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
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
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:	result
nnz(chol(P*(A+A'+s*I)*P')) with AMD	115,326
Cholesky flop count	5.5e+06
nnz(L+U), no partial pivoting, with AMD	226,395
nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD	180,860
nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD	336,323

SVD-based statistics:
norm(A)	145.643
min(svd(A))	7.4683e-15
cond(A)	1.95014e+16
rank(A)	4,256
sprank(A)-rank(A)	1
null space dimension	1
full numerical rank?	no
singular value gap	4.93698e+07

singular values (MAT file):	click here
SVD method used:	s = svd (full (A)) ;
status:	ok

For a description of the statistics displayed above, click here.

Maintained by Tim Davis, last updated 12-Mar-2014.
Matrix pictures by cspy, a MATLAB function in the CSparse package.
Matrix graphs by Yifan Hu, AT&T Labs Visualization Group.