21489819490

Committed 29 Jan 2026 06:21PM UTC coverage: 80.077% (-1.9%) from 81.953%

Build # 21489819490

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Pull #3757

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Merge d08626053 into f7a734189

Pull Request Pull Request #3757: Testing point detectors

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90.63

/openmc/surface.py

from __future__ import annotations
from abc import ABC, abstractmethod
from collections.abc import Iterable
from copy import deepcopy
import math
from numbers import Real
from warnings import warn, catch_warnings, simplefilter

import lxml.etree as ET
import numpy as np

from .checkvalue import check_type, check_value, check_length, check_greater_than
from .mixin import IDManagerMixin, IDWarning
from .region import Region, Intersection, Union
from .bounding_box import BoundingBox
from ._xml import get_elem_list, get_text


_BOUNDARY_TYPES = {'transmission', 'vacuum', 'reflective', 'periodic', 'white'}
_ALBEDO_BOUNDARIES = {'reflective', 'periodic', 'white'}

_WARNING_UPPER = """\
"{}(...) accepts an argument named '{}', not '{}'. Future versions of OpenMC \
will not accept the capitalized version.\
"""

_WARNING_KWARGS = """\
"{}(...) accepts keyword arguments only for '{}'. Future versions of OpenMC \
will not accept positional parameters for superclass arguments.\
"""


class SurfaceCoefficient:
    """Descriptor class for surface coefficients.

    Parameters
    -----------
    value : float or str
        Value of the coefficient (float) or the name of the coefficient that
        it is equivalent to (str).

    """
    def __init__(self, value):
        self.value = value

    def __get__(self, instance, owner=None):
        if instance is None:
            return self
        else:
            if isinstance(self.value, str):
                return instance._coefficients[self.value]
            else:
                return self.value

    def __set__(self, instance, value):
        if isinstance(self.value, Real):
            raise AttributeError('This coefficient is read-only')
        check_type(f'{self.value} coefficient', value, Real)
        instance._coefficients[self.value] = value


def _future_kwargs_warning_helper(cls, *args, **kwargs):
    # Warn if Surface parameters are passed by position, not by keyword
    argsdict = dict(zip(('boundary_type', 'name', 'surface_id'), args))
    for k in argsdict:
        warn(_WARNING_KWARGS.format(cls.__name__, k), FutureWarning)
    kwargs.update(argsdict)
    return kwargs


def get_rotation_matrix(rotation, order='xyz'):
    r"""Generate a 3x3 rotation matrix from input angles

    .. versionadded:: 0.12

    Parameters
    ----------
    rotation : 3-tuple of float
        A 3-tuple of angles :math:`(\phi, \theta, \psi)` in degrees where the
        first element is the rotation about the x-axis in the fixed laboratory
        frame, the second element is the rotation about the y-axis in the fixed
        laboratory frame, and the third element is the rotation about the
        z-axis in the fixed laboratory frame. The rotations are active
        rotations.
    order : str, optional
        A string of 'x', 'y', and 'z' in some order specifying which rotation
        to perform first, second, and third. Defaults to 'xyz' which means, the
        rotation by angle :math:`\phi` about x will be applied first, followed
        by :math:`\theta` about y and then :math:`\psi` about z. This
        corresponds to an x-y-z extrinsic rotation as well as a z-y'-x''
        intrinsic rotation using Tait-Bryan angles :math:`(\phi, \theta, \psi)`.

    """
    check_type('surface rotation', rotation, Iterable, Real)
    check_length('surface rotation', rotation, 3)

    phi, theta, psi = np.array(rotation)*(math.pi/180.)
    cx, sx = math.cos(phi), math.sin(phi)
    cy, sy = math.cos(theta), math.sin(theta)
    cz, sz = math.cos(psi), math.sin(psi)
    R = {
        'x': np.array([[1., 0., 0.], [0., cx, -sx], [0., sx, cx]]),
        'y': np.array([[cy, 0., sy], [0., 1., 0.], [-sy, 0., cy]]),
        'z': np.array([[cz, -sz, 0.], [sz, cz, 0.], [0., 0., 1.]]),
    }

    R1, R2, R3 = (R[xi] for xi in order)
    return R3 @ R2 @ R1


class Surface(IDManagerMixin, ABC):
    """An implicit surface with an associated boundary condition.

    An implicit surface is defined as the set of zeros of a function of the
    three Cartesian coordinates. Surfaces in OpenMC are limited to a set of
    algebraic surfaces, i.e., surfaces that are polynomial in x, y, and z.

    Parameters
    ----------
    surface_id : int, optional
        Unique identifier for the surface. If not specified, an identifier will
        automatically be assigned.
    boundary_type : {'transmission', 'vacuum', 'reflective', 'periodic', 'white'}, optional
        Boundary condition that defines the behavior for particles hitting the
        surface. Defaults to transmissive boundary condition where particles
        freely pass through the surface. Note that only axis-aligned
        periodicity is supported around the x-, y-, and z-axes.
    albedo : float, optional
        Albedo of the surfaces as a ratio of particle weight after interaction
        with the surface to the initial weight. Values must be positive. Only
        applicable if the boundary type is 'reflective', 'periodic', or 'white'.
    name : str, optional
        Name of the surface. If not specified, the name will be the empty
        string.

    Attributes
    ----------
    boundary_type : {'transmission', 'vacuum', 'reflective', 'periodic', 'white'}
        Boundary condition that defines the behavior for particles hitting the
        surface.
    albedo : float
        Boundary albedo as a positive multiplier of particle weight
    coefficients : dict
        Dictionary of surface coefficients
    id : int
        Unique identifier for the surface
    name : str
        Name of the surface
    type : str
        Type of the surface

    """

    next_id = 1
    used_ids = set()
    _atol = 1.e-12

    def __init__(self, surface_id=None, boundary_type='transmission',
                 albedo=1., name=''):
        self.id = surface_id
        self.name = name
        self.boundary_type = boundary_type
        self.albedo = albedo

        # A dictionary of the quadratic surface coefficients
        # Key      - coefficient name
        # Value    - coefficient value
        self._coefficients = {}

    def __neg__(self):
        return Halfspace(self, '-')

    def __pos__(self):
        return Halfspace(self, '+')

    def __repr__(self):
        string = 'Surface\n'
        string += '{0: <20}{1}{2}\n'.format('\tID', '=\t', self._id)
        string += '{0: <20}{1}{2}\n'.format('\tName', '=\t', self._name)
        string += '{0: <20}{1}{2}\n'.format('\tType', '=\t', self._type)
        string += '{0: <20}{1}{2}\n'.format('\tBoundary', '=\t',
                                            self._boundary_type)
        if (self._boundary_type in _ALBEDO_BOUNDARIES and
            not math.isclose(self._albedo, 1.0)):
            string += '{0: <20}{1}{2}\n'.format('\tBoundary Albedo', '=\t',
                                                self._albedo)

        coefficients = '{0: <20}'.format('\tCoefficients') + '\n'

        for coeff in self._coefficients:
            coefficients += f'{coeff: <20}=\t{self._coefficients[coeff]}\n'

        string += coefficients

        return string

    @property
    def name(self):
        return self._name

    @name.setter
    def name(self, name):
        if name is not None:
            check_type('surface name', name, str)
            self._name = name
        else:
            self._name = ''

    @property
    def type(self):
        return self._type

    @property
    def boundary_type(self):
        return self._boundary_type

    @boundary_type.setter
    def boundary_type(self, boundary_type):
        check_type('boundary type', boundary_type, str)
        check_value('boundary type', boundary_type, _BOUNDARY_TYPES)
        self._boundary_type = boundary_type

    @property
    def albedo(self):
        return self._albedo

    @albedo.setter
    def albedo(self, albedo):
        check_type('albedo', albedo, Real)
        check_greater_than('albedo', albedo, 0.0)
        self._albedo = float(albedo)

    @property
    def coefficients(self):
        return self._coefficients

    def bounding_box(self, side):
        """Determine an axis-aligned bounding box.

        An axis-aligned bounding box for surface half-spaces is represented by
        its lower-left and upper-right coordinates. If the half-space is
        unbounded in a particular direction, numpy.inf is used to represent
        infinity.

        Parameters
        ----------
        side : {'+', '-'}
            Indicates the negative or positive half-space

        Returns
        -------
        numpy.ndarray
            Lower-left coordinates of the axis-aligned bounding box for the
            desired half-space
        numpy.ndarray
            Upper-right coordinates of the axis-aligned bounding box for the
            desired half-space

        """
        return BoundingBox.infinite()

    def clone(self, memo=None):
        """Create a copy of this surface with a new unique ID.

        Parameters
        ----------
        memo : dict or None
            A nested dictionary of previously cloned objects. This parameter
            is used internally and should not be specified by the user.

        Returns
        -------
        clone : openmc.Surface
            The clone of this surface

        """

        if memo is None:
            memo = {}

        # If no memoize'd clone exists, instantiate one
        if self not in memo:
            clone = deepcopy(self)
            clone.id = None

            # Memoize the clone
            memo[self] = clone

        return memo[self]

    def normalize(self, coeffs=None):
        """Normalize coefficients by first nonzero value

        .. versionadded:: 0.12

        Parameters
        ----------
        coeffs : tuple, optional
            Tuple of surface coefficients to normalize. Defaults to None. If no
            coefficients are supplied then the coefficients will be taken from
            the current Surface.

        Returns
        -------
        tuple of normalized coefficients

        """
        if coeffs is None:
            coeffs = self._get_base_coeffs()
        coeffs = np.asarray(coeffs)
        nonzeros = ~np.isclose(coeffs, 0., rtol=0., atol=self._atol)
        norm_factor = coeffs[nonzeros][0]
        return tuple([c/norm_factor for c in coeffs])

    def is_equal(self, other):
        """Determine if this Surface is equivalent to another

        Parameters
        ----------
        other : instance of openmc.Surface
            Instance of openmc.Surface that should be compared to the current
            surface

        """
        coeffs1 = self.normalize(self._get_base_coeffs())
        coeffs2 = self.normalize(other._get_base_coeffs())

        return np.allclose(coeffs1, coeffs2, rtol=0., atol=self._atol)

    @abstractmethod
    def _get_base_coeffs(self):
        """Return polynomial coefficients representing the implicit surface
        equation.

        """

    @abstractmethod
    def evaluate(self, point):
        """Evaluate the surface equation at a given point.

        Parameters
        ----------
        point : 3-tuple of float
            The Cartesian coordinates, :math:`(x',y',z')`, at which the surface
            equation should be evaluated.

        Returns
        -------
        float
            Evaluation of the surface polynomial at point :math:`(x',y',z')`

        """

    @abstractmethod
    def translate(self, vector, inplace=False):
        """Translate surface in given direction

        Parameters
        ----------
        vector : iterable of float
            Direction in which surface should be translated
        inplace : bool
            Whether or not to return a new instance of this Surface or to
            modify the coefficients of this Surface.

        Returns
        -------
        instance of openmc.Surface
            Translated surface

        """

    @abstractmethod
    def rotate(self, rotation, pivot=(0., 0., 0.), order='xyz', inplace=False):
        r"""Rotate surface by angles provided or by applying matrix directly.

