The WAVGET subroutine is used to return information that is encoded in a wavelet decomposition.
The required input arguments are as follows:
- decomp
-
specifies a wavelet decomposition that has been computed by using a call to the WAVFT subroutine.
- request
-
specifies a scalar that indicates what information is to be returned.
You can specify different optional arguments depending on the value of request:
- request=1
-
requests the number of points in the input data vector.
- result
-
returns as a scalar that contains this number.
- request=2
-
requests the detail coefficients at a specified level. Valid syntax is
The arguments are as follows:
- level
-
is the level at which the detail coefficients are requested.
- opt
-
is an optional vector which specifies the thresholding to be applied to the returned detail coefficients. See the WAVIFT subroutine for details. If you omit this argument, no thresholding is applied.
- result
-
returns as a column vector that contains the specified detail coefficients.
- request=3
-
requests the scaling coefficients at a specified level. Valid syntax is
The arguments are as follows:
- level
-
is the level at which the scaling coefficients are requested.
- opt
-
is an optional vector that specifies the thresholding to be applied. See the WAVIFT subroutine for a description of this vector. The scaling coefficients at the requested level are obtained by using the inverse wavelet transform, after applying the specified thresholding. If you omit this argument, no thresholding is applied.
- result
-
returns as a column vector that contains the specified scaling coefficients.
- request=4
-
requests the thresholding status of the detail coefficients in decomp.
- result
-
returns as a scalar whose value is
- 0,
-
if the detail coefficients have not been thresholded
- 1,
-
otherwise
- request=5
-
requests the wavelet options vector that you specified in the WAVFT subroutine to compute decomp.
- result
-
returns as a column vector with 4 elements that contains the specified options vector. See the WAVFT subroutine for the interpretation of the vector entries.
- request=6
-
requests the index of the top level in decomp.
- result
-
returns as a scalar that contains this number.
- request=7
-
requests the index of the lowest level in decomp.
- result
-
returns as a scalar that contains this number.
- request=8
-
requests a vector evaluating the father wavelet used in decomp, at an equally spaced grid spanning the support of the father wavelet. The number of points in the grid is specified as a power of 2 times the support width of the father wavelet. For wavelets in the Daubechies extremal phase and least asymmetric families, the support width of the father wavelet is
, where 
is the family member. Valid syntax is
The optional argument has the following meaning:
- power
-
is the exponent of 2 that determines the number of grid points used. power defaults to
if you do not specify this argument.
- result
-
returns as a column vector that contains the specified evaluation of the father wavelet.
An example is available in the documentation for the WAVFT subroutine.