def __init__(self, psf, imsize, nthreads=1, backward_undersize=None):
self.nthreads = nthreads
self.nband, nx_psf, ny_psf = psf.shape
_, nx, ny = imsize
npad_xl = (nx_psf - nx) // 2
npad_xr = nx_psf - nx - npad_xl
npad_yl = (ny_psf - ny) // 2
npad_yr = ny_psf - ny - npad_yl
self.padding = ((0, 0), (npad_xl, npad_xr), (npad_yl, npad_yr))
self.ax = (1, 2)
self.unpad_x = slice(npad_xl, -npad_xr)
self.unpad_y = slice(npad_yl, -npad_yr)
self.lastsize = ny + np.sum(self.padding[-1])
self.psf = psf
psf_pad = iFs(psf, axes=self.ax)
self.psfhat = r2c(psf_pad,
axes=self.ax,
forward=True,
nthreads=nthreads,
inorm=0)
# LB - failed experiment?
# self.psfhatinv = 1/(self.psfhat + 1.0)
if backward_undersize is not None:
# set up for backward step
nx_psfb = good_size(int(backward_undersize * nx))
ny_psfb = good_size(int(backward_undersize * ny))
npad_xlb = (nx_psfb - nx) // 2
npad_xrb = nx_psfb - nx - npad_xlb
npad_ylb = (ny_psfb - ny) // 2
npad_yrb = ny_psfb - ny - npad_ylb
self.paddingb = ((0, 0), (npad_xlb, npad_xrb), (npad_ylb,
npad_yrb))
self.unpad_xb = slice(npad_xlb, -npad_xrb)
self.unpad_yb = slice(npad_ylb, -npad_yrb)
self.lastsizeb = ny + np.sum(self.paddingb[-1])
xlb = (nx_psf - nx_psfb) // 2
xrb = nx_psf - nx_psfb - xlb
ylb = (ny_psf - ny_psfb) // 2
yrb = ny_psf - ny_psfb - ylb
psf_padb = iFs(psf[:, slice(xlb, -xrb),
slice(ylb, -yrb)],
axes=self.ax)
self.psfhatb = r2c(psf_padb,
axes=self.ax,
forward=True,
nthreads=nthreads,
inorm=0)
else:
self.paddingb = self.padding
self.unpad_xb = self.unpad_x
self.unpad_yb = self.unpad_y
self.lastsizeb = self.lastsize
self.psfhatb = self.psfhat
def _hessian(x, psfhat, padding, nthreads, unpad_x, unpad_y, lastsize):
xhat = iFs(np.pad(x, padding, mode='constant'), axes=(1, 2))
xhat = r2c(xhat, axes=(1, 2), nthreads=nthreads, forward=True, inorm=0)
xhat = c2r(xhat * psfhat,
axes=(1, 2),
forward=False,
lastsize=lastsize,
inorm=2,
nthreads=nthreads)
return Fs(xhat, axes=(1, 2))[:, unpad_x, unpad_y]
def convolve2gaussres(image, xx, yy, gaussparf, nthreads, gausspari=None, pfrac=0.5, norm_kernel=False):
"""
Convolves the image to a specified resolution.
Parameters
----------
Image - (nband, nx, ny) array to convolve
xx/yy - coordinates on the grid in the same units as gaussparf.
gaussparf - tuple containing Gaussian parameters of desired resolution (emaj, emin, pa).
gausspari - initial resolution . By default it is assumed that the image is a clean component image with no associated resolution.
If beampari is specified, it must be a tuple containing gausspars for each imaging band in the same format.
nthreads - number of threads to use for the FFT's.