        .. versionadded:: 0.12

        Parameters
        ----------
        rotation : 3-tuple of float, or 3x3 iterable
            A 3-tuple of angles :math:`(\phi, \theta, \psi)` in degrees where
            the first element is the rotation about the x-axis in the fixed
            laboratory frame, the second element is the rotation about the
            y-axis in the fixed laboratory frame, and the third element is the
            rotation about the z-axis in the fixed laboratory frame. The
            rotations are active rotations. Additionally a 3x3 rotation matrix
            can be specified directly either as a nested iterable or array.
        pivot : iterable of float, optional
            (x, y, z) coordinates for the point to rotate about. Defaults to
            (0., 0., 0.)
        order : str, optional
            A string of 'x', 'y', and 'z' in some order specifying which
            rotation to perform first, second, and third. Defaults to 'xyz'
            which means, the rotation by angle :math:`\phi` about x will be
            applied first, followed by :math:`\theta` about y and then
            :math:`\psi` about z. This corresponds to an x-y-z extrinsic
            rotation as well as a z-y'-x'' intrinsic rotation using Tait-Bryan
            angles :math:`(\phi, \theta, \psi)`.
        inplace : bool
            Whether or not to return a new instance of Surface or to modify the
            coefficients of this Surface in place. Defaults to False.

        Returns
        -------
        openmc.Surface
            Rotated surface

        """

    def to_xml_element(self):
        """Return XML representation of the surface

        Returns
        -------
        element : lxml.etree._Element
            XML element containing source data

        """
        element = ET.Element("surface")
        element.set("id", str(self._id))

        if len(self._name) > 0:
            element.set("name", str(self._name))

        element.set("type", self._type)
        if self.boundary_type != 'transmission':
            element.set("boundary", self.boundary_type)
            if (self.boundary_type in _ALBEDO_BOUNDARIES and
                not math.isclose(self.albedo, 1.0)):
                element.set("albedo", str(self.albedo))
        element.set("coeffs", ' '.join([str(self._coefficients.setdefault(key, 0.0))
                                        for key in self._coeff_keys]))

        return element

    @staticmethod
    def from_xml_element(elem):
        """Generate surface from an XML element

        Parameters
        ----------
        elem : lxml.etree._Element
            XML element

        Returns
        -------
        openmc.Surface
            Instance of a surface subclass

        """

        # Determine appropriate class
        surf_type = get_text(elem, "type")
        cls = _SURFACE_CLASSES[surf_type]

        # Determine ID, boundary type, boundary albedo, coefficients
        kwargs = {}
        kwargs['surface_id'] = int(get_text(elem, "id"))
        kwargs['boundary_type'] = get_text(elem, "boundary", "transmission")
        if kwargs['boundary_type'] in _ALBEDO_BOUNDARIES:
            kwargs['albedo'] = float(get_text(elem, "albedo", 1.0))
        kwargs['name'] = get_text(elem, "name")
        coeffs = get_elem_list(elem, "coeffs", float)
        kwargs.update(dict(zip(cls._coeff_keys, coeffs)))

        return cls(**kwargs)

    @staticmethod
    def from_hdf5(group):
        """Create surface from HDF5 group

        Parameters
        ----------
        group : h5py.Group
            Group in HDF5 file

        Returns
        -------
        openmc.Surface
            Instance of surface subclass

        """

        # If this is a DAGMC surface, do nothing for now
        geom_type = group.get('geom_type')
        if geom_type and geom_type[()].decode() == 'dagmc':
            return

        surface_id = int(group.name.split('/')[-1].lstrip('surface '))
        name = group['name'][()].decode() if 'name' in group else ''

        bc = group['boundary_type'][()].decode()
        if 'albedo' in group:
            bc_alb = float(group['albedo'][()].decode())
        else:
            bc_alb = 1.0
        coeffs = group['coefficients'][...]
        kwargs = {'boundary_type': bc, 'albedo': bc_alb, 'name': name,
                  'surface_id': surface_id}

        surf_type = group['type'][()].decode()
        cls = _SURFACE_CLASSES[surf_type]

        return cls(*coeffs, **kwargs)


class PlaneMixin:
    """A Plane mixin class for all operations on order 1 surfaces"""
    def __init__(self, **kwargs):
        super().__init__(**kwargs)
        self._periodic_surface = None

    @property
    def periodic_surface(self):
        return self._periodic_surface

    @periodic_surface.setter
    def periodic_surface(self, periodic_surface):
        check_type('periodic surface', periodic_surface, Plane)
        self._periodic_surface = periodic_surface
        periodic_surface._periodic_surface = self

    def _get_base_coeffs(self):
        return (self.a, self.b, self.c, self.d)

    def _get_normal(self):
        a, b, c = self._get_base_coeffs()[:3]
        return np.array((a, b, c)) / math.sqrt(a*a + b*b + c*c)

    def bounding_box(self, side):
        """Determine an axis-aligned bounding box.

        An axis-aligned bounding box for Plane half-spaces is represented by
        its lower-left and upper-right coordinates. If the half-space is
        unbounded in a particular direction, numpy.inf is used to represent
        infinity.

        Parameters
        ----------
        side : {'+', '-'}
            Indicates the negative or positive half-space

        Returns
        -------
        numpy.ndarray
            Lower-left coordinates of the axis-aligned bounding box for the
            desired half-space
        numpy.ndarray
            Upper-right coordinates of the axis-aligned bounding box for the
            desired half-space

        """
        # Compute the bounding box based on the normal vector to the plane
        nhat = self._get_normal()
        ll = np.array([-np.inf, -np.inf, -np.inf])
        ur = np.array([np.inf, np.inf, np.inf])
        # If the plane is axis aligned, find the proper bounding box
        if np.any(np.isclose(np.abs(nhat), 1., rtol=0., atol=self._atol)):
            sign = nhat.sum()
            a, b, c, d = self._get_base_coeffs()
            vals = [d/val if not np.isclose(val, 0., rtol=0., atol=self._atol)
                    else np.nan for val in (a, b, c)]
            if side == '-':
                if sign > 0:
                    ur = np.array([v if not np.isnan(v) else np.inf for v in vals])
                else:
                    ll = np.array([v if not np.isnan(v) else -np.inf for v in vals])
            elif side == '+':
                if sign > 0:
                    ll = np.array([v if not np.isnan(v) else -np.inf for v in vals])
                else:
                    ur = np.array([v if not np.isnan(v) else np.inf for v in vals])

        return BoundingBox(ll, ur)

    def evaluate(self, point):
        """Evaluate the surface equation at a given point.

        Parameters
        ----------
        point : 3-tuple of float
            The Cartesian coordinates, :math:`(x',y',z')`, at which the surface
            equation should be evaluated.

        Returns
        -------
        float
            :math:`Ax' + By' + Cz' - D`

        """

        x, y, z = point
        a, b, c, d = self._get_base_coeffs()
        return a*x + b*y + c*z - d

    def translate(self, vector, inplace=False):
        """Translate surface in given direction

        Parameters
        ----------
        vector : iterable of float
            Direction in which surface should be translated
        inplace : bool
            Whether or not to return a new instance of a Plane or to modify the
            coefficients of this plane.

        Returns
        -------
        openmc.Plane
            Translated surface

        """
        if np.allclose(vector, 0., rtol=0., atol=self._atol):
            return self

        a, b, c, d = self._get_base_coeffs()
        d = d + np.dot([a, b, c], vector)

        surf = self if inplace else self.clone()

        setattr(surf, surf._coeff_keys[-1], d)

        return surf

    def rotate(self, rotation, pivot=(0., 0., 0.), order='xyz', inplace=False):
        pivot = np.asarray(pivot)
        rotation = np.asarray(rotation, dtype=float)

        # Allow rotation matrix to be passed in directly, otherwise build it
        if rotation.ndim == 2:
            check_length('surface rotation', rotation.ravel(), 9)
            Rmat = rotation
        else:
            Rmat = get_rotation_matrix(rotation, order=order)

        # Translate surface to pivot
        surf = self.translate(-pivot, inplace=inplace)

        a, b, c, d = surf._get_base_coeffs()
        # Compute new rotated coefficients a, b, c
        a, b, c = Rmat @ [a, b, c]

        kwargs = {'boundary_type': surf.boundary_type,
                  'albedo': surf.albedo,
                  'name': surf.name}
        if inplace:
            kwargs['surface_id'] = surf.id

        surf = Plane(a=a, b=b, c=c, d=d, **kwargs)

        return surf.translate(pivot, inplace=inplace)

    def to_xml_element(self):
        """Return XML representation of the surface

        Returns
        -------
        element : lxml.etree._Element
            XML element containing source data

        """
        element = super().to_xml_element()

        # Add periodic surface pair information
        if self.boundary_type == 'periodic':
            if self.periodic_surface is not None:
                element.set("periodic_surface_id",
                            str(self.periodic_surface.id))
        return element


class Plane(PlaneMixin, Surface):
    """An arbitrary plane of the form :math:`Ax + By + Cz = D`.

    Parameters
    ----------
    a : float, optional
        The 'A' parameter for the plane. Defaults to 1.
    b : float, optional
        The 'B' parameter for the plane. Defaults to 0.
    c : float, optional
        The 'C' parameter for the plane. Defaults to 0.
    d : float, optional
        The 'D' parameter for the plane. Defaults to 0.
    boundary_type : {'transmission', 'vacuum', 'reflective', 'periodic', 'white'}, optional
        Boundary condition that defines the behavior for particles hitting the
        surface. Defaults to transmissive boundary condition where particles
        freely pass through the surface.
    albedo : float, optional
        Albedo of the surfaces as a ratio of particle weight after interaction
        with the surface to the initial weight. Values must be positive. Only
        applicable if the boundary type is 'reflective', 'periodic', or 'white'.
    name : str, optional
        Name of the plane. If not specified, the name will be the empty string.
    surface_id : int, optional
        Unique identifier for the surface. If not specified, an identifier will
        automatically be assigned.

    Attributes
    ----------
    a : float
        The 'A' parameter for the plane
    b : float
        The 'B' parameter for the plane
    c : float
        The 'C' parameter for the plane
    d : float
        The 'D' parameter for the plane
    boundary_type : {'transmission', 'vacuum', 'reflective', 'periodic', 'white'}
        Boundary condition that defines the behavior for particles hitting the
        surface.
    albedo : float
        Boundary albedo as a positive multiplier of particle weight
    periodic_surface : openmc.Surface
        If a periodic boundary condition is used, the surface with which this
        one is periodic with
    coefficients : dict
        Dictionary of surface coefficients
    id : int
        Unique identifier for the surface
    name : str
        Name of the surface
    type : str
        Type of the surface

    """

    _type = 'plane'
    _coeff_keys = ('a', 'b', 'c', 'd')

    def __init__(self, a=1., b=0., c=0., d=0., *args, **kwargs):
        # *args should ultimately be limited to a, b, c, d as specified in
        # __init__, but to preserve the API it is allowed to accept Surface
        # parameters for now, but will raise warnings if this is done.
        kwargs = _future_kwargs_warning_helper(type(self), *args, **kwargs)
        # Warn if capital letter arguments are passed
        capdict = {}
        for k in 'ABCD':
            val = kwargs.pop(k, None)
            if val is not None:
                warn(_WARNING_UPPER.format(type(self), k.lower(), k),
                     FutureWarning)
                capdict[k.lower()] = val

        super().__init__(**kwargs)

        for key, val in zip(self._coeff_keys, (a, b, c, d)):
            setattr(self, key, val)

        for key, val in capdict.items():
            setattr(self, key, val)

    @classmethod
    def __subclasshook__(cls, c):
        if cls is Plane and c in (XPlane, YPlane, ZPlane):
            return True
        return NotImplemented

    a = SurfaceCoefficient('a')
    b = SurfaceCoefficient('b')
    c = SurfaceCoefficient('c')
    d = SurfaceCoefficient('d')

    @classmethod
    def from_points(cls, p1, p2, p3, **kwargs):
        """Return a plane given three points that pass through it.

