def create_griddata_from_array(
data: numpy.array, grid_wcs: WCS, projection_wcs: WCS,
polarisation_frame: PolarisationFrame) -> GridData:
""" Create a griddata from an array and wcs's
The griddata has axes [chan, pol, z, y, x] where z, y, x are spatial axes in either sky or Fourier plane. The
order in the WCS is reversed so the grid_WCS describes UU, VV, WW, STOKES, FREQ axes
Griddata holds the original sky plane projection in the projection_wcs.
:param data: Numpy.array
:param grid_wcs: Grid world coordinate system
:param projection_wcs: Projection world coordinate system
:param polarisation_frame: Polarisation Frame
:return: GridData
"""
fgriddata = GridData()
fgriddata.polarisation_frame = polarisation_frame
fgriddata.data = data
fgriddata.grid_wcs = grid_wcs.deepcopy()
fgriddata.projection_wcs = projection_wcs.deepcopy()
if griddata_sizeof(fgriddata) >= 1.0:
log.debug(
"create_griddata_from_array: created %s image of shape %s, size %.3f (GB)"
% (fgriddata.data.dtype, str(
fgriddata.shape), griddata_sizeof(fgriddata)))
assert isinstance(fgriddata, GridData), "Type is %s" % type(fgriddata)
return fgriddata
def grid_visibility_weight_to_griddata(vis, griddata: GridData, cf):
"""Grid Visibility weight onto a GridData
:param vis: Visibility to be gridded
:param griddata: GridData
:return: GridData
"""
assert isinstance(vis, Visibility), vis
assert vis.polarisation_frame == griddata.polarisation_frame
nchan, npol, nz, ny, nx = griddata.shape
sumwt = numpy.zeros([nchan, npol])
pu_grid, pu_offset, pv_grid, pv_offset, pwg_grid, pwg_fraction, pwc_grid, pwc_fraction, pfreq_grid = \
convolution_mapping_visibility(vis, griddata, vis.frequency, cf)
_, _, _, _, _, gv, gu = cf.shape
coords = zip(vis.flagged_imaging_weight, pfreq_grid, pu_grid, pv_grid, pwg_grid)
griddata.data[...] = 0.0
real_gd = numpy.real(griddata.data)
for vwt, chan, xx, yy, zzg in coords:
real_gd[chan, :, zzg, yy, xx] += vwt
sumwt[chan, :] += vwt
griddata.data = real_gd.astype("complex")
return griddata, sumwt
def grid_blockvisibility_weight_to_griddata(vis, griddata: GridData, cf):
"""Grid BlockVisibility weight onto a GridData
:param vis: BlockVisibility to be gridded
:param griddata: GridData
:param cf: Convolution function
:return: GridData
"""
assert isinstance(vis, BlockVisibility), vis
assert vis.polarisation_frame == griddata.polarisation_frame
nchan, npol, nz, ny, nx = griddata.shape
sumwt = numpy.zeros([nchan, npol])
_, _, _, _, _, gv, gu = cf.shape
vis_to_im = numpy.round(
griddata.grid_wcs.sub([5]).wcs_world2pix(vis.frequency, 0)[0]).astype('int')
griddata.data[...] = 0.0
real_gd = numpy.real(griddata.data)
nrows, nants, _, nvchan, nvpol = vis.vis.shape
# Transpose to get row varying fastest
fwtt = vis.flagged_imaging_weight.reshape([nrows * nants * nants, nvchan, nvpol]).T
for vchan in range(nvchan):
imchan = vis_to_im[vchan]
pu_grid, pu_offset, pv_grid, pv_offset, pwg_grid, _, _, _ = \
convolution_mapping_blockvisibility(vis, griddata, vis.frequency[vchan], cf)
for pol in range(nvpol):
for row in range(nrows * nants * nants):
real_gd[imchan, pol, pwg_grid[row], pv_grid[row], pu_grid[row]] += fwtt[
pol, vchan, row]
sumwt[imchan, pol] += fwtt[pol, vchan, row]
griddata.data = real_gd.astype("complex")
return griddata, sumwt
def copy_griddata(gd):
""" Copy griddata
:param gd:
:return:
"""
assert isinstance(gd, GridData), gd
newgd = GridData()
newgd.polarisation_frame = gd.polarisation_frame
newgd.data = copy.deepcopy(gd.data)
if gd.grid_wcs is None:
newgd.grid_wcs = None
else:
newgd.grid_wcs = copy.deepcopy(gd.grid_wcs)
if gd.projection_wcs is None:
newgd.projection_wcs = None
else:
newgd.projection_wcs = copy.deepcopy(gd.projection_wcs)
if griddata_sizeof(newgd) >= 1.0:
log.debug("copy_image: copied %s image of shape %s, size %.3f (GB)" %
(newgd.data.dtype, str(newgd.shape), griddata_sizeof(newgd)))
assert type(newgd) == GridData
return newgd