C*FFTRANS.FOR************************************************************
C                                                                       *
C         This program will do 2-dimensional FFT's in either            *
C       direction. The real-space origin is at (1,1) and                *
C       the origin of reciprocal space is at (1,NY/2+1).                *
C       The FT of an image NX,NY is NX/2+1,NY complex value.            *
C                                                                       *
C         All transforms are done using Lynn ten Eyck's subroutines.    *
C       These allow arbitrary-sized images having a LARGEST PRIME       *
C       factor of 19!!.                                                 *
C                                                                       *
C       Very large images are transformed using the disk-based routine  *
C       GIANTFFT (current dimensions up to 16384 x 16384). The switch   *
C       point is now determined in UNIX by the dimension of the         *
C       parameter IARRMXSIZ.                                             *
C       Smaller images, currently up to 6000x6000 are done in core      *
C       using the in-core routine TDXFFT.                               *
C                                                                       *
C       NOTE:  3-D images are treated as image stacks.                  *
C         Each section is transformed independently!!                   *
C         HOWEVER, only single sections of LARGE images may be used!    *
C                                                                       *
C       No input parametrs are required.                                *
C                                                                       *
C       Logical I/O assignments are:                                    *
C                                                                       *
C       IN                      input image or FT                       *
C       OUT                     output FT or image                      *
C                                                                       *
C                                                                       *
C       Version   1.00  18.10.81        DAA             FOR VAX         *
C       Version   1.01  27.MAY.82       DAA             FOR VAX         *
C       Version   1.02  10.JUNE.82      DAA             FOR VAX         *
C       Version   1.03  23.JULY.82      DAA             FOR VAX         *
C       Version   1.04  01.OCTOBER.82   DAA             FOR VAX         *
C       Version   1.05  08.November.82  DAA             FOR VAX         *
C       Update    1.05  18.November.82  DAA             FOR VAX         *
C       Revision  1.06  27.November.84  RH              FOR VAX         *
C       Noscratch 1.07  23.March.85     RH              FOR VAX         *
C       Parameter 1.08  13.February.87  RH              FOR VAX         *
C       Cosmetic  1.09  04.June.87      RH              FOR VAX         *
C       Convert   2.00  13.July.90      RH              FOR 5400        *
C       Convert         11.September.91 RB              for Alliant     *
C       Dimension 2.01  31.December.91  RB and RH       for Alliant     *
C       Dimension 2.02  25.January.95   RH              remove COMMON   *
C       Dimension 2.03  22.April.96     RH              added comment   *
C       Version   2.04  29.August.00    RH              extra IMPOSN    *
C       Version   2.05  09.July.04      JMS             increase size   *
C                                                                       *
C************************************************************************
C
C*** Note : if IARRMXSIZ is increased, arrays must be declared in COMMON
C***        in order for the SGI to compile this program  22.04.96 JMS
C***        this should not now be necessary as I have put it in common anyway
C***        jms 25.04.96