomShuffle(a, seed):
    """
    Random uniform op.
    """
    if seed:
        np.random.seed(seed)
    r = a.copy()
    np.random.shuffle(r)
    return r,


#
# casting
#

@Operation.factory(types=("Cast", "StringToNumber"), output_dtypes=True)
def Cast(a, output_dtypes):
    """
    Cast op.
    """
    return np.copy(a).astype(output_dtypes[0]),


#
# shapes and shaping
#

@Operation.factory
def Shape(a):
    """
    Shape op.
    """
    return np.array(a.shape, dtype=np.int32),


@Operation.factory
def Size(a):
    """
    Size op.
    """
    return np.array([a.size], dtype=np.int32),


@Operation.factory
def Rank(a):
    """
    Rank op.
    """
    return np.array([len(a.shape)], dtype=np.int32),


@Operation.factory
def Reshape(a, shape):
    """
    Reshape op.
    """
    return np.copy(a).reshape(shape),


@Operation.factory(attrs=("squeeze_dims",))
def Squeeze(a, squeeze_dims):
    """
    Squeeze op, i.e. removes singular axes.
    """
    if not squeeze_dims:
        squeeze_dims = list(range(len(a.shape)))
    slices = [(0 if (dim == 1 and i in squeeze_dims) else slice(None)) \
              for i, dim in enumerate(a.shape)]
    return np.copy(a)[slices],


@Operation.factory
def ExpandDims(a, dim):
    """
    Expand dim op, i.e. add singular axis at dim.
    """
    shape = list(a.shape)
    if dim >= 0:
        shape.insert(dim, 1)
    else:
        shape.insert(len(shape) + dim + 1, 1)
    return np.copy(a).reshape(*shape),


#
# slicing and joining
#

@Operation.factory
def Slice(a, begin, size):
    """
    Slicing op.
    """
    return np.copy(a)[[slice(*tpl) for tpl in zip(begin, begin+size)]],


@Operation.factory(attrs=("num_split",))
def Split(axis, a, n):
    """
    Split op with n splits.
    """
    return tuple(np.split(np.copy(a), n, axis=axis))


@Operation.factory
def SplitV(a, splits, axis):
    """
    Split op with multiple split sizes.
    """
    return tuple(np.split(np.copy(a), np.cumsum(splits), axis=axis))


@Operation.factory
def Tile(a, n):
    """
    Tile op.
    """
    return np.tile(a, n),


@Operation.factory
def Pad(a, paddings):
    """
    Zero padping op.
    """
    return np.pad(a, paddings, mode="constant", constant_values=0),


@Operation.factory(unpack=False)
def ConcatV2(inputs):
    """
    Concat op.
    """
    axis = inputs.pop()
    return np.concatenate(inputs, axis=axis),


@Operation.factory(attrs=("axis",), unpack=False)
def Pack(inputs, axis):
    """
    Pack op.
    """
    return np.stack(inputs, axis=axis),


@Operation.factory(attrs=("num", "axis"))
def Unpack(a, num, axis):
    """
    Unpack op.
    """
    return tuple(np.squeeze(b, axis=axis) for b in np.split(a, num, axis=axis))


@Operation.factory(attrs=("seq_dim", "batch_dim"))
def ReverseSequence(a, seq_lengths, seq_dim, batch_dim):
    """
    Sequential reverse op.
    """
    r = np.copy(a)
    invidxs = (len(r.shape) - 1) * [slice(None)]
    if seq_dim < batch_dim:
        invidxs[seq_dim] = slice(None, None, -1)
    else:
        invidxs[seq_dim - 1] = slice(None, None, -1)
    _invidxs = tuple(invidxs)
    selidxs = len(r.shape) * [slice(None)]
    for i, l in enumerate(seq_lengths):
        if not l:
            continue
        selidxs[batch_dim] = i
        selidxs[seq_dim] = slice(0, l)
        _selidxs = tuple(selidxs)
        r[_selidxs] = a[_selidxs][_invidxs]
    return r,


@Operation.factory
def ReverseV2(a, axes):
    """
    Reverse op.
    """
    idxs = tuple(slice(None, None, 2 * int(i not in axes) - 1) for i in range(len(a.shape)))
    return np.copy(a[idxs]),


