  This work presents a general framework for solving the low rank and/or sparse
matrix minimization problems, which may involve multiple non-smooth terms. The
Iteratively Reweighted Least Squares (IRLS) method is a fast solver, which
smooths the objective function and minimizes it by alternately updating the
variables and their weights. However, the traditional IRLS can only solve a
sparse only or low rank only minimization problem with squared loss or an
affine constraint. This work generalizes IRLS to solve joint/mixed low rank and
sparse minimization problems, which are essential formulations for many tasks.
As a concrete example, we solve the Schatten-$p$ norm and $\ell_{2,q}$-norm
regularized Low-Rank Representation (LRR) problem by IRLS, and theoretically
prove that the derived solution is a stationary point (globally optimal if
$p,q\geq1$). Our convergence proof of IRLS is more general than previous one
which depends on the special properties of the Schatten-$p$ norm and
$\ell_{2,q}$-norm. Extensive experiments on both synthetic and real data sets
demonstrate that our IRLS is much more efficient.
