Matrix properties
number of rows	512
number of columns	394,792
nonzeros	1,127,525
structural full rank?	no
structural rank	458
# of blocks from dmperm	8
# strongly connected comp.	256
explicit zero entries	0
nonzero pattern symmetry	0%
numeric value symmetry	0%
type	binary
structure	rectangular
Cholesky candidate?	no
positive definite?	no

author	S. Buss
editor	T. Davis
date	2009
kind	undirected bipartite graph
2D/3D problem?	no

Notes:

This is a matrix from Steven Buss, for a website recommendation system (to
be called www.connectious.com).  Each row of the matrix is a unique user. 
Eachc olumn of the matrix is a web page.  A(i,j)=1 if user i has tagged   
web page j as favorable, and a 0 represents no opinion.  The data was     
obtained from digg.com.  Note that the matrix A*A' contains one           
connected component of size 342, and 170 singletons (nodes with no edges) 
This means that a group of 341 users share some interests, at least       
indirectly, and that there are 171 other users that share no interests    
at all with any other users (they have no pages in common with anyone).   

SVD-based statistics:
norm(A)	483.341
min(svd(A))	0
cond(A)	Inf
rank(A)	456
sprank(A)-rank(A)	2
null space dimension	56
full numerical rank?	no
singular value gap	1.03249e+10

singular values (MAT file):	click here
SVD method used:	s = svd (full (R)) ; where [~,R,E] = spqr (A') with droptol of zero
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.