@Operation.factory
def Transpose(a, perm=None):
    """
    Transpose op.
    """
    return np.transpose(a, axes=perm),


#
# arithmetic math ops
#

@Operation.factory(types=("Add", "BiasAdd"))
def Add(a, b):
    """
    Addition op.
    """
    return np.add(a, b),


@Operation.factory(types=("Subtract", "Sub"))
def Subtract(a, b):
    """
    Subtraction op.
    """
    return np.subtract(a, b),


@Operation.factory(types=("Multiply", "Mul"))
def Multiply(a, b):
    """
    Multiplication op.
    """
    return np.multiply(a, b),


@Operation.factory(types=("Div", "RealDiv"))
def Div(a, b):
    """
    Division op.
    """
    return np.divide(a, b),


@Operation.factory
def FloorDiv(a, b):
    """
    Floor division op, i.e., a // b.
    """
    return np.floor_divide(a, b),


@Operation.factory(types=("Mod", "FloorMod"))
def Mod(a, b):
    """
    Modulo op.
    """
    return np.mod(a, b),


@Operation.factory
def Cross(a, b):
    """
    Cross product op.
    """
    return np.cross(a, b),


#
# basic math ops
#

@Operation.factory(unpack=False)
def AddN(inputs):
    """
    Multi add op.
    """
    return reduce(np.add, inputs),


@Operation.factory
def Abs(a):
    """
    Abs op.
    """
    return np.abs(a),


@Operation.factory(types=("Negative", "Neg"))
def Negative(a):
    """
    Negative op.
    """
    return np.negative(a),


@Operation.factory
def Sign(a):
    """
    Sign op.
    """
    return np.sign(a),


@Operation.factory
def Inv(a):
    """
    Reciprocal op.
    """
    return np.reciprocal(a),


@Operation.factory
def Square(a):
    """
    Square op.
    """
    return np.square(a),


@Operation.factory
def Round(a):
    """
    Round op.
    """
    return np.round(a),


@Operation.factory
def Sqrt(a):
    """
    Square root op.
    """
    return np.sqrt(a),


@Operation.factory
def Rsqrt(a):
    """
    Reciprocal square root op.
    """
    return np.reciprocal(np.sqrt(a)),


@Operation.factory
def Pow(a, b):
    """
    Power op.
    """
    return np.power(a, b),


@Operation.factory
def Exp(a):
    """
    Exponential op.
    """
    return np.exp(a),


@Operation.factory
def Log(a):
    """
    Logarithm op.
    """
    return np.log(a),


@Operation.factory
def Ceil(a):
    """
    Ceil round op.
    """
    return np.ceil(a),


@Operation.factory
def Floor(a):
    """
    Floor round op.
    """
    return np.floor(a),


@Operation.factory
def Maximum(a, b):
    """
    Maximum op.
    """
    return np.maximum(a, b),


@Operation.factory
def Minimum(a, b):
    """
    Minimum op.
    """
    return np.minimum(a, b),


@Operation.factory
def Cos(a):
    """
    Cos op.
    """
    return np.cos(a),


@Operation.factory
def Sin(a):
    """
    Sin op.
    """
    return np.sin(a),


@Operation.factory
def Tan(a):
    """
    Tan op.
    """
    return np.tan(a),


@Operation.factory
def Acos(a):
    """
    Acos op.
    """
    return np.arccos(a),


@Operation.factory
def Asin(a):
    """
    Asin op.
    """
    return np.arcsin(a),


@Operation.factory
def Atan(a):
    """
    Atan op.
    """
    return np.arctan(a),


@Operation.factory
def Lgamma(a):
    """
    lgamma op.
    """
    return lgamma_vec(a),

@Lgamma.add_impl(IMPL_SCIPY)
def Lgamma(a):
    return sp.special.gammaln(a),


@Operation.factory(impl=IMPL_SCIPY)
def Digamma(a):
    """
    Digamma op.
    """
    return sp.special.digamma(a),


@Operation.factory
def Erf(a):
    """
    Gaussian error function op.
    """
    return erf_vec(a),

@Erf.add_impl(IMPL_SCIPY)
def Erf(a):
    return sp.special.erf(a),


@Operation.factory
def Erfc(a):
    """
    Complementary gaussian error function op.
    """
    return erfc_vec(a),