        Parameters
        ----------
        p1, p2, p3 : 3-tuples
            Points that pass through the plane
        kwargs : dict
            Keyword arguments passed to the :class:`Plane` constructor

        Returns
        -------
        Plane
            Plane that passes through the three points

        Raises
        ------
        ValueError
            If all three points lie along a line

        """
        # Convert to numpy arrays
        p1 = np.asarray(p1, dtype=float)
        p2 = np.asarray(p2, dtype=float)
        p3 = np.asarray(p3, dtype=float)

        # Find normal vector to plane by taking cross product of two vectors
        # connecting p1->p2 and p1->p3
        n = np.cross(p2 - p1, p3 - p1)

        # Check for points along a line
        if np.allclose(n, 0.):
            raise ValueError("All three points appear to lie along a line.")

        # The equation of the plane will by n·(<x,y,z> - p1) = 0. Determine
        # coefficients a, b, c, and d based on that
        a, b, c = n
        d = np.dot(n, p1)
        return cls(a=a, b=b, c=c, d=d, **kwargs)

    def flip_normal(self):
        """Modify plane coefficients to reverse the normal vector."""
        self.a = -self.a
        self.b = -self.b
        self.c = -self.c
        self.d = -self.d


class XPlane(PlaneMixin, Surface):
    """A plane perpendicular to the x axis of the form :math:`x - x_0 = 0`

    Parameters
    ----------
    x0 : float, optional
        Location of the plane in [cm]. Defaults to 0.
    boundary_type : {'transmission', 'vacuum', 'reflective', 'periodic', 'white'}, optional
        Boundary condition that defines the behavior for particles hitting the
        surface. Defaults to transmissive boundary condition where particles
        freely pass through the surface.
    albedo : float, optional
        Albedo of the surfaces as a ratio of particle weight after interaction
        with the surface to the initial weight. Values must be positive. Only
        applicable if the boundary type is 'reflective', 'periodic', or 'white'.
    name : str, optional
        Name of the plane. If not specified, the name will be the empty string.
    surface_id : int, optional
        Unique identifier for the surface. If not specified, an identifier will
        automatically be assigned.

    Attributes
    ----------
    x0 : float
        Location of the plane in [cm]
    boundary_type : {'transmission', 'vacuum', 'reflective', 'periodic', 'white'}
        Boundary condition that defines the behavior for particles hitting the
        surface.
    albedo : float
        Boundary albedo as a positive multiplier of particle weight
    periodic_surface : openmc.Surface
        If a periodic boundary condition is used, the surface with which this
        one is periodic with
    coefficients : dict
        Dictionary of surface coefficients
    id : int
        Unique identifier for the surface
    name : str
        Name of the surface
    type : str
        Type of the surface

    """

    _type = 'x-plane'
    _coeff_keys = ('x0',)

    def __init__(self, x0=0., *args, **kwargs):
        # work around for accepting Surface kwargs as positional parameters
        # until they are deprecated
        kwargs = _future_kwargs_warning_helper(type(self), *args, **kwargs)
        super().__init__(**kwargs)
        self.x0 = x0

    x0 = SurfaceCoefficient('x0')
    a = SurfaceCoefficient(1.)
    b = SurfaceCoefficient(0.)
    c = SurfaceCoefficient(0.)
    d = x0

    def evaluate(self, point):
        return point[0] - self.x0


class YPlane(PlaneMixin, Surface):
    """A plane perpendicular to the y axis of the form :math:`y - y_0 = 0`

    Parameters
    ----------
    y0 : float, optional
        Location of the plane in [cm]
    boundary_type : {'transmission', 'vacuum', 'reflective', 'periodic', 'white'}, optional
        Boundary condition that defines the behavior for particles hitting the
        surface. Defaults to transmissive boundary condition where particles
        freely pass through the surface.
    albedo : float, optional
        Albedo of the surfaces as a ratio of particle weight after interaction
        with the surface to the initial weight. Values must be positive. Only
        applicable if the boundary type is 'reflective', 'periodic', or 'white'.
    name : str, optional
        Name of the plane. If not specified, the name will be the empty string.
    surface_id : int, optional
        Unique identifier for the surface. If not specified, an identifier will
        automatically be assigned.

    Attributes
    ----------
    y0 : float
        Location of the plane in [cm]
    boundary_type : {'transmission', 'vacuum', 'reflective', 'periodic', 'white'}
        Boundary condition that defines the behavior for particles hitting the
        surface.
    albedo : float
        Boundary albedo as a positive multiplier of particle weight
    periodic_surface : openmc.Surface
        If a periodic boundary condition is used, the surface with which this
        one is periodic with
    coefficients : dict
        Dictionary of surface coefficients
    id : int
        Unique identifier for the surface
    name : str
        Name of the surface
    type : str
        Type of the surface

    """

    _type = 'y-plane'
    _coeff_keys = ('y0',)

    def __init__(self, y0=0., *args, **kwargs):
        # work around for accepting Surface kwargs as positional parameters
        # until they are deprecated
        kwargs = _future_kwargs_warning_helper(type(self), *args, **kwargs)
        super().__init__(**kwargs)
        self.y0 = y0

    y0 = SurfaceCoefficient('y0')
    a = SurfaceCoefficient(0.)
    b = SurfaceCoefficient(1.)
    c = SurfaceCoefficient(0.)
    d = y0

    def evaluate(self, point):
        return point[1] - self.y0


class ZPlane(PlaneMixin, Surface):
    """A plane perpendicular to the z axis of the form :math:`z - z_0 = 0`

    Parameters
    ----------
    z0 : float, optional
        Location of the plane in [cm]. Defaults to 0.
    boundary_type : {'transmission', 'vacuum', 'reflective', 'periodic', 'white'}, optional
        Boundary condition that defines the behavior for particles hitting the
        surface. Defaults to transmissive boundary condition where particles
        freely pass through the surface.
    albedo : float, optional
        Albedo of the surfaces as a ratio of particle weight after interaction
        with the surface to the initial weight. Values must be positive. Only
        applicable if the boundary type is 'reflective', 'periodic', or 'white'.
    name : str, optional
        Name of the plane. If not specified, the name will be the empty string.
    surface_id : int, optional
        Unique identifier for the surface. If not specified, an identifier will
        automatically be assigned.

    Attributes
    ----------
    z0 : float
        Location of the plane in [cm]
    boundary_type : {'transmission', 'vacuum', 'reflective', 'periodic', 'white'}
        Boundary condition that defines the behavior for particles hitting the
        surface.
    albedo : float
        Boundary albedo as a positive multiplier of particle weight
    periodic_surface : openmc.Surface
        If a periodic boundary condition is used, the surface with which this
        one is periodic with
    coefficients : dict
        Dictionary of surface coefficients
    id : int
        Unique identifier for the surface
    name : str
        Name of the surface
    type : str
        Type of the surface

    """

    _type = 'z-plane'
    _coeff_keys = ('z0',)

    def __init__(self, z0=0., *args, **kwargs):
        # work around for accepting Surface kwargs as positional parameters
        # until they are deprecated
        kwargs = _future_kwargs_warning_helper(type(self), *args, **kwargs)
        super().__init__(**kwargs)
        self.z0 = z0

    z0 = SurfaceCoefficient('z0')
    a = SurfaceCoefficient(0.)
    b = SurfaceCoefficient(0.)
    c = SurfaceCoefficient(1.)
    d = z0

    def evaluate(self, point):
        return point[2] - self.z0


class QuadricMixin:
    """A Mixin class implementing common functionality for quadric surfaces"""

    @property
    def _origin(self):
        return np.array((self.x0, self.y0, self.z0))

    @property
    def _axis(self):
        axis = np.array((self.dx, self.dy, self.dz))
        return axis / np.linalg.norm(axis)

    def get_Abc(self, coeffs=None):
        """Compute matrix, vector, and scalar coefficients for this surface or
        for a specified set of coefficients.

        Parameters
        ----------
        coeffs : tuple, optional
            Tuple of coefficients from which to compute the quadric elements.
            If none are supplied the coefficients of this surface will be used.
        """
        if coeffs is None:
            a, b, c, d, e, f, g, h, j, k = self._get_base_coeffs()
        else:
            a, b, c, d, e, f, g, h, j, k = coeffs

        A = np.array([[a, d/2, f/2], [d/2, b, e/2], [f/2, e/2, c]])
        bvec = np.array([g, h, j])

        return A, bvec, k

    def eigh(self, coeffs=None):
        """Wrapper method for returning eigenvalues and eigenvectors of this
        quadric surface which is used for transformations.

        Parameters
        ----------
        coeffs : tuple, optional
            Tuple of coefficients from which to compute the quadric elements.
            If none are supplied the coefficients of this surface will be used.

        Returns
        -------
        w, v : tuple of numpy arrays with shapes (3,) and (3,3) respectively
            Returns the eigenvalues and eigenvectors of the quadric matrix A
            that represents the supplied coefficients. The vector w contains
            the eigenvalues in ascending order and the matrix v contains the
            eigenvectors such that v[:,i] is the eigenvector corresponding to
            the eigenvalue w[i].

        """
        return np.linalg.eigh(self.get_Abc(coeffs=coeffs)[0])

    def evaluate(self, point):
        """Evaluate the surface equation at a given point.

        Parameters
        ----------
        point : 3-tuple of float
            The Cartesian coordinates, :math:`(x',y',z')`, in [cm] at which the
            surface equation should be evaluated.

        Returns
        -------
        float
            :math:`Ax'^2 + By'^2 + Cz'^2 + Dx'y' + Ey'z' + Fx'z' + Gx' + Hy' +
            Jz' + K = 0`

        """
        x = np.asarray(point)
        A, b, c = self.get_Abc()
        return x.T @ A @ x + b.T @ x + c

    def translate(self, vector, inplace=False):
        """Translate surface in given direction

        Parameters
        ----------
        vector : iterable of float
            Direction in which surface should be translated
        inplace : bool
            Whether to return a clone of the Surface or the Surface itself.

