Amatdual: Amatdual

In nunesmatt/adlift: An Adaptive Lifting Scheme Algorithm

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 X 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 ([e-mail]), 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.
#

nunesmatt/adlift documentation built on June 12, 2025, 5:58 a.m.