— Loadable Function: p = dmperm (s)
— Loadable Function: [p. q. r, s] = dmperm (s)

Perform a Deulmage-Mendelsohn permutation on the sparse matrix s. With a single output argument dmperm performs the row permutations p such that s (p,:) has no zero elements on the diagonal.

Called with two or more output arguments, returns the row and column permutations, such that s (p, q) is in block triangular form. The values of r and s define the boundaries of the blocks. If s is square then r == s.

The method used is described in: A. Pothen & C.-J. Fan. Computing the block triangular form of a sparse matrix. ACM Trans. Math. Software, 16(4):303-324, 1990.

See also: colamd, ccolamd.