        Returns
        -------
        openmc.Surface
            Translated surface

        """
        vector = np.asarray(vector)
        if np.allclose(vector, 0., rtol=0., atol=self._atol):
            return self

        surf = self if inplace else self.clone()

        if hasattr(self, 'x0'):
            for vi, xi in zip(vector, ('x0', 'y0', 'z0')):
                val = getattr(surf, xi)
                try:
                    setattr(surf, xi, val + vi)
                except AttributeError:
                    # That attribute is read only i.e x0 for XCylinder
                    pass

        else:
            A, bvec, cnst = self.get_Abc()

            g, h, j = bvec - 2*vector.T @ A
            k = cnst + vector.T @ A @ vector - bvec.T @ vector

            for key, val in zip(('g', 'h', 'j', 'k'), (g, h, j, k)):
                setattr(surf, key, val)

        return surf

    def rotate(self, rotation, pivot=(0., 0., 0.), order='xyz', inplace=False):
        # Get pivot and rotation matrix
        pivot = np.asarray(pivot)
        rotation = np.asarray(rotation, dtype=float)

        # Allow rotation matrix to be passed in directly, otherwise build it
        if rotation.ndim == 2:
            check_length('surface rotation', rotation.ravel(), 9)
            Rmat = rotation
        else:
            Rmat = get_rotation_matrix(rotation, order=order)

        # Translate surface to the pivot point
        tsurf = self.translate(-pivot, inplace=inplace)

        # If the surface is already generalized just clone it
        if type(tsurf) is tsurf._virtual_base:
            surf = tsurf if inplace else tsurf.clone()
        else:
            base_cls = type(tsurf)._virtual_base
            # Copy necessary surface attributes to new kwargs dictionary
            kwargs = {'boundary_type': tsurf.boundary_type,
                      'albedo': tsurf.albedo, 'name': tsurf.name}
            if inplace:
                kwargs['surface_id'] = tsurf.id
            kwargs.update({k: getattr(tsurf, k) for k in base_cls._coeff_keys})
            # Create new instance of the virtual base class
            surf = base_cls(**kwargs)

        # Perform rotations on axis, origin, or quadric coefficients
        if hasattr(surf, 'dx'):
            for key, val in zip(('dx', 'dy', 'dz'), Rmat @ tsurf._axis):
                setattr(surf, key, val)
        if hasattr(surf, 'x0'):
            for key, val in zip(('x0', 'y0', 'z0'), Rmat @ tsurf._origin):
                setattr(surf, key, val)
        else:
            A, bvec, k = surf.get_Abc()
            Arot = Rmat @ A @ Rmat.T

            a, b, c = np.diagonal(Arot)
            d, e, f = 2*Arot[0, 1], 2*Arot[1, 2], 2*Arot[0, 2]
            g, h, j = Rmat @ bvec

            for key, val in zip(surf._coeff_keys, (a, b, c, d, e, f, g, h, j, k)):
                setattr(surf, key, val)

        # translate back to the original frame and return the surface
        return surf.translate(pivot, inplace=inplace)


class Cylinder(QuadricMixin, Surface):
    """A cylinder with radius r, centered on the point (x0, y0, z0) with an
    axis specified by the line through points (x0, y0, z0) and (x0+dx, y0+dy,
    z0+dz)

    Parameters
    ----------
    x0 : float, optional
        x-coordinate for the origin of the Cylinder in [cm]. Defaults to 0
    y0 : float, optional
        y-coordinate for the origin of the Cylinder in [cm]. Defaults to 0
    z0 : float, optional
        z-coordinate for the origin of the Cylinder in [cm]. Defaults to 0
    r : float, optional
        Radius of the cylinder in [cm]. Defaults to 1.
    dx : float, optional
        x-component of the vector representing the axis of the cylinder.
        Defaults to 0.
    dy : float, optional
        y-component of the vector representing the axis of the cylinder.
        Defaults to 0.
    dz : float, optional
        z-component of the vector representing the axis of the cylinder.
        Defaults to 1.
    boundary_type : {'transmission', 'vacuum', 'reflective', 'white'}, optional
        Boundary condition that defines the behavior for particles hitting the
        surface. Defaults to transmissive boundary condition where particles
        freely pass through the surface.
    albedo : float, optional
        Albedo of the surfaces as a ratio of particle weight after interaction
        with the surface to the initial weight. Values must be positive. Only
        applicable if the boundary type is 'reflective', 'periodic', or 'white'.
    name : str, optional
        Name of the cylinder. If not specified, the name will be the empty
        string.
    surface_id : int, optional
        Unique identifier for the surface. If not specified, an identifier will
        automatically be assigned.

    Attributes
    ----------
    x0 : float
        x-coordinate for the origin of the Cylinder in [cm]
    y0 : float
        y-coordinate for the origin of the Cylinder in [cm]
    z0 : float
        z-coordinate for the origin of the Cylinder in [cm]
    r : float
        Radius of the cylinder in [cm]
    dx : float
        x-component of the vector representing the axis of the cylinder
    dy : float
        y-component of the vector representing the axis of the cylinder
    dz : float
        z-component of the vector representing the axis of the cylinder
    boundary_type : {'transmission', 'vacuum', 'reflective', 'white'}
        Boundary condition that defines the behavior for particles hitting the
        surface.
    albedo : float
        Boundary albedo as a positive multiplier of particle weight
    coefficients : dict
        Dictionary of surface coefficients
    id : int
        Unique identifier for the surface
    name : str
        Name of the surface
    type : str
        Type of the surface

    """
    _type = 'cylinder'
    _coeff_keys = ('x0', 'y0', 'z0', 'r', 'dx', 'dy', 'dz')

    def __init__(self, x0=0., y0=0., z0=0., r=1., dx=0., dy=0., dz=1., *args,
                 **kwargs):
        kwargs = _future_kwargs_warning_helper(type(self), *args, **kwargs)
        super().__init__(**kwargs)

        for key, val in zip(self._coeff_keys, (x0, y0, z0, r, dx, dy, dz)):
            setattr(self, key, val)

    @classmethod
    def __subclasshook__(cls, c):
        if cls is Cylinder and c in (XCylinder, YCylinder, ZCylinder):
            return True
        return NotImplemented

    x0 = SurfaceCoefficient('x0')
    y0 = SurfaceCoefficient('y0')
    z0 = SurfaceCoefficient('z0')
    r = SurfaceCoefficient('r')
    dx = SurfaceCoefficient('dx')
    dy = SurfaceCoefficient('dy')
    dz = SurfaceCoefficient('dz')

    def bounding_box(self, side):
        if side == '-':
            r = self.r
            ll = [xi - r if np.isclose(dxi, 0., rtol=0., atol=self._atol)
                  else -np.inf for xi, dxi in zip(self._origin, self._axis)]
            ur = [xi + r if np.isclose(dxi, 0., rtol=0., atol=self._atol)
                  else np.inf for xi, dxi in zip(self._origin, self._axis)]
            return BoundingBox(np.array(ll), np.array(ur))
        elif side == '+':
            return BoundingBox.infinite()

    def _get_base_coeffs(self):
        # Get x, y, z coordinates of two points
        x1, y1, z1 = self._origin
        x2, y2, z2 = self._origin + self._axis
        r = self.r

        # Define intermediate terms
        dx = x2 - x1
        dy = y2 - y1
        dz = z2 - z1
        cx = y1*z2 - y2*z1
        cy = x2*z1 - x1*z2
        cz = x1*y2 - x2*y1

        # Given p=(x,y,z), p1=(x1, y1, z1), p2=(x2, y2, z2), the equation
        # for the cylinder can be derived as
        # r = |(p - p1) ⨯ (p - p2)| / |p2 - p1|.
        # Expanding out all terms and grouping according to what Quadric
        # expects gives the following coefficients.
        a = dy*dy + dz*dz
        b = dx*dx + dz*dz
        c = dx*dx + dy*dy
        d = -2*dx*dy
        e = -2*dy*dz
        f = -2*dx*dz
        g = 2*(cy*dz - cz*dy)
        h = 2*(cz*dx - cx*dz)
        j = 2*(cx*dy - cy*dx)
        k = cx*cx + cy*cy + cz*cz - (dx*dx + dy*dy + dz*dz)*r*r

        return (a, b, c, d, e, f, g, h, j, k)

    @classmethod
    def from_points(cls, p1, p2, r=1., **kwargs):
        """Return a cylinder given points that define the axis and a radius.

        .. versionadded:: 0.12

        Parameters
        ----------
        p1, p2 : 3-tuples
            Points that pass through the cylinder axis.
        r : float, optional
            Radius of the cylinder in [cm]. Defaults to 1.
        kwargs : dict
            Keyword arguments passed to the :class:`Cylinder` constructor

        Returns
        -------
        Cylinder
            Cylinder that has an axis through the points p1 and p2, and a
            radius r.

        """
        # Convert to numpy arrays
        p1 = np.asarray(p1)
        p2 = np.asarray(p2)
        x0, y0, z0 = p1
        dx, dy, dz = p2 - p1

        return cls(x0=x0, y0=y0, z0=z0, r=r, dx=dx, dy=dy, dz=dz, **kwargs)

    def to_xml_element(self):
        """Return XML representation of the surface

        Returns
        -------
        element : lxml.etree._Element
            XML element containing source data

        """
        # This method overrides Surface.to_xml_element to generate a Quadric
        # since the C++ layer doesn't support Cylinders right now
        with catch_warnings():
            simplefilter('ignore', IDWarning)
            kwargs = {'boundary_type': self.boundary_type, 'albedo': self.albedo,
                      'name': self.name, 'surface_id': self.id}
            quad_rep = Quadric(*self._get_base_coeffs(), **kwargs)
        return quad_rep.to_xml_element()


class XCylinder(QuadricMixin, Surface):
    """An infinite cylinder whose length is parallel to the x-axis of the form
    :math:`(y - y_0)^2 + (z - z_0)^2 = r^2`.

    Parameters
    ----------
    y0 : float, optional
        y-coordinate for the origin of the Cylinder in [cm]. Defaults to 0
    z0 : float, optional
        z-coordinate for the origin of the Cylinder in [cm]. Defaults to 0
    r : float, optional
        Radius of the cylinder in [cm]. Defaults to 1.
    boundary_type : {'transmission', 'vacuum', 'reflective', 'white'}, optional
        Boundary condition that defines the behavior for particles hitting the
        surface. Defaults to transmissive boundary condition where particles
        freely pass through the surface.
    albedo : float, optional
        Albedo of the surfaces as a ratio of particle weight after interaction
        with the surface to the initial weight. Values must be positive. Only
        applicable if the boundary type is 'reflective', 'periodic', or 'white'.
    name : str, optional
        Name of the cylinder. If not specified, the name will be the empty
        string.
    surface_id : int, optional
        Unique identifier for the surface. If not specified, an identifier will
        automatically be assigned.

    Attributes
    ----------
    y0 : float
        y-coordinate for the origin of the Cylinder in [cm]
    z0 : float
        z-coordinate for the origin of the Cylinder in [cm]
    r : float
        Radius of the cylinder in [cm]
    boundary_type : {'transmission', 'vacuum', 'reflective', 'white'}
        Boundary condition that defines the behavior for particles hitting the
        surface.
    albedo : float
        Boundary albedo as a positive multiplier of particle weight
    coefficients : dict
        Dictionary of surface coefficients
    id : int
        Unique identifier for the surface
    name : str
        Name of the surface
    type : str
        Type of the surface

    """

    _type = 'x-cylinder'
    _coeff_keys = ('y0', 'z0', 'r')

    def __init__(self, y0=0., z0=0., r=1., *args, **kwargs):
        R = kwargs.pop('R', None)
        if R is not None:
            warn(_WARNING_UPPER.format(type(self).__name__, 'r', 'R'),
                 FutureWarning)
            r = R
        kwargs = _future_kwargs_warning_helper(type(self), *args, **kwargs)
        super().__init__(**kwargs)

        for key, val in zip(self._coeff_keys, (y0, z0, r)):
            setattr(self, key, val)

    x0 = SurfaceCoefficient(0.)
    y0 = SurfaceCoefficient('y0')
    z0 = SurfaceCoefficient('z0')
    r = SurfaceCoefficient('r')
    dx = SurfaceCoefficient(1.)
    dy = SurfaceCoefficient(0.)
    dz = SurfaceCoefficient(0.)

    def _get_base_coeffs(self):
        y0, z0, r = self.y0, self.z0, self.r

        a = d = e = f = g = 0.
        b = c = 1.
        h, j, k = -2*y0, -2*z0, y0*y0 + z0*z0 - r*r

        return (a, b, c, d, e, f, g, h, j, k)

    def bounding_box(self, side):
        if side == '-':
            return BoundingBox(
                np.array([-np.inf, self.y0 - self.r, self.z0 - self.r]),
                np.array([np.inf, self.y0 + self.r, self.z0 + self.r])
            )
        elif side == '+':
            return BoundingBox.infinite()

    def evaluate(self, point):
        y = point[1] - self.y0
        z = point[2] - self.z0
        return y*y + z*z - self.r**2


class YCylinder(QuadricMixin, Surface):
    """An infinite cylinder whose length is parallel to the y-axis of the form
    :math:`(x - x_0)^2 + (z - z_0)^2 = r^2`.

