Network Display
The Network Display component is used to visualize the network as a
graph. A variety of graph layouts are available.
Network Model. Network Display must
be added only to a Network Model.
Properties are the items that appear in the property pane when you click
on a component in the project tree. For more information of properties, see
here.
Width |
The width in pixels of the display window.
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Height |
The height in pixels of the display window.
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Layout |
The layout property defines how the network will be laid out on the
display. There are four types of layouts and you can edit the
particular attributes of each layout by clicking the edit button.
- Circular. Lays out the nodes in a circle.
- Fruchman-Reingold. Lays out the nodes according to a modified
Fruchman-Reingold algorithm. Nodes are positioned according to an
iterative algorithm that assumes that nodes repel each other when
close, but are attracted to connected nodes. Convergence is obtained
by using a "simulated annealing"-style technique with an arbitrary
cooling function. See, Fruchterman, T.M.J and Reingold, E.M. (1991)
"Graph Drawing by Force-directed Placement" in Software-Practice and
Experience, Vol 21(11), 1129-1164.
- Kamada-Kawai lays out the nodes according to a modified
Kamada-Kawai algorithm. The Kamada-Kawai graph layout attempts to
position nodes on the space so that the geometric (Euclidean) distance
between them is as close as possible to the graph-theoretic (path)
distance between them. See, Kamada, Tomihisa and Satoru Kawai (1989)
"An Algorithm for Drawing Undirected Graphs" Information Processing
Letters 31:7-15.
- Random. Lays out the nodes at random.
Fruchman-Reingold and Kamada-Kawai are considerably slower than
circular or random, particularly with large networks.
When the Repast simulation is running and the display is visible, you
can move the nodes with the mouse by clicking and dragging them.
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Node Shape |
The shape of the displayed nodes (Oval or Rectangle).
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Schedule |
See the schedule help and
tutorial 3 for more information on the
schedule property.
The schedule property defines the execution schedule of any actions
defined in your network display.
Although there are no user-definable actions associated with the
Network Display component, Network Display implicitly defines two
actions. These two actions are:
- update_display. This will update the display showing any changes to
node color, label, and links since the last call to update_display.
- update_layout. This will update the layout of the nodes, that is,
their x and y coordinates in the display window. Provided the nodes
have not moved their is no real reason to schedule the update_layout
action for execution if you are using the circular or random
layouts. However, if you are using Fruchman-Reingold or Kamada-Kawai
where the x and y coordinates are dependent on node links, then you
probably want to schedule update_layout for execution.
Typically, update_display is scheduled for execution every tick
(iteration) and the scheduling of update_layout depends on the size of
the network and how long you are willing to wait between
iterations. As mentioned above, Fruchman-Reingold and Kamada-Kawai are
comptuationaly expensive algorithms and can be slow.
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