some new features

.venv/lib/python3.12/site-packages/scipy/_lib/_uarray/LICENSE

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+BSD 3-Clause License
+
+Copyright (c) 2018, Quansight-Labs
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+* Redistributions of source code must retain the above copyright notice, this
+  list of conditions and the following disclaimer.
+
+* Redistributions in binary form must reproduce the above copyright notice,
+  this list of conditions and the following disclaimer in the documentation
+  and/or other materials provided with the distribution.
+
+* Neither the name of the copyright holder nor the names of its
+  contributors may be used to endorse or promote products derived from
+  this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

.venv/lib/python3.12/site-packages/scipy/_lib/_uarray/__init__.py

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+"""
+.. note:
+    If you are looking for overrides for NumPy-specific methods, see the
+    documentation for :obj:`unumpy`. This page explains how to write
+    back-ends and multimethods.
+
+``uarray`` is built around a back-end protocol, and overridable multimethods.
+It is necessary to define multimethods for back-ends to be able to override them.
+See the documentation of :obj:`generate_multimethod` on how to write multimethods.
+
+
+
+Let's start with the simplest:
+
+``__ua_domain__`` defines the back-end *domain*. The domain consists of period-
+separated string consisting of the modules you extend plus the submodule. For
+example, if a submodule ``module2.submodule`` extends ``module1``
+(i.e., it exposes dispatchables marked as types available in ``module1``),
+then the domain string should be ``"module1.module2.submodule"``.
+
+
+For the purpose of this demonstration, we'll be creating an object and setting
+its attributes directly. However, note that you can use a module or your own type
+as a backend as well.
+
+>>> class Backend: pass
+>>> be = Backend()
+>>> be.__ua_domain__ = "ua_examples"
+
+It might be useful at this point to sidetrack to the documentation of
+:obj:`generate_multimethod` to find out how to generate a multimethod
+overridable by :obj:`uarray`. Needless to say, writing a backend and
+creating multimethods are mostly orthogonal activities, and knowing
+one doesn't necessarily require knowledge of the other, although it
+is certainly helpful. We expect core API designers/specifiers to write the
+multimethods, and implementors to override them. But, as is often the case,
+similar people write both.
+
+Without further ado, here's an example multimethod:
+
+>>> import uarray as ua
+>>> from uarray import Dispatchable
+>>> def override_me(a, b):
+...   return Dispatchable(a, int),
+>>> def override_replacer(args, kwargs, dispatchables):
+...     return (dispatchables[0], args[1]), {}
+>>> overridden_me = ua.generate_multimethod(
+...     override_me, override_replacer, "ua_examples"
+... )
+
+Next comes the part about overriding the multimethod. This requires
+the ``__ua_function__`` protocol, and the ``__ua_convert__``
+protocol. The ``__ua_function__`` protocol has the signature
+``(method, args, kwargs)`` where ``method`` is the passed
+multimethod, ``args``/``kwargs`` specify the arguments and ``dispatchables``
+is the list of converted dispatchables passed in.
+
+>>> def __ua_function__(method, args, kwargs):
+...     return method.__name__, args, kwargs
+>>> be.__ua_function__ = __ua_function__
+
+The other protocol of interest is the ``__ua_convert__`` protocol. It has the
+signature ``(dispatchables, coerce)``. When ``coerce`` is ``False``, conversion
+between the formats should ideally be an ``O(1)`` operation, but it means that
+no memory copying should be involved, only views of the existing data.
+
+>>> def __ua_convert__(dispatchables, coerce):
+...     for d in dispatchables:
+...         if d.type is int:
+...             if coerce and d.coercible:
+...                 yield str(d.value)
+...             else:
+...                 yield d.value
+>>> be.__ua_convert__ = __ua_convert__
+
+Now that we have defined the backend, the next thing to do is to call the multimethod.
+
+>>> with ua.set_backend(be):
+...      overridden_me(1, "2")
+('override_me', (1, '2'), {})
+
+Note that the marked type has no effect on the actual type of the passed object.
+We can also coerce the type of the input.
+
+>>> with ua.set_backend(be, coerce=True):
+...     overridden_me(1, "2")
+...     overridden_me(1.0, "2")
+('override_me', ('1', '2'), {})
+('override_me', ('1.0', '2'), {})
+
+Another feature is that if you remove ``__ua_convert__``, the arguments are not
+converted at all and it's up to the backend to handle that.
