This module is currently for internal use only
It defines various built-in and external ordering methods for sparse matrices. They are typically used to reduce the number of elements during the sparse matrix decomposition (LLT, LU, QR). Precisely, in a preprocessing step, a permutation matrix P is computed using those ordering methods and applied to the columns of the matrix. Using for instance the sparse Cholesky decomposition, it is expected that the nonzeros elements in LLT(A*P) will be much smaller than that in LLT(A).
A simple usage is as a template parameter in the sparse decomposition classes :
It is possible as well to call directly a particular ordering method for your own purpose,
|class||Eigen::AMDOrdering< Index >|
|class||Eigen::COLAMDOrdering< StorageIndex >|
|class||Eigen::NaturalOrdering< StorageIndex >|