accessD              package:wavethresh              R Documentation

_G_e_t _w_a_v_e_l_e_t _e_x_p_a_n_s_i_o_n _c_o_e_f_f_i_c_i_e_n_t_s _f_r_o_m _w_a_v_e_l_e_t _s_t_r_u_c_t_u_r_e.

_D_e_s_c_r_i_p_t_i_o_n:

     The coefficients from a wavelet expansion in a wavelet
     decomposition structure (returned from 'wd' or 'wr') are packed
     into a single vector in that structure. This function extracts the
     coefficients corresponding to a particular resolution level.

_U_s_a_g_e:

     accessD(wd.obj, level, boundary=FALSE)

_A_r_g_u_m_e_n_t_s:

  wd.obj: Wavelet decomposition structure from which you wish to
          extract the expansion coefficients.

   level: The level that you wish to extract. If the "original" data
          has 2^m data points then there are m possible levels that you
          could want to access, indexed by 0,1,...{},(m-1).

boundary: If this argument is TRUE then all of the boundary correction
          values will be returned as well (note: the length of the
          returned vector may not be a power of 2). If boundary is
          false, then just the coefficients will be returned. If the
          decomposition (or reconstruction) was done using periodic
          boundary handling then this option has no effect.

_D_e_t_a_i_l_s:

     The wd (wr) function produces a *w*avelet *d*ecomposition
     (*r*econstruction) structure.

     The need for this function is a consequence of the pyramidal
     structure of Mallat's algorithm and the memory efficiency gain
     achieved by storing the pyramid as a linear vector.  AccessD
     obtains information about where the coefficients appear from the
     fl.dbase component of wd.obj, in particular the array
     'fl.dbase$first.last.d' which gives a complete specification of
     index numbers and offsets for 'wd.obj$D'.

     Note that this function and accessC only work on objects of class
     'wd'. Also, you have to use 'putD' to put wavelet coefficients
     into a wd object.

_V_a_l_u_e:

     A vector of the extracted coefficients.

_S_e_e _A_l_s_o:

     'wr' and 'wd' for background information; 'accessC',
     'filter.select', 'threshold', 'putC', 'putD'.

_E_x_a_m_p_l_e_s:

     example(wd)

     ## Get the 3rd level coefficients of a decomposition
     accessD(wds, level=3)

     ## Do a qqnorm plot to assess the normality of some coefficients
     qqnorm(accessD(wds, level=8))

