hp_space.py 4.52 KB
Newer Older
csongor's avatar
csongor committed
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
# NIFTY (Numerical Information Field Theory) has been developed at the
# Max-Planck-Institute for Astrophysics.
#
# Copyright (C) 2015 Max-Planck-Society
#
# Author: Marco Selig
# Project homepage: <http://www.mpa-garching.mpg.de/ift/nifty/>
#
# 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/>.

"""
    ..                  __   ____   __
    ..                /__/ /   _/ /  /_
    ..      __ ___    __  /  /_  /   _/  __   __
    ..    /   _   | /  / /   _/ /  /   /  / /  /
    ..   /  / /  / /  / /  /   /  /_  /  /_/  /
    ..  /__/ /__/ /__/ /__/    \___/  \___   /  lm
    ..                               /______/

    NIFTY submodule for grids on the two-sphere.

"""
from __future__ import division

import numpy as np
37

38
from nifty.spaces.space import Space
csongor's avatar
csongor committed
39

40
from nifty.config import nifty_configuration as gc, \
csongor's avatar
csongor committed
41
                         dependency_injector as gdi
theos's avatar
theos committed
42
from hp_space_paradict import HPSpaceParadict
csongor's avatar
csongor committed
43 44 45

hp = gdi.get('healpy')

46 47

class HPSpace(Space):
csongor's avatar
csongor committed
48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96
    """
        ..        __
        ..      /  /
        ..     /  /___    ______
        ..    /   _   | /   _   |
        ..   /  / /  / /  /_/  /
        ..  /__/ /__/ /   ____/  space class
        ..           /__/

        NIFTY subclass for HEALPix discretizations of the two-sphere [#]_.

        Parameters
        ----------
        nside : int
            Resolution parameter for the HEALPix discretization, resulting in
            ``12*nside**2`` pixels.

        See Also
        --------
        gl_space : A class for the Gauss-Legendre discretization of the
            sphere [#]_.
        lm_space : A class for spherical harmonic components.

        Notes
        -----
        Only powers of two are allowed for `nside`.

        References
        ----------
        .. [#] K.M. Gorski et al., 2005, "HEALPix: A Framework for
               High-Resolution Discretization and Fast Analysis of Data
               Distributed on the Sphere", *ApJ* 622..759G.
        .. [#] M. Reinecke and D. Sverre Seljebotn, 2013, "Libsharp - spherical
               harmonic transforms revisited";
               `arXiv:1303.4945 <http://www.arxiv.org/abs/1303.4945>`_

        Attributes
        ----------
        para : numpy.ndarray
            Array containing the number `nside`.
        dtype : numpy.dtype
            Data type of the field values, which is always numpy.float64.
        discrete : bool
            Whether or not the underlying space is discrete, always ``False``
            for spherical spaces.
        vol : numpy.ndarray
            An array with one element containing the pixel size.
    """

97
    def __init__(self, nside=2, dtype=np.dtype('float')):
csongor's avatar
csongor committed
98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120
        """
            Sets the attributes for a hp_space class instance.

            Parameters
            ----------
            nside : int
                Resolution parameter for the HEALPix discretization, resulting
                in ``12*nside**2`` pixels.

            Returns
            -------
            None

            Raises
            ------
            ImportError
                If the healpy module is not available.
            ValueError
                If input `nside` is invaild.

        """
        # check imports
        if not gc['use_healpy']:
Jait Dixit's avatar
Jait Dixit committed
121
            raise ImportError("ERROR: healpy not available.")
csongor's avatar
csongor committed
122

Jait Dixit's avatar
Jait Dixit committed
123 124
        # setup paradict
        self.paradict = HPSpaceParadict(nside=nside)
csongor's avatar
csongor committed
125

Jait Dixit's avatar
Jait Dixit committed
126
        # setup dtype
127
        self.dtype = np.dtype(dtype)
csongor's avatar
csongor committed
128

129 130
        # HPSpace is not harmonic
        self._harmonic = False
csongor's avatar
csongor committed
131 132 133

    @property
    def shape(self):
Jait Dixit's avatar
Jait Dixit committed
134
        return (np.int(12 * self.paradict['nside'] ** 2),)
csongor's avatar
csongor committed
135 136

    @property
Jait Dixit's avatar
Jait Dixit committed
137 138
    def dim(self):
        return np.int(12 * self.paradict['nside'] ** 2)
csongor's avatar
csongor committed
139

140 141 142
    @property
    def total_volume(self):
        return 4 * np.pi
143

144 145
    def weight(self, x, power=1, axes=None, inplace=False):
        weight = ((4*np.pi) / (12 * self.paradict['nside']**2)) ** power
146 147 148 149 150 151 152 153

        if inplace:
            x *= weight
            result_x = x
        else:
            result_x = x * weight

        return result_x