Matrix properties
number of rows	999,999
number of columns	999,999
nonzeros	4,995,991
structural full rank?	yes
structural rank	999,999
# 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	B. McRae
editor	T. Davis
date	2008
kind	2D/3D problem
2D/3D problem?	yes

Notes:

Landscape ecology problem, using electrical network theory to model 
animal movement an gene flow.  The McRae/ecology2 matrix comes from 
a 2D, 1000-by-1000 mesh (5 pt stencil).  It is a symmetric positive 
definite matrix.  Source: Brad McRae, National Center for Ecological
Analysis and Synthesis Santa Barbara, CA.                           

Ordering statistics:	result
nnz(chol(P*(A+A'+s*I)*P')) with AMD	45,752,523
Cholesky flop count	2.0e+10
nnz(L+U), no partial pivoting, with AMD	90,505,047
nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD	69,455,113
nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD	128,056,728

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.