Function: dtwfbinit
DTWFBINIT Dual-Tree Wavelet Filterbank Initialization
  Usage:  dualwt=dtwfbinit(dualwtdef);

  Input parameters:
        dualwtdef : Dual-tree filterbank definition.

  Output parameters:
        dualwt    : Dual-tree filtarbank structure.

  dtwfinit() (a call without aguments) creates an empty structure. It
  has the same fields as the struct. returned from WFBTINIT plus a field
  to hold nodes from the second tree:

     .nodes      Filterbank nodes of the first tree

     .dualnodes  Filterbank nodes of the second tree

     .children   Indexes of children nodes

     .parents    Indexes of a parent node

     .forder     Frequency ordering of the resultant frequency bands.   

  dtwfinit({dualw,J,flag}) creates a structure representing a dual-tree
  wavelet filterbank of depth J, using dual-tree wavelet filters 
  specified by dualw. The shape of the tree is controlled by flag.
  Please see help on DTWFB or DTWFBREAL for description of the
  parameters.

  [dualwt,info]=dtwfinit(...) additionally returns info struct which
  provides some information about the computed window:

  info.tight
     True if the overall tree construct a tight frame.

  info.dw
     A structure containing basic dual-tree filters as returned from
     fwtinit(dualwtdef,'wfiltdt_').
  
  Additional optional flags
  -------------------------

  'freq','nat'
     Frequency or natural ordering of the resulting coefficient subbands.
     Default ordering is 'freq'.

Url: http://ltfat.github.io/doc/wavelets/dtwfbinit.html

Package: ltfat