The clustering mode
ibm_ilog.graphlayout.circular.CircularLayout.BY_CLUSTER_IDS
uses
a built-in radial tree layout that does not provide the full functionality
of the ibm_ilog.graphlayout.tree.TreeLayout
used
in clustering mode AUTOMATIC
. It is simple
and tuned for speed. However, it has some useful expert parameters. Area minimization (CL)
For large graphs, the radius of the concentric circles
on which the clusters are placed can become very large. Therefore,
the Circular Layout provides an optional mode that reduces the total
area of the layout. To reduce the total area, the clusters are distributed
more equally on the circle.
Example of specifying area minimization mode (CL algorithm)
To enable or disable the area minimization mode:
Use the method:
layout.setAreaMinimizationEnabled(true)
The default value is
false
(area
minimization is disabled). Deciding whether to enable the area minimization mode
essentially depends on the size of the network; the area minimization
mode is most suitable for large networks.
To get an idea of the difference that area minimization
mode makes, compare the following layouts of the same network.

Area minimization disabled (default)

Area minimization enabled
This parameter has no effect if the clustering mode is
AUTOMATIC
or BY_SUBGRAPHS
. Handling of disconnected graphs
As explained in the CL Algorithm, each connected component
of the network is laid out separately. When the clustering mode
BY_CLUSTER_IDS
is
enabled, there are two ways to arrange the components. The one way
is using the generic mechanism to lay out connected components that
places the components using a grid layout. In this case, layout parameters
concerning component distances must be set on the grid layout. For
more information about this mechanism, see Layout of connected components (CL). The other way is using the built-in radial tree layout
directly. It arranges the components within the specified layout region.
In this case, the minimum offset between two components can be specified
in the following way (see Dimensional parameters (CL)).
Example of specifying the offset between each connected
component (CL algorithm)
To specify the offset between each connected component:
Use the method:
layout.setDisconnectedGraphOffset(20)
This parameter has no effect if the clustering mode is
BY_SUBGRAPHS
.