## Monitor Windows

In run mode you can open monitor windows for all or some of the nodes. This is done by selecting the nodes and then choosing the Show Monitor Windows item from the View menu. You can also choose the Show Monitors item from the network pane menu which is activated when you press the right mouse button somewhere in the network pane while working in run mode.

There are three types of monitor windows (see figure 1, figure 2, and figure 3) - one for each of the node types: discrete chance node, continuous chance node, and decision node. You cannot open a monitor window for a utility node.

Figure 1: A monitor window for a discrete chance node

Figure 2: A monitor window for a continuous chance node

Figure 3: A monitor window for a decision node

The monitor windows show (monitor) the calculated results for a node:

- Discrete chance nodes: The probability of each state.
- Continuous chance nodes: The mean, variance (SD), and the pdf graph.
- Decision nodes: The expected utility of each action.

Monitor windows for continuous chance nodes can open with or without showing the graph display below the pane showing mean and variance (depending on the settings in Network Properties as described later). You can open and close it by clicking the small button on the right of the mean and variance. You can chose different end points as the mean plus/minus an integral multiple of the variance from the two drop down lists below the pane containing the graph.

On the right side of the graph there is a slider which can be used to zoom in on the x-axis to spot local peaks on the graph. Just below this slider is a button which should be pressed after each propagation to update the graph if auto update of graphs is not enabled. Hugin does not automatically update the graphs because this could take a very long time on large Bbns.

You can customize the monitor windows to your needs in the Monitors tab of the Network Properties dialog box. Figure 4 shows the Monitors tab.

Figure 4: The Network Properties dialog box showing the Monitors tab.

You can set the monitors to show at most a certain number of states in the Monitor States group box. For continuous chance nodes, you can specify if you always want the monitor to open with the graph pane and you can specify the end points (in multiples of the variance) of the graph.

You can also specify the graph precision. Normally, you would want the graph as precise as possible but if you have a large network with many continuous chance nodes and poor performance, you might save some time if you decrease graph precision.

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