Matrix properties
number of rows	1,824
number of columns	1,824
nonzeros	39,208
structural full rank?	yes
structural rank	1,824
# of blocks from dmperm	1
# strongly connected comp.	1
entries not in dmperm blocks	0
explicit zero entries	0
nonzero pattern symmetry	symmetric
numeric value symmetry	symmetric
type	real
structure	symmetric
Cholesky candidate?	yes
positive definite?	no

author	R. Grimes
editor	T. Davis
date	1995
kind	duplicate structural problem
2D/3D problem?	yes

Additional fields	size and type
b	full 1824-by-1

Notes:

Let A1=Nasa/nasa1824 and A2=Boeing/nasa1824.  A1 and A2 have the same 
nonzero pattern.  A1 and A2 differ in value in only 386 entries out of
39208, and only in 21 columns of the lower triangular part;           
tril(A(196:321,196:216)) and the same rows of the upper triangular    
part.  The magnitudes of the entries in A2 in this region of the      
matrix are all tiny, and have only 9 digits if printed in base-10     
(unlike the other entries, which have full precision).  I suspect A2  
(Boeing/nasa1824) is a corrupted version of A1 (Nasa/nasa1824).       

Ordering statistics:	AMD	METIS
nnz(chol(P*(A+A'+s*I)*P'))	69,309	79,854
Cholesky flop count	4.6e+06	5.8e+06
nnz(L+U), no partial pivoting	136,794	157,884
nnz(V) for QR, upper bound nnz(L) for LU	157,808	138,536
nnz(R) for QR, upper bound nnz(U) for LU	289,058	259,834

Maintained by Tim Davis, last updated 04-May-2008.
Matrix pictures by cspy, a MATLAB function in the CSparse package.
Matrix graphs by Yifan Hu, AT&T Labs Visualization Group.