Matrix properties
number of rows	66,917
number of columns	66,917
nonzeros	1,703,365
structural full rank?	yes
structural rank	66,917
# of blocks from dmperm	1
# strongly connected comp.	1
explicit zero entries	0
nonzero pattern symmetry	symmetric
numeric value symmetry	symmetric
type	real
structure	symmetric
Cholesky candidate?	no
positive definite?	no

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

Additional fields	size and type
E	sparse 66917-by-66917
B	sparse 66917-by-1
C	sparse 28-by-66917
cname	full 28-by-7

Notes:

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

Ordering statistics:	result
nnz(chol(P*(A+A'+s*I)*P')) with AMD	55,993,092
Cholesky flop count	1.2e+11
nnz(L+U), no partial pivoting, with AMD	111,919,267
nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD	86,330,206
nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD	154,029,283

Maintained by Tim Davis, last updated 01-Apr-2011.
Matrix pictures by cspy, a MATLAB function in the CSparse package.
Matrix graphs by Yifan Hu, AT&T Labs Visualization Group.