Piecewise separable matrices (Q2504982)

In the paper, piecewise separable and piecewise quasiseparable matrices are defined. A piecewise separable matrix with \(p\) boundaries can be written as a sum of \(O(p)\) standard one-piece matrices. For a standard one-piece matrix an algorithm with \(O(n)\) estimate of the operation count is given. Quasiseparable and weakly semiseparable matrices can be also considered as piecewise separable matrices.