@Erfc.add_impl(IMPL_SCIPY)
def Erfc(a):
    return sp.special.erfc(a),


@Operation.factory
def SquaredDifference(a, b):
    """
    Squared diff op, i.e. (a-b)**2
    """
    return (a - b)**2,


@Operation.factory(impl=IMPL_SCIPY)
def Igamma(a, b):
    """
    Incomplete gamma op.
    """
    return sp.special.gammainc(a, b),


@Operation.factory(impl=IMPL_SCIPY)
def Igammac(a, b):
    """
    Complemented, incomplete gamma op.
    """
    return sp.special.gammaincc(a, b),


@Operation.factory(impl=IMPL_SCIPY)
def Zeta(a, b):
    """
    Zeta op.
    """
    return sp.special.zeta(a, b),


@Operation.factory(impl=IMPL_SCIPY)
def Polygamma(a, b):
    """
    Polygamma op.
    """
    return sp.special.polygamma(a, b),


@Operation.factory(impl=IMPL_SCIPY)
def Betainc(a, b, x):
    """
    Complemented, incomplete gamma op.
    """
    return sp.special.betainc(a, b, x),


#
# matrix math ops
#

@Operation.factory
def Diag(a):
    """
    Diag op.
    """
    r = np.zeros(2 * a.shape, dtype=a.dtype)
    for idx, v in np.ndenumerate(a):
        r[2 * idx] = v
    return r,


@Operation.factory
def DiagPart(a):
    """
    Diag op that returns only the diagonal elements.
    """
    return np.diagonal(a),


@Operation.factory
def MatrixDiagPart(a):
    """
    Batched diag op that returns only the diagonal elements.
    """
    r = np.zeros(a.shape[:-2] + (min(a.shape[-2:]),))
    for coord in np.ndindex(a.shape[:-2]):
        pos = coord + (Ellipsis,)
        r[pos] = np.diagonal(a[pos])
    return r,


@Operation.factory(attrs=("transpose_a", "transpose_b"))
def MatMul(a, b, transpose_a, transpose_b):
    """
    Matrix multiplication op.
    """
    return np.dot(a if not transpose_a else np.transpose(a),
                  b if not transpose_b else np.transpose(b)),


@Operation.factory
def MatrixDeterminant(a):
    """
    Matrix det op.
    """
    return np.linalg.det(a),


@Operation.factory(attrs=("adjoint",))
def MatrixInverse(a, adj):
    """
    Matrix inversion op.
    """
    return np.linalg.inv(a if not adj else _adjoint(a)),


@Operation.factory
def Cholesky(a):
    """
    Cholesky decomposition op.
    """
    return np.linalg.cholesky(a),


@Operation.factory(attrs=("adjoint",))
def MatrixSolve(a, rhs, adj):
    """
    Matrix solve op.
    """
    return np.linalg.solve(a if not adj else _adjoint(a), rhs),


@Operation.factory(attrs=("lower", "adjoint"), impl=IMPL_SCIPY)
def MatrixTriangularSolve(a, rhs, lower, adj):
    """
    Matrix triangular solve op.
    """
    trans = 0 if not adj else 2

    r = np.empty(rhs.shape).astype(a.dtype)
    for coord in np.ndindex(a.shape[:-2]):
        pos = coord + (Ellipsis,)
        r[pos] = sp.linalg.solve_triangular(a[pos] if not adj else np.conj(a[pos]), rhs[pos],
                                            trans=trans, lower=lower)

    return r,


@Operation.factory
def MatrixSolveLs(a, rhs, l2_reg):
    """
    Matrix least-squares solve op.
    """
    r = np.empty(rhs.shape).astype(a.dtype)
    for coord in np.ndindex(a.shape[:-2]):
        pos = coord + (Ellipsis,)
        r[pos] = np.linalg.lstsq(a[pos], rhs[pos])[0]

    return r,


@Operation.factory
def SelfAdjointEig(a):
    """
    Eigen decomp op.
    """
    shape = list(a.shape)
    shape[-2] += 1
    return np.append(*np.linalg.eig(a)).reshape(*shape),


@Operation.factory
def SelfAdjointEigV2(a):
    """
    Eigen decomp op.
    """
    return np.linalg.eig(a)


