putC.mwd {wavethresh} | R Documentation

## Put smoothed data into wavelet structure

### Description

The smoothed and original data from a multiple wavelet decomposition structure, `mwd.object`, (e.g. returned from `mwd`) are packed into a single matrix in that structure. This function copies the `mwd.object`, replaces some smoothed data in the copy, and then returns the copy.

### Usage

    putC.mwd(mwd, level, M, boundary = FALSE, index = FALSE, ...)

### Arguments

`mwd` | Multiple wavelet decomposition structure whose coefficients you wish to replace.
`level` | The level that you wish to replace.
`M` | Matrix of replacement coefficients.
`boundary` | If `boundary` is `FALSE` then only the "real" data is replaced (and it is easy to predict the required length of `M`). If boundary is TRUE then you can replace the boundary values at a particular level as well (but it is hard to predict the required length of `M`, and the information has to be obtained from the `mfirst.last` database component of `mwd`).
`index` | If index is `TRUE` then the index numbers into the `mwd$C` array where the matrix `M` would be stored is returned. Otherwise, (default) the modified `mwd.object` is returned.
`...` | any other arguments

### Details

The `mwd` function produces a wavelet decomposition 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 matrix of coefficients. PutC obtains information about where the smoothed data appears from the fl.dbase component of mwd, in particular the array `fl.dbase$first.last.c` which gives a complete specification of index numbers and offsets for `mwd$C`.

Note also that this function only puts information into `mwd` class objects. To extract coefficients from `mwd` structures you have to use the `accessC.mwd` function.

See Downie and Silverman, 1998.

### Value

An object of class `mwd.object` if `index` is `FALSE`, otherwise the index numbers indicating where the `M` matrix would have been inserted into the `mwd$C` object are returned.

### RELEASE

Version 3.9.6 (Although Copyright Tim Downie 1995-6).

### See Also

`accessC.mwd`, `accessD.mwd`, `draw.mwd`, `mfirst.last`, `mfilter.select`, `mwd`, `mwd.object`, `mwr`, `plot.mwd`, `print.mwd`, `putD.mwd`, `summary.mwd`, `threshold.mwd`, `wd`, `wr.mwd`.

### Examples

    #
    # Generate an mwd object
    #
    #tmp <- mwd(rnorm(32))
    #
    # Now let's examine the finest resolution smooth...
    #
    #accessC(tmp, level=3)
    #           [,1]       [,2]       [,3]       [,4]        [,5]      [,6]
    #[1,] -0.4669103 -1.3150580 -0.7094966 -0.1979214  0.32079986 0.5052254
    #[2,] -0.7645379 -0.8680941  0.1004062  0.6633268 -0.05860848 0.5757286
    #          [,7]       [,8]
    #[1,] 0.5187380  0.6533843
    #[2,] 0.2864293 -0.4433788
    #
    # A matrix. There are two rows one for each father wavelet in this
    # two-ple multiple wavelet transform and at level 3 there are 2^3 columns.
    #
    # Let's set the coefficients of the first father wavelet all equal to zero
    # for this example
    #
    #newcmat <- accessC(tmp, level=3)
    #newcmat[1,] <- 0
    #
    # Ok, let's insert it back at level 3
    #
    #tmp2 <- putC(tmp, level=3, M=newcmat)
    #
    # And check it
    #
    #accessC(tmp2, level=3)
    #           [,1]       [,2]      [,3]      [,4]        [,5]      [,6]      [,7]
    #[1,]  0.0000000  0.0000000 0.0000000 0.0000000  0.00000000 0.0000000 0.0000000
    #[2,] -0.7645379 -0.8680941 0.1004062 0.6633268 -0.05860848 0.5757286 0.2864293
    #           [,8]
    #[1,]  0.0000000
    #[2,] -0.4433788
    #
    # Yep, all the first father wavelet coefficients at level 3 are now zero.

[Package wavethresh version 4.0-2 Index]