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putD.wd

Puts a whole resolution level of mother wavelet coeffients into wd wavelet object.

DESCRIPTION

Makes a copy of the wd object, replaces some mother wavelet coefficients data in the copy, and then returns the copy.

USAGE

putD.wd(wdobj, level, v, boundary=F, index=F)

REQUIRED ARGUMENTS

wdobj: Wavelet decomposition object into which you wish to insert the mother wavelet coefficients.
level: the resolution level at which you wish to replace the mother wavelet coefficients.
v: the replacement data, this should be of the correct length.

OPTIONAL ARGUMENTS

boundary: If boundary is F then only "real" data is replaced. If boundary is T then the boundary (bookeeping) elements are replaced as well. Information about the lengths of the vectors can be found in the first.last database function and Nason and Silverman, 1994.
index: If index is T then the index numbers into the 1D array where the coefficient insertion would take place are returned. If index is F (default) then the modified wavelet decomposition object is returned.

VALUE

A wd class object containing the modified mother wavelet coefficients.

DETAILS

The function accessD obtains the mother wavelet coefficients for a particular level. The function putD.wd replaces mother wavelet coefficients at a particular resolution level and returns a modified wd object reflecting the change.

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. PutD.wd obtains information about where the smoothed data appears from the fl.dbase component of an wd object, in particular the array

fl.dbase$first.last.d

which gives a complete specification of index numbers and offsets for

wd.object$D.

Note that this function is method for the generic function putD. When the wd object is definitely a wd class object then you only need use the generic version of this function.

Note also that this function only puts information into wd class objects. To extract coefficients from a wd object you have to use the accessD function (or more precisely, the accessD.wd method).

RELEASE

EXAMPLES

#
# Generate an EMPTY wd object:
#
> zero <- rep(0, 16)
> zerowd <- wd(zero)
#
# Put some random mother wavelet coefficients into the object at
# resolution level 2. For the decimated wavelet transform there
# are always 2^i coefficients at resolution level i. So we have to
# insert 4 coefficients
#
> mod.zerowd <- putD( zerowd, level=2, v=rnorm(4))
#
# If you plot mod.zerowd you will see that there are only 
# coefficients at resolution level 2 where you just put the coefficients.
#
# Now, for a time-ordered non-decimated wavelet transform object the
# procedure is exactly the same EXCEPT that there are going to be
# 16 coefficients at each resolution level. I.e.
#
# Create empty TIME-ORDERED NON-DECIMATED wavelet transform object
#
> zerowdS <- wd(zero, type="station")
#
# Now insert 16 random coefficients at resolution level 2
#
> mod.zerowdS <- putD(zerowdS, level=2, v=rnorm(16))
#
# Once more if you plot mod.zerowdS then there will only be
# coefficients at resolution level 2.