def gather_fitsheader_if_needed(header, comm=MPI.COMM_WORLD):
"""
Combine headers of local arrays into a global one unless the input is
global.
"""
if 'NAXIS' not in header:
raise KeyError("The FITS header does not contain the 'NAXIS' keyword.")
if 'NAXIS1' not in header:
raise KeyError('Scalar FITS headers cannot be combined.')
if comm.size == 1:
return header
if not has_wcs(header):
raise ValueError('The input FITS header does not define a world coordin'
'ate system.')
naxis = header['NAXIS']
required_same = ['CRVAL1', 'CRVAL2', 'CRTYPE1', 'CRTYPE2',
'CDELT1', 'CDELT2']
required_same += ['NAXIS' + str(i+1) for i in range(naxis-1)]
required_same += ['CRPIX' + str(i+1) for i in range(naxis-1)]
headers = comm.allgather(header)
for keyword in required_same:
if keyword not in header:
continue
values = [h[keyword] for h in headers]
if any(v != headers[0][keyword] for v in values):
raise ValueError("The FITS keyword '{0}' has different values acros"
"s MPI processes: {1}".format(keyword, values))
keyword = 'CRPIX' + str(naxis)
if all(h[keyword] == headers[0][keyword] for h in headers):
return header
return gather_fitsheader(header, comm=comm)
def gather_fitsheader_if_needed(header, comm=MPI.COMM_WORLD):
"""
Combine headers of local arrays into a global one unless the input is
global.
"""
if 'NAXIS' not in header:
raise KeyError("The FITS header does not contain the 'NAXIS' keyword.")
if 'NAXIS1' not in header:
raise KeyError('Scalar FITS headers cannot be combined.')
if comm.size == 1:
return header
if not has_wcs(header):
raise ValueError(
'The input FITS header does not define a world coordin'
'ate system.')
naxis = header['NAXIS']
required_same = [
'CRVAL1', 'CRVAL2', 'CRTYPE1', 'CRTYPE2', 'CDELT1', 'CDELT2'
]
required_same += ['NAXIS' + str(i + 1) for i in range(naxis - 1)]
required_same += ['CRPIX' + str(i + 1) for i in range(naxis - 1)]
headers = comm.allgather(header)
for keyword in required_same:
if keyword not in header:
continue
values = [h[keyword] for h in headers]
if any(v != headers[0][keyword] for v in values):
raise ValueError(
"The FITS keyword '{0}' has different values acros"
"s MPI processes: {1}".format(keyword, values))
keyword = 'CRPIX' + str(naxis)
if all(h[keyword] == headers[0][keyword] for h in headers):
return header
return gather_fitsheader(header, comm=comm)
def test_has_wcs():
header = create_fitsheader([2, 4])
assert not has_wcs(header)
header = create_fitsheader([2, 4], cdelt=1)
assert has_wcs(header)
