R: Compute number of non-zero coefficients in wd object

dof {wavethresh} | R Documentation

## Compute number of non-zero coefficients in wd object

### Description

Compute number of non-zero coefficients in `wd` object

### Usage

    dof(wd)

### Arguments

`wd` | A `wavelet decomposition` object (such as that returned by the `wd` function).

### Details

Very simple function that counts the number of non-zero coefficients in a `wd` class object.

### Value

An integer that represents the number of non-zero coefficients in the input `wd` object.

### RELEASE

Version 3.0 Copyright Guy Nason 1994

### Author(s)

G P Nason

### See Also

`wd`, `wd.object`, `threshold`, `threshold.wd`.

### Examples

    #
    # Let's generate some purely random numbers!!
    #
    myrandom <- rnorm(512)
    #
    # Take the discrete wavelet transform
    #
    myrandomWD <- wd(myrandom)
    #
    # How many coefficients are non-zero?
    #
    dof(myrandomWD)
    # [1] 512
    #
    # All of them were nonzero!
    #
    # Threshold it
    #
    myrandomWDT <- threshold(myrandomWD, policy="universal")
    #
    # Now lets see how many are nonzero
    #
    dof(myrandomWDT)
    # [1] 8
    #
    # Wow so 504 of the coefficients were set to zero! Spooky!
    #

[Package wavethresh version 4.6.8 Index]