AIPS HELP file for FFT in 31DEC21
As of Fri Sep 17 14:06:49 2021
FFT: Task to FFT a real or complex image.
Real part of image.
INNAME Image name (name)
INCLASS Image name (class)
INSEQ 0.0 9999.0 Image name (seq. #)
INDISK 0.0 9.0 Image disk drive #
Imag. part of image.
Not used for OPCODEs
'UVRE' 'MARE' 'UVIR'
IN2NAME Image name (name)
IN2CLASS Image name (class)
IN2SEQ 0.0 9999.0 Image name (seq. #)
IN2DISK 0.0 9.0 Image disk drive #
OUTNAME Image name (name)
CLASS picked by the task
OUTSEQ -1.0 9999.0 Image name (seq. #)
OUTDISK 0.0 9.0 Image disk drive #
OPCODE OPCODE 'UVRE','UVCX','MARE',
'UVIR', 'UVIX' for UVIMG
BADDISK Disks to avoid for scratch.
Use: FFT Fourier transforms a complex image from either the
map (sky) or uv plane to the other. On request the imag.
part of the input image can be set to zero. In all cases
the result is a complex image whose real and imaginary
parts are in separate files. The headers in the uv plane
are now correct and contain 2 extra axes to convey the RA
and Dec should those coordinates be needed later (i.e. by
a reverse execution of FFT). The phases in the uv plane
are corrected for position shifts made in making the map.
Currently only floating format images are read or written.
INNAME......The input real part name. Size must be a
power of 2. Standard defaults.
INCLASS.....The input real part class. Standard defaults.
INSEQ.......The input real part seq. no. 0 => highest.
INDISK......The input real part disk no. 0 => any.
IN2NAME.....The input imag. part name. Not used for
OPCODEs 'MARE' 'UVRE' 'UVIR'.
Must be same size and cell spacing as INNAME.
IN2CLASS....The input imag. part class. Standard defaults.
IN2SEQ......The input imag. part seq. #. 0 => highest.
IN2DISK.....The input imag. part disk drive #. 0 => any
OUTNAME.....The output image name. Standard defaults.
The output CLASSes are fixed by the task and
indicate whether the image is the real or imag.
part and whether they are in the map 'MA' or
uv 'UV' plane. the four possibilities are:
'UVREAL','UVIMAG','MAREAL' and 'MAIMAG'.
OUTSEQ......The output image seq. #. 0 => highest unique.
Both output images will have the same seq. no.
If >0; image will be created if new.
Old files may NOT be overwritten.
OUTDISK.....The output disk drive no. 0 => highest with space
OPCODE......Code for operation requested.
'UVRE' real uv => complex map
'UVCX' complex uv => complex map.
'MARE' real map => complex uv
'MACX' complex map => real uv
'UVIR' real uv centered image from UVIMG to
complex map (sort='UV' in UVIMG)
'UVIX' complex uv centered image from UVIMG
to complex map (sort='UV' in UVIMG)
' ' => 'MARE'
BADDISK.....This array contains the numbers of disks on which
it is desired that scratch files not be located.
BADDISK has no effect on input and output maps.