Matrix properties
number of rows	4,257
number of columns	4,257
nonzeros	37,465
structural full rank?	yes
structural rank	4,257
# of blocks from dmperm	1
# strongly connected comp.	1
entries not in dmperm blocks	0
explicit zero entries	0
nonzero pattern symmetry	symmetric
numeric value symmetry	symmetric
type	real
structure	symmetric
Cholesky candidate?	no
positive definite?	no

author	E. Rudnyi
editor	E. Rudnyi
date	2004
kind	model reduction problem
2D/3D problem?	yes

Additional fields	size and type
E	sparse 4257-by-4257
Abottom	sparse 4257-by-4257
Aside	sparse 4257-by-4257
Atop	sparse 4257-by-4257
B	sparse 4257-by-1
C	sparse 7-by-4257
cname	full 7-by-7

Notes:

Primary matrix in this model reduction problem is the Oberwolfach A matrix

Ordering statistics:	AMD	METIS
nnz(chol(P*(A+A'+s*I)*P'))	115,326	111,783
Cholesky flop count	5.5e+06	4.6e+06
nnz(L+U), no partial pivoting	226,395	219,309
nnz(V) for QR, upper bound nnz(L) for LU	180,860	167,442
nnz(R) for QR, upper bound nnz(U) for LU	336,323	314,459

Maintained by Tim Davis, last updated 30-Sep-2008.
Matrix pictures by cspy, a MATLAB function in the CSparse package.
Matrix graphs by Yifan Hu, AT&T Labs Visualization Group.