pfrac - padding used for the FFT based convolution. Will pad by pfrac/2 on both sides of image
"""
nband, nx, ny = image.shape
padding, unpad_x, unpad_y = get_padding_info(nx, ny, pfrac)
ax = (1, 2) # axes over which to perform fft
lastsize = ny + np.sum(padding[-1])
gausskern = Gaussian2D(xx, yy, gaussparf, normalise=norm_kernel)
gausskern = np.pad(gausskern[None], padding, mode='constant')
gausskernhat = r2c(iFs(gausskern, axes=ax), axes=ax, forward=True, nthreads=nthreads, inorm=0)
image = np.pad(image, padding, mode='constant')
imhat = r2c(iFs(image, axes=ax), axes=ax, forward=True, nthreads=nthreads, inorm=0)
# convolve to desired resolution
if gausspari is None:
imhat *= gausskernhat
else:
for i in range(nband):
thiskern = Gaussian2D(xx, yy, gausspari[i], normalise=norm_kernel)
thiskern = np.pad(thiskern[None], padding, mode='constant')
thiskernhat = r2c(iFs(thiskern, axes=ax), axes=ax, forward=True, nthreads=nthreads, inorm=0)
convkernhat = np.where(np.abs(thiskernhat)>0.0, gausskernhat/thiskernhat, 0.0)
imhat[i] *= convkernhat[0]
image = Fs(c2r(imhat, axes=ax, forward=False, lastsize=lastsize, inorm=2, nthreads=nthreads), axes=ax)[:, unpad_x, unpad_y]
return image, gausskern[:, unpad_x, unpad_y]
def __init__(self, sigma0, nband, nx, ny, nthreads=8):
self.nthreads = nthreads
self.nx = nx
self.ny = ny
nx_psf = 2 * self.nx
npad_x = (nx_psf - nx) // 2
ny_psf = 2 * self.ny
npad_y = (ny_psf - ny) // 2
self.padding = ((0, 0), (npad_x, npad_x), (npad_y, npad_y))
self.ax = (1, 2)
self.unpad_x = slice(npad_x, -npad_x)
self.unpad_y = slice(npad_y, -npad_y)
self.lastsize = ny + np.sum(self.padding[-1])
# set length scales
length_scale = 0.5
K = make_kernel(nx_psf, ny_psf, sigma0, length_scale)
self.K = K
K_pad = iFs(self.K, axes=self.ax)
self.Khat = r2c(K_pad,
axes=self.ax,
forward=True,
nthreads=nthreads,
inorm=0)
self.Khatinv = np.where(self.Khat.real > 1e-14, 1.0 / self.Khat, 1e-14)
# get covariance in each dimension
# pixel coordinates
self.Kv = mock_array(nband) # np.eye(nband) * sigma0**2
self.Kvinv = mock_array(nband) # np.eye(nband) / sigma0**2
if nx == ny:
l_coord = m_coord = np.arange(-(nx // 2), nx // 2)
self.Kl = self.Km = expsq(l_coord, l_coord, 1.0, length_scale)
self.Klinv = self.Kminv = np.linalg.pinv(self.Kl,
hermitian=True,
rcond=1e-12)
self.Kl *= sigma0**2
self.Klinv /= sigma0**2
else:
l_coord = np.arange(-(nx // 2), nx // 2)
m_coord = np.arange(-(ny // 2), ny // 2)
self.Kl = expsq(l_coord, l_coord, sigma0, length_scale)
self.Km = expsq(m_coord, m_coord, 1.0, length_scale)
self.Klinv = np.linalg.pinv(self.Kl, hermitian=True, rcond=1e-12)
self.Kminv = np.linalg.pinv(self.Km, hermitian=True, rcond=1e-12)
# Kronecker matrices for "fast" matrix vector products
self.Kkron = (self.Kv, self.Kl, self.Km)
self.Kinvkron = (self.Kvinv, self.Klinv, self.Kminv)
def convolveb(self, x):
xhat = iFs(np.pad(x, self.paddingb, mode='constant'), axes=self.ax)
xhat = r2c(xhat,
axes=self.ax,
nthreads=self.nthreads,
forward=True,
inorm=0)
xhat = c2r(xhat * self.psfhatb,
axes=self.ax,
forward=False,
lastsize=self.lastsizeb,
inorm=2,
nthreads=self.nthreads)
