R: Plot variance factors of wavelet transform coefficients for...

plot.irregwd {wavethresh} | R Documentation

## Plot variance factors of wavelet transform coefficients for irregularly spaced wavelet transform object

### Description

This function plots the variance factors associated with the wavelet coefficients arising from a `irregwd.objects` irregularly spaced wavelet decomposition object.

### Usage

    ## S3 method for class 'irregwd'
    plot(x, xlabels, first.level = 1,
    	main = "Wavelet Decomposition Coefficients", scaling = "by.level",
    	rhlab = FALSE, sub, ...)

### Arguments

`x` | The `irregwd.objects` object whose coefficients you wish to plot.
`xlabels` | A vector containing the "true" x-axis numbers that went with the vector that was transformed to produce the irregwd object supplied as the first argument to this function. If this argument is missing then the function tries to make up a sensible set of x-axis labels.
`first.level` | The first resolution level to begin plotting at. This argument can be quite useful when you want to supress some of the coarser levels in the diagram.
`main` | The main title of the plot.
`scaling` | How you want the coefficients to be scaled. The options are: `global` - one scale factor is chosen for the whole plot. The scale factor depends on the variance factor to be included on the plot that has the largest absolute value. The global option is useful when comparing factors that might appear anywhere in the plot; `by.level` - a scale factor is chosen for each resolution level in the plot. The scale factor for a level depends on the variance factor in that level that has the largest absolute value. The `by.level` option is useful when you wish to compare coefficients within a resolution level.
`rhlab` | If `TRUE` then a set of labels is produced on the right hand axis. The axis labels in this case refer to the scale factors used to scale each level and correspond to value of the largest variance factor (in absolute value) in each scale (when `scaling=="by.level"`) or absolutely (when `scaling="global"`). If the `rhlab=FALSE` then no right hand axis labels are produced.
`sub` | A subtitle for the plot.
`...` | Other arguments supplied to the actual plot

### Details

Produces a plot similar in style to the ones in Donoho and Johnstone, 1994. This function is basically the same as `plot.wd` except that variance factors and not coefficients are plotted. A variance factor is a number that quantifies the variability of a coefficient induced by the irregular design that was interpolated to a regular grid by the `makegrid` function which is used the by `irregwd` irregular wavelet transform function.

High values of the variance factor correspond to large variance in the wavelet coefficients but due to the irregular design, not the original noise structure on the coefficients.

### Value

If `rhlab==TRUE` then the scaling factors applied to each scale level are returned. Otherwise `NULL` is returned.

### Author(s)

Arne Kovac

### Examples

    #
    # The help for makegrid contains an example
    # of using this function.
    #

[Package wavethresh version 4.6.8 Index]