naginterfaces.library.wav.dim1_multi_inv(nwlinv, c, n, comm)[source]

dim1_multi_inv computes the inverse one-dimensional multi-level discrete wavelet transform (DWT). This function reconstructs data from (possibly filtered or otherwise manipulated) wavelet transform coefficients calculated by dim1_multi_fwd() from an original set of data. The initialization function dim1_init() must be called first to set up the DWT options.

For full information please refer to the NAG Library document for c09cd


The number of levels to be used in the inverse multi-level transform. The number of levels must be less than or equal to , which has the value of argument as used in the computation of the wavelet coefficients using dim1_multi_fwd(). The data will be reconstructed to level , where level is the original input dataset provided to dim1_multi_fwd().

cfloat, array-like, shape

The coefficients of a multi-level wavelet transform of the dataset.

Let be the number of coefficients (of each type) at level , for .

Then, setting and , for , the coefficients are stored in as follows:

, for

Contains the level approximation coefficients, .

, for

Contains the level detail coefficients .

, for

Contains the level detail coefficients, for .

The values , for , are contained in which is produced as output by a preceding call to dim1_multi_fwd().

See dim1_multi_fwd() for details.


, the length of the data array, , to be reconstructed. For a full reconstruction of levels, where is as supplied to dim1_multi_fwd(), this must be the same as argument used in the call to dim1_multi_fwd(). For a partial reconstruction of , this must be equal to , as returned from dim1_multi_fwd().

commdict, communication object

Communication structure.

This argument must have been initialized by a prior call to dim1_init().

yfloat, ndarray, shape

The dataset reconstructed from the multi-level wavelet transform coefficients and the transformation options supplied to the initialization function dim1_init().

(errno )

On entry, is larger than the number of levels computed by the preceding call to dim1_multi_fwd(): , expected .

(errno )

On entry, .

Constraint: .

(errno )

On entry, is set too small: .

Constraint: .

(errno )

On entry, is inconsistent with the value passed to the initialization function: , should be .

(errno )

Either the initialization function has not been called first or array [‘icomm’] has been corrupted.

(errno )

Either the initialization function was called with or array [‘icomm’] has been corrupted.


dim1_multi_inv performs the inverse operation of dim1_multi_fwd(). That is, given a set of wavelet coefficients, computed up to level by dim1_multi_fwd() using a DWT as set up by the initialization function dim1_init(), on a real data array of length , dim1_multi_inv will reconstruct the data array , for , from which the coefficients were derived. If the original input dataset is level , then it is possible to terminate reconstruction at a higher level by specifying fewer than the number of levels used in the call to dim1_multi_fwd(). This results in a partial reconstruction.