Wavelets - implied values of offset and negation

[PhilipOakley]

I'm looking at doing some work with wavelets using the extension pack.

The particular issue is that the dlls appear to carry hidden information about the parameters being passed.

When doing a dwt (discrete wavelet transform) and other similar transforms, somehow the extension pack claims to know which wavelet is being used and make corrections for the offset and negation of those wavelets. Yet if you pass a user define wavelet it assumes zero for the offset and negation !

What isn't clear is how or when the association of the built-in wavlet functions, such as daublet(6), are passed into the dwt(,,) and at what point it is lost.

I.e. can I assign wave=daublet(6)
then do w=dwt(wave,,)

I think the extension packs are now packaged with the code, even if the licence isn't.

Philip Oakley

[ptc-1368288]

Philip,

I have tried all the built-in wavelets, they all work as coded. If you have a user one, it will have to go by its own coding. If you aren't expert enough in that stuff, it is deemed to fail or be untraceable. And if your own is not traceable, may as well consider not proofed and useless. Not much help !

jmG

[PhilipOakley]

jean,

have a look at the help files and see if you can decode them!

Help>Wavelet Filters
User-defined wavelets
Many of the functions in the Wavelets Extension Pack work with user-defined filters which are based on other known filters. To specify a user-defined filter, include a filter f and an offset o and/or negation i as arguments to any of the following functions:
...


help>Wavelet transforms
...If not specified, o is a default offset.


So how do those 'default' offsets get passed for built in functions????

see C:\Program Files\Mathsoft\Mathcad 11 Enterprise Edition\Handbook\WAVELETS\userfilt.mcd
and then the pop-up at popups\offsets.mcd

The mystery deepens.

Philip Oakley

[ptc-1368288]

On 8/5/2009 10:00:31 AM, philipoakley wrote:
>jean,
>
>have a look at the help files
>and see if you can decode
>them!
>
>Help>Wavelet Filters
>User-defined wavelets
>Many of the functions in the
>Wavelets Extension Pack work
>with user-defined filters
>which are based on other known
>filters. To specify a
>user-defined filter, include a
>filter f and an offset o
>and/or negation i as arguments
>to any of the following
>functions:
>...
>
>
>help>Wavelet transforms
>...If not specified, o is a
>default offset.
>
>
>So how do those 'default'
>offsets get passed for built
>in functions????
>
>see C:\Program
>Files\Mathsoft\Mathcad 11
>Enterprise
>Edition\Handbook\WAVELETS\user
>filt.mcd
>and then the pop-up at
>popups\offsets.mcd
>
>The mystery deepens.
>
>Philip Oakley
______________________________

For another day, Philip !

Jean