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# Source code for astropy.cosmology.core

    # Licensed under a 3-clause BSD style license - see LICENSE.rst

    from __future__ import annotations

    import abc
    import inspect
    from typing import TYPE_CHECKING, Any, Mapping, TypeVar

    import numpy as np

    from astropy.io.registry import UnifiedReadWriteMethod
    from astropy.utils.decorators import classproperty
    from astropy.utils.metadata import MetaData

    from .connect import (
        CosmologyFromFormat,
        CosmologyRead,
        CosmologyToFormat,
        CosmologyWrite,
    )
    from .parameter import Parameter

    if TYPE_CHECKING:  # pragma: no cover
        from astropy.cosmology.funcs.comparison import _FormatType

    # Originally authored by Andrew Becker (becker@astro.washington.edu),
    # and modified by Neil Crighton (neilcrighton@gmail.com), Roban Kramer
    # (robanhk@gmail.com), and Nathaniel Starkman (n.starkman@mail.utoronto.ca).

    # Many of these adapted from Hogg 1999, astro-ph/9905116
    # and Linder 2003, PRL 90, 91301

    __all__ = ["Cosmology", "CosmologyError", "FlatCosmologyMixin"]

    __doctest_requires__ = {}  # needed until __getattr__ removed

    ##############################################################################
    # Parameters

    # registry of cosmology classes with {key=name : value=class}
    _COSMOLOGY_CLASSES = dict()

    # typing
    _CosmoT = TypeVar("_CosmoT", bound="Cosmology")
    _FlatCosmoT = TypeVar("_FlatCosmoT", bound="FlatCosmologyMixin")

    ##############################################################################

    class CosmologyError(Exception):
        pass

    class Cosmology(metaclass=abc.ABCMeta):
        """Base-class for all Cosmologies.

        Parameters
        ----------
        *args
            Arguments into the cosmology; used by subclasses, not this base class.
        name : str or None (optional, keyword-only)
            The name of the cosmology.
        meta : dict or None (optional, keyword-only)
            Metadata for the cosmology, e.g., a reference.
        **kwargs
            Arguments into the cosmology; used by subclasses, not this base class.

        Notes
        -----
        Class instances are static -- you cannot (and should not) change the values
        of the parameters.  That is, all of the above attributes (except meta) are
        read only.

        For details on how to create performant custom subclasses, see the
        documentation on :ref:`astropy-cosmology-fast-integrals`.
        """

        meta = MetaData()

        # Unified I/O object interchange methods
        from_format = UnifiedReadWriteMethod(CosmologyFromFormat)
        to_format = UnifiedReadWriteMethod(CosmologyToFormat)

        # Unified I/O read and write methods
        read = UnifiedReadWriteMethod(CosmologyRead)
        write = UnifiedReadWriteMethod(CosmologyWrite)

        # Parameters
        __parameters__: tuple[str, ...] = ()
        __all_parameters__: tuple[str, ...] = ()

        # ---------------------------------------------------------------

        def __init_subclass__(cls):
            super().__init_subclass__()

            # -------------------
            # Parameters

            # Get parameters that are still Parameters, either in this class or above.
            parameters = []
            derived_parameters = []
            for n in cls.__parameters__:
                p = getattr(cls, n)
                if isinstance(p, Parameter):
                    derived_parameters.append(n) if p.derived else parameters.append(n)

            # Add new parameter definitions
            for n, v in cls.__dict__.items():
                if n in parameters or n.startswith("_") or not isinstance(v, Parameter):
                    continue
                derived_parameters.append(n) if v.derived else parameters.append(n)

            # reorder to match signature
            ordered = [
                parameters.pop(parameters.index(n))
                for n in cls._init_signature.parameters.keys()
                if n in parameters
            ]
            parameters = ordered + parameters  # place "unordered" at the end
            cls.__parameters__ = tuple(parameters)
            cls.__all_parameters__ = cls.__parameters__ + tuple(derived_parameters)

            # -------------------
            # register as a Cosmology subclass
            _COSMOLOGY_CLASSES[cls.__qualname__] = cls