+
+>>> del be.__ua_convert__
+>>> with ua.set_backend(be):
+...     overridden_me(1, "2")
+('override_me', (1, '2'), {})
+
+You also have the option to return ``NotImplemented``, in which case processing moves on
+to the next back-end, which in this case, doesn't exist. The same applies to
+``__ua_convert__``.
+
+>>> be.__ua_function__ = lambda *a, **kw: NotImplemented
+>>> with ua.set_backend(be):
+...     overridden_me(1, "2")
+Traceback (most recent call last):
+    ...
+uarray.BackendNotImplementedError: ...
+
+The last possibility is if we don't have ``__ua_convert__``, in which case the job is
+left up to ``__ua_function__``, but putting things back into arrays after conversion
+will not be possible.
+"""
+
+from ._backend import *
+__version__ = '0.8.8.dev0+aa94c5a4.scipy'

.venv/lib/python3.12/site-packages/scipy/_lib/_uarray/_backend.py

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+import typing
+import types
+import inspect
+import functools
+from . import _uarray
+import copyreg
+import pickle
+import contextlib
+
+from ._uarray import (  # type: ignore
+    BackendNotImplementedError,
+    _Function,
+    _SkipBackendContext,
+    _SetBackendContext,
+    _BackendState,
+)
+
+__all__ = [
+    "set_backend",
+    "set_global_backend",
+    "skip_backend",
+    "register_backend",
+    "determine_backend",
+    "determine_backend_multi",
+    "clear_backends",
+    "create_multimethod",
+    "generate_multimethod",
+    "_Function",
+    "BackendNotImplementedError",
+    "Dispatchable",
+    "wrap_single_convertor",
+    "wrap_single_convertor_instance",
+    "all_of_type",
+    "mark_as",
+    "set_state",
+    "get_state",
+    "reset_state",
+    "_BackendState",
+    "_SkipBackendContext",
+    "_SetBackendContext",
+]
+
+ArgumentExtractorType = typing.Callable[..., tuple["Dispatchable", ...]]
+ArgumentReplacerType = typing.Callable[
+    [tuple, dict, tuple], tuple[tuple, dict]
+]
+
+def unpickle_function(mod_name, qname, self_):
+    import importlib
+
+    try:
+        module = importlib.import_module(mod_name)
+        qname = qname.split(".")
+        func = module
+        for q in qname:
+            func = getattr(func, q)
+
+        if self_ is not None:
+            func = types.MethodType(func, self_)
+
+        return func
+    except (ImportError, AttributeError) as e:
+        from pickle import UnpicklingError
+
+        raise UnpicklingError from e
+
+
+def pickle_function(func):
+    mod_name = getattr(func, "__module__", None)
+    qname = getattr(func, "__qualname__", None)
+    self_ = getattr(func, "__self__", None)
+
+    try:
+        test = unpickle_function(mod_name, qname, self_)
+    except pickle.UnpicklingError:
+        test = None
+
+    if test is not func:
+        raise pickle.PicklingError(
+            f"Can't pickle {func}: it's not the same object as {test}"
+        )
+
+    return unpickle_function, (mod_name, qname, self_)
+
+
+def pickle_state(state):
+    return _uarray._BackendState._unpickle, state._pickle()
+
+
+def pickle_set_backend_context(ctx):
+    return _SetBackendContext, ctx._pickle()
+
+
+def pickle_skip_backend_context(ctx):
+    return _SkipBackendContext, ctx._pickle()
+
+
+copyreg.pickle(_Function, pickle_function)
+copyreg.pickle(_uarray._BackendState, pickle_state)
+copyreg.pickle(_SetBackendContext, pickle_set_backend_context)
+copyreg.pickle(_SkipBackendContext, pickle_skip_backend_context)
+
+
+def get_state():
+    """
+    Returns an opaque object containing the current state of all the backends.
+
+    Can be used for synchronization between threads/processes.
+
+    See Also
+    --------
+    set_state
+        Sets the state returned by this function.
+    """
+    return _uarray.get_state()
+
+
+@contextlib.contextmanager
+def reset_state():
+    """
+    Returns a context manager that resets all state once exited.
+
+    See Also
+    --------
+    set_state
+        Context manager that sets the backend state.
+    get_state
+        Gets a state to be set by this context manager.
+    """
+    with set_state(get_state()):
+        yield
+
+
+@contextlib.contextmanager
+def set_state(state):
+    """
+    A context manager that sets the state of the backends to one returned by :obj:`get_state`.