return Fs(xhat, axes=self.ax)[:, self.unpad_xb, self.unpad_yb]
def __init__(self, psf, nthreads, sigma0=1.0):
self.nthreads = nthreads
self.nband, nx_psf, ny_psf = psf.shape
nx = nx_psf // 2
ny = ny_psf // 2
npad_x = (nx_psf - nx) // 2
npad_y = (ny_psf - ny) // 2
self.padding = ((0, 0), (npad_x, npad_x), (npad_y, npad_y))
self.ax = (1, 2)
self.unpad_x = slice(npad_x, -npad_x)
self.unpad_y = slice(npad_y, -npad_y)
self.lastsize = ny + np.sum(self.padding[-1])
self.psf = psf
psf_pad = iFs(psf, axes=self.ax)
self.psfhat = r2c(psf_pad,
axes=self.ax,
forward=True,
nthreads=nthreads,
inorm=0)
def _forward(**kw):
args = OmegaConf.create(kw)
OmegaConf.set_struct(args, True)
import numpy as np
import numexpr as ne
import dask
import dask.array as da
from dask.distributed import performance_report
from pfb.utils.fits import load_fits, set_wcs, save_fits, data_from_header
from pfb.opt.hogbom import hogbom
from astropy.io import fits
print("Loading residual", file=log)
residual = load_fits(args.residual, dtype=args.output_type).squeeze()
nband, nx, ny = residual.shape
hdr = fits.getheader(args.residual)
print("Loading psf", file=log)
psf = load_fits(args.psf, dtype=args.output_type).squeeze()
_, nx_psf, ny_psf = psf.shape
hdr_psf = fits.getheader(args.psf)
wsums = np.amax(psf.reshape(-1, nx_psf*ny_psf), axis=1)
wsum = np.sum(wsums)
psf /= wsum
psf_mfs = np.sum(psf, axis=0)
assert (psf_mfs.max() - 1.0) < 1e-4
residual /= wsum
residual_mfs = np.sum(residual, axis=0)
# get info required to set WCS
ra = np.deg2rad(hdr['CRVAL1'])
dec = np.deg2rad(hdr['CRVAL2'])
radec = [ra, dec]
cell_deg = np.abs(hdr['CDELT1'])
if cell_deg != np.abs(hdr['CDELT2']):
raise NotImplementedError('cell sizes have to be equal')
cell_rad = np.deg2rad(cell_deg)
l_coord, ref_l = data_from_header(hdr, axis=1)
l_coord -= ref_l
m_coord, ref_m = data_from_header(hdr, axis=2)
m_coord -= ref_m
freq_out, ref_freq = data_from_header(hdr, axis=3)
hdr_mfs = set_wcs(cell_deg, cell_deg, nx, ny, radec, ref_freq)
save_fits(args.output_filename + '_residual_mfs.fits', residual_mfs, hdr_mfs,
dtype=args.output_type)
rms = np.std(residual_mfs)
rmax = np.abs(residual_mfs).max()
print("Initial peak residual = %f, rms = %f" % (rmax, rms), file=log)
# load beam
if args.beam_model is not None:
if args.beam_model.endswith('.fits'): # beam already interpolated
bhdr = fits.getheader(args.beam_model)
l_coord_beam, ref_lb = data_from_header(bhdr, axis=1)
l_coord_beam -= ref_lb
if not np.array_equal(l_coord_beam, l_coord):
raise ValueError("l coordinates of beam model do not match those of image. Use power_beam_maker to interpolate to fits header.")
m_coord_beam, ref_mb = data_from_header(bhdr, axis=2)
m_coord_beam -= ref_mb
if not np.array_equal(m_coord_beam, m_coord):
raise ValueError("m coordinates of beam model do not match those of image. Use power_beam_maker to interpolate to fits header.")
freq_beam, _ = data_from_header(bhdr, axis=freq_axis)
if not np.array_equal(freq_out, freq_beam):
raise ValueError("Freqs of beam model do not match those of image. Use power_beam_maker to interpolate to fits header.")
