#!/usr/bin/env python """ An example of the MultiDiGraph clas The function chess_pgn_graph reads a collection of chess matches stored in the specified PGN file (PGN ="Portable Game Notation") Here the (compressed) default file --- chess_masters_WCC.pgn.bz2 --- contains all 685 World Chess Championship matches from 1886 - 1985. (data from http://chessproblem.my-free-games.com/chess/games/Download-PGN.php) The chess_pgn_graph() function returns a MultiDiGraph with multiple edges. Each node is the last name of a chess master. Each edge is directed from white to black and contains selected game info. The key statement in chess_pgn_graph below is G.add_edge(white, black, game_info) where game_info is a dict describing each game. """ # Copyright (C) 2006 by # Aric Hagberg <hagberg@lanl.gov> # Dan Schult <dschult@colgate.edu> # Pieter Swart <swart@lanl.gov> # All rights reserved. # BSD license. import networkx as nx # tag names specifying what game info should be # stored in the dict on each digraph edge game_details=[ "Event", "Date", "Result", "ECO", "Site" ] def chess_pgn_graph(pgn_file="chess_masters_WCC.pgn.bz2"): """Read chess games in pgn format in pgn_file. Filenames ending in .gz or .bz2 will be uncompressed. Return the MultiDiGraph of players connected by a chess game. Edges contain game data in a dict. """ try:# use networkx.utils._get_fh to uncompress # pgn file if required datafile=nx.utils._get_fh(pgn_file,mode='rb') except IOError: print "Could not read file %s."%(pgn_file) raise G=nx.MultiDiGraph(weighted=False) game_info={} for line in datafile.read().splitlines(): # check for tag pairs if len(line)>0 and line[0]=='[': line=line[1:-1] # remove extra quotes tag = line.split()[0] value=line[len(tag)+2:-1] if tag=='White': white=value.split(',')[0] elif tag=='Black': black=value.split(',')[0] elif tag in game_details: game_info[tag]=value # empty line after tag set indicates # we finished reading game info elif len(line)==0: if len(game_info)>0: G.add_edge(white, black, **game_info) game_info={} return G if __name__ == '__main__': import networkx as nx import matplotlib.pyplot as plt plt.rcParams['text.usetex'] = False G=chess_pgn_graph() ngames=G.number_of_edges() nplayers=G.number_of_nodes() print "Loaded %d chess games between %d players\n"\ % (ngames,nplayers) # identify connected components # of the undirected version Gcc=nx.connected_component_subgraphs(G.to_undirected()) if len(Gcc)>1: print "Note the disconnected component consisting of:" print Gcc[1].nodes() # find all games with B97 opening (as described in ECO) openings=set([game_info['ECO'] for (white,black,game_info) in G.edges(data=True)]) print "\nFrom a total of %d different openings,"%len(openings) print 'the following games used the Sicilian opening' print 'with the Najdorff 7...Qb6 "Poisoned Pawn" variation.\n' for (white,black,game_info) in G.edges(data=True): if game_info['ECO']=='B97': print white,"vs",black for k,v in game_info.items(): print " ",k,": ",v print "\n" plt.figure(figsize=(8,8)) # make new undirected graph H without multi-edges H=nx.Graph(G) # edge width is proportional number of games played edgewidth=[] for (u,v,d) in H.edges(data=True): edgewidth.append(len(G.get_edge_data(u,v))) # node size is proportional to number of games won wins=dict.fromkeys(G.nodes(),0.0) for (u,v,d) in G.edges(data=True): r=d['Result'].split('-') if r[0]=='1': wins[u]+=1.0 elif r[0]=='1/2': wins[u]+=0.5 wins[v]+=0.5 else: wins[v]+=1.0 print H.edges(data=True) A=nx.to_numpy_matrix(H) try: pos=nx.graphviz_layout(H) except: pos=nx.spring_layout(H,iterations=20) nx.draw_networkx_edges(H,pos,alpha=0.3,width=edgewidth, edge_color='m') nodesize=[wins[v]*50 for v in H] nx.draw_networkx_nodes(H,pos,node_size=nodesize,node_color='w',alpha=0.4) nx.draw_networkx_edges(H,pos,alpha=0.4,node_size=0,width=1,edge_color='k') nx.draw_networkx_labels(H,pos,fontsize=14) font = {'fontname' : 'Helvetica', 'color' : 'k', 'fontweight' : 'bold', 'fontsize' : 14} plt.title("World Chess Championship Games: 1886 - 1985", font) # change font and write text (using data coordinates) font = {'fontname' : 'Helvetica', 'color' : 'r', 'fontweight' : 'bold', 'fontsize' : 14} plt.text(0.5, 0.97, "edge width = # games played", horizontalalignment='center', transform=plt.gca().transAxes) plt.text(0.5, 0.94, "node size = # games won", horizontalalignment='center', transform=plt.gca().transAxes) plt.axis('off') plt.savefig("chess_masters.png",dpi=75) print "Wrote chess_masters.png" plt.show() # display