Source code for nifty8.domains.gl_space
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
#
# Copyright(C) 2013-2019 Max-Planck-Society
#
# NIFTy is being developed at the Max-Planck-Institut fuer Astrophysik.
import numpy as np
from .structured_domain import StructuredDomain
[docs]
class GLSpace(StructuredDomain):
"""Represents a 2-sphere with Gauss-Legendre pixelization.
Its harmonic partner domain is the
:class:`~nifty8.domains.lm_space.LMSpace`.
Parameters
----------
nlat : int
Number of latitudinal bins (or rings) that are used for this
pixelization.
nlon : int, optional
Number of longitudinal bins that are used for this pixelization.
Default value is 2*nlat - 1.
"""
_needed_for_hash = ["_nlat", "_nlon"]
[docs]
def __init__(self, nlat, nlon=None):
self._nlat = int(nlat)
if self._nlat < 1:
raise ValueError("nlat must be a positive number.")
if nlon is None:
self._nlon = 2*self._nlat - 1
else:
self._nlon = int(nlon)
if self._nlon < 1:
raise ValueError("nlon must be a positive number.")
self._dvol = None
[docs]
def __repr__(self):
return "GLSpace(nlat={}, nlon={})".format(self.nlat, self.nlon)
@property
def harmonic(self):
return False
@property
def shape(self):
return (int(self.nlat * self.nlon),)
@property
def size(self):
return int(self.nlat * self.nlon)
@property
def scalar_dvol(self):
return None
# MR FIXME: this is potentially wasteful, since the return array is
# blown up by a factor of self.nlon
@property
def dvol(self):
from ducc0.misc import GL_weights
if self._dvol is None:
self._dvol = GL_weights(self.nlat, self.nlon)
return np.repeat(self._dvol, self.nlon)
@property
def total_volume(self):
return 4*np.pi
@property
def nlat(self):
"""int : number of rings in this domain"""
return self._nlat
@property
def nlon(self):
"""int : pixels per ring in this domain"""
return self._nlon
[docs]
def get_default_codomain(self):
"""Returns a :class:`LMSpace` object, which is capable of storing an
accurate representation of data residing on `self` (if this data is
band-limited).
Returns
-------
LMSpace
The partner domain
"""
from ..domains.lm_space import LMSpace
mmax = self._nlon//2
lmax = max(mmax, self._nlat-1)
return LMSpace(lmax=lmax, mmax=mmax)
[docs]
def check_codomain(self, codomain):
"""Raises `TypeError` if `codomain` is not a matching partner domain
for `self`.
Notes
-----
This function only checks whether `codomain` is of type
:class:`LMSpace`.
"""
from ..domains.lm_space import LMSpace
if not isinstance(codomain, LMSpace):
raise TypeError("codomain must be a LMSpace.")