        @classproperty(lazy=True)
        def _init_signature(cls):
            """Initialization signature (without 'self')."""
            # get signature, dropping "self" by taking arguments [1:]
            sig = inspect.signature(cls.__init__)
            sig = sig.replace(parameters=list(sig.parameters.values())[1:])
            return sig

        # ---------------------------------------------------------------

        def __init__(self, name=None, meta=None):
            self._name = str(name) if name is not None else name
            self.meta.update(meta or {})

        @property
        def name(self):
            """The name of the Cosmology instance."""
            return self._name

        @property
        @abc.abstractmethod
        def is_flat(self):
            """
            Return bool; `True` if the cosmology is flat.
            This is abstract and must be defined in subclasses.
            """
            raise NotImplementedError("is_flat is not implemented")

        def clone(self, *, meta=None, **kwargs):
            """Returns a copy of this object with updated parameters, as specified.

            This cannot be used to change the type of the cosmology, so ``clone()``
            cannot be used to change between flat and non-flat cosmologies.

            Parameters
            ----------
            meta : mapping or None (optional, keyword-only)
                Metadata that will update the current metadata.
            **kwargs
                Cosmology parameter (and name) modifications. If any parameter is
                changed and a new name is not given, the name will be set to "[old
                name] (modified)".

            Returns
            -------
            newcosmo : `~astropy.cosmology.Cosmology` subclass instance
                A new instance of this class with updated parameters as specified.
                If no arguments are given, then a reference to this object is
                returned instead of copy.

            Examples
            --------
            To make a copy of the ``Planck13`` cosmology with a different matter
            density (``Om0``), and a new name:

                >>> from astropy.cosmology import Planck13
                >>> Planck13.clone(name="Modified Planck 2013", Om0=0.35)
                FlatLambdaCDM(name="Modified Planck 2013", H0=67.77 km / (Mpc s),
                              Om0=0.35, ...

            If no name is specified, the new name will note the modification.

                >>> Planck13.clone(Om0=0.35).name
                'Planck13 (modified)'
            """
            # Quick return check, taking advantage of the Cosmology immutability.
            if meta is None and not kwargs:
                return self

            # There are changed parameter or metadata values.
            # The name needs to be changed accordingly, if it wasn't already.
            _modname = self.name + " (modified)"
            kwargs.setdefault("name", (_modname if self.name is not None else None))

            # mix new meta into existing, preferring the former.
            meta = meta if meta is not None else {}
            new_meta = {**self.meta, **meta}
            # Mix kwargs into initial arguments, preferring the former.
            new_init = {**self._init_arguments, "meta": new_meta, **kwargs}
            # Create BoundArgument to handle args versus kwargs.
            # This also handles all errors from mismatched arguments
            ba = self._init_signature.bind_partial(**new_init)
            # Instantiate, respecting args vs kwargs
            cloned = type(self)(*ba.args, **ba.kwargs)

            # Check if nothing has changed.
            # TODO! or should return self?
            if (cloned.name == _modname) and not meta and cloned.is_equivalent(self):
                cloned._name = self.name

            return cloned

        @property
        def _init_arguments(self):
            # parameters
            kw = {n: getattr(self, n) for n in self.__parameters__}

            # other info
            kw["name"] = self.name
            kw["meta"] = self.meta

            return kw

        # ---------------------------------------------------------------
        # comparison methods

        def is_equivalent(self, other: Any, /, *, format: _FormatType = False) -> bool:
            r"""Check equivalence between Cosmologies.

            Two cosmologies may be equivalent even if not the same class.
            For example, an instance of ``LambdaCDM`` might have :math:`\Omega_0=1`
            and :math:`\Omega_k=0` and therefore be flat, like ``FlatLambdaCDM``.