    Parameters
    ----------
    x0 : float, optional
        x-coordinate for the origin of the Cylinder in [cm]. Defaults to 0
    z0 : float, optional
        z-coordinate for the origin of the Cylinder in [cm]. Defaults to 0
    r : float, optional
        Radius of the cylinder in [cm]. Defaults to 1.
    boundary_type : {'transmission', 'vacuum', 'reflective', 'white'}, optional
        Boundary condition that defines the behavior for particles hitting the
        surface. Defaults to transmissive boundary condition where particles
        freely pass through the surface.
    albedo : float, optional
        Albedo of the surfaces as a ratio of particle weight after interaction
        with the surface to the initial weight. Values must be positive. Only
        applicable if the boundary type is 'reflective', 'periodic', or 'white'.
    name : str, optional
        Name of the cylinder. If not specified, the name will be the empty
        string.
    surface_id : int, optional
        Unique identifier for the surface. If not specified, an identifier will
        automatically be assigned.

    Attributes
    ----------
    x0 : float
        x-coordinate for the origin of the Cylinder in [cm]
    z0 : float
        z-coordinate for the origin of the Cylinder in [cm]
    r : float
        Radius of the cylinder in [cm]
    boundary_type : {'transmission', 'vacuum', 'reflective', 'white'}
        Boundary condition that defines the behavior for particles hitting the
        surface.
    albedo : float
        Boundary albedo as a positive multiplier of particle weight
    coefficients : dict
        Dictionary of surface coefficients
    id : int
        Unique identifier for the surface
    name : str
        Name of the surface
    type : str
        Type of the surface

    """

    _type = 'y-cylinder'
    _coeff_keys = ('x0', 'z0', 'r')

    def __init__(self, x0=0., z0=0., r=1., *args, **kwargs):
        R = kwargs.pop('R', None)
        if R is not None:
            warn(_WARNING_UPPER.format(type(self).__name__, 'r', 'R'),
                 FutureWarning)
            r = R
        kwargs = _future_kwargs_warning_helper(type(self), *args, **kwargs)
        super().__init__(**kwargs)

        for key, val in zip(self._coeff_keys, (x0, z0, r)):
            setattr(self, key, val)

    x0 = SurfaceCoefficient('x0')
    y0 = SurfaceCoefficient(0.)
    z0 = SurfaceCoefficient('z0')
    r = SurfaceCoefficient('r')
    dx = SurfaceCoefficient(0.)
    dy = SurfaceCoefficient(1.)
    dz = SurfaceCoefficient(0.)

    def _get_base_coeffs(self):
        x0, z0, r = self.x0, self.z0, self.r

        b = d = e = f = h = 0.
        a = c = 1.
        g, j, k = -2*x0, -2*z0, x0*x0 + z0*z0 - r*r

        return (a, b, c, d, e, f, g, h, j, k)

    def bounding_box(self, side):
        if side == '-':
            return BoundingBox(
                np.array([self.x0 - self.r, -np.inf, self.z0 - self.r]),
                np.array([self.x0 + self.r, np.inf, self.z0 + self.r])
            )
        elif side == '+':
            return BoundingBox.infinite()

    def evaluate(self, point):
        x = point[0] - self.x0
        z = point[2] - self.z0
        return x*x + z*z - self.r**2


class ZCylinder(QuadricMixin, Surface):
    """An infinite cylinder whose length is parallel to the z-axis of the form
    :math:`(x - x_0)^2 + (y - y_0)^2 = r^2`.

    Parameters
    ----------
    x0 : float, optional
        x-coordinate for the origin of the Cylinder in [cm]. Defaults to 0
    y0 : float, optional
        y-coordinate for the origin of the Cylinder in [cm]. Defaults to 0
    r : float, optional
        Radius of the cylinder in [cm]. Defaults to 1.
    boundary_type : {'transmission', 'vacuum', 'reflective', 'white'}, optional
        Boundary condition that defines the behavior for particles hitting the
        surface. Defaults to transmissive boundary condition where particles
        freely pass through the surface.
    albedo : float, optional
        Albedo of the surfaces as a ratio of particle weight after interaction
        with the surface to the initial weight. Values must be positive. Only
        applicable if the boundary type is 'reflective', 'periodic', or 'white'.
    name : str, optional
        Name of the cylinder. If not specified, the name will be the empty
        string.
    surface_id : int, optional
        Unique identifier for the surface. If not specified, an identifier will
        automatically be assigned.

    Attributes
    ----------
    x0 : float
        x-coordinate for the origin of the Cylinder in [cm]
    y0 : float
        y-coordinate for the origin of the Cylinder in [cm]
    r : float
        Radius of the cylinder in [cm]
    boundary_type : {'transmission', 'vacuum', 'reflective', 'white'}
        Boundary condition that defines the behavior for particles hitting the
        surface.
    albedo : float
        Boundary albedo as a positive multiplier of particle weight
    coefficients : dict
        Dictionary of surface coefficients
    id : int
        Unique identifier for the surface
    name : str
        Name of the surface
    type : str
        Type of the surface

    """

    _type = 'z-cylinder'
    _coeff_keys = ('x0', 'y0', 'r')

    def __init__(self, x0=0., y0=0., r=1., *args, **kwargs):
        R = kwargs.pop('R', None)
        if R is not None:
            warn(_WARNING_UPPER.format(type(self).__name__, 'r', 'R'),
                 FutureWarning)
            r = R
        kwargs = _future_kwargs_warning_helper(type(self), *args, **kwargs)
        super().__init__(**kwargs)

        for key, val in zip(self._coeff_keys, (x0, y0, r)):
            setattr(self, key, val)

    x0 = SurfaceCoefficient('x0')
    y0 = SurfaceCoefficient('y0')
    z0 = SurfaceCoefficient(0.)
    r = SurfaceCoefficient('r')
    dx = SurfaceCoefficient(0.)
    dy = SurfaceCoefficient(0.)
    dz = SurfaceCoefficient(1.)

    def _get_base_coeffs(self):
        x0, y0, r = self.x0, self.y0, self.r

        c = d = e = f = j = 0.
        a = b = 1.
        g, h, k = -2*x0, -2*y0, x0*x0 + y0*y0 - r*r

        return (a, b, c, d, e, f, g, h, j, k)

    def bounding_box(self, side):
        if side == '-':
            return BoundingBox(
                np.array([self.x0 - self.r, self.y0 - self.r, -np.inf]),
                np.array([self.x0 + self.r, self.y0 + self.r, np.inf])
            )
        elif side == '+':
            return BoundingBox.infinite()

    def evaluate(self, point):
        x = point[0] - self.x0
        y = point[1] - self.y0
        return x*x + y*y - self.r**2


class Sphere(QuadricMixin, Surface):
    """A sphere of the form :math:`(x - x_0)^2 + (y - y_0)^2 + (z - z_0)^2 = r^2`.

    Parameters
    ----------
    x0 : float, optional
        x-coordinate of the center of the sphere in [cm]. Defaults to 0.
    y0 : float, optional
        y-coordinate of the center of the sphere in [cm]. Defaults to 0.
    z0 : float, optional
        z-coordinate of the center of the sphere in [cm]. Defaults to 0.
    r : float, optional
        Radius of the sphere in [cm]. Defaults to 1.
    boundary_type : {'transmission', 'vacuum', 'reflective', 'white'}, optional
        Boundary condition that defines the behavior for particles hitting the
        surface. Defaults to transmissive boundary condition where particles
        freely pass through the surface.
    albedo : float, optional
        Albedo of the surfaces as a ratio of particle weight after interaction
        with the surface to the initial weight. Values must be positive. Only
        applicable if the boundary type is 'reflective', 'periodic', or 'white'.
    name : str, optional
        Name of the sphere. If not specified, the name will be the empty string.
    surface_id : int, optional
        Unique identifier for the surface. If not specified, an identifier will
        automatically be assigned.

    Attributes
    ----------
    x0 : float
        x-coordinate of the center of the sphere in [cm]
    y0 : float
        y-coordinate of the center of the sphere in [cm]
    z0 : float
        z-coordinate of the center of the sphere in [cm]
    r : float
        Radius of the sphere in [cm]
    boundary_type : {'transmission', 'vacuum', 'reflective', 'white'}
        Boundary condition that defines the behavior for particles hitting the
        surface.
    albedo : float
        Boundary albedo as a positive multiplier of particle weight
    coefficients : dict
        Dictionary of surface coefficients
    id : int
        Unique identifier for the surface
    name : str
        Name of the surface
    type : str
        Type of the surface

    """

    _type = 'sphere'
    _coeff_keys = ('x0', 'y0', 'z0', 'r')

    def __init__(self, x0=0., y0=0., z0=0., r=1., *args, **kwargs):
        R = kwargs.pop('R', None)
        if R is not None:
            warn(_WARNING_UPPER.format(type(self).__name__, 'r', 'R'),
                 FutureWarning)
            r = R
        kwargs = _future_kwargs_warning_helper(type(self), *args, **kwargs)
        super().__init__(**kwargs)

        for key, val in zip(self._coeff_keys, (x0, y0, z0, r)):
            setattr(self, key, val)

    x0 = SurfaceCoefficient('x0')
    y0 = SurfaceCoefficient('y0')
    z0 = SurfaceCoefficient('z0')
    r = SurfaceCoefficient('r')

    def _get_base_coeffs(self):
        x0, y0, z0, r = self.x0, self.y0, self.z0, self.r
        a = b = c = 1.
        d = e = f = 0.
        g, h, j = -2*x0, -2*y0, -2*z0
        k = x0*x0 + y0*y0 + z0*z0 - r*r

        return (a, b, c, d, e, f, g, h, j, k)

    def bounding_box(self, side):
        if side == '-':
            return BoundingBox(
                np.array([self.x0 - self.r, self.y0 - self.r, self.z0 - self.r]),
                np.array([self.x0 + self.r, self.y0 + self.r, self.z0 + self.r])
            )
        elif side == '+':
            return BoundingBox.infinite()

    def evaluate(self, point):
        x = point[0] - self.x0
        y = point[1] - self.y0
        z = point[2] - self.z0
        return x*x + y*y + z*z - self.r**2


class Cone(QuadricMixin, Surface):
    r"""A conical surface parallel to the x-, y-, or z-axis.

    .. Note::
        This creates a double cone, which is two one-sided cones that meet at their apex.
        For a one-sided cone see :class:`~openmc.model.XConeOneSided`,
        :class:`~openmc.model.YConeOneSided`, and :class:`~openmc.model.ZConeOneSided`.

    Parameters
    ----------
    x0 : float, optional
        x-coordinate of the apex in [cm].
    y0 : float, optional
        y-coordinate of the apex in [cm].
    z0 : float, optional
        z-coordinate of the apex in [cm].
    r2 : float, optional
        The square of the slope of the cone. It is defined as
        :math:`\left(\frac{r}{h}\right)^2` for a radius, :math:`r` and an axial
        distance :math:`h` from the apex. An easy way to define this quantity is
        to take the square of the radius of the cone (in cm) 1 cm from the apex.
    dx : float, optional
        x-component of the vector representing the axis of the cone.
    dy : float, optional
        y-component of the vector representing the axis of the cone.
    dz : float, optional
        z-component of the vector representing the axis of the cone.
    surface_id : int, optional
        Unique identifier for the surface. If not specified, an identifier will
        automatically be assigned.
    boundary_type : {'transmission', 'vacuum', 'reflective', 'white'}, optional
        Boundary condition that defines the behavior for particles hitting the
        surface. Defaults to transmissive boundary condition where particles
        freely pass through the surface.
    albedo : float, optional
        Albedo of the surfaces as a ratio of particle weight after interaction
        with the surface to the initial weight. Values must be positive. Only
        applicable if the boundary type is 'reflective', 'periodic', or 'white'.

    name : str
        Name of the cone. If not specified, the name will be the empty string.