beam_image = load_fits(args.beam_model, dtype=args.output_type).squeeze()
elif args.beam_model.lower() == "jimbeam":
from katbeam import JimBeam
if args.band.lower() == 'l':
beam = JimBeam('MKAT-AA-L-JIM-2020')
elif args.band.lower() == 'uhf':
beam = JimBeam('MKAT-AA-UHF-JIM-2020')
else:
raise ValueError("Unkown band %s"%args.band[i])
xx, yy = np.meshgrid(l_coord, m_coord, indexing='ij')
beam_image = np.zeros(residual.shape, dtype=args.output_type)
for v in range(freq_out.size):
# freq must be in MHz
beam_image[v] = beam.I(xx, yy, freq_out[v]/1e6).astype(args.output_type)
else:
beam_image = np.ones((nband, nx, ny), dtype=args.output_type)
if args.mask is not None:
mask = load_fits(args.mask).squeeze()
assert mask.shape == (nx, ny)
beam_image *= mask[None, :, :]
beam_image = da.from_array(beam_image, chunks=(1, -1, -1))
# if weight table is provided we use the vis space Hessian approximation
if args.weight_table is not None:
print("Solving for update using vis space approximation", file=log)
normfact = wsum
from pfb.utils.misc import plan_row_chunk
from daskms.experimental.zarr import xds_from_zarr
xds = xds_from_zarr(args.weight_table)[0]
nrow = xds.row.size
freq = xds.chan.data
nchan = freq.size
# bin edges
fmin = freq.min()
fmax = freq.max()
fbins = np.linspace(fmin, fmax, nband + 1)
# chan <-> band mapping
band_mapping = {}
chan_chunks = {}
freq_bin_idx = {}
freq_bin_counts = {}
band_map = np.zeros(freq.size, dtype=np.int32)
for band in range(nband):
indl = freq >= fbins[band]
indu = freq < fbins[band + 1] + 1e-6
band_map = np.where(indl & indu, band, band_map)
# to dask arrays
bands, bin_counts = np.unique(band_map, return_counts=True)
band_mapping = tuple(bands)
chan_chunks = {'chan': tuple(bin_counts)}
freq = da.from_array(freq, chunks=tuple(bin_counts))
bin_idx = np.append(np.array([0]), np.cumsum(bin_counts))[0:-1]
freq_bin_idx = da.from_array(bin_idx, chunks=1)
freq_bin_counts = da.from_array(bin_counts, chunks=1)
max_chan_chunk = bin_counts.max()
bin_counts = tuple(bin_counts)
# the first factor of 3 accounts for the intermediate visibilities
# produced in Hessian (i.e. complex data + real weights)
memory_per_row = (3 * max_chan_chunk * xds.WEIGHT.data.itemsize +
3 * xds.UVW.data.itemsize)
# get approx image size
pixel_bytes = np.dtype(args.output_type).itemsize
band_size = nx * ny * pixel_bytes
if args.host_address is None:
# nworker bands on single node
row_chunk = plan_row_chunk(args.mem_limit/args.nworkers, band_size, nrow,
memory_per_row, args.nthreads_per_worker)
else:
# single band per node
row_chunk = plan_row_chunk(args.mem_limit, band_size, nrow,
memory_per_row, args.nthreads_per_worker)
print("nrows = %i, row chunks set to %i for a total of %i chunks per node" %
(nrow, row_chunk, int(np.ceil(nrow / row_chunk))), file=log)
residual = da.from_array(residual, chunks=(1, -1, -1))
x0 = da.zeros((nband, nx, ny), chunks=(1, -1, -1), dtype=residual.dtype)
xds = xds_from_zarr(args.weight_table, chunks={'row': -1, #row_chunk,
'chan': bin_counts})[0]
from pfb.opt.pcg import pcg_wgt
model = pcg_wgt(xds.UVW.data,
xds.WEIGHT.data.astype(args.output_type),
residual,
x0,
beam_image,
freq,
freq_bin_idx,
freq_bin_counts,
cell_rad,
args.wstack,
args.epsilon,
args.double_accum,
args.nvthreads,
args.sigmainv,
wsum,
args.cg_tol,
args.cg_maxit,
args.cg_minit,
args.cg_verbose,
args.cg_report_freq,
args.backtrack).compute()
else: # we use the image space approximation
print("Solving for update using image space approximation", file=log)
normfact = 1.0
from pfb.operators.psf import hessian
from ducc0.fft import r2c