+
+    See Also
+    --------
+    get_state
+        Gets a state to be set by this context manager.
+    """  # noqa: E501
+    old_state = get_state()
+    _uarray.set_state(state)
+    try:
+        yield
+    finally:
+        _uarray.set_state(old_state, True)
+
+
+def create_multimethod(*args, **kwargs):
+    """
+    Creates a decorator for generating multimethods.
+
+    This function creates a decorator that can be used with an argument
+    extractor in order to generate a multimethod. Other than for the
+    argument extractor, all arguments are passed on to
+    :obj:`generate_multimethod`.
+
+    See Also
+    --------
+    generate_multimethod
+        Generates a multimethod.
+    """
+
+    def wrapper(a):
+        return generate_multimethod(a, *args, **kwargs)
+
+    return wrapper
+
+
+def generate_multimethod(
+    argument_extractor: ArgumentExtractorType,
+    argument_replacer: ArgumentReplacerType,
+    domain: str,
+    default: typing.Optional[typing.Callable] = None,
+):
+    """
+    Generates a multimethod.
+
+    Parameters
+    ----------
+    argument_extractor : ArgumentExtractorType
+        A callable which extracts the dispatchable arguments. Extracted arguments
+        should be marked by the :obj:`Dispatchable` class. It has the same signature
+        as the desired multimethod.
+    argument_replacer : ArgumentReplacerType
+        A callable with the signature (args, kwargs, dispatchables), which should also
+        return an (args, kwargs) pair with the dispatchables replaced inside the
+        args/kwargs.
+    domain : str
+        A string value indicating the domain of this multimethod.
+    default: Optional[Callable], optional
+        The default implementation of this multimethod, where ``None`` (the default)
+        specifies there is no default implementation.
+
+    Examples
+    --------
+    In this example, ``a`` is to be dispatched over, so we return it, while marking it
+    as an ``int``.
+    The trailing comma is needed because the args have to be returned as an iterable.
+
+    >>> def override_me(a, b):
+    ...   return Dispatchable(a, int),
+
+    Next, we define the argument replacer that replaces the dispatchables inside
+    args/kwargs with the supplied ones.
+
+    >>> def override_replacer(args, kwargs, dispatchables):
+    ...     return (dispatchables[0], args[1]), {}
+
+    Next, we define the multimethod.
+
+    >>> overridden_me = generate_multimethod(
+    ...     override_me, override_replacer, "ua_examples"
+    ... )
+
+    Notice that there's no default implementation, unless you supply one.
+
+    >>> overridden_me(1, "a")
+    Traceback (most recent call last):
+        ...
+    uarray.BackendNotImplementedError: ...
+
+    >>> overridden_me2 = generate_multimethod(
+    ...     override_me, override_replacer, "ua_examples", default=lambda x, y: (x, y)
+    ... )
+    >>> overridden_me2(1, "a")
+    (1, 'a')
+
+    See Also
+    --------
+    uarray
+        See the module documentation for how to override the method by creating
+        backends.
+    """
+    kw_defaults, arg_defaults, opts = get_defaults(argument_extractor)
+    ua_func = _Function(
+        argument_extractor,
+        argument_replacer,
+        domain,
+        arg_defaults,
+        kw_defaults,
+        default,
+    )
+
+    return functools.update_wrapper(ua_func, argument_extractor)
+
+
+def set_backend(backend, coerce=False, only=False):
+    """
+    A context manager that sets the preferred backend.
+
+    Parameters
+    ----------
+    backend
+        The backend to set.
+    coerce
+        Whether or not to coerce to a specific backend's types. Implies ``only``.
+    only
+        Whether or not this should be the last backend to try.
+
+    See Also
+    --------
+    skip_backend: A context manager that allows skipping of backends.
+    set_global_backend: Set a single, global backend for a domain.
+    """
+    try:
+        return backend.__ua_cache__["set", coerce, only]
+    except AttributeError:
+        backend.__ua_cache__ = {}
+    except KeyError:
+        pass
+
+    ctx = _SetBackendContext(backend, coerce, only)
+    backend.__ua_cache__["set", coerce, only] = ctx
+    return ctx
+
+
+def skip_backend(backend):
+    """
+    A context manager that allows one to skip a given backend from processing
+    entirely. This allows one to use another backend's code in a library that
+    is also a consumer of the same backend.
