Bounded Simplex-Structured Matrix Factorization: Algorithms,
Identifiability and Applications
- URL: http://arxiv.org/abs/2209.12638v2
- Date: Fri, 31 Mar 2023 06:59:28 GMT
- Title: Bounded Simplex-Structured Matrix Factorization: Algorithms,
Identifiability and Applications
- Abstract summary: We propose a new low-rank matrix factorization model dubbed simplex-structured matrix factorization (BSSMF)
BSSMF is particularly well suited when the entries of the input matrix $X$ belong to a given interval.
In this paper, we first propose a fast algorithm for BSSMF, even in the presence of missing data in $X$.
- Score: 20.836492835594843
- License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
- Abstract: In this paper, we propose a new low-rank matrix factorization model dubbed
bounded simplex-structured matrix factorization (BSSMF). Given an input matrix
$X$ and a factorization rank $r$, BSSMF looks for a matrix $W$ with $r$ columns
and a matrix $H$ with $r$ rows such that $X \approx WH$ where the entries in
each column of $W$ are bounded, that is, they belong to given intervals, and
the columns of $H$ belong to the probability simplex, that is, $H$ is column
stochastic. BSSMF generalizes nonnegative matrix factorization (NMF), and
simplex-structured matrix factorization (SSMF). BSSMF is particularly well
suited when the entries of the input matrix $X$ belong to a given interval; for
example when the rows of $X$ represent images, or $X$ is a rating matrix such
as in the Netflix and MovieLens datasets where the entries of $X$ belong to the
interval $[1,5]$. The simplex-structured matrix $H$ not only leads to an easily
understandable decomposition providing a soft clustering of the columns of $X$,
but implies that the entries of each column of $WH$ belong to the same
intervals as the columns of $W$. In this paper, we first propose a fast
algorithm for BSSMF, even in the presence of missing data in $X$. Then we
provide identifiability conditions for BSSMF, that is, we provide conditions
under which BSSMF admits a unique decomposition, up to trivial ambiguities.
Finally, we illustrate the effectiveness of BSSMF on two applications:
extraction of features in a set of images, and the matrix completion problem
for recommender systems.
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