iFs = np.fft.ifftshift
npad_xl = (nx_psf - nx)//2
npad_xr = nx_psf - nx - npad_xl
npad_yl = (ny_psf - ny)//2
npad_yr = ny_psf - ny - npad_yl
padding = ((0, 0), (npad_xl, npad_xr), (npad_yl, npad_yr))
unpad_x = slice(npad_xl, -npad_xr)
unpad_y = slice(npad_yl, -npad_yr)
lastsize = ny + np.sum(padding[-1])
psf_pad = iFs(psf, axes=(1, 2))
psfhat = r2c(psf_pad, axes=(1, 2), forward=True,
nthreads=nthreads, inorm=0)
psfhat = da.from_array(psfhat, chunks=(1, -1, -1))
residual = da.from_array(residual, chunks=(1, -1, -1))
x0 = da.zeros((nband, nx, ny), chunks=(1, -1, -1))
from pfb.opt.pcg import pcg_psf
model = pcg_psf(psfhat,
residual,
x0,
beam_image,
args.sigmainv,
args.nvthreads,
padding,
unpad_x,
unpad_y,
lastsize,
args.cg_tol,
args.cg_maxit,
args.cg_minit,
args.cg_verbose,
args.cg_report_freq,
args.backtrack).compute()
print("Saving results", file=log)
save_fits(args.output_filename + '_update.fits', model, hdr)
model_mfs = np.mean(model, axis=0)
save_fits(args.output_filename + '_update_mfs.fits', model_mfs, hdr_mfs)
print("All done here.", file=log)
def rfftn(a, axes=None, inorm=0, nthreads=1):
return fft.r2c(a, axes=axes, forward=True, inorm=inorm, nthreads=nthreads)
def _clean(**kw):
args = OmegaConf.create(kw)
OmegaConf.set_struct(args, True)
import numpy as np
import numexpr as ne
import dask
import dask.array as da
from dask.distributed import performance_report
from pfb.utils.fits import load_fits, set_wcs, save_fits, data_from_header
from pfb.opt.hogbom import hogbom
from astropy.io import fits
print("Loading dirty", file=log)
dirty = load_fits(args.dirty, dtype=args.output_type).squeeze()
nband, nx, ny = dirty.shape
hdr = fits.getheader(args.dirty)
print("Loading psf", file=log)
psf = load_fits(args.psf, dtype=args.output_type).squeeze()
_, nx_psf, ny_psf = psf.shape
hdr_psf = fits.getheader(args.psf)
wsums = np.amax(psf.reshape(-1, nx_psf * ny_psf), axis=1)
wsum = np.sum(wsums)
psf /= wsum
psf_mfs = np.sum(psf, axis=0)
assert (psf_mfs.max() - 1.0) < 1e-4
dirty /= wsum
dirty_mfs = np.sum(dirty, axis=0)
# get info required to set WCS
ra = np.deg2rad(hdr['CRVAL1'])
dec = np.deg2rad(hdr['CRVAL2'])
radec = [ra, dec]
cell_deg = np.abs(hdr['CDELT1'])
if cell_deg != np.abs(hdr['CDELT2']):
raise NotImplementedError('cell sizes have to be equal')
cell_rad = np.deg2rad(cell_deg)
freq_out, ref_freq = data_from_header(hdr, axis=3)
hdr_mfs = set_wcs(cell_deg, cell_deg, nx, ny, radec, ref_freq)
save_fits(args.output_filename + '_dirty_mfs.fits',
dirty_mfs,
hdr_mfs,
dtype=args.output_type)
# set up Hessian approximation
if args.weight_table is not None:
normfact = wsum
from africanus.gridding.wgridder.dask import hessian
from pfb.utils.misc import plan_row_chunk
from daskms.experimental.zarr import xds_from_zarr
xds = xds_from_zarr(args.weight_table)[0]
nrow = xds.row.size
freqs = xds.chan.data
nchan = freqs.size
# bin edges
fmin = freqs.min()
fmax = freqs.max()
fbins = np.linspace(fmin, fmax, nband + 1)
# chan <-> band mapping
band_mapping = {}
chan_chunks = {}
freq_bin_idx = {}
freq_bin_counts = {}
band_map = np.zeros(freqs.size, dtype=np.int32)
for band in range(nband):
indl = freqs >= fbins[band]
indu = freqs < fbins[band + 1] + 1e-6
band_map = np.where(indl & indu, band, band_map)
# to dask arrays
bands, bin_counts = np.unique(band_map, return_counts=True)
band_mapping = tuple(bands)
chan_chunks = {'chan': tuple(bin_counts)}
freqs = da.from_array(freqs, chunks=tuple(bin_counts))
bin_idx = np.append(np.array([0]), np.cumsum(bin_counts))[0:-1]
freq_bin_idx = da.from_array(bin_idx, chunks=1)
freq_bin_counts = da.from_array(bin_counts, chunks=1)