    Attributes
    ----------
    x0 : float
        x-coordinate of the apex in [cm]
    y0 : float
        y-coordinate of the apex in [cm]
    z0 : float
        z-coordinate of the apex in [cm]
    r2 : float
        Parameter related to the aperture
    dx : float
        x-component of the vector representing the axis of the cone.
    dy : float
        y-component of the vector representing the axis of the cone.
    dz : float
        z-component of the vector representing the axis of the cone.
    boundary_type : {'transmission', 'vacuum', 'reflective', 'white'}
        Boundary condition that defines the behavior for particles hitting the
        surface.
    albedo : float
        Boundary albedo as a positive multiplier of particle weight
    coefficients : dict
        Dictionary of surface coefficients
    id : int
        Unique identifier for the surface
    name : str
        Name of the surface
    type : str
        Type of the surface

    """

    _type = 'cone'
    _coeff_keys = ('x0', 'y0', 'z0', 'r2', 'dx', 'dy', 'dz')

    def __init__(self, x0=0., y0=0., z0=0., r2=1., dx=0., dy=0., dz=1., *args,
                 **kwargs):
        R2 = kwargs.pop('R2', None)
        if R2 is not None:
            warn(_WARNING_UPPER.format(type(self).__name__, 'r2', 'R2'),
                 FutureWarning)
            r2 = R2
        kwargs = _future_kwargs_warning_helper(type(self), *args, **kwargs)
        super().__init__(**kwargs)

        for key, val in zip(self._coeff_keys, (x0, y0, z0, r2, dx, dy, dz)):
            setattr(self, key, val)

    @classmethod
    def __subclasshook__(cls, c):
        if cls is Cone and c in (XCone, YCone, ZCone):
            return True
        return NotImplemented

    x0 = SurfaceCoefficient('x0')
    y0 = SurfaceCoefficient('y0')
    z0 = SurfaceCoefficient('z0')
    r2 = SurfaceCoefficient('r2')
    dx = SurfaceCoefficient('dx')
    dy = SurfaceCoefficient('dy')
    dz = SurfaceCoefficient('dz')

    def _get_base_coeffs(self):
        # The equation for a general cone with vertex at point p = (x0, y0, z0)
        # and axis specified by the unit vector d = (dx, dy, dz) and opening
        # half angle theta can be described by the equation
        #
        # (d*(r - p))^2 - (r - p)*(r - p)cos^2(theta) = 0
        #
        # where * is the dot product and the vector r is the evaluation point
        # r = (x, y, z)
        #
        # The argument r2 for cones is actually tan^2(theta) so that
        # cos^2(theta) = 1 / (1 + r2)

        x0, y0, z0 = self._origin
        dx, dy, dz = self._axis
        cos2 = 1 / (1 + self.r2)

        a = cos2 - dx*dx
        b = cos2 - dy*dy
        c = cos2 - dz*dz
        d = -2*dx*dy
        e = -2*dy*dz
        f = -2*dx*dz
        g = 2*(dx*(dy*y0 + dz*z0) - a*x0)
        h = 2*(dy*(dx*x0 + dz*z0) - b*y0)
        j = 2*(dz*(dx*x0 + dy*y0) - c*z0)
        k = a*x0*x0 + b*y0*y0 + c*z0*z0 - 2*(dx*dy*x0*y0 + dy*dz*y0*z0 +
                                             dx*dz*x0*z0)

        return (a, b, c, d, e, f, g, h, j, k)

    def to_xml_element(self):
        """Return XML representation of the surface

        Returns
        -------
        element : lxml.etree._Element
            XML element containing source data

        """
        # This method overrides Surface.to_xml_element to generate a Quadric
        # since the C++ layer doesn't support Cones right now
        with catch_warnings():
            simplefilter('ignore', IDWarning)
            kwargs = {'boundary_type': self.boundary_type,
                      'albedo': self.albedo,
                      'name': self.name,
                      'surface_id': self.id}
            quad_rep = Quadric(*self._get_base_coeffs(), **kwargs)
        return quad_rep.to_xml_element()


class XCone(QuadricMixin, Surface):
    r"""A cone parallel to the x-axis of the form :math:`(y - y_0)^2 + (z - z_0)^2 =
    r^2 (x - x_0)^2`.

    .. Note::
        This creates a double cone, which is two one-sided cones that meet at their apex.
        For a one-sided cone see :class:`~openmc.model.XConeOneSided`.

    Parameters
    ----------
    x0 : float, optional
        x-coordinate of the apex in [cm].
    y0 : float, optional
        y-coordinate of the apex in [cm].
    z0 : float, optional
        z-coordinate of the apex in [cm].
    r2 : float, optional
        The square of the slope of the cone. It is defined as
        :math:`\left(\frac{r}{h}\right)^2` for a radius, :math:`r` and an axial
        distance :math:`h` from the apex. An easy way to define this quantity is
        to take the square of the radius of the cone (in cm) 1 cm from the apex.
    boundary_type : {'transmission', 'vacuum', 'reflective', 'white'}, optional
        Boundary condition that defines the behavior for particles hitting the
        surface. Defaults to transmissive boundary condition where particles
        freely pass through the surface.
    albedo : float, optional
        Albedo of the surfaces as a ratio of particle weight after interaction
        with the surface to the initial weight. Values must be positive. Only
        applicable if the boundary type is 'reflective', 'periodic', or 'white'.
    name : str, optional
        Name of the cone. If not specified, the name will be the empty string.
    surface_id : int, optional
        Unique identifier for the surface. If not specified, an identifier will
        automatically be assigned.

    Attributes
    ----------
    x0 : float
        x-coordinate of the apex in [cm]
    y0 : float
        y-coordinate of the apex in [cm]
    z0 : float
        z-coordinate of the apex in [cm]
    r2 : float
        Parameter related to the aperture
    boundary_type : {'transmission', 'vacuum', 'reflective', 'white'}
        Boundary condition that defines the behavior for particles hitting the
        surface.
    albedo : float
        Boundary albedo as a positive multiplier of particle weight
    coefficients : dict
        Dictionary of surface coefficients
    id : int
        Unique identifier for the surface
    name : str
        Name of the surface
    type : str
        Type of the surface

    """

    _type = 'x-cone'
    _coeff_keys = ('x0', 'y0', 'z0', 'r2')

    def __init__(self, x0=0., y0=0., z0=0., r2=1., *args, **kwargs):
        R2 = kwargs.pop('R2', None)
        if R2 is not None:
            warn(_WARNING_UPPER.format(type(self).__name__, 'r2', 'R2'),
                 FutureWarning)
            r2 = R2
        kwargs = _future_kwargs_warning_helper(type(self), *args, **kwargs)
        super().__init__(**kwargs)

        for key, val in zip(self._coeff_keys, (x0, y0, z0, r2)):
            setattr(self, key, val)

    x0 = SurfaceCoefficient('x0')
    y0 = SurfaceCoefficient('y0')
    z0 = SurfaceCoefficient('z0')
    r2 = SurfaceCoefficient('r2')
    dx = SurfaceCoefficient(1.)
    dy = SurfaceCoefficient(0.)
    dz = SurfaceCoefficient(0.)

    def _get_base_coeffs(self):
        x0, y0, z0, r2 = self.x0, self.y0, self.z0, self.r2

        a = -r2
        b = c = 1.
        d = e = f = 0.
        g, h, j = 2*x0*r2, -2*y0, -2*z0
        k = y0*y0 + z0*z0 - r2*x0*x0

        return (a, b, c, d, e, f, g, h, j, k)

    def evaluate(self, point):
        x = point[0] - self.x0
        y = point[1] - self.y0
        z = point[2] - self.z0
        return y*y + z*z - self.r2*x*x


class YCone(QuadricMixin, Surface):
    r"""A cone parallel to the y-axis of the form :math:`(x - x_0)^2 + (z - z_0)^2 =
    r^2 (y - y_0)^2`.

    .. Note::
        This creates a double cone, which is two one-sided cones that meet at their apex.
        For a one-sided cone see :class:`~openmc.model.YConeOneSided`.

    Parameters
    ----------
    x0 : float, optional
        x-coordinate of the apex in [cm].
    y0 : float, optional
        y-coordinate of the apex in [cm].
    z0 : float, optional
        z-coordinate of the apex in [cm].
    r2 : float, optional
        The square of the slope of the cone. It is defined as
        :math:`\left(\frac{r}{h}\right)^2` for a radius, :math:`r` and an axial
        distance :math:`h` from the apex. An easy way to define this quantity is
        to take the square of the radius of the cone (in cm) 1 cm from the apex.
    boundary_type : {'transmission', 'vacuum', 'reflective', 'white'}, optional
        Boundary condition that defines the behavior for particles hitting the
        surface. Defaults to transmissive boundary condition where particles
        freely pass through the surface.
    albedo : float, optional
        Albedo of the surfaces as a ratio of particle weight after interaction
        with the surface to the initial weight. Values must be positive. Only
        applicable if the boundary type is 'reflective', 'periodic', or 'white'.
    name : str, optional
        Name of the cone. If not specified, the name will be the empty string.
    surface_id : int, optional
        Unique identifier for the surface. If not specified, an identifier will
        automatically be assigned.

    Attributes
    ----------
    x0 : float
        x-coordinate of the apex in [cm]
    y0 : float
        y-coordinate of the apex in [cm]
    z0 : float
        z-coordinate of the apex in [cm]
    r2 : float
        Parameter related to the aperture
    boundary_type : {'transmission', 'vacuum', 'reflective', 'white'}
        Boundary condition that defines the behavior for particles hitting the
        surface.
    albedo : float
        Boundary albedo as a positive multiplier of particle weight
    coefficients : dict
        Dictionary of surface coefficients
    id : int
        Unique identifier for the surface
    name : str
        Name of the surface
    type : str
        Type of the surface

    """

    _type = 'y-cone'
    _coeff_keys = ('x0', 'y0', 'z0', 'r2')

    def __init__(self, x0=0., y0=0., z0=0., r2=1., *args, **kwargs):
        R2 = kwargs.pop('R2', None)
        if R2 is not None:
            warn(_WARNING_UPPER.format(type(self).__name__, 'r2', 'R2'),
                 FutureWarning)
            r2 = R2
        kwargs = _future_kwargs_warning_helper(type(self), *args, **kwargs)
        super().__init__(**kwargs)

        for key, val in zip(self._coeff_keys, (x0, y0, z0, r2)):
            setattr(self, key, val)

    x0 = SurfaceCoefficient('x0')
    y0 = SurfaceCoefficient('y0')
    z0 = SurfaceCoefficient('z0')
    r2 = SurfaceCoefficient('r2')
    dx = SurfaceCoefficient(0.)
    dy = SurfaceCoefficient(1.)
    dz = SurfaceCoefficient(0.)

    def _get_base_coeffs(self):
        x0, y0, z0, r2 = self.x0, self.y0, self.z0, self.r2

        b = -r2
        a = c = 1.
        d = e = f = 0.
        g, h, j = -2*x0, 2*y0*r2, -2*z0
        k = x0*x0 + z0*z0 - r2*y0*y0

        return (a, b, c, d, e, f, g, h, j, k)

    def evaluate(self, point):
        x = point[0] - self.x0
        y = point[1] - self.y0
        z = point[2] - self.z0
        return x*x + z*z - self.r2*y*y


class ZCone(QuadricMixin, Surface):
    r"""A cone parallel to the z-axis of the form :math:`(x - x_0)^2 + (y - y_0)^2 =
    r^2 (z - z_0)^2`.