+
+    Parameters
+    ----------
+    backend
+        The backend to skip.
+
+    See Also
+    --------
+    set_backend: A context manager that allows setting of backends.
+    set_global_backend: Set a single, global backend for a domain.
+    """
+    try:
+        return backend.__ua_cache__["skip"]
+    except AttributeError:
+        backend.__ua_cache__ = {}
+    except KeyError:
+        pass
+
+    ctx = _SkipBackendContext(backend)
+    backend.__ua_cache__["skip"] = ctx
+    return ctx
+
+
+def get_defaults(f):
+    sig = inspect.signature(f)
+    kw_defaults = {}
+    arg_defaults = []
+    opts = set()
+    for k, v in sig.parameters.items():
+        if v.default is not inspect.Parameter.empty:
+            kw_defaults[k] = v.default
+        if v.kind in (
+            inspect.Parameter.POSITIONAL_ONLY,
+            inspect.Parameter.POSITIONAL_OR_KEYWORD,
+        ):
+            arg_defaults.append(v.default)
+        opts.add(k)
+
+    return kw_defaults, tuple(arg_defaults), opts
+
+
+def set_global_backend(backend, coerce=False, only=False, *, try_last=False):
+    """
+    This utility method replaces the default backend for permanent use. It
+    will be tried in the list of backends automatically, unless the
+    ``only`` flag is set on a backend. This will be the first tried
+    backend outside the :obj:`set_backend` context manager.
+
+    Note that this method is not thread-safe.
+
+    .. warning::
+        We caution library authors against using this function in
+        their code. We do *not* support this use-case. This function
+        is meant to be used only by users themselves, or by a reference
+        implementation, if one exists.
+
+    Parameters
+    ----------
+    backend
+        The backend to register.
+    coerce : bool
+        Whether to coerce input types when trying this backend.
+    only : bool
+        If ``True``, no more backends will be tried if this fails.
+        Implied by ``coerce=True``.
+    try_last : bool
+        If ``True``, the global backend is tried after registered backends.
+
+    See Also
+    --------
+    set_backend: A context manager that allows setting of backends.
+    skip_backend: A context manager that allows skipping of backends.
+    """
+    _uarray.set_global_backend(backend, coerce, only, try_last)
+
+
+def register_backend(backend):
+    """
+    This utility method sets registers backend for permanent use. It
+    will be tried in the list of backends automatically, unless the
+    ``only`` flag is set on a backend.
+
+    Note that this method is not thread-safe.
+
+    Parameters
+    ----------
+    backend
+        The backend to register.
+    """
+    _uarray.register_backend(backend)
+
+
+def clear_backends(domain, registered=True, globals=False):
+    """
+    This utility method clears registered backends.
+
+    .. warning::
+        We caution library authors against using this function in
+        their code. We do *not* support this use-case. This function
+        is meant to be used only by users themselves.
+
+    .. warning::
+        Do NOT use this method inside a multimethod call, or the
+        program is likely to crash.
+
+    Parameters
+    ----------
+    domain : Optional[str]
+        The domain for which to de-register backends. ``None`` means
+        de-register for all domains.
+    registered : bool
+        Whether or not to clear registered backends. See :obj:`register_backend`.
+    globals : bool
+        Whether or not to clear global backends. See :obj:`set_global_backend`.
+
+    See Also
+    --------
+    register_backend : Register a backend globally.
+    set_global_backend : Set a global backend.
+    """
+    _uarray.clear_backends(domain, registered, globals)
+
+
+class Dispatchable:
+    """
+    A utility class which marks an argument with a specific dispatch type.
+
+
+    Attributes
+    ----------
+    value
+        The value of the Dispatchable.
+
+    type
+        The type of the Dispatchable.
+
+    Examples
+    --------
+    >>> x = Dispatchable(1, str)
+    >>> x
+    <Dispatchable: type=<class 'str'>, value=1>
+
+    See Also
+    --------
+    all_of_type
+        Marks all unmarked parameters of a function.
+
+    mark_as
+        Allows one to create a utility function to mark as a given type.
+    """
+
+    def __init__(self, value, dispatch_type, coercible=True):
+        self.value = value
+        self.type = dispatch_type
+        self.coercible = coercible
+
+    def __getitem__(self, index):
+        return (self.type, self.value)[index]
+
+    def __str__(self):
+        return f"<{type(self).__name__}: type={self.type!r}, value={self.value!r}>"
+
+    __repr__ = __str__
+
+
+def mark_as(dispatch_type):
+    """
+    Creates a utility function to mark something as a specific type.
