Matrix properties
number of rows	20,360
number of columns	20,360
nonzeros	509,866
structural full rank?	yes
structural rank	20,360
# 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 20360-by-20360
B	sparse 20360-by-1
C	sparse 7-by-20360
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	11,761,002
Cholesky flop count	1.6e+10
nnz(L+U), no partial pivoting, with AMD	23,501,644
nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD	17,068,760
nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD	29,662,013

SVD-based statistics:
norm(A)	1.19771
min(svd(A))	1.96359e-15
cond(A)	6.0996e+14
rank(A)	20,359
sprank(A)-rank(A)	1
null space dimension	1
full numerical rank?	no
singular value gap	1.79811e+08

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.