max_chan_chunk = bin_counts.max()
bin_counts = tuple(bin_counts)
# the first factor of 3 accounts for the intermediate visibilities
# produced in Hessian (i.e. complex data + real weights)
memory_per_row = (3 * max_chan_chunk * xds.WEIGHT.data.itemsize +
3 * xds.UVW.data.itemsize)
# get approx image size
pixel_bytes = np.dtype(args.output_type).itemsize
band_size = nx * ny * pixel_bytes
if args.host_address is None:
# nworker bands on single node
row_chunk = plan_row_chunk(args.mem_limit / args.nworkers,
band_size, nrow, memory_per_row,
args.nthreads_per_worker)
else:
# single band per node
row_chunk = plan_row_chunk(args.mem_limit, band_size, nrow,
memory_per_row,
args.nthreads_per_worker)
print(
"nrows = %i, row chunks set to %i for a total of %i chunks per node"
% (nrow, row_chunk, int(np.ceil(nrow / row_chunk))),
file=log)
def convolver(x):
model = da.from_array(x, chunks=(1, nx, ny), name=False)
xds = xds_from_zarr(args.weight_table,
chunks={
'row': row_chunk,
'chan': bin_counts
})[0]
convolvedim = hessian(xds.UVW.data,
freqs,
model,
freq_bin_idx,
freq_bin_counts,
cell_rad,
weights=xds.WEIGHT.data.astype(
args.output_type),
nthreads=args.nvthreads,
epsilon=args.epsilon,
do_wstacking=args.wstack,
double_accum=args.double_accum)
return convolvedim
else:
normfact = 1.0
from pfb.operators.psf import hessian
from ducc0.fft import r2c
iFs = np.fft.ifftshift
npad_xl = (nx_psf - nx) // 2
npad_xr = nx_psf - nx - npad_xl
npad_yl = (ny_psf - ny) // 2
npad_yr = ny_psf - ny - npad_yl
padding = ((0, 0), (npad_xl, npad_xr), (npad_yl, npad_yr))
unpad_x = slice(npad_xl, -npad_xr)
unpad_y = slice(npad_yl, -npad_yr)
lastsize = ny + np.sum(padding[-1])
psf_pad = iFs(psf, axes=(1, 2))
psfhat = r2c(psf_pad,
axes=(1, 2),
forward=True,
nthreads=nthreads,
inorm=0)
psfhat = da.from_array(psfhat, chunks=(1, -1, -1))
def convolver(x):
model = da.from_array(x, chunks=(1, nx, ny), name=False)
convolvedim = hessian(model, psfhat, padding, nvthreads, unpad_x,
unpad_y, lastsize)
return convolvedim
# psfo = PSF(psf, dirty.shape, nthreads=args.nthreads)
# def convolver(x): return psfo.convolve(x)
rms = np.std(dirty_mfs)
rmax = np.abs(dirty_mfs).max()
print("Iter %i: peak residual = %f, rms = %f" % (0, rmax, rms), file=log)
residual = dirty.copy()
residual_mfs = dirty_mfs.copy()
model = np.zeros_like(residual)
for k in range(args.nmiter):
print("Running Hogbom", file=log)
x = hogbom(residual,
psf,
gamma=args.hb_gamma,
pf=args.hb_peak_factor,
maxit=args.hb_maxit,
verbosity=args.hb_verbose,
report_freq=args.hb_report_freq)
model += x
print("Getting residual", file=log)
convimage = convolver(model)
dask.visualize(convimage,
filename=args.output_filename + '_hessian' + str(k) +
'_graph.pdf',
optimize_graph=False)
with performance_report(filename=args.output_filename + '_hessian' +
str(k) + '_per.html'):
convimage = dask.compute(convimage, optimize_graph=False)[0]
ne.evaluate('dirty - convimage/normfact',
out=residual,
casting='same_kind')
ne.evaluate('sum(residual, axis=0)',
out=residual_mfs,
casting='same_kind')
rms = np.std(residual_mfs)
rmax = np.abs(residual_mfs).max()
print("Iter %i: peak residual = %f, rms = %f" % (k + 1, rmax, rms),
file=log)
print("Saving results", file=log)
save_fits(args.output_filename + '_model.fits', model, hdr)
model_mfs = np.mean(model, axis=0)
save_fits(args.output_filename + '_model_mfs.fits', model_mfs, hdr_mfs)
save_fits(args.output_filename + '_residual.fits',
residual * wsums[:, None, None], hdr)
save_fits(args.output_filename + '_residual.fits', residual_mfs, hdr_mfs)
print("All done here.", file=log)