added path2 scripts

jena/path2.qry

+prefix : <http://example.org/stuff/1.0/>
+SELECT (count(*) as ?resultcount) WHERE {?a :par / :par ?b}

neo4j/path2.qry

+MATCH (n)
+DETACH DELETE n;
+
+LOAD CSV FROM 'file://INSTANCE' AS line
+MERGE (a:Node {n: toInteger(line[0])})
+MERGE (b:Node {n: toInteger(trim(line[1]))})
+CREATE (a)-[:PAR]->(b);
+
+MATCH (a)-[:PAR]->(t)-[:PAR]->(b)
+RETURN COUNT(DISTINCT [a,b]);

souffle/path2.dl

+
+//
+// par - "parent"/"edge" relation
+//
+.decl par (n:number, m:number)
+.input par(IO=file, filename="INSTANCE")
+// par(1,2).
+// par(2,3).
+
+//.decl path2 (n:number, m:number) output
+.decl path2 (n:number, m:number)
+//.output path2(IO=stdout)
+.printsize path2
+
+path2(X, Y)  :- par(X, Z), par(Z, Y).

sql/path2.sql

+
+WITH path2(a,b) AS (
+	SELECT p1.a, p2.b from par p1 JOIN par p2c ON p1.b = p2.a
+) SELECT Count(*) FROM path2;