@Operation.factory(attrs=("compute_uv", "full_matrices"))
def Svd(a, uv, full):
    """
    Single value decomp op.
    """
    u, s, v = np.linalg.svd(a, full_matrices=full, compute_uv=uv)
    return s, u, v


#
# complex number ops
#

@Operation.factory
def Complex(a, b):
    """
    Complex number op.
    """
    return np.add(a, np.multiply(b, 1j)),


@Operation.factory
def Conj(a):
    """
    Complex conjugate op.
    """
    return np.conj(a),


@Operation.factory
def Imag(a):
    """
    Complex imag op.
    """
    return np.imag(a),


@Operation.factory
def Real(a):
    """
    Complex real op.
    """
    return np.real(a),


#
# Fourier transform ops
#

@Operation.factory
def FFT2D(a):
    """
    Discrete 2D FT op.
    """
    return np.fft.fft2(a),


@Operation.factory
def IFFT2D(a):
    """
    Discrete inverse 2D FT op.
    """
    return np.fft.ifft2(a),


@Operation.factory
def FFT3D(a):
    """
    Discrete 3D FT op.
    """
    return np.fft.fftn(a),


@Operation.factory
def IFFT3D(a):
    """
    Discrete inverse 3D FT op.
    """
    return np.fft.ifftn(a),


#
# reduction
#

@Operation.factory(attrs=("keep_dims",))
def Sum(a, axis, keep_dims):
    """
    Sum reduction op.
    """
    return np.sum(a, axis=axis if not isinstance(axis, np.ndarray) else tuple(axis),
                  keepdims=keep_dims),


@Operation.factory(attrs=("keep_dims",))
def Prod(a, axis, keep_dims):
    """
    Prod reduction op.
    """
    return np.prod(a, axis=axis if not isinstance(axis, np.ndarray) else tuple(axis),
                   keepdims=keep_dims),


@Operation.factory(attrs=("keep_dims",))
def Min(a, axis, keep_dims):
    """
    Min reduction op.
    """
    return np.amin(a, axis=axis if not isinstance(axis, np.ndarray) else tuple(axis),
                   keepdims=keep_dims),


@Operation.factory(attrs=("keep_dims",))
def Max(a, axis, keep_dims):
    """
    Max reduction op.
    """
    return np.amax(a, axis=axis if not isinstance(axis, np.ndarray) else tuple(axis),
                   keepdims=keep_dims),


@Operation.factory(attrs=("keep_dims",))
def Mean(a, axis, keep_dims):
    """
    Mean reduction op.
    """
    return np.mean(a, axis=axis if not isinstance(axis, np.ndarray) else tuple(axis),
                   keepdims=keep_dims),


@Operation.factory(attrs=("keep_dims",))
def All(a, axis, keep_dims):
    """
    All reduction op.
    """
    return np.all(a, axis=axis if not isinstance(axis, np.ndarray) else tuple(axis),
                  keepdims=keep_dims),


@Operation.factory(attrs=("keep_dims",))
def Any(a, axis, keep_dims):
    """
    Any reduction op.
    """
    return np.any(a, axis=axis if not isinstance(axis, np.ndarray) else tuple(axis),
                  keepdims=keep_dims),


#
# segmentation
#

def seg_map(func, a, ids):
    m = defaultdict(list)
    for i, e in enumerate(ids):
        m[e].append(i)
    r = np.empty((len(m),) + a.shape[1:], dtype=a.dtype)
    for i, idxs in m.items():
        r[i] = func(idxs)
    return r


@Operation.factory(types=("SegmentSum", "UnsortedSegmentSum"))
def SegmentSum(a, ids, *args):
    """
    Segmented sum op.
    """
    func = lambda idxs: reduce(np.add, a[idxs])
    return seg_map(func, a, ids),


@Operation.factory
def SegmentProd(a, ids):
    """
    Segmented prod op.
    """
    func = lambda idxs: reduce(np.multiply, a[idxs])
    return seg_map(func, a, ids),


@Operation.factory
def SegmentMin(a, ids):
    """
    Segmented min op.
    """
    func = lambda idxs: np.amin(a[idxs], axis=0)
    return seg_map(func, a, ids),


@Operation.factory
def SegmentMax(a, ids):
    """
    Segmented max op.
    """
    func = lambda idxs: np.amax(a[idxs], axis=0)
    return seg_map(func, a, ids),


