Matrix properties
number of rows	20,209
number of columns	20,209
nonzeros	139,233
structural full rank?	yes
structural rank	20,209
# 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	P. Benner, J. Saak
editor	E. Rudnyi
date	2002
kind	model reduction problem
2D/3D problem?	yes

Additional fields	size and type
E	sparse 20209-by-20209
B	sparse 20209-by-7
C	sparse 6-by-20209

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	331,190
Cholesky flop count	1.4e+07
nnz(L+U), no partial pivoting, with AMD	642,171
nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD	790,024
nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD	1,698,034

SVD-based statistics:
norm(A)	5.5875e-05
min(svd(A))	2.38323e-10
cond(A)	234451
rank(A)	20,209
sprank(A)-rank(A)	0
null space dimension	0
full numerical rank?	yes

singular values (MAT file):	click here
SVD method used:	s = svd (full (R)) ; where [~,R,E] = spqr (A) with droptol of zero
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.