def to_pixel(self, Nside=None, Npix=None, dtype=None, out=None):
"""
::
>>> insh = harmonic_sphere_map(0, 0, 4)
>>> insh.to_pixel(8)
Pixel sphere map (ring-ordered, Nside=8, Npix=768)
Convert a uniform map::
>>> shmap = harmonic_sphere_map([[23], [0, 0], [0, 0, 0]])
>>> pixmap = shmap.to_pixel(8); pixmap
Pixel sphere map (ring-ordered, Nside=8, Npix=768)
>>> np.allclose(pixmap, 23.0 / np.sqrt(4*np.pi))
True
One can convert multiple maps at once::
>>> M = shmap
>>> M = np.hstack((M[:,None], M[:,None], M[:,None], M[:,None]))
>>> M = np.dstack((M, M))
>>> M = harmonic_sphere_map(M, 0, 2); M
(4, 2)-stack of brief complex harmonic sphere maps with l=0..2 (6 coefficients)
>>> x = M.to_pixel(4); x
(4, 2)-stack of pixel sphere maps (ring-ordered, Nside=4, Npix=192)
>>> np.allclose(x, 23.0 / np.sqrt(4*np.pi))
True
"""
self._check_not_pretending()
if self.format is not COMPLEX_BRIEF:
return self.to_complex().to_pixel(Nside, Npix, dtype, out)
if Nside is None:
if Npix is None: raise ValueError("Provide Nside or Npix")
Nside = npix2nside(Npix)
if Npix is None:
Npix = nside2npix(Nside)
if dtype is None:
dtype = self.dtype
dtype = to_real_dtype(dtype)
# for now, only double...
assert dtype == np.float64
size = self.shape[1:]
if out is None:
out = np.empty((Npix,) + size, dtype, order='F')
# Todo: Optimize -- have lmin in complexpacked2complexmatrix
if self.lmin == 0:
source = self
else:
source = np.empty((l_to_lm(self.lmax + 1),) + size, complex_dtype, order='F')
source[:l_to_lm(self.lmin)] = 0
source[l_to_lm(self.lmin):] = self
for mapidx in np.ndindex(*size):
idx = (slice(None),) + mapidx
alm_matrix = mapdatautils.alm_complexpacked2complexmatrix(source[idx])
mapdatautils.alm2map(Nside, alm_matrix, out=out[idx])
return _PixelSphereMap(out, pixel_order='ring')
def rotate(self, psi, theta, phi):
"""
Returns a rotated copy of self. O(lmax^3).
::
>>> M = harmonic_sphere_map([[1, 0], [1, 0, 0]], lmin=1)
>>> R = M.rotate(0, np.pi, 0); R
Brief complex harmonic sphere map with l=1..2 (5 coefficients)
>>> np.round(R.to_array(), 4)
array([-1.+0.j, -0.+0.j, 1.+0.j, 0.+0.j, 0.+0.j])
One can convert multiple maps at once::
TODO write tests
"""
from healpix import rotate_alm_d
self._check_not_pretending()
if psi == 0 and theta == 0 and phi == 0:
return self.copy()
if self.format is not COMPLEX_BRIEF:
x = self.to_complex().rotate(psi, theta, phi)
if self.format is REAL_FULL:
return x.to_real()
else:
assert False
size = self.shape[1:]
# Todo: Optimize -- have lmin in complexpacked2complexmatrix
out = np.empty((l_to_lm(self.lmax + 1),) + size, complex_dtype, order='F')
out[:l_to_lm(self.lmin), ...] = 0
out[l_to_lm(self.lmin):, ...] = self
alm_matrix = np.empty((1, self.lmax + 1, self.lmax + 1), complex_dtype, order='F')
for mapidx in np.ndindex(*size):
idx = (slice(None),) + mapidx
mapdatautils.alm_complexpacked2complexmatrix(out[idx], alm_matrix[0,:,:])
rotate_alm_d(self.lmax, alm_matrix, psi, theta, phi)
mapdatautils.alm_complexmatrix2complexpacked(alm_matrix[0,:,:], out[idx])
out = out[l_to_lm(self.lmin):, ...]
return _HarmonicSphereMap(out, self.lmin, self.lmax, COMPLEX_BRIEF)
