Matrix properties
number of rows	89,400
number of columns	89,400
nonzeros	1,156,224
structural full rank?	yes
structural rank	89,400
# 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?	yes
positive definite?	yes

author	J. Castrillon
editor	T. Davis
date	2008
kind	counter-example problem
2D/3D problem?	no

Notes:

The problem is x=(A+alpha*I)\b as alpha varies from 0 to 100.  However,
as this occurs, performance suffers because of the many denormals that 
appear below the diagonal in L.                                        

Ordering statistics:	result
nnz(chol(P*(A+A'+s*I)*P')) with AMD	8,231,641
Cholesky flop count	2.5e+09
nnz(L+U), no partial pivoting, with AMD	16,373,882
nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD	16,686,436
nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD	30,789,903

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.