            Parameters
            ----------
            other : `~astropy.cosmology.Cosmology` subclass instance, positional-only
                The object to which to compare.
            format : bool or None or str, optional keyword-only
                Whether to allow, before equivalence is checked, the object to be
                converted to a |Cosmology|. This allows, e.g. a |Table| to be
                equivalent to a Cosmology.
                `False` (default) will not allow conversion. `True` or `None` will,
                and will use the auto-identification to try to infer the correct
                format. A `str` is assumed to be the correct format to use when
                converting.
                ``format`` is broadcast to match the shape of ``other``.
                Note that the cosmology arguments are not broadcast against
                ``format``, so it cannot determine the output shape.

            Returns
            -------
            bool
                True if cosmologies are equivalent, False otherwise.

            Examples
            --------
            Two cosmologies may be equivalent even if not of the same class.
            In this examples the ``LambdaCDM`` has ``Ode0`` set to the same value
            calculated in ``FlatLambdaCDM``.

                >>> import astropy.units as u
                >>> from astropy.cosmology import LambdaCDM, FlatLambdaCDM
                >>> cosmo1 = LambdaCDM(70 * (u.km/u.s/u.Mpc), 0.3, 0.7)
                >>> cosmo2 = FlatLambdaCDM(70 * (u.km/u.s/u.Mpc), 0.3)
                >>> cosmo1.is_equivalent(cosmo2)
                True

            While in this example, the cosmologies are not equivalent.

                >>> cosmo3 = FlatLambdaCDM(70 * (u.km/u.s/u.Mpc), 0.3, Tcmb0=3 * u.K)
                >>> cosmo3.is_equivalent(cosmo2)
                False

            Also, using the keyword argument, the notion of equivalence is extended
            to any Python object that can be converted to a |Cosmology|.

                >>> from astropy.cosmology import Planck18
                >>> tbl = Planck18.to_format("astropy.table")
                >>> Planck18.is_equivalent(tbl, format=True)
                True

            The list of valid formats, e.g. the |Table| in this example, may be
            checked with ``Cosmology.from_format.list_formats()``.

            As can be seen in the list of formats, not all formats can be
            auto-identified by ``Cosmology.from_format.registry``. Objects of
            these kinds can still be checked for equivalence, but the correct
            format string must be used.

                >>> tbl = Planck18.to_format("yaml")
                >>> Planck18.is_equivalent(tbl, format="yaml")
                True
            """
            from .funcs import cosmology_equal

            try:
                return cosmology_equal(
                    self, other, format=(None, format), allow_equivalent=True
                )
            except Exception:
                # `is_equivalent` allows `other` to be any object and returns False
                # if `other` cannot be converted to a Cosmology, rather than
                # raising an Exception.
                return False

        def __equiv__(self, other: Any, /) -> bool:
            """Cosmology equivalence. Use ``.is_equivalent()`` for actual check!

            Parameters
            ----------
            other : `~astropy.cosmology.Cosmology` subclass instance, positional-only
                The object in which to compare.

            Returns
            -------
            bool or `NotImplemented`
                `NotImplemented` if ``other`` is from a different class.
                `True` if ``other`` is of the same class and has matching parameters
                and parameter values.
                `False` otherwise.
            """
            if other.__class__ is not self.__class__:
                return NotImplemented  # allows other.__equiv__

            # Check all parameters in 'other' match those in 'self' and 'other' has
            # no extra parameters (latter part should never happen b/c same class)
            return set(self.__all_parameters__) == set(other.__all_parameters__) and all(
                np.all(getattr(self, k) == getattr(other, k))
                for k in self.__all_parameters__
            )

        def __eq__(self, other: Any, /) -> bool:
            """Check equality between Cosmologies.

            Checks the Parameters and immutable fields (i.e. not "meta").

            Parameters
            ----------
            other : `~astropy.cosmology.Cosmology` subclass instance, positional-only
                The object in which to compare.

