NAME
     FT - NMRPipe Fourier Transform

SYNOPSIS
     nmrPipe -fn FT [-auto | -real | -bruk | -inv] [-alt] [-neg]

DESCRIPTION
     FT applies a complex Fourier transform  (FT)  to  produce  a
     complex  result.   Options  include  selection of forward or
     inverse transform, negation of imaginaries before  transfor-
     mation,   and   sign-alternation  (negation  of  alternating
     points) of the data before  transformation.   An  option  to
     apply  a complex FT to a real data sequence is also provided
     for TPPI  mode  data.   FT  options  can  also  be  selected
     automatically  from  the  header,  provided that acquisition
     mode information was recorded appropriately  during  conver-
     sion.

OPTIONS
     -real
          This flag selects a complex  Fourier  transform  for  a
          real-only  sequence.   It  is  commonly  used  for data
          recorded in the TPPI mode.  This option will reduce the
          data size by a factor of two.

     -alt This flag causes sign alternation to be applied to  the
          data  before the FT.  In the case of complex data, sign
          alternation has the effect of exchanging the  left  and
          right halves of the corresponding spectrum:

             | nmrPipe -fn FT -alt      \


          is equivalent to:


             | nmrPipe -fn FT           \
             | nmrPipe -fn SHUF -exlr   \



     -neg This flag causes the imaginary part of the data  to  be
          negated before the FT.  It is equivalent to reversal of
          the corresponding  spectrum  followed  by  a  one-point
          right circular shift:


             | nmrPipe -fn FT -neg      \


          is equivalent to:

             | nmrPipe -fn FT           \
             | nmrPipe -fn REV -sw      \
             | nmrPipe -fn CS -rs 1 -sw \


     -bruk
          This flag applies a sign-alternated  real  FT  suitable
          for  Bruker  Sequential  Mode (QSEQ) data.  This option
          will reduce the data size by a factor of  two.   It  is
          equivalent to:


             nmrPipe -fn FT -real -alt



     -auto
          This flag enables automatic selection of the FT  modes.
          Inverse  mode  will  be selected if the data are in the
          frequency-domain.  Real transform mode will be selected
          if  the  acquisition mode is recorded as Real, TPPI, or
          Sequential (Bruker).  Negation of imaginaries  will  be
          selected   if  the  acquisition  mode  is  recorded  as
          Complex-N States-N, or States-TPPI-N.  Sign-alternation
          will be selected if the acquisition mode is recorded as
          States-TPPI, States-TPPI-N, or Sequential (Bruker).

     -inv This flag selects an inverse Fourier transform.

EXAMPLES
     The following is a basic 2D  Fourier  transform  scheme  for
     States,  States-TPPI,  or TPPI phase-sensitive data.  Use of
     FT -auto will select  the  correct  Fourier  Transform  type
     (real  or complex), and if the acquisition modes were speci-
     fied correctly during conversion, it will also automatically
     select the proper sign-adjustment mode.


      nmrPipe -in test.fid \
      | nmrPipe  -fn SP -off 0.5 -end 0.95 -pow 1 -c 1.0    \
      | nmrPipe  -fn ZF -auto                               \
      | nmrPipe  -fn FT -auto                               \
      | nmrPipe  -fn PS -p0 0.00 -p1 0.00 -di -verb         \
      | nmrPipe  -fn TP                                     \
      | nmrPipe  -fn SP -off 0.5 -end 0.95 -pow 1 -c 1.0    \
      | nmrPipe  -fn ZF -auto                               \
      | nmrPipe  -fn FT -auto                               \
      | nmrPipe  -fn PS -p0 0.00 -p1 0.00 -di -verb         \
         -ov -out test.ft2



     The  following  is  a  basic  magnitude-mode  2D  processing
     scheme;  note  that  in  this  case, the imaginaries are not
     deleted after the first Fourier transform, and the magnitude
     calculation  function MC is used after the second transform.
     Note also that the second FT is a complex one, which can  be
     specified  as "FT -neg" if the Y-Axis of the result needs to
     be reversed:


      nmrPipe -in test.fid   \
      | nmrPipe -fn SP -verb \
      | nmrPipe -fn ZF -auto \
      | nmrPipe -fn FT -auto \
      | nmrPipe -fn TP       \
      | nmrPipe -fn SP -verb \
      | nmrPipe -fn ZF -auto \
      | nmrPipe -fn FT       \
      | nmrPipe -fn MC       \
         -out test.ft2 -verb -ov


     The following is a  general  2D  inverse  Fourier  transform
     scheme,  which  will regenerate a 2D hypercomplex FID from a
     real-only 2D spectrum.  Note  use  of  the  generic  nmrPipe
     option  -ad  to make room for hypercomplex data, and the use
     of the hypercomplex transpose option TP -hyper:


      nmrPipe -in test.ft2             \
      | nmrPipe -fn HT -auto -verb     \
      | nmrPipe -fn PS -inv -hdr       \
      | nmrPipe -fn FT -inv            \
      | nmrPipe -fn ZF -inv            \
      | nmrPipe -fn APOD -inv -hdr -ad \
      | nmrPipe -fn TP -hyper          \
      | nmrPipe -fn HT -auto -verb     \
      | nmrPipe -fn PS -inv -hdr       \
      | nmrPipe -fn FT -inv            \
      | nmrPipe -fn ZF -inv            \
      | nmrPipe -fn APOD -inv -hdr     \
         -out test.fid -ov