@Operation.factory
def SegmentMean(a, ids):
    """
    Segmented mean op.
    """
    func = lambda idxs: np.mean(a[idxs], axis=0)
    return seg_map(func, a, ids),


@Operation.factory
def SparseSegmentSum(a, idxs, ids):
    """
    Sparse segmented sum op.
    """
    return SegmentSum.func(a[idxs], ids)


@Operation.factory
def SparseSegmentMean(a, idxs, ids):
    """
    Sparse segmented mean op.
    """
    return SegmentMean.func(a[idxs], ids)


@Operation.factory
def SparseSegmentSqrtN(a, idxs, ids):
    """
    Sparse segmented sum / sqrt(n=len(idxs)) op.
    """
    func = lambda _idxs: np.divide(reduce(np.add, a[idxs][_idxs]), np.math.sqrt(len(_idxs)))
    return seg_map(func, a, ids),


#
# sequence comparison and indexing
#

@Operation.factory
def ArgMin(a, dim):
    """
    Argmin op.
    """
    return np.argmin(a, axis=dim),


@Operation.factory
def ArgMax(a, dim):
    """
    Argmax op.
    """
    return np.argmax(a, axis=dim),


@Operation.factory
def ListDiff(a, b):
    """
    List diff op.
    """
    d = np.setdiff1d(a, b)
    return d, np.searchsorted(a, d).astype(np.int32)


@Operation.factory
def Where(a):
    """
    Boolean where op.
    """
    return np.argwhere(a),


@Operation.factory(attrs=("out_idx",))
def Unique(a, t):
    """
    Unique op.
    """
    _, idxs, inv = np.unique(a, return_index=True, return_inverse=True)
    return np.copy(a)[np.sort(idxs)], idxs[inv].astype(dtype_map[t])


@Operation.factory
def InvertPermutation(a):
    """
    Invert perm op.
    """
    return np.argsort(a).astype(np.int32),


#
# control flow ops
#

@Operation.factory
def Identity(a):
    """
    Identity op.
    """
    return np.copy(a),


#
# NN activation ops
#

@Operation.factory
def Relu(a):
    """
    Relu op.
    """
    return np.maximum(a, 0),


@Operation.factory
def Relu6(a):
    """
    Relu6 op.
    """
    return np.clip(a, 0, 6),


@Operation.factory
def Elu(a):
    """
    Elu op.
    """
    return np.where(a < 0, np.subtract(np.exp(a), 1), a),


@Operation.factory
def Softplus(a):
    """
    Softplus op.
    """
    return np.log(np.add(np.exp(a), 1)),


@Operation.factory
def Softsign(a):
    """
    Softsign op.
    """
    return np.divide(a, np.add(np.abs(a), 1)),


@Operation.factory
def Sigmoid(a):
    """
    Sogmoid (logistic) op.
    """
    return np.reciprocal(np.add(1, np.exp(-a))),


@Operation.factory
def Tanh(a):
    """
    Tanh op.
    """
    return np.tanh(a),


@Operation.factory
def Softmax(a):
    """
    Softmax op.
    """
    e = np.exp(a)
    return np.divide(e, np.sum(e, axis=-1, keepdims=True)),


#
# NN convolution ops
#

def _prepare_patches(a, f, strides, padding, padmode):
    v = np.array((0,) + (a.ndim - 2) * (1,) + (0,))
    w = np.array((0,) + f.shape[:-2] + (0,))

    src = a
    if padding == "SAME":
        out_shape = np.ceil(np.array(a.shape).astype(np.float) / strides).astype(np.int)
        pad = ((out_shape - v) * strides + w - a.shape).clip(min=0)
        pad_start = pad // 2
        if np.any(pad):
            src = np.pad(a, list(zip(pad_start, pad - pad_start)), padmode)
    else: # VALID
        out_shape = np.ceil((np.array(a.shape).astype(np.float) - w + v) \
                            / strides).astype(np.int)
        pad = np.zeros(len(a.shape))

    return out_shape, src


def _conv_patches(a, f, strides, padding):
    out_shape, src = _prepare_patches(a, f, strides, padding, "constant")