+
+    Examples
+    --------
+    >>> mark_int = mark_as(int)
+    >>> mark_int(1)
+    <Dispatchable: type=<class 'int'>, value=1>
+    """
+    return functools.partial(Dispatchable, dispatch_type=dispatch_type)
+
+
+def all_of_type(arg_type):
+    """
+    Marks all unmarked arguments as a given type.
+
+    Examples
+    --------
+    >>> @all_of_type(str)
+    ... def f(a, b):
+    ...     return a, Dispatchable(b, int)
+    >>> f('a', 1)
+    (<Dispatchable: type=<class 'str'>, value='a'>,
+     <Dispatchable: type=<class 'int'>, value=1>)
+    """
+
+    def outer(func):
+        @functools.wraps(func)
+        def inner(*args, **kwargs):
+            extracted_args = func(*args, **kwargs)
+            return tuple(
+                Dispatchable(arg, arg_type)
+                if not isinstance(arg, Dispatchable)
+                else arg
+                for arg in extracted_args
+            )
+
+        return inner
+
+    return outer
+
+
+def wrap_single_convertor(convert_single):
+    """
+    Wraps a ``__ua_convert__`` defined for a single element to all elements.
+    If any of them return ``NotImplemented``, the operation is assumed to be
+    undefined.
+
+    Accepts a signature of (value, type, coerce).
+    """
+
+    @functools.wraps(convert_single)
+    def __ua_convert__(dispatchables, coerce):
+        converted = []
+        for d in dispatchables:
+            c = convert_single(d.value, d.type, coerce and d.coercible)
+
+            if c is NotImplemented:
+                return NotImplemented
+
+            converted.append(c)
+
+        return converted
+
+    return __ua_convert__
+
+
+def wrap_single_convertor_instance(convert_single):
+    """
+    Wraps a ``__ua_convert__`` defined for a single element to all elements.
+    If any of them return ``NotImplemented``, the operation is assumed to be
+    undefined.
+
+    Accepts a signature of (value, type, coerce).
+    """
+
+    @functools.wraps(convert_single)
+    def __ua_convert__(self, dispatchables, coerce):
+        converted = []
+        for d in dispatchables:
+            c = convert_single(self, d.value, d.type, coerce and d.coercible)
+
+            if c is NotImplemented:
+                return NotImplemented
+
+            converted.append(c)
+
+        return converted
+
+    return __ua_convert__
+
+
+def determine_backend(value, dispatch_type, *, domain, only=True, coerce=False):
+    """Set the backend to the first active backend that supports ``value``
+
+    This is useful for functions that call multimethods without any dispatchable
+    arguments. You can use :func:`determine_backend` to ensure the same backend
+    is used everywhere in a block of multimethod calls.
+
+    Parameters
+    ----------
+    value
+        The value being tested
+    dispatch_type
+        The dispatch type associated with ``value``, aka
+        ":ref:`marking <MarkingGlossary>`".
+    domain: string
+        The domain to query for backends and set.
+    coerce: bool
+        Whether or not to allow coercion to the backend's types. Implies ``only``.
+    only: bool
+        Whether or not this should be the last backend to try.
+
+    See Also
+    --------
+    set_backend: For when you know which backend to set
+
+    Notes
+    -----
+
+    Support is determined by the ``__ua_convert__`` protocol. Backends not
+    supporting the type must return ``NotImplemented`` from their
+    ``__ua_convert__`` if they don't support input of that type.
+
+    Examples
+    --------
+
+    Suppose we have two backends ``BackendA`` and ``BackendB`` each supporting
+    different types, ``TypeA`` and ``TypeB``. Neither supporting the other type:
+
+    >>> with ua.set_backend(ex.BackendA):
+    ...     ex.call_multimethod(ex.TypeB(), ex.TypeB())
+    Traceback (most recent call last):
+        ...
+    uarray.BackendNotImplementedError: ...
+
+    Now consider a multimethod that creates a new object of ``TypeA``, or
+    ``TypeB`` depending on the active backend.
+
+    >>> with ua.set_backend(ex.BackendA), ua.set_backend(ex.BackendB):
+    ...         res = ex.creation_multimethod()
+    ...         ex.call_multimethod(res, ex.TypeA())
+    Traceback (most recent call last):
+        ...
+    uarray.BackendNotImplementedError: ...
