class GradientCylinder(cylinder.UnpolarisedCylinderTelescope):
min_spacing = config.Property(proptype=float, default=-1.0)
max_spacing = config.Property(proptype=float, default=20.0)
def feed_positions_cylinder(self, cylinder_index):
if cylinder_index >= self.num_cylinders or cylinder_index < 0:
raise Exception("Cylinder index is invalid.")
nf = self.num_feeds
# Parameters for gradient feedspacing
a = self.wavelengths[
-1] / 2.0 if self.min_spacing < 0.0 else self.min_spacing
# b = 2 * (sp - a) / nf
b = 2.0 * (self.max_spacing - a * (nf - 1)) / (nf - 1)**2.0
pos = np.empty([nf, 2], dtype=np.float64)
i = np.arange(nf)
pos[:, 0] = cylinder_index * self.cylinder_spacing
pos[:, 1] = a * i + 0.5 * b * i**2
return pos
class RestrictedBeam(cylinder.CylinderTelescope):
beam_height = config.Property(proptype=typeutil.nonnegative_float, default=30.0)
beam_type = config.Property(proptype=str, default='box')
def bmask_gaussian(self, feed, freq):
pointing = self.zenith
bdist = (self._angpos - pointing[np.newaxis, :])
bdist = np.abs(np.where((bdist[:, 1] < np.pi)[:, np.newaxis], bdist, bdist - np.array([0, 2*np.pi])[np.newaxis, :]))
bmask = gaussian_fwhm(bdist[:, 0], np.radians(self.beam_height))
return bmask
def bmask_box(self, feed, freq):
pointing = self.zenith
bdist = (self._angpos - pointing[np.newaxis, :])
bdist = np.abs(np.where((bdist[:, 1] < np.pi)[:, np.newaxis], bdist, bdist - np.array([0, 2*np.pi])[np.newaxis, :]))
bmask = (np.abs(bdist[:, 0] / np.radians(self.beam_height)) < 0.5)
return bmask
class UnequalFeedsCylinder(cylinder.PolarisedCylinderTelescope):
"""A polarized unequal number of feeds cylinder array.
A class for multiple side by side placed cylinders, each may have different number of equal spacing feeds.
"""
num_cylinders = config.Property(proptype=typeutil.positive_int, default=3)
num_feeds = config.Property(
proptype=typeutil.positive_int_or_non_empty_list, default=[31, 32, 33])
feed_spacing = config.Property(
proptype=typeutil.positive_float_or_non_empty_list,
default=[15.5 / 30, 0.5, 15.5 / 32])
cylinder_width = config.Property(proptype=typeutil.positive_float,
default=15.0)
def feed_positions_cylinder(self, cylinder_index):
"""Get the feed positions on the specified cylinder.
Parameters
----------
cylinder_index : integer
The cylinder index, an integer from 0 to self.num_cylinders.
Returns
-------
feed_positions : np.ndarray
The positions in the telescope plane of the receivers. Packed as
[[u1, v1], [u2, v2], ...].
"""
if cylinder_index >= self.num_cylinders or cylinder_index < 0:
raise Exception("Cylinder index is invalid.")
ncyl = self.num_cylinders
if len(self.num_feeds) == 1:
self.num_feeds *= ncyl
if len(self.num_feeds) != ncyl:
raise Exception('Invalid num_feeds.')
if len(self.feed_spacing) == 1:
self.feed_spacing *= ncyl
if len(self.feed_spacing) != ncyl:
raise Exception('Invalid feed_spacings.')
nf = self.num_feeds[cylinder_index]
sp = self.feed_spacing[cylinder_index]
if self.non_commensurate:
nf = nf - cylinder_index
sp = sp / (nf - 1.0) * nf
pos = np.empty([nf, 2], dtype=np.float64)
pos[:, 0] = cylinder_index * self.cylinder_spacing
pos[:, 1] = np.arange(nf) * sp
return pos
class CylinderExtra(cylinder.UnpolarisedCylinderTelescope):
extra_feeds = config.Property(proptype=np.array, default=[])
def feed_positions_cylinder(self, cylinder_index):
pos = super(CylinderExtra,
self).feed_positions_cylinder(cylinder_index)
nextra = self.extra_feeds.shape[0]
pos2 = np.zeros((pos.shape[0] + nextra, 2), dtype=np.float64)
pos2[nextra:] = pos
pos2[:nextra, 0] = cylinder_index * self.cylinder_spacing
pos2[:nextra, 1] = self.extra_feeds
return pos2
class PolarisedCylinderShift(cylinder.PolarisedCylinderTelescope):
shift = config.Property(proptype=typeutil.float_or_non_empty_list,
default=0.0)
def feed_positions_cylinder(self, cylinder_index):
if cylinder_index >= self.num_cylinders or cylinder_index < 0:
raise Exception("Cylinder index is invalid.")
ncyl = self.num_cylinders
if len(self.shift) == 1:
self.shift *= ncyl
if len(self.shift) != ncyl:
raise Exception('Invalid shifts.')
pos = super(PolarisedCylinderShift,
self).feed_positions_cylinder(cylinder_index)
v_shift = np.ones_like(pos)
v_shift[:, 0] = 0.0 # u-direction doesn't change
pos += self.shift[cylinder_index] * v_shift
return pos
class GmrtArray(telescope.TransitTelescope):
"""A Telescope describing an interferometric array of dishes.
Attributes
----------
gridu, gridv : integer
Number of dishes in u and v directions.
dish_width : scalar
Width of the dish in metres.