    .. Note::
        This creates a double cone, which is two one-sided cones that meet at their apex.
        For a one-sided cone see :class:`~openmc.model.ZConeOneSided`.

    Parameters
    ----------
    x0 : float, optional
        x-coordinate of the apex in [cm].
    y0 : float, optional
        y-coordinate of the apex in [cm].
    z0 : float, optional
        z-coordinate of the apex in [cm].
    r2 : float, optional
        The square of the slope of the cone. It is defined as
        :math:`\left(\frac{r}{h}\right)^2` for a radius, :math:`r` and an axial
        distance :math:`h` from the apex. An easy way to define this quantity is
        to take the square of the radius of the cone (in cm) 1 cm from the apex.
    boundary_type : {'transmission', 'vacuum', 'reflective', 'white'}, optional
        Boundary condition that defines the behavior for particles hitting the
        surface. Defaults to transmissive boundary condition where particles
        freely pass through the surface.
    albedo : float, optional
        Albedo of the surfaces as a ratio of particle weight after interaction
        with the surface to the initial weight. Values must be positive. Only
        applicable if the boundary type is 'reflective', 'periodic', or 'white'.
    name : str, optional
        Name of the cone. If not specified, the name will be the empty string.
    surface_id : int, optional
        Unique identifier for the surface. If not specified, an identifier will
        automatically be assigned.

    Attributes
    ----------
    x0 : float
        x-coordinate of the apex in [cm]
    y0 : float
        y-coordinate of the apex in [cm]
    z0 : float
        z-coordinate of the apex in [cm]
    r2 : float
        Parameter related to the aperture.
    boundary_type : {'transmission', 'vacuum', 'reflective', 'white'}
        Boundary condition that defines the behavior for particles hitting the
        surface.
    albedo : float
        Boundary albedo as a positive multiplier of particle weight
    coefficients : dict
        Dictionary of surface coefficients
    id : int
        Unique identifier for the surface
    name : str
        Name of the surface
    type : str
        Type of the surface

    """

    _type = 'z-cone'
    _coeff_keys = ('x0', 'y0', 'z0', 'r2')

    def __init__(self, x0=0., y0=0., z0=0., r2=1., *args, **kwargs):
        R2 = kwargs.pop('R2', None)
        if R2 is not None:
            warn(_WARNING_UPPER.format(type(self).__name__, 'r2', 'R2'),
                 FutureWarning)
            r2 = R2
        kwargs = _future_kwargs_warning_helper(type(self), *args, **kwargs)
        super().__init__(**kwargs)

        for key, val in zip(self._coeff_keys, (x0, y0, z0, r2)):
            setattr(self, key, val)

    x0 = SurfaceCoefficient('x0')
    y0 = SurfaceCoefficient('y0')
    z0 = SurfaceCoefficient('z0')
    r2 = SurfaceCoefficient('r2')
    dx = SurfaceCoefficient(0.)
    dy = SurfaceCoefficient(0.)
    dz = SurfaceCoefficient(1.)

    def _get_base_coeffs(self):
        x0, y0, z0, r2 = self.x0, self.y0, self.z0, self.r2

        c = -r2
        a = b = 1.
        d = e = f = 0.
        g, h, j = -2*x0, -2*y0, 2*z0*r2
        k = x0*x0 + y0*y0 - r2*z0*z0

        return (a, b, c, d, e, f, g, h, j, k)

    def evaluate(self, point):
        x = point[0] - self.x0
        y = point[1] - self.y0
        z = point[2] - self.z0
        return x*x + y*y - self.r2*z*z


class Quadric(QuadricMixin, Surface):
    """A surface of the form :math:`Ax^2 + By^2 + Cz^2 + Dxy + Eyz + Fxz + Gx + Hy +
    Jz + K = 0`.

    Parameters
    ----------
    a, b, c, d, e, f, g, h, j, k : float, optional
        coefficients for the surface. All default to 0.
    boundary_type : {'transmission', 'vacuum', 'reflective', 'white'}, optional
        Boundary condition that defines the behavior for particles hitting the
        surface. Defaults to transmissive boundary condition where particles
        freely pass through the surface.
    albedo : float, optional
        Albedo of the surfaces as a ratio of particle weight after interaction
        with the surface to the initial weight. Values must be positive. Only
        applicable if the boundary type is 'reflective', 'periodic', or 'white'.
    name : str, optional
        Name of the surface. If not specified, the name will be the empty string.
    surface_id : int, optional
        Unique identifier for the surface. If not specified, an identifier will
        automatically be assigned.

    Attributes
    ----------
    a, b, c, d, e, f, g, h, j, k : float
        coefficients for the surface
    boundary_type : {'transmission', 'vacuum', 'reflective', 'white'}
        Boundary condition that defines the behavior for particles hitting the
        surface.
    albedo : float
        Boundary albedo as a positive multiplier of particle weight
    coefficients : dict
        Dictionary of surface coefficients
    id : int
        Unique identifier for the surface
    name : str
        Name of the surface
    type : str
        Type of the surface

    """

    _type = 'quadric'
    _coeff_keys = ('a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'j', 'k')

    def __init__(self, a=0., b=0., c=0., d=0., e=0., f=0., g=0., h=0., j=0.,
                 k=0., *args, **kwargs):
        kwargs = _future_kwargs_warning_helper(type(self), *args, **kwargs)
        super().__init__(**kwargs)

        for key, val in zip(self._coeff_keys, (a, b, c, d, e, f, g, h, j, k)):
            setattr(self, key, val)

    a = SurfaceCoefficient('a')
    b = SurfaceCoefficient('b')
    c = SurfaceCoefficient('c')
    d = SurfaceCoefficient('d')
    e = SurfaceCoefficient('e')
    f = SurfaceCoefficient('f')
    g = SurfaceCoefficient('g')
    h = SurfaceCoefficient('h')
    j = SurfaceCoefficient('j')
    k = SurfaceCoefficient('k')

    def _get_base_coeffs(self):
        return tuple(getattr(self, c) for c in self._coeff_keys)


class TorusMixin:
    """A Mixin class implementing common functionality for torus surfaces"""
    _coeff_keys = ('x0', 'y0', 'z0', 'a', 'b', 'c')

    def __init__(self, x0=0., y0=0., z0=0., a=0., b=0., c=0., **kwargs):
        super().__init__(**kwargs)
        for key, val in zip(self._coeff_keys, (x0, y0, z0, a, b, c)):
            setattr(self, key, val)

    x0 = SurfaceCoefficient('x0')
    y0 = SurfaceCoefficient('y0')
    z0 = SurfaceCoefficient('z0')
    a = SurfaceCoefficient('a')
    b = SurfaceCoefficient('b')
    c = SurfaceCoefficient('c')

    def translate(self, vector, inplace=False):
        surf = self if inplace else self.clone()
        surf.x0 += vector[0]
        surf.y0 += vector[1]
        surf.z0 += vector[2]
        return surf

    def rotate(self, rotation, pivot=(0., 0., 0.), order='xyz', inplace=False):
        pivot = np.asarray(pivot)
        rotation = np.asarray(rotation, dtype=float)

        # Allow rotation matrix to be passed in directly, otherwise build it
        if rotation.ndim == 2:
            check_length('surface rotation', rotation.ravel(), 9)
            Rmat = rotation
        else:
            Rmat = get_rotation_matrix(rotation, order=order)

        # Only can handle trivial rotation matrices
        close = np.isclose
        if not np.all(close(Rmat, -1.0) | close(Rmat, 0.0) | close(Rmat, 1.0)):
            raise NotImplementedError('Torus surfaces cannot handle generic rotations')

        # Translate surface to pivot
        surf = self.translate(-pivot, inplace=inplace)

        # Determine "center" of torus and a point above it (along main axis)
        center = [surf.x0, surf.y0, surf.z0]
        above_center = center.copy()
        index = ['x-torus', 'y-torus', 'z-torus'].index(surf._type)
        above_center[index] += 1

        # Compute new rotated torus center
        center = Rmat @ center

        # Figure out which axis should be used after rotation
        above_center = Rmat @ above_center
        new_index = np.where(np.isclose(np.abs(above_center - center), 1.0))[0][0]
        cls = [XTorus, YTorus, ZTorus][new_index]

        # Create rotated torus
        kwargs = {
            'boundary_type': surf.boundary_type,
            'albedo': surf.albedo,
            'name': surf.name,
            'a': surf.a, 'b': surf.b, 'c': surf.c
        }
        if inplace:
            kwargs['surface_id'] = surf.id
        surf = cls(x0=center[0], y0=center[1], z0=center[2], **kwargs)

        return surf.translate(pivot, inplace=inplace)

    def _get_base_coeffs(self):
        raise NotImplementedError


class XTorus(TorusMixin, Surface):
    r"""A torus of the form :math:`(x - x_0)^2/B^2 + (\sqrt{(y - y_0)^2 + (z -
    z_0)^2} - A)^2/C^2 - 1 = 0`.

    .. versionadded:: 0.13.0

    Parameters
    ----------
    x0 : float
        x-coordinate of the center of the axis of revolution in [cm]
    y0 : float
        y-coordinate of the center of the axis of revolution in [cm]
    z0 : float
        z-coordinate of the center of the axis of revolution in [cm]
    a : float
        Major radius of the torus in [cm]
    b : float
        Minor radius of the torus in [cm] (parallel to axis of revolution)
    c : float
        Minor radius of the torus in [cm] (perpendicular to axis of revolution)
    kwargs : dict
        Keyword arguments passed to the :class:`Surface` constructor

    Attributes
    ----------
    x0 : float
        x-coordinate of the center of the axis of revolution in [cm]
    y0 : float
        y-coordinate of the center of the axis of revolution in [cm]
    z0 : float
        z-coordinate of the center of the axis of revolution in [cm]
    a : float
        Major radius of the torus in [cm]
    b : float
        Minor radius of the torus in [cm] (parallel to axis of revolution)
    c : float
        Minor radius of the torus in [cm] (perpendicular to axis of revolution)
    boundary_type : {'transmission', 'vacuum', 'reflective', 'white'}
        Boundary condition that defines the behavior for particles hitting the
        surface.
    albedo : float
        Boundary albedo as a positive multiplier of particle weight
    coefficients : dict
        Dictionary of surface coefficients
    id : int
        Unique identifier for the surface
    name : str
        Name of the surface
    type : str
        Type of the surface

    """
    _type = 'x-torus'

    def evaluate(self, point):
        x = point[0] - self.x0
        y = point[1] - self.y0
        z = point[2] - self.z0
        a = self.a
        b = self.b
        c = self.c
        return (x*x)/(b*b) + (math.sqrt(y*y + z*z) - a)**2/(c*c) - 1

    def bounding_box(self, side):
        x0, y0, z0 = self.x0, self.y0, self.z0
        a, b, c = self.a, self.b, self.c
        if side == '-':
            return BoundingBox(
                np.array([x0 - b, y0 - a - c, z0 - a - c]),
                np.array([x0 + b, y0 + a + c, z0 + a + c])
            )
        elif side == '+':
            return BoundingBox.infinite()


class YTorus(TorusMixin, Surface):
    r"""A torus of the form :math:`(y - y_0)^2/B^2 + (\sqrt{(x - x_0)^2 + (z -
    z_0)^2} - A)^2/C^2 - 1 = 0`.