    patches = np.empty(tuple(out_shape)[:-1] + f.shape).astype(a.dtype)

    s = (slice(None),)
    e = (Ellipsis,)
    en = (Ellipsis, np.newaxis)
    for coord in np.ndindex(*out_shape[1:-1]):
        pos = np.array(strides[1:-1]) * coord
        patches[s + coord + e] = \
            src[s + tuple(slice(*tpl) for tpl in zip(pos, pos + f.shape[:-2]))][en] * f

    return patches


@Operation.factory(attrs=("strides", "padding", "data_format"))
def Conv1D(a, f, strides, padding, data_format):
    """
    1D conv op.
    """
    if data_format.decode("ascii") == "NCHW":
        a = np.rollaxis(a, 1, -1),

    patches = _conv_patches(a, f, 3 * [strides], padding.decode("ascii"))
    conv = np.sum(patches, axis=tuple(range(-f.ndim, -1)))

    if data_format.decode("ascii") == "NCHW":
        conv = np.rollaxis(conv, -1, 1)

    return conv,


@Operation.factory(attrs=("strides", "padding", "data_format"))
def Conv2D(a, f, strides, padding, data_format):
    """
    2D conv op.
    """
    if data_format.decode("ascii") == "NCHW":
        a = np.rollaxis(a, 1, -1),

    patches = _conv_patches(a, f, strides, padding.decode("ascii"))
    conv = np.sum(patches, axis=tuple(range(-f.ndim, -1)))

    if data_format.decode("ascii") == "NCHW":
        conv = np.rollaxis(conv, -1, 1)

    return conv,


@Operation.factory(attrs=("strides", "padding"))
def Conv3D(a, f, strides, padding):
    """
    3D conv op.
    """
    patches = _conv_patches(a, f, strides, padding.decode("ascii"))
    return np.sum(patches, axis=tuple(range(-f.ndim, -1))),


#
# NN pooling ops
#

def _pool_patches(a, k, strides, padding):
    f = np.ones(k[1:] + [a.shape[-1]])

    out_shape, src = _prepare_patches(a, f, strides, padding, "edge")

    patches = np.empty(tuple(out_shape) + f.shape).astype(a.dtype)

    s = (slice(None),)
    e = (Ellipsis,)
    en = (Ellipsis, np.newaxis)
    for coord in np.ndindex(*out_shape[1:]):
        pos = np.array(strides[1:]) * coord
        patches[s + coord + e] = \
            src[s + tuple(slice(*tpl) for tpl in zip(pos, pos + f.shape[:-1]))][en] * f

    return patches


@Operation.factory(attrs=("ksize", "strides", "padding", "data_format"))
def AvgPool(a, k, strides, padding, data_format):
    """
    Average pooling op.
    """
    if data_format.decode("ascii") == "NCHW":
        a = np.rollaxis(a, 1, -1),

    patches = _pool_patches(a, k, strides, padding.decode("ascii"))
    pool = np.average(patches, axis=tuple(range(-len(k), 0)))

    if data_format.decode("ascii") == "NCHW":
        pool = np.rollaxis(pool, -1, 1)

    return pool,


@Operation.factory(attrs=("ksize", "strides", "padding", "data_format"))
def MaxPool(a, k, strides, padding, data_format):
    """
    Maximum pooling op.
    """
    if data_format.decode("ascii") == "NCHW":
        a = np.rollaxis(a, 1, -1),

    patches = _pool_patches(a, k, strides, padding.decode("ascii"))
    pool = np.amax(patches, axis=tuple(range(-len(k), 0)))

    if data_format.decode("ascii") == "NCHW":
        pool = np.rollaxis(pool, -1, 1)

    return pool,


@Operation.factory(attrs=("ksize", "strides", "padding"))
def AvgPool3D(a, k, strides, padding):
    """
    Average 3D pooling op.
    """
    patches = _pool_patches(a, k, strides, padding.decode("ascii"))
    return np.average(patches, axis=tuple(range(-len(k), 0))),


@Operation.factory(attrs=("ksize", "strides", "padding"))
def MaxPool3D(a, k, strides, padding):
    """
    Maximum 3D pooling op.
    """
    patches = _pool_patches(a, k, strides, padding.decode("ascii"))
    return np.amax(patches, axis=tuple(range(-len(k), 0))),