accessD.mwd            package:wavethresh            R Documentation

_G_e_t _w_a_v_e_l_e_t _c_o_e_f_f_i_c_i_e_n_t_s _f_r_o_m _m_u_l_t_i_p_l_e _w_a_v_e_l_e_t _s_t_r_u_c_t_u_r_e (_m_w_d).

_D_e_s_c_r_i_p_t_i_o_n:

     The wavelet coefficients from a multiple wavelet decomposition
     structure, 'mwd.object', (e.g. returned from 'mwd') are packed
     into a single matrix in that structure. This function extracts the
     coefficients corresponding to a particular resolution level.

_U_s_a_g_e:

     accessD.mwd(mwd, level, ...)

_A_r_g_u_m_e_n_t_s:

     mwd: Multiple 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 'mwd$filter$npsi*2^m' data points ('mwd$filter$npsi'
          being the multiplicity of the multiple wavelets) then there
          are m possible levels that you could want to access, indexed
          by 0,1,...,(m-1) 

     ...: any other arguments

_D_e_t_a_i_l_s:

     The 'mwd' function produces a 'multiple wavelet decomposition
     object' .

     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 matrix. AccessD
     obtains information about where the coefficients appear from the
     fl.dbase component of 'mwd', in particular the array
     'fl.dbase$first.last.d' which gives a complete specification of
     index numbers and offsets for 'mwd$D'. 

     Note that this function and 'accessC' only work on objects of
     class 'mwd' to _extract_ coefficients. You have to use 'putD.mwd'
     to insert wavelet coefficients into a 'mwd' object. 

     See Downie and Silverman, 1998.

_V_a_l_u_e:

     A matrix with 'mwd$filter$npsi' rows containing the extracted
     coefficients.

_R_E_L_E_A_S_E:

     Tim Downie 1995-6

_S_e_e _A_l_s_o:

     'accessD.mwd', 'draw.mwd', 'mfirst.last', 'mfilter.select', 'mwd',
     'mwd.object', 'plot.mwd', 'print.mwd', 'putC.mwd', 'putD.mwd',
     'summary.mwd', 'threshold.mwd', 'wd', 'wr.mwd'

_E_x_a_m_p_l_e_s:

     #
     # Get the 3rd level of smoothed data from a decomposition
     #
     data(ipd)
     accessD.mwd(mwd(ipd), level=3)