            Returns
            -------
            bool
                `True` if Parameters and names are the same, `False` otherwise.
            """
            if other.__class__ is not self.__class__:
                return NotImplemented  # allows other.__eq__

            eq = (
                # non-Parameter checks: name
                self.name == other.name
                # check all parameters in 'other' match those in 'self' and 'other'
                # has no extra parameters (latter part should never happen b/c same
                # class) TODO! element-wise when there are array cosmologies
                and set(self.__all_parameters__) == set(other.__all_parameters__)
                and all(
                    np.all(getattr(self, k) == getattr(other, k))
                    for k in self.__all_parameters__
                )
            )

            return eq

        # ---------------------------------------------------------------

        def __repr__(self):
            namelead = f"{self.__class__.__qualname__}("
            if self.name is not None:
                namelead += f'name="{self.name}", '
            # nicely formatted parameters
            fmtps = (f"{k}={getattr(self, k)}" for k in self.__parameters__)

            return namelead + ", ".join(fmtps) + ")"

        def __astropy_table__(self, cls, copy, **kwargs):
            """Return a `~astropy.table.Table` of type ``cls``.

            Parameters
            ----------
            cls : type
                Astropy ``Table`` class or subclass.
            copy : bool
                Ignored.
            **kwargs : dict, optional
                Additional keyword arguments. Passed to ``self.to_format()``.
                See ``Cosmology.to_format.help("astropy.table")`` for allowed kwargs.

            Returns
            -------
            `astropy.table.Table` or subclass instance
                Instance of type ``cls``.
            """
            return self.to_format("astropy.table", cls=cls, **kwargs)

    class FlatCosmologyMixin(metaclass=abc.ABCMeta):
        """
        Mixin class for flat cosmologies. Do NOT instantiate directly.
        Note that all instances of ``FlatCosmologyMixin`` are flat, but not all
        flat cosmologies are instances of ``FlatCosmologyMixin``. As example,
        ``LambdaCDM`` **may** be flat (for the a specific set of parameter values),
        but ``FlatLambdaCDM`` **will** be flat.
        """

        __all_parameters__: tuple[str, ...]
        __parameters__: tuple[str, ...]

        def __init_subclass__(cls: type[_FlatCosmoT]) -> None:
            super().__init_subclass__()

            # Determine the non-flat class.
            # This will raise a TypeError if the MRO is inconsistent.
            cls.__nonflatclass__

        # ===============================================================

        @classmethod  # TODO! make metaclass-method
        def _get_nonflat_cls(
            cls, kls: type[_CosmoT] | None = None
        ) -> type[Cosmology] | None:
            """Find the corresponding non-flat class.

            The class' bases are searched recursively.

            Parameters
            ----------
            kls : :class:`astropy.cosmology.Cosmology` class or None, optional
                If `None` (default) this class is searched instead of `kls`.

            Raises
            ------
            TypeError
                If more than one non-flat class is found at the same level of the
                inheritance. This is similar to the error normally raised by Python
                for an inconsistent method resolution order.

            Returns
            -------
            type
                A :class:`Cosmology` subclass this class inherits from that is not a
                :class:`FlatCosmologyMixin` subclass.
            """
            _kls = cls if kls is None else kls

            # Find non-flat classes
            nonflat: set[type[Cosmology]]
            nonflat = {
                b
                for b in _kls.__bases__
                if issubclass(b, Cosmology) and not issubclass(b, FlatCosmologyMixin)
            }

            if not nonflat:  # e.g. subclassing FlatLambdaCDM
                nonflat = {
                    k for b in _kls.__bases__ if (k := cls._get_nonflat_cls(b)) is not None
                }

            if len(nonflat) > 1:
                raise TypeError(
                    "cannot create a consistent non-flat class resolution order "
                    f"for {_kls} with bases {nonflat} at the same inheritance level."
                )
            if not nonflat:  # e.g. FlatFLRWMixin(FlatCosmologyMixin)
                return None

            return nonflat.pop()

        __nonflatclass__ = classproperty(
            _get_nonflat_cls, lazy=True, doc="Return the corresponding non-flat class."
        )

        # ===============================================================

        @property
        def is_flat(self):
            """Return `True`, the cosmology is flat."""
            return True

        @abc.abstractmethod
        def nonflat(self: _FlatCosmoT) -> _CosmoT:
            """Return the equivalent non-flat-class instance of this cosmology."""

        def clone(self, *, meta: Mapping | None = None, to_nonflat: bool = False, **kwargs):
            """Returns a copy of this object with updated parameters, as specified.

