<s> """<STR_LIT>""" <EOL> import os <EOL> from pycascading . helpers import * <EOL> def test ( graph_file , d , iterations ) : <EOL> """<STR_LIT>""" <EOL> in_links = { } <EOL> out_degree = { } <EOL> pagerank = { } <EOL> file = open ( graph_file ) <EOL> for line in file : <EOL> ( source , dest ) = line . rstrip ( ) . split ( ) <EOL> try : <EOL> in_links [ dest ] . add ( source ) <EOL> except KeyError : <EOL> in_links [ dest ] = set ( source ) <EOL> try : <EOL> out_degree [ source ] += <NUM_LIT:1> <EOL> except KeyError : <EOL> out_degree [ source ] = <NUM_LIT:1> <EOL> pagerank [ source ] = <NUM_LIT:1.0> <EOL> pagerank [ dest ] = <NUM_LIT:1.0> <EOL> file . close ( ) <EOL> old_pr = pagerank <EOL> new_pr = { } <EOL> for iteration in xrange ( <NUM_LIT:0> , iterations ) : <EOL> for node in old_pr : <EOL> new_pr [ node ] = ( <NUM_LIT:1> - d ) <EOL> try : <EOL> new_pr [ node ] += d * sum ( [ old_pr [ n ] / out_degree [ n ] for n in in_links [ node ] ] ) <EOL> except KeyError : <EOL> pass <EOL> tmp = old_pr <EOL> old_pr = new_pr <EOL> new_pr = tmp <EOL> return old_pr <EOL> def main ( ) : <EOL> """<STR_LIT>""" <EOL> d = <NUM_LIT> <EOL> iterations = <NUM_LIT:5> <EOL> graph_file = '<STR_LIT>' <EOL> graph_source = Hfs ( TextDelimited ( Fields ( [ '<STR_LIT>' , '<STR_LIT:to>' ] ) , '<STR_LIT:U+0020>' , <EOL> [ String , String ] ) , graph_file ) <EOL> out_links_file = '<STR_LIT>' <EOL> pr_values_1 = '<STR_LIT>' <EOL> pr_values_2 = '<STR_LIT>' <EOL> flow = Flow ( ) <EOL> graph = flow . source ( graph_source ) <EOL> graph | group_by ( '<STR_LIT>' ) | native . count ( '<STR_LIT>' ) | flow . binary_sink ( out_links_file ) <EOL> @ udf <EOL> def constant ( tuple , c ) : <EOL> """<STR_LIT>""" <EOL> yield [ c ] <EOL> @ udf <EOL> def both_nodes ( tuple ) : <EOL> """<STR_LIT>""" <EOL> yield [ tuple . get ( <NUM_LIT:0> ) ] <EOL> yield [ tuple . get ( <NUM_LIT:1> ) ] <EOL> graph | map_replace ( both_nodes , '<STR_LIT>' ) | native . unique ( Fields . ALL ) | map_add ( constant ( <NUM_LIT:1.0> ) , '<STR_LIT>' ) | flow . binary_sink ( pr_values_1 ) <EOL> flow . run ( num_reducers = <NUM_LIT:1> ) <EOL> pr_input = pr_values_1 <EOL> pr_output = pr_values_2 <EOL> for iteration in xrange ( <NUM_LIT:0> , iterations ) : <EOL> flow = Flow ( ) <EOL> graph = flow . source ( graph_source ) <EOL> pageranks = flow . meta_source ( pr_input ) <EOL> out_links = flow . meta_source ( out_links_file ) <EOL> p = ( graph & pageranks & ( out_links | rename ( '<STR_LIT>' , '<STR_LIT>' ) ) ) | inner_join ( [ '<STR_LIT>' , '<STR_LIT>' , '<STR_LIT>' ] ) | rename ( [ '<STR_LIT>' , '<STR_LIT>' ] , [ '<STR_LIT>' , '<STR_LIT>' ] ) | retain ( '<STR_LIT>' , '<STR_LIT>' , '<STR_LIT>' , '<STR_LIT:to>' ) <EOL> @ udf <EOL> def incremental_pagerank ( tuple , d ) : <EOL> yield [ d * tuple . get ( '<STR_LIT>' ) / tuple . get ( '<STR_LIT>' ) ] <EOL> p = p | map_replace ( [ '<STR_LIT>' , '<STR_LIT>' , '<STR_LIT>' ] , <EOL> incremental_pagerank ( d ) , '<STR_LIT>' ) | rename ( '<STR_LIT:to>' , '<STR_LIT>' ) | retain ( '<STR_LIT>' , '<STR_LIT>' ) <EOL> p = ( p & ( pageranks | map_replace ( '<STR_LIT>' , constant ( <NUM_LIT:1.0> - d ) , '<STR_LIT>' ) ) ) | group_by ( ) <EOL> p = p | group_by ( '<STR_LIT>' , '<STR_LIT>' , native . sum ( '<STR_LIT>' ) ) <EOL> if iteration == iterations - <NUM_LIT:1> : <EOL> p | flow . tsv_sink ( pr_output ) <EOL> else : <EOL> p | flow . binary_sink ( pr_output ) <EOL> tmp = pr_input <EOL> pr_input = pr_output <EOL> pr_output = tmp <EOL> flow . run ( num_reducers = <NUM_LIT:1> ) <EOL> print '<STR_LIT>' , pr_input <EOL> os . system ( '<STR_LIT>' % ( pr_input , pr_input ) ) <EOL> print '<STR_LIT>' <EOL> test_pr = test ( graph_file , d , iterations ) <EOL> print '<STR_LIT>' <EOL> for n in sorted ( test_pr . iterkeys ( ) ) : <EOL> print '<STR_LIT>' % ( n , test_pr [ n ] ) </s>
