R: Amatdual

Amatdual {adlift} | R Documentation

## Amatdual

### Description

Combines filter matrices to produce a refinement matrix A for a wavelet transform.

### Usage

    Amatdual(steps, pointsin, removelist, nbrs, weights, alpha)

### Arguments

`steps` | a value indicating which refinement matrix to construct. It refers to the number of points already removed during the transform.
`pointsin` | The indices of gridpoints still to be removed.
`removelist` | a vector of indices into envX of the lifted coefficients during the transform (in the order of removal).
`nbrs` | indices of the neighbours used in the last step of the decomposition.
`weights` | the prediction weights obtained from the regression in the prediction step of the transform.
`alpha` | the update weights used to update lengths and coeff.

### Details

The function uses the prediction and update weights to construct the filter matrices Hdual and Gdual. Combining these two matrices results in the refinement matrix Adual.

### Value

`Adual` | the refinement matrix for the particular step of the transform.
`Hdual` | the high-pass filter matrix for the current step of the transform.
`Gdual` | the low-pass filter matrix for the current step of the transform.
`o` | the indices of nbrs into the vector of pointsin and the steps removed points of the transform.
`alpha` | the update weights used to update lengths and coeff.
`weights` | the prediction weights obtained from the regression in the prediction step of the transform.

### Note

This function has been left in the package for completeness. However, the transform matrix is (optionally) computed within the forward lifting transform function `fwtnp`.

### Author(s)

Matt Nunes (nunesrpackages@gmail.com), Marina Knight

### See Also

`transmatdual`, `fwtnp`

### Examples

    #
    x<-runif(256)
    y<-make.signal2("doppler",x=x)
    a<-fwtnp(x,y,LocalPred=AdaptNeigh,neighbours=2)
    #
    Adual<-Amatdual(90,a$pointsin,a$removelist,a$neighbrs[[90]],
    a$gamlist[[90]],a$alphalist[[90]])
    #
    Adual
    #
    #the 90th refinement matrix for the transform above.
    #

[Package adlift version 1.4-1 Index]