            This cannot be used to change the type of the cosmology, except for
            changing to the non-flat version of this cosmology.

            Parameters
            ----------
            meta : mapping or None (optional, keyword-only)
                Metadata that will update the current metadata.
            to_nonflat : bool, optional keyword-only
                Whether to change to the non-flat version of this cosmology.
            **kwargs
                Cosmology parameter (and name) modifications. If any parameter is
                changed and a new name is not given, the name will be set to "[old
                name] (modified)".

            Returns
            -------
            newcosmo : `~astropy.cosmology.Cosmology` subclass instance
                A new instance of this class with updated parameters as specified.
                If no arguments are given, then a reference to this object is
                returned instead of copy.

            Examples
            --------
            To make a copy of the ``Planck13`` cosmology with a different matter
            density (``Om0``), and a new name:

                >>> from astropy.cosmology import Planck13
                >>> Planck13.clone(name="Modified Planck 2013", Om0=0.35)
                FlatLambdaCDM(name="Modified Planck 2013", H0=67.77 km / (Mpc s),
                              Om0=0.35, ...

            If no name is specified, the new name will note the modification.

                >>> Planck13.clone(Om0=0.35).name
                'Planck13 (modified)'

            The keyword 'to_nonflat' can be used to clone on the non-flat equivalent
            cosmology.

                >>> Planck13.clone(to_nonflat=True)
                LambdaCDM(name="Planck13", ...

                >>> Planck13.clone(H0=70, to_nonflat=True)
                LambdaCDM(name="Planck13 (modified)", H0=70.0 km / (Mpc s), ...
            """
            if to_nonflat:
                return self.nonflat.clone(meta=meta, **kwargs)
            return super().clone(meta=meta, **kwargs)

        # ===============================================================

        def __equiv__(self, other):
            """flat-|Cosmology| equivalence.

            Use `astropy.cosmology.funcs.cosmology_equal` with
            ``allow_equivalent=True`` for actual checks!

            Parameters
            ----------
            other : `~astropy.cosmology.Cosmology` subclass instance
                The object to which to compare for equivalence.

            Returns
            -------
            bool or `NotImplemented`
                `True` if ``other`` is of the same class / non-flat class (e.g.
                |FlatLambdaCDM| and |LambdaCDM|) has matching parameters and
                parameter values.
                `False` if ``other`` is of the same class but has different
                parameters.
                `NotImplemented` otherwise.
            """
            if isinstance(other, FlatCosmologyMixin):
                return super().__equiv__(other)  # super gets from Cosmology

            # check if `other` is the non-flat version of this class this makes the
            # assumption that any further subclass of a flat cosmo keeps the same
            # physics.
            if not issubclass(other.__class__, self.__nonflatclass__):
                return NotImplemented

            # Check if have equivalent parameters and all parameters in `other`
            # match those in `self`` and `other`` has no extra parameters.
            params_eq = (
                set(self.__all_parameters__) == set(other.__all_parameters__)  # no extra
                # equal
                and all(
                    np.all(getattr(self, k) == getattr(other, k))
                    for k in self.__parameters__
                )
                # flatness check
                and other.is_flat
            )

            return params_eq

    # -----------------------------------------------------------------------------

    def __getattr__(attr):
        from . import flrw

        if hasattr(flrw, attr) and attr not in ("__path__",):
            import warnings

            from astropy.utils.exceptions import AstropyDeprecationWarning

            warnings.warn(
                f"`astropy.cosmology.core.{attr}` has been moved (since v5.0) and "
                f"should be imported as ``from astropy.cosmology import {attr}``."
                " In future this will raise an exception.",
                AstropyDeprecationWarning,
            )

            return getattr(flrw, attr)

        raise AttributeError(f"module {__name__!r} has no attribute {attr!r}.")