%-------------------------------------------------------------------------------
% UF Sparse Matrix Collection, Tim Davis
% http://www.cise.ufl.edu/research/sparse/matrices/SNAP/cit-Patents
% name: SNAP/cit-Patents
% [Citation network among US Patents]
% id: 2294
% date: 1999
% author: B. Hall, A. Jaffe, M. Trajtenberg
% ed: J. Leskovec
% fields: name title A id date author ed kind notes aux
% aux: nodename
% kind: directed graph
%-------------------------------------------------------------------------------
% notes:
% Networks from SNAP (Stanford Network Analysis Platform) Network Data Sets,     
% Jure Leskovec http://snap.stanford.edu/data/index.html                         
% email jure at cs.stanford.edu                                                  
%                                                                                
% Patent citation network                                                        
%                                                                                
% Dataset information                                                            
%                                                                                
% U.S. patent dataset is maintained by the National Bureau of Economic Research. 
% The data set spans 37 years (January 1, 1963 to December 30, 1999), and        
% includes all the utility patents granted during that period, totaling 3,923,922
% patents. The citation graph includes all citations made by patents granted     
% between 1975 and 1999, totaling 16,522,438 citations. For the patents dataset  
% there are 1,803,511 nodes for which we have no information about their         
% citations (we only have the in-links).                                         
%                                                                                
% The data was originally released by NBER.                                      
%                                                                                
% Dataset statistics                                                             
% Nodes   3774768                                                                
% Edges   16518948                                                               
% Nodes in largest WCC    3764117 (0.997)                                        
% Edges in largest WCC    16511741 (1.000)                                       
% Nodes in largest SCC    1 (0.000)                                              
% Edges in largest SCC    0 (0.000)                                              
% Average clustering coefficient  0.0919                                         
% Number of triangles     7515023                                                
% Fraction of closed triangles    0.06714                                        
% Diameter (longest shortest path)    22                                         
% 90-percentile effective diameter    9.4                                        
%                                                                                
% Source (citation)                                                              
%                                                                                
% J. Leskovec, J. Kleinberg and C. Faloutsos. Graphs over Time: Densification    
% Laws, Shrinking Diameters and Possible Explanations. ACM SIGKDD International  
% Conference on Knowledge Discovery and Data Mining (KDD), 2005.                 
%                                                                                
% Hall, B. H., A. B. Jaffe, and M. Trajtenberg (2001). "The NBER Patent Citation 
% Data File: Lessons, Insights and Methodological Tools." NBER Working Paper     
% 8498.  http://papers.nber.org/papers/w8498.pdf                                 
%                                                                                
% Files                                                                          
% File    Description                                                            
% cit-Patents.txt.gz  US Patent citation network 1975-1999                       
% NBER Patents    Complete US Patent data (includes time, classification, and    
%                 patent invernetor data), at http://www.nber.org/patents/       
%                                                                                
%                                                                                
% NOTE: a similar version this problem already appears in the UF Collection:     
%                                                                                
% cit-Patents         in SNAP         n: 3,774,768   nz: 16,518,948              
%                     Pajek/patents   n: same        nz: 14,970,767              
%                                                                                
%                     Both of these come from the NBER data.  However,           
%                     the edges are not the same.  The SNAP/cit-Patents          
%                     data is a strict superset of the Pajek/patents graph.      
%                     If A0 = Pajek/patents and A1 = SNAP/cit-Patents,           
%                     then nnz(A1-A0) = nnz(A1)-nnz(A0) = 1,548,181.             
%                     All edges in A0 appear in A1.                              
%                                                                                
%                     The aux data is not the same.  Pajek/patents contains      
%                     more auxiliary data for each node.  This data can be       
%                     used to interpret the SNAP/cit-Patents graph as well,      
%                     since the nodes match up from one graph to the other.      
%                                                                                
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