Biomedical Engineering Reference
In-Depth Information
Hiliting a frequent fragment also hilites the molecules
in which the fragment occurs
Figure 6.2
6.1.2 Meta-nodes
Workfl ows for complex tasks tend to increase considerably in size. Meta-
nodes are a practical way of structuring them. They encapsulate sub-
workfl ows, which require several nodes to accomplish a certain task in
the parent workfl ow. Meta-nodes can either be created as empty sub-
workfl ows, to which other nodes are added, or a number of nodes in an
existing workfl ow can be selected and collapsed into a meta-node. Meta-
nodes can even be nested to arbitrary depths. Moreover, certain common
tasks, such as cross-validation or feature elimination, which require more
than one node are available as pre-confi gured meta-nodes in the node
repository.
6.1.3 Loops
The workfl ows' conceptual structure is a directed acyclic graph, that is
there are no loops from the output of one node to the input of one of its
predecessors. Data fl ows strictly in one direction. However, there are cases
Search WWH ::
Custom Search