NAG FL Interface
c09daf (dim1_​mxolap_​fwd)

1 Purpose

2 Specification

3 Description

4 References

5 Arguments

1: $\mathbf{n}$ – Integer Input

On entry: the number of elements, $n$, in the data array $x$.

Constraint: this must be the same as the value n passed to the initialization routine c09aaf.

2: $\mathbf{x}\left(\mathbf{n}\right)$ – Real (Kind=nag_wp) array Input

On entry: x contains the input dataset $x_{\mathit{i}}$, for $\mathit{i}=1,2,\dots ,n$.

3: $\mathbf{lenc}$ – Integer Input

On entry: the dimension of the arrays ca and cd as declared in the (sub)program from which c09daf is called. This must be at least the number, $n_c$, of approximation coefficients, $C_a$, and detail coefficients, $C_d$, of the discrete wavelet transform as returned in nwc by the call to the initialization routine c09aaf. Note that $n_c=n$ for periodic end extension, but this is not the case for other end extension methods which will be available in future releases.

Constraint: $\mathbf{lenc}\ge n_c$, where $n_c$ is the value returned in nwc by the call to the initialization routine c09aaf.

4: $\mathbf{ca}\left(\mathbf{lenc}\right)$ – Real (Kind=nag_wp) array Output

On exit: $\mathbf{ca}\left(i\right)$ contains the $i$th approximation coefficient, $C_a\left(\mathit{i}\right)$, for $\mathit{i}=1,2,\dots ,n_c$.

5: $\mathbf{cd}\left(\mathbf{lenc}\right)$ – Real (Kind=nag_wp) array Output

On exit: $\mathbf{cd}\left(\mathit{i}\right)$ contains the $\mathit{i}$th detail coefficient, $C_d\left(\mathit{i}\right)$, for $\mathit{i}=1,2,\dots ,n_c$.

6: $\mathbf{icomm}\left(100\right)$ – Integer array Communication Array

On entry: contains details of the discrete wavelet transform and the problem dimension as setup in the call to the initialization routine c09aaf.

On exit: contains additional information on the computed transform.

7: $\mathbf{ifail}$ – Integer Input/Output

On entry: ifail must be set to $0$, $-1\text{ or }1$. If you are unfamiliar with this argument you should refer to Section 4 in the Introduction to the NAG Library FL Interface for details.

For environments where it might be inappropriate to halt program execution when an error is detected, the value $-1\text{ or }1$ is recommended. If the output of error messages is undesirable, then the value $1$ is recommended. Otherwise, if you are not familiar with this argument, the recommended value is $0$. When the value $-\mathbf{1}\text{ or }\mathbf{1}$ is used it is essential to test the value of ifail on exit.

On exit: $\mathbf{ifail}=\mathbf{0}$ unless the routine detects an error or a warning has been flagged (see Section 6).

6 Error Indicators and Warnings

$\mathbf{ifail}=1$

On entry, n is inconsistent with the value passed to the initialization routine: $\mathbf{n}=〈\mathit{\text{value}}〉$, n should be $〈\mathit{\text{value}}〉$.

$\mathbf{ifail}=3$

On entry, array dimension lenc not large enough: $\mathbf{lenc}=〈\mathit{\text{value}}〉$ but must be at least $〈\mathit{\text{value}}〉$.

$\mathbf{ifail}=6$

On entry, the initialization routine c09aaf has not been called first or it has not been called with $\mathbf{wtrans}=\text{'T'}$, or the communication array icomm has become corrupted.

$\mathbf{ifail}=-99$

An unexpected error has been triggered by this routine. Please contact NAG.

See Section 7 in the Introduction to the NAG Library FL Interface for further information.

$\mathbf{ifail}=-399$

Your licence key may have expired or may not have been installed correctly.

See Section 8 in the Introduction to the NAG Library FL Interface for further information.

$\mathbf{ifail}=-999$

Dynamic memory allocation failed.

See Section 9 in the Introduction to the NAG Library FL Interface for further information.

7 Accuracy

8 Parallelism and Performance

9 Further Comments

10 Example

10.1 Program Text

10.2 Program Data

10.3 Program Results