    .. versionadded:: 0.13.0

    Parameters
    ----------
    x0 : float
        x-coordinate of the center of the axis of revolution in [cm]
    y0 : float
        y-coordinate of the center of the axis of revolution in [cm]
    z0 : float
        z-coordinate of the center of the axis of revolution in [cm]
    a : float
        Major radius of the torus in [cm]
    b : float
        Minor radius of the torus in [cm] (parallel to axis of revolution)
    c : float
        Minor radius of the torus in [cm] (perpendicular to axis of revolution)
    kwargs : dict
        Keyword arguments passed to the :class:`Surface` constructor

    Attributes
    ----------
    x0 : float
        x-coordinate of the center of the axis of revolution in [cm]
    y0 : float
        y-coordinate of the center of the axis of revolution in [cm]
    z0 : float
        z-coordinate of the center of the axis of revolution in [cm]
    a : float
        Major radius of the torus in [cm]
    b : float
        Minor radius of the torus in [cm] (parallel to axis of revolution)
    c : float
        Minor radius of the torus (perpendicular to axis of revolution)
    boundary_type : {'transmission', 'vacuum', 'reflective', 'white'}
        Boundary condition that defines the behavior for particles hitting the
        surface.
    albedo : float
        Boundary albedo as a positive multiplier of particle weight
    coefficients : dict
        Dictionary of surface coefficients
    id : int
        Unique identifier for the surface
    name : str
        Name of the surface
    type : str
        Type of the surface

    """
    _type = 'y-torus'

    def evaluate(self, point):
        x = point[0] - self.x0
        y = point[1] - self.y0
        z = point[2] - self.z0
        a = self.a
        b = self.b
        c = self.c
        return (y*y)/(b*b) + (math.sqrt(x*x + z*z) - a)**2/(c*c) - 1

    def bounding_box(self, side):
        x0, y0, z0 = self.x0, self.y0, self.z0
        a, b, c = self.a, self.b, self.c
        if side == '-':
            return BoundingBox(
                np.array([x0 - a - c, y0 - b, z0 - a - c]),
                np.array([x0 + a + c, y0 + b, z0 + a + c])
            )
        elif side == '+':
            return BoundingBox.infinite()


class ZTorus(TorusMixin, Surface):
    r"""A torus of the form :math:`(z - z_0)^2/B^2 + (\sqrt{(x - x_0)^2 + (y -
    y_0)^2} - A)^2/C^2 - 1 = 0`.

    .. versionadded:: 0.13.0

    Parameters
    ----------
    x0 : float
        x-coordinate of the center of the axis of revolution in [cm]
    y0 : float
        y-coordinate of the center of the axis of revolution in [cm]
    z0 : float
        z-coordinate of the center of the axis of revolution in [cm]
    a : float
        Major radius of the torus in [cm]
    b : float
        Minor radius of the torus in [cm] (parallel to axis of revolution)
    c : float
        Minor radius of the torus in [cm] (perpendicular to axis of revolution)
    kwargs : dict
        Keyword arguments passed to the :class:`Surface` constructor

    Attributes
    ----------
    x0 : float
        x-coordinate of the center of the axis of revolution in [cm]
    y0 : float
        y-coordinate of the center of the axis of revolution in [cm]
    z0 : float
        z-coordinate of the center of the axis of revolution in [cm]
    a : float
        Major radius of the torus in [cm]
    b : float
        Minor radius of the torus in [cm] (parallel to axis of revolution)
    c : float
        Minor radius of the torus in [cm] (perpendicular to axis of revolution)
    boundary_type : {'transmission', 'vacuum', 'reflective', 'white'}
        Boundary condition that defines the behavior for particles hitting the
        surface.
    albedo : float
        Boundary albedo as a positive multiplier of particle weight
    coefficients : dict
        Dictionary of surface coefficients
    id : int
        Unique identifier for the surface
    name : str
        Name of the surface
    type : str
        Type of the surface
    """

    _type = 'z-torus'

    def evaluate(self, point):
        x = point[0] - self.x0
        y = point[1] - self.y0
        z = point[2] - self.z0
        a = self.a
        b = self.b
        c = self.c
        return (z*z)/(b*b) + (math.sqrt(x*x + y*y) - a)**2/(c*c) - 1

    def bounding_box(self, side):
        x0, y0, z0 = self.x0, self.y0, self.z0
        a, b, c = self.a, self.b, self.c
        if side == '-':
            return BoundingBox(
                np.array([x0 - a - c, y0 - a - c, z0 - b]),
                np.array([x0 + a + c, y0 + a + c, z0 + b])
            )
        elif side == '+':
            return BoundingBox.infinite()


class Halfspace(Region):
    """A positive or negative half-space region.

    A half-space is either of the two parts into which a two-dimension surface
    divides the three-dimensional Euclidean space. If the equation of the
    surface is :math:`f(x,y,z) = 0`, the region for which :math:`f(x,y,z) < 0`
    is referred to as the negative half-space and the region for which
    :math:`f(x,y,z) > 0` is referred to as the positive half-space.

    Instances of Halfspace are generally not instantiated directly. Rather, they
    can be created from an existing Surface through the __neg__ and __pos__
    operators, as the following example demonstrates:

    >>> sphere = openmc.Sphere(surface_id=1, r=10.0)
    >>> inside_sphere = -sphere
    >>> outside_sphere = +sphere
    >>> type(inside_sphere)
    <class 'openmc.surface.Halfspace'>

    Parameters
    ----------
    surface : openmc.Surface
        Surface which divides Euclidean space.
    side : {'+', '-'}
        Indicates whether the positive or negative half-space is used.

    Attributes
    ----------
    surface : openmc.Surface
        Surface which divides Euclidean space.
    side : {'+', '-'}
        Indicates whether the positive or negative half-space is used.
    bounding_box : openmc.BoundingBox
        Lower-left and upper-right coordinates of an axis-aligned bounding box

    """

    def __init__(self, surface, side):
        self.surface = surface
        self.side = side

    def __and__(self, other):
        if isinstance(other, Intersection):
            return Intersection([self] + other[:])
        else:
            return Intersection((self, other))

    def __or__(self, other):
        if isinstance(other, Union):
            return Union([self] + other[:])
        else:
            return Union((self, other))

    def __invert__(self) -> Halfspace:
        return -self.surface if self.side == '+' else +self.surface

    def __contains__(self, point):
        """Check whether a point is contained in the half-space.

        Parameters
        ----------
        point : 3-tuple of float
            Cartesian coordinates, :math:`(x',y',z')`, of the point

        Returns
        -------
        bool
            Whether the point is in the half-space

        """

        val = self.surface.evaluate(point)
        return val >= 0. if self.side == '+' else val < 0.

    @property
    def surface(self):
        return self._surface

    @surface.setter
    def surface(self, surface):
        check_type('surface', surface, Surface)
        self._surface = surface

    @property
    def side(self):
        return self._side

    @side.setter
    def side(self, side):
        check_value('side', side, ('+', '-'))
        self._side = side

    @property
    def bounding_box(self):
        return self.surface.bounding_box(self.side)

    def __str__(self):
        return '-' + str(self.surface.id) if self.side == '-' \
            else str(self.surface.id)

    def get_surfaces(self, surfaces=None):
        """
        Returns the surface that this is a halfspace of.

        Parameters
        ----------
        surfaces : dict, optional
            Dictionary mapping surface IDs to :class:`openmc.Surface` instances

        Returns
        -------
        surfaces : dict
            Dictionary mapping surface IDs to :class:`openmc.Surface` instances

        """
        if surfaces is None:
            surfaces = {}

        surfaces[self.surface.id] = self.surface
        return surfaces

    def remove_redundant_surfaces(self, redundant_surfaces):
        """Recursively remove all redundant surfaces referenced by this region

        Parameters
        ----------
        redundant_surfaces : dict
            Dictionary mapping redundant surface IDs to surface IDs for the
            :class:`openmc.Surface` instances that should replace them.

        """

        surf = redundant_surfaces.get(self.surface.id)
        if surf is not None:
            self.surface = surf

    def clone(self, memo=None):
        """Create a copy of this halfspace, with a cloned surface with a
        unique ID.

        Parameters
        ----------
        memo : dict or None
            A nested dictionary of previously cloned objects. This parameter
            is used internally and should not be specified by the user.

        Returns
        -------
        clone : openmc.Halfspace
            The clone of this halfspace

        """

        if memo is None:
            memo = dict

        clone = deepcopy(self)
        clone.surface = self.surface.clone(memo)
        return clone

    def translate(self, vector, inplace=False, memo=None):
        """Translate half-space in given direction

        Parameters
        ----------
        vector : iterable of float
            Direction in which region should be translated
        memo : dict or None
            Dictionary used for memoization

        Returns
        -------
        openmc.Halfspace
            Translated half-space

        """
        if memo is None:
            memo = {}

        # If translated surface not in memo, add it
        key = (self.surface, tuple(vector))
        if key not in memo:
            memo[key] = self.surface.translate(vector, inplace)

        # Return translated half-space
        return type(self)(memo[key], self.side)

    def rotate(self, rotation, pivot=(0., 0., 0.), order='xyz', inplace=False,
               memo=None):
        r"""Rotate surface by angles provided or by applying matrix directly.

        .. versionadded:: 0.12

        Parameters
        ----------
        rotation : 3-tuple of float, or 3x3 iterable
            A 3-tuple of angles :math:`(\phi, \theta, \psi)` in degrees where
            the first element is the rotation about the x-axis in the fixed
            laboratory frame, the second element is the rotation about the
            y-axis in the fixed laboratory frame, and the third element is the
            rotation about the z-axis in the fixed laboratory frame. The
            rotations are active rotations. Additionally a 3x3 rotation matrix
            can be specified directly either as a nested iterable or array.
        pivot : iterable of float, optional
            (x, y, z) coordinates for the point to rotate about. Defaults to
            (0., 0., 0.)
        order : str, optional
            A string of 'x', 'y', and 'z' in some order specifying which
            rotation to perform first, second, and third. Defaults to 'xyz'
            which means, the rotation by angle :math:`\phi` about x will be
            applied first, followed by :math:`\theta` about y and then
            :math:`\psi` about z. This corresponds to an x-y-z extrinsic
            rotation as well as a z-y'-x'' intrinsic rotation using Tait-Bryan
            angles :math:`(\phi, \theta, \psi)`.
        inplace : bool
            Whether or not to return a new instance of Surface or to modify the
            coefficients of this Surface in place. Defaults to False.
        memo : dict or None
            Dictionary used for memoization

        Returns
        -------
        openmc.Halfspace
            Translated half-space

        """
        if memo is None:
            memo = {}

        # If rotated surface not in memo, add it
        key = (self.surface, tuple(np.ravel(rotation)), tuple(pivot), order, inplace)
        if key not in memo:
            memo[key] = self.surface.rotate(rotation, pivot=pivot, order=order,
                                            inplace=inplace)

        # Return rotated half-space
        return type(self)(memo[key], self.side)


_SURFACE_CLASSES = {cls._type: cls for cls in Surface.__subclasses__()}


# Set virtual base classes for "casting" up the hierarchy
Plane._virtual_base = Plane
XPlane._virtual_base = Plane
YPlane._virtual_base = Plane
ZPlane._virtual_base = Plane
Cylinder._virtual_base = Cylinder
XCylinder._virtual_base = Cylinder
YCylinder._virtual_base = Cylinder
ZCylinder._virtual_base = Cylinder
Cone._virtual_base = Cone
XCone._virtual_base = Cone
YCone._virtual_base = Cone
ZCone._virtual_base = Cone
Sphere._virtual_base = Sphere
Quadric._virtual_base = Quadric

openmc-dev / openmc / 21489819490

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