%-------------------------------------------------------------------------------
% SuiteSparse Matrix Collection, Tim Davis
% https://sparse.tamu.edu/SNAP/soc-sign-bitcoin-alpha
% name: SNAP/soc-sign-bitcoin-alpha
% [SNAP network: Bitcoin Alpha trust weighted signed network]
% id: 2790
% date: 2016
% author: S. Kumar, F. Spezzano, V.S. Subrahmanian, C. Faloutsos
% ed: J. Leskovec
% fields: name title A id date author ed kind notes aux
% aux: nodeid temporal_edges Time
% kind: directed weighted temporal graph
%-------------------------------------------------------------------------------
% notes:
% SNAP (Stanford Network Analysis Platform) Large Network Dataset Collection,
% Jure Leskovec and Anrej Krevl, http://snap.stanford.edu/data, June 2014.   
% email: jure at cs.stanford.edu                                             
%                                                                            
% Bitcoin Alpha trust weighted signed network                                
%                                                                            
% https://snap.stanford.edu/data/soc-sign-bitcoin-alpha.html                 
%                                                                            
% Dataset information                                                        
%                                                                            
% This is who-trusts-whom network of people who trade using Bitcoin on a     
% platform called Bitcoin Alpha (http://www.btcalpha.com/). Since Bitcoin    
% users are anonymous, there is a need to maintain a record of users'        
% reputation to prevent transactions with fraudulent and risky users. Members
% of Bitcoin Alpha rate other members in a scale of -10 (total distrust) to  
% +10 (total trust) in steps of 1. This is the first explicit weighted signed
% directed network available for research.                                   
%                                                                            
% Dataset statistics                                                         
% Nodes   3,783                                                              
% Edges   24,186                                                             
% Range of edge weight    -10 to +10                                         
% Percentage of positive edges    93%                                        
%                                                                            
% Similar network from another Bitcoin platform, Bitcoin OTC, is available at
% https://snap.stanford.edu/data/soc-sign-bitcoinotc.html (and as            
% SNAP/bitcoin-otc in the SuiteSparse Matrix Collection).                    
%                                                                            
% Source (citation) Please cite the following paper if you use this dataset: 
% S. Kumar, F. Spezzano, V.S. Subrahmanian, C. Faloutsos. Edge Weight        
% Prediction in Weighted Signed Networks. IEEE International Conference on   
% Data Mining (ICDM), 2016.                                                  
% http://cs.stanford.edu/~srijan/pubs/wsn-icdm16.pdf                         
%                                                                            
% The following BibTeX citation can be used:                                 
% @inproceedings{kumar2016edge,                                              
%   title={Edge weight prediction in weighted signed networks},              
%   author={Kumar, Srijan and Spezzano, Francesca and                        
%      Subrahmanian, VS and Faloutsos, Christos},                            
%   booktitle={Data Mining (ICDM), 2016 IEEE 16th Intl. Conf. on},           
%   pages={221--230},                                                        
%   year={2016},                                                             
%   organization={IEEE}                                                      
% }                                                                          
%                                                                            
% The project webpage for this paper, along with its code to calculate two   
% signed network metrics---fairness and goodness---is available at           
% http://cs.umd.edu/~srijan/wsn/                                             
%                                                                            
% Files                                                                      
% File    Description                                                        
% soc-sign-bitcoinalpha.csv.gz                                               
%     Weighted Signed Directed Bitcoin Alpha web of trust network            
%                                                                            
% Data format                                                                
% Each line has one rating with the following format:                        
%                                                                            
%     SOURCE, TARGET, RATING, TIME                                           
%                                                                            
% where                                                                      
%                                                                            
%     SOURCE: node id of source, i.e., rater                                 
%     TARGET: node id of target, i.e., ratee                                 
%     RATING: the source's rating for the target,                            
%             ranging from -10 to +10 in steps of 1                          
%     TIME: the time of the rating, measured as seconds since Epoch.         
%                                                                            
% ---------------------------------------------------------------------------
% Notes on inclusion into the SuiteSparse Matrix Collection, July 2018:      
% ---------------------------------------------------------------------------
%                                                                            
% The SNAP data set is 1-based, with nodes numbered 1 to 7,604.              
%                                                                            
% In the SuiteSparse Matrix Collection, Problem.A is the directed rating     
% graph, a matrix of size n-by-n with n=3,783, which is the number of        
% unique node id's appearing in the SOURCE or TARGET of any edge.            
%                                                                            
% Problem.aux.nodeid is an array of size 3783 that gives the node id's       
% corresponding to each row and column of the matrix.  nodeid(i)=id if the   
% id in the temporal edge appears as the ith row and column of the A matrix. 
% A(i,j) is the rating that member nodeid(i) gave member nodeid(j).          
%                                                                            
% Since there are no duplicate ratings, the Problem.A matrix can hold all    
% the edges without losing any information.  The ratings are in the range    
% -10 to 10, but are never zero, so the MATLAB Problem.A sparse matrix       
% contains all the edges.                                                    
%                                                                            
% The timestamps appear in the Problem.aux.Time matrix.  It has the same     
% nonzero pattern as Problem.A.                                              
%-------------------------------------------------------------------------------
