GroIMP wiki

This page is read only. You can view the source, but not change it. Ask your administrator if you think this is wrong.
====== Transitive closure ======

Transitive closures of relations follow the well-known syntax of regular expressions where patterns to be repeated are enclosed in parentheses with a quantifier appended. The possible
quantifiers are:
  * ''+'' : 1-to-n repetitions.
  * ''*'' : 0-to-n repetitions.
  * ''?'' : 0-to-1 repetitions.
  * ''{n}'' : exactly n repetitions,
  * ''{n,m}'' : n-to-m repetitions.
  * ''{n,}'' : least n repetitions.

=====  =====

Transitive closures can be applied on combined path predicates. E.g. ''%%(-branch-> b:B (-successor->)*, (b.prod > 0))*%%'' matches all paths which traverse a branch edge and a possibly empty sequence of successor edges alternatingly. In addition, target nodes of branch edges have to be of type B and fulfill the condition b.prod > 0.

Note: Using transitive closure it is possible to find the same node several time.

===== Example =====

| query  | description |
| ''%% A (>)+ B %%'' | All B's that have a A above connected by one successor edges or more| 
| ''%% A (>)* +> B %%'' | All B's that have a A above connected by one or more successor edges and one branch-edge directly before the B| 
| ''%% A ((>)* +>)+ B %%'' | All B's conntected to A by one or more repetition of the pattern above| 
| ''%% A (>)* +> (>)* B %%'' | As many sucessors followed by a branch followed by as many successors |
| ''%% A (-->)* C (-->)* B %%''| All B' that have an ancestor of the type A and an ancestor of the type C with C between the A and the B |
| ''%% A (>){2} B %%''| All B's conntected to an A by two incoming successor edge |