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dof


Compute number of non-zero coefficients in wd object

DESCRIPTION

Compute number of non-zero coefficients in wd object

USAGE

dof(wd)

REQUIRED ARGUMENTS

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

OPTIONAL ARGUMENTS

None.

VALUE

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

SIDE EFFECTS

None.

DETAILS

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

RELEASE

Version 3.0 Copyright Guy Nason 1994

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!
#