Evidence Scenario File Syntax

As with BayesiaLab's Dictionaries, the syntax of an Evidence Scenario File is straightforward. However, we need to distinguish between the syntax for Contemporaneous and Temporal networks:

Contemporaneous Networks

  • Each line of an Evidence Scenario File represents one Evidence Scenario.

  • Encoding an Evidence Scenario always follows the same pattern, with the node name and the evidence separated by a colon (:). The optional scenario name follows after a double slash (//). ?<NodeName>?:<Evidence>//<ScenarioName>

  • Evidence can be encoded in several ways in an Evidence Scenario File:

    • Hard Evidence: ?<NodeA>?:<State1>//Scenario1

    • Numerical Evidence: ?<NodeB>?:m{<value>}//Scenario2

    • Probabilistic Evidence: ?<NodeC>?:p{<StateA>:0.3;<StateB>:0.5;<StateC>:0.2}//Scenario3

    • Likelihood Evidence: ?<NodeD?:l{<StateX>:1;<StateY>:0.5}//Scenario4

  • To encode multiple pieces of evidence in one Evidence Scenario, simply separate the individual pieces of evidence with a semicolon. The scenario name remains at the end of the line, separated by a double slash.

?<NodeA>?:<State1>;?<NodeB>?:m{<value>} ;?<NodeC>?:p{<StateA>:0.3;<StateB>:0.5;<StateC>:0.2};?<NodeD>?:l{<StateX>:1;<StateY>:0.5}//Scenario5   

Temporal Networks

  • For Temporal Bayesian networks, the syntax of the Evidence Scenario File is slightly different. Here, each line in the text file refers to a time step, in which the evidence specified in that line will be applied.

  • Each line starts with an integer value that represents the time step, in which the evidence of that line will be set.

  • Evidence can be encoded in several ways in an Evidence Scenario File:

<TimeStep2>;?<NodeName>?:<Evidence>
<TimeStep4>;?<NodeName>?:<Evidence>
<TimeStep19>;?<NodeName>?:<Evidence>
  • To encode multiple pieces of evidence in one Time Step, simply separate the individual pieces of evidence with a semicolon.

<TimeStep3>;?<NodeA>?:<State1>;?<NodeB>?:m{<value>} ;?<NodeC>?:p{<StateA>:0.3;<StateB>:0.5;<StateC>:0.2};?<NodeD>?:l{<StateX>:1;<StateY>:0.5}\Evidence for Step 3
<TimeStep5>;?<NodeA>?:<State3>;?<NodeB>?:m{<value>} ;?<NodeC>?:p{<StateA>:0.1;<StateB>:0.7;<StateC>:0.2};?<NodeD>?:l{<StateX>:0.1;<StateY>:0.5}\Evidence for Step 5 
  • For Temporal networks, recalling evidence from the Evidence Scenario File is different compared to Contemporaneous networks.

  • Now, the time-specific Evidence Scenarios will be set automatically as you perform a temporal simulation.

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