+
+    ``res`` is an object of ``TypeB`` because ``BackendB`` is set in the
+    innermost with statement. So, ``call_multimethod`` fails since the types
+    don't match.
+
+    Instead, we need to first find a backend suitable for all of our objects.
+
+    >>> with ua.set_backend(ex.BackendA), ua.set_backend(ex.BackendB):
+    ...     x = ex.TypeA()
+    ...     with ua.determine_backend(x, "mark", domain="ua_examples"):
+    ...         res = ex.creation_multimethod()
+    ...         ex.call_multimethod(res, x)
+    TypeA
+
+    """
+    dispatchables = (Dispatchable(value, dispatch_type, coerce),)
+    backend = _uarray.determine_backend(domain, dispatchables, coerce)
+
+    return set_backend(backend, coerce=coerce, only=only)
+
+
+def determine_backend_multi(
+    dispatchables, *, domain, only=True, coerce=False, **kwargs
+):
+    """Set a backend supporting all ``dispatchables``
+
+    This is useful for functions that call multimethods without any dispatchable
+    arguments. You can use :func:`determine_backend_multi` to ensure the same
+    backend is used everywhere in a block of multimethod calls involving
+    multiple arrays.
+
+    Parameters
+    ----------
+    dispatchables: Sequence[Union[uarray.Dispatchable, Any]]
+        The dispatchables that must be supported
+    domain: string
+        The domain to query for backends and set.
+    coerce: bool
+        Whether or not to allow coercion to the backend's types. Implies ``only``.
+    only: bool
+        Whether or not this should be the last backend to try.
+    dispatch_type: Optional[Any]
+        The default dispatch type associated with ``dispatchables``, aka
+        ":ref:`marking <MarkingGlossary>`".
+
+    See Also
+    --------
+    determine_backend: For a single dispatch value
+    set_backend: For when you know which backend to set
+
+    Notes
+    -----
+
+    Support is determined by the ``__ua_convert__`` protocol. Backends not
+    supporting the type must return ``NotImplemented`` from their
+    ``__ua_convert__`` if they don't support input of that type.
+
+    Examples
+    --------
+
+    :func:`determine_backend` allows the backend to be set from a single
+    object. :func:`determine_backend_multi` allows multiple objects to be
+    checked simultaneously for support in the backend. Suppose we have a
+    ``BackendAB`` which supports ``TypeA`` and ``TypeB`` in the same call,
+    and a ``BackendBC`` that doesn't support ``TypeA``.
+
+    >>> with ua.set_backend(ex.BackendAB), ua.set_backend(ex.BackendBC):
+    ...     a, b = ex.TypeA(), ex.TypeB()
+    ...     with ua.determine_backend_multi(
+    ...         [ua.Dispatchable(a, "mark"), ua.Dispatchable(b, "mark")],
+    ...         domain="ua_examples"
+    ...     ):
+    ...         res = ex.creation_multimethod()
+    ...         ex.call_multimethod(res, a, b)
+    TypeA
+
+    This won't call ``BackendBC`` because it doesn't support ``TypeA``.
+
+    We can also use leave out the ``ua.Dispatchable`` if we specify the
+    default ``dispatch_type`` for the ``dispatchables`` argument.
+
+    >>> with ua.set_backend(ex.BackendAB), ua.set_backend(ex.BackendBC):
+    ...     a, b = ex.TypeA(), ex.TypeB()
+    ...     with ua.determine_backend_multi(
+    ...         [a, b], dispatch_type="mark", domain="ua_examples"
+    ...     ):
+    ...         res = ex.creation_multimethod()
+    ...         ex.call_multimethod(res, a, b)
+    TypeA
+
+    """
+    if "dispatch_type" in kwargs:
+        disp_type = kwargs.pop("dispatch_type")
+        dispatchables = tuple(
+            d if isinstance(d, Dispatchable) else Dispatchable(d, disp_type)
+            for d in dispatchables
+        )
+    else:
+        dispatchables = tuple(dispatchables)
+        if not all(isinstance(d, Dispatchable) for d in dispatchables):
+            raise TypeError("dispatchables must be instances of uarray.Dispatchable")
+
+    if len(kwargs) != 0:
+        raise TypeError(f"Received unexpected keyword arguments: {kwargs}")
+
+    backend = _uarray.determine_backend(domain, dispatchables, coerce)
+
+    return set_backend(backend, coerce=coerce, only=only)