Virtual class of composite matrices; i.e., matrices that can be factorized, typically as a product of simpler matrices.
A virtual Class: No objects may be created from it.
Class "Matrix", directly.
signature(x = "compMatrix", value = "list"): set
      the dimnames to a list of length 2, see
      dimnames<-.  The factors slot is currently reset to
      empty, as the factorization dimnames would have to be adapted, too.
The matrix factorization classes
  "'>MatrixFactorization" and their generators,
  lu(),
  qr(),
  chol() and Cholesky(),
  BunchKaufman(), Schur().