sparseness(x, ...)
signature(x = "numeric")
: Base
method that computes the sparseness of a numeric vector. It returns a single numeric value, computed following the
definition given in section Description. signature(x = "matrix")
:
Computes the sparseness of a matrix as the mean
sparseness of its column vectors. It returns a single
numeric value. signature(x = "NMF")
: Compute
the sparseness of an object of class NMF
, as the
sparseness of the basis and coefficient matrices computed
separately. It returns the two values in a numeric vector with names
basis and coef. , where $n$ is the length of $x$.
The sparseness is a real number in $[0,1]$. It is
equal to 1 if and only if x
contains a single
nonzero component, and is equal to 0 if and only if all
components of x
are equal. It interpolates
smoothly between these two extreme values. The closer to
1 is the sparseness the sparser is the vector.
The basic definition is for a numeric
vector, and
is extended for matrices as the mean sparseness of its
column vectors.
entropy
, purity