Matrix properties
number of rows	841
number of columns	841
nonzeros	4,089
structural full rank?	yes
structural rank	841
# of blocks from dmperm	1
# strongly connected comp.	1
explicit zero entries	0
nonzero pattern symmetry	symmetric
numeric value symmetry	85%
type	complex
structure	unsymmetric
Cholesky candidate?	no
positive definite?	no

author	D. Young
editor	I. Duff, R. Grimes, J. Lewis
date	1984
kind	acoustics problem
2D/3D problem?	yes

Notes:

The YOUNG*C matrices originally appeared in the Harwell/Boeing     
collection as type CSA (complex symmetric).  However, both upper   
and lower triangular parts are present in the original files       
(an invalid specification; only the lower part can be present      
in the file).  If the entries in the upper triangular part are     
considered as part of the matrix, the matrices become unsymmetric. 
The matrices have been corrected in the UF Sparse Matrix Collection
by changing their type to CUA so that the entries in the original  
files are not ignored.  In addition, the YOUNG3C matrix has a zero 
imaginary part, and thus appears here as a real matrix.            

Ordering statistics:	result
nnz(chol(P*(A+A'+s*I)*P')) with AMD	9,198
Cholesky flop count	1.6e+05
nnz(L+U), no partial pivoting, with AMD	17,555
nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD	15,517
nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD	27,859

SVD-based statistics:
norm(A)	470.196
min(svd(A))	1.13296
cond(A)	415.015
rank(A)	841
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 (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.