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.