Matrix properties
number of rows	57
number of columns	57
nonzeros	281
structural full rank?	yes
structural rank	57
# of blocks from dmperm	1
# strongly connected comp.	1
explicit zero entries	0
nonzero pattern symmetry	87%
numeric value symmetry	87%
type	binary
structure	unsymmetric
Cholesky candidate?	no
positive definite?	no

author	R. Willoughby
editor	I. Duff, R. Grimes, J. Lewis
date	1970
kind	semiconductor device problem
2D/3D problem?	yes

Ordering statistics:	result
nnz(chol(P*(A+A'+s*I)*P')) with AMD	191
Cholesky flop count	6.8e+02
nnz(L+U), no partial pivoting, with AMD	325
nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD	235
nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD	450

SVD-based statistics:
norm(A)	6.14869
min(svd(A))	2.24858e-17
cond(A)	2.73448e+17
rank(A)	50
sprank(A)-rank(A)	7
null space dimension	7
full numerical rank?	no
singular value gap	1.95656e+14

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.