accessD.mwd(mwd, level)
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)
mwd$filter$npsi rows
containing the extracted coefficients.
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.
# # Get the 3rd level of smoothed data from a decomposition # accessD.mwd(mwd(data), level=3)