wr.wd               package:wavethresh               R Documentation

_W_a_v_e_l_e_t _r_e_c_o_n_s_t_r_u_c_t_i_o_n _f_o_r _w_d _c_l_a_s_s _o_b_j_e_c_t_s (_i_n_v_e_r_s_e _d_i_s_c_r_e_t_e _w_a_v_e_l_e_t _t_r_a_n_s_f_o_r_m).

_D_e_s_c_r_i_p_t_i_o_n:

     This function performs the reconstruction stage of Mallat's
     pyramid algorithm (Mallat 1989), i.e. the discrete inverse wavelet
     transform. The actual transform is performed by some C code, this
     is dynamically linked into S (if your machine can do this).

_U_s_a_g_e:

     wr.wd(wd, start.level = 0, verbose = FALSE, bc = wd$bc,
             return.object = FALSE, filter.number = wd$filter$filter.number,
             family = wd$filter$family, ...)

_A_r_g_u_m_e_n_t_s:

      wd: A wavelet decomposition object as returned by 'wd', and
          described in the help for that function and the help for
          'wd.object'.

start.level: The level you wish to start reconstruction at. The is
          usually the first (level 0). This argument is ignored for a
          wd object computed using the ``wavelets on the interval''
          transform (i.e. using the 'bc="interval"' option of 'wd'.

 verbose: Controls the printing of "informative" messages whilst the
          computations progress. Such messages are generally annoying
          so it is turned off by default.

      bc: The boundary conditions used. Usually these are determined by
          those used to create the supplied wd object, but you
          sometimes change them with possibly silly results.

filter.number: The filter number of the wavelet used to do the
          reconstruction. Again, as for bc, you should probably leave
          this argument alone. Ignored if the bvc component of the 'wd'
          object is "'interval'".

  family: The type of wavelet used to do the reconstruction. You can
          change this argument from the default but it is probably NOT
          wise. Ignored if the bvc component of the 'wd' object is
          "'interval'".

return.object: If this is F then the top level of the reconstruction is
          returned (this is the reconstructed function at the highest
          resolution). Otherwise if it is T the whole wd reconstructed
          object is returned. Ignored if the 'bvc' component of the
          'wd' object is "'interval'".

     ...: any other arguments

_D_e_t_a_i_l_s:

     The code implements Mallat's inverse pyramid algorithm. In the
     reconstruction the quadrature mirror filters G and H are supplied
     with c0 and d0, d1, ... d(m- 1) (the wavelet coefficients) and
     rebuild c1,..., cm. 

     If the 'bc' component of the 'wd' object is "'interval'" then the
     'wr.int' function which implements the inverse ``wavelet on the
     interval'' transform due to Cohen, Daubechies and Vial, 1993 is
     used instead.

_V_a_l_u_e:

     Either a vector containing the top level reconstruction or an
     object of class wd containing the results of the reconstruction,
     details to be found in help for 'wd.object'.

_R_E_L_E_A_S_E:

     Version 3 Copyright Guy Nason 1994 Integration of ``wavelets on
     the interval'' code by Piotr Fryzlewicz and Markus Monnerjahn was
     at Version 3.9.6, 1999.

_S_e_e _A_l_s_o:

     'wd', 'wr.int', 'accessC', 'accessD', 'filter.select', 'plot.wd',
     'threshold'

_E_x_a_m_p_l_e_s:

     #
     # Take the wd object generated in the examples to wd (called wds)
     #
     # Invert this wd object
     #
     #yans <- wr(wds)
     #
     # Compare it to the original, called y
     #
     #sum((yans-y)^2)
     #[1] 9.805676e-017
     #
     # A very small number
     #

