Robust principal component analysis¶
Robust principal component analysis (RPCA) seeks a decomposition of a matrix as a sum of a low-rank and sparse matrix, i.e.,
\[M = L + S,\]
where a balance is sought between the rank of \(L\) and the number of nonzeros in \(S\). Such a balance is (weakly) imposed via convex relaxations of penalties on the number of nonzero singular values of \(L\) and entries of \(S\) to their \(\ell_1\) counterparts. In particular, a solution is sought for the problem
\[\min_{L,S} \| L \|_* + \| \text{vec}(S) \|_1 \text{ such that } M = L + S,\]
where \(\| \cdot \|_*\) denotes the nuclear norm and \(\| \text{vec}(\cdot) \|_1\) denotes the entrywise one-norm.