nag_idwt (c09cbc) computes the inverse one-dimensional discrete wavelet transform (DWT) at a single level. The initialization function nag_wfilt (c09aac)
must be called first to set up the DWT options.
nag_idwt (c09cbc) performs the inverse operation of nag_dwt (c09cac)
. That is, given sets of
approximation coefficients and detail coefficients, computed by nag_dwt (c09cac)
using a DWT as set up by the initialization function nag_wfilt (c09aac)
, on a real data array of length
, nag_idwt (c09cbc) will reconstruct the data array
from which the coefficients were derived.
The accuracy of the wavelet transform depends only on the floating point operations used in the convolution and downsampling and should thus be close to machine precision.