"""
fwhm = 3.1 # degrees
freq_lower = 139.33
freq_upper = 156.00
num_freq = 64
_pos_file = os.path.dirname(__file__) + '/gmrtpositions.dat'
_compact = True
_bc_freq = None
_bc_nside = None
_positions = None
pointing = config.Property(proptype=float, default=0.0)
dish_width = 45.0
tsys_flat = 582.0
minlength = 0.0
maxlength = 600.0
def __init__(self, pointing=0.0):
super(GmrtArray, self).__init__(latitude=19.09, longitude=74.05)
self._positions = np.loadtxt(self._pos_file)
#self._positions = self._positions[np.where((self._positions**2).sum(axis=1)**0.5 < 1000)]
self.pointing = pointing
@property
def u_width(self):
return self.dish_width
@property
def v_width(self):
return self.dish_width
def beam(self, feed, freq):
"""Beam for a particular feed.
Parameters
----------
feed : integer
Index for the feed.
freq : integer
Index for the frequency.
Returns
-------
beam : np.ndarray
A Healpix map (of size self._nside) of the beam. Potentially
complex.
"""
if self._bc_freq != freq or self._bc_nside != self._nside:
sigma = np.radians(self.fwhm) / (8.0 * np.log(2.0))**0.5 / (
self.frequencies[freq] / 150.0)
pointing = np.array(
[np.pi / 2.0 - np.radians(self.pointing), self.zenith[1]])
x2 = (1.0 - coord.sph_dot(self._angpos, pointing)**2) / (4 *
sigma**2)
self._bc_map = np.exp(-x2)
self._bc_freq = freq
self._bc_nside = self._nside
return self._bc_map
beamx = beam
beamy = beam
@property
def _single_feedpositions(self):
"""The set of feed positions in the CMU telescope.
Returns
-------
feedpositions : np.ndarray
The positions in the telescope plane of the receivers. Packed as
[[u1, v1], [u2, v2], ...].
"""
if self._positions is None:
self._positions = np.loadtxt(self._pos_file)
return self._positions
class FocalPlaneArray(telescope.UnpolarisedTelescope):
beam_num_u = config.Property(proptype=typeutil.positive_int, default=10)
beam_num_v = config.Property(proptype=typeutil.positive_int, default=10)
beam_spacing_u = config.Property(proptype=typeutil.positive_float, default=0.1)
beam_spacing_v = config.Property(proptype=typeutil.positive_float, default=0.1)
beam_size = config.Property(proptype=typeutil.positive_float, default=0.1)
beam_pivot = config.Property(proptype=typeutil.positive_float, default=400.0)
beam_freq_scale = config.Property(proptype=bool, default=True)
square_beam = config.Property(proptype=bool, default=False)
@property
def beam_pointings(self):
pnt_u = self.beam_spacing_u * (np.arange(self.beam_num_u) - (self.beam_num_u - 1) / 2.0)
pnt_v = self.beam_spacing_v * (np.arange(self.beam_num_v) - (self.beam_num_v - 1) / 2.0)
pnt_u = np.radians(pnt_u) + self.zenith[1]
pnt_v = np.radians(pnt_v) + self.zenith[0]
pnt = np.zeros((self.beam_num_u, self.beam_num_v, 2))
pnt[:, :, 1] = pnt_u[:, np.newaxis]
pnt[:, :, 0] = pnt_v[np.newaxis, :]
return pnt.reshape(-1, 2)
#== Methods for calculating the unique baselines ===
@util.cache_last
def beam_gaussian(self, feed, freq):
pointing = self.beam_pointings[feed]
if self.beam_freq_scale:
fwhm = self.beam_size * self.frequencies[freq] / self.beam_pivot
else:
fwhm = self.beam_size
return gaussian_beam(self._angpos, pointing, fwhm)
@util.cache_last
def beam_square(self, feed, freq):
pointing = self.beam_pointings[feed]
bdist = (self._angpos - pointing[np.newaxis, :])
bdist = np.abs(np.where((bdist[:, 1] < np.pi)[:, np.newaxis], bdist, bdist - np.array([0, 2*np.pi])[np.newaxis, :])) / np.radians(self.beam_size)
#bdist = np.abs(np.where((bdist[:, 1] < np.pi)[:, np.newaxis], bdist, bdist - np.array([0, 2*np.pi])[np.newaxis, :])) / np.radians(self.beam_size)
beam = np.logical_and(bdist[:, 0] < 0.5, bdist[:, 1] < 0.5).astype(np.float64)
return beam
def beam(self, feed, freq):
if self.square_beam:
return self.beam_square(feed, freq)
else:
return self.beam_gaussian(feed, freq)
@property
def dish_width(self):
lpivot = (units.c / self.beam_pivot * 1e-6)
return (lpivot / np.radians(self.beam_size))
@property
def u_width(self):
return self.dish_width
@property
def v_width(self):
return self.dish_width
@property
def nfeed(self):
return self.beam_num_u * self.beam_num_v
@property
def feedpositions(self):
"""Feed positions (all zero in FPA).
"""
return np.zeros([self.nfeed, 2])
def _unique_beams(self):
beam_mask = np.identity(self.nfeed, dtype=np.bool)
beam_map = telescope._remap_keyarray(np.diag(np.arange(self.nfeed)), mask=beam_mask)
return beam_map, beam_mask
class PersonWithPet(Person):
petname = config.Property(default='Molly', proptype=str)
petage = 36
class Person(config.Reader):
name = config.Property(default='Bill', proptype=str)
age = config.Property(default=26, proptype=float, key='ageinyears')
