def facet_centers(N, ncrd=2):
"""Return the coordinates of N points equally spaced around the sphere.
Will return xyz or ra,dec depending on ncrd. Shuffles the order of the
pointing centers wrt pack_sphere so that widely spaced points are done
first, and then the gaps between them, and then the gaps between those.."""
assert(ncrd == 2 or ncrd == 3)
ind1 = n.arange(N); _local_shuffle(ind1)
ind2 = _bit_reverse_order(N)
ind = ind1.take(ind2)
pnts = pack_sphere(N)
pnts = pnts.take(ind, axis=1)
if ncrd == 3: return pnts
else: return coord.eq2radec(pnts)
def facet_centers(N, ncrd=2):
"""Return the coordinates of N points equally spaced around the sphere.
Will return xyz or ra,dec depending on ncrd. Shuffles the order of the
pointing centers wrt pack_sphere so that widely spaced points are done
first, and then the gaps between them, and then the gaps between those.."""
assert (ncrd == 2 or ncrd == 3)
ind1 = n.arange(N)
_local_shuffle(ind1)
ind2 = _bit_reverse_order(N)
ind = ind1.take(ind2)
pnts = pack_sphere(N)
pnts = pnts.take(ind, axis=1)
if ncrd == 3: return pnts
else: return coord.eq2radec(pnts)
def get_baseline(self, i, j, src='z'):
"""Return the baseline corresponding to i,j in various coordinate
projections: src='e' for current equatorial, 'z' for zenith
topocentric, 'r' for unrotated equatorial, or a RadioBody for
projection toward that source."""
bl = self[j] - self[i]
if type(src) == str:
if src == 'e': return n.dot(self._eq2now, bl)
elif src == 'z': return n.dot(self._eq2zen, bl)
elif src == 'r': return bl
else: raise ValueError('Unrecognized source:' + src)
try:
if src.alt < 0:
raise PointingError('%s below horizon' % src.src_name)
m = src.map
except(AttributeError):
ra,dec = coord.eq2radec(src)
m = coord.eq2top_m(self.sidereal_time() - ra, dec)
return n.dot(m, bl).transpose()
def get_baseline(self, i, j, src='z'):
"""Return the baseline corresponding to i,j in various coordinate
projections: src='e' for current equatorial, 'z' for zenith
topocentric, 'r' for unrotated equatorial, or a RadioBody for
projection toward that source."""
bl = self[j] - self[i]
if type(src) == str:
if src == 'e': return n.dot(self._eq2now, bl)
elif src == 'z': return n.dot(self._eq2zen, bl)
elif src == 'r': return bl
else: raise ValueError('Unrecognized source:' + src)
try:
if src.alt < 0:
raise PointingError('%s below horizon' % src.src_name)
m = src.map
except (AttributeError):
ra, dec = coord.eq2radec(src)
m = coord.eq2top_m(self.sidereal_time() - ra, dec)
return n.dot(m, bl).transpose()
