Chapter 15
Variables and Parameters
Describes variables and parameters and how to use them within a KB.
- Introduction
- Comparing Variables and Parameters
- Parameter Features
- Variable Features
- Memory Considerations
- Summary of Variable and Parameter Differences
- Variables, Parameters, and Rules
- Obtaining Values for Variables
- Obtaining Unrequested Values
- Obtaining Requested Values
- Inference Engine Data Server
- G2-Simulator Data Server
- G2, G2 Gateway, or GFI Data Server
- Handling a Variable Failure
- Invoking Whenever Rules for Failed Variables
- Retrying the Variable
- Obtaining Values for Parameters
- Creating Variables and Parameters
- Specifying Forward and Backward Chaining
- Defining Debugging and Tracing
- Specifying the Type
- Specifying an Initial Value
- Obtaining the Last Recorded Value
- Specifying Whether to Keep a History of Values
- Specifying a Validity Interval
- Effect of Validity Interval on Expiration Time Stamp
- Using a Specific Interval
- Using an Indefinite Interval
- Using a Supplied Interval
- Creating a Specific Formula
- Specifying Simulation Details
- Determining the Initial Simulation Value
- Specifying a Data Server
- Specifying a Default Update Interval
- History Keeping in G2
- Storing and Accessing History Values
- Collection Time
- Saving a Maximum Number of Data Points
- Saving Data Points over a Maximum Time Period
- Saving a Maximum Number of Data Points Over a Specific Time Period
- Specifying a Minimum Interval Between History Data Points
- Event-based History
- Keeping a Single Data Point per Interval
- Working With History Keeping Using Attribute Access
- Displaying History Values Dynamically
- Specifying History-keeping Programmatically
- Changing the History-keeping Specification
- Removing History Keeping
- History Expressions
- Obtaining a History Value
- Computing the Number of History Datapoints
- Computing the Average History Value
- Computing the Integral
- Computing the Interpolated Value
- Computing Maximum and Minimum Values
- Computing the Rate of Change
- Computing the Standard Deviation
- Actions To Use With Variables and Parameters
- Concluding An Attribute Variable to Have No Value
- Concluding Values for Variables and Parameters
- Concluding a Logical Value
- Concluding a Quantitative Value
- Concluding a Symbolic Value
- Concluding a Text Value
- Concluding that a Variable Does Not Have a Value
- Variable and Parameter Rules
- Whenever a Variable or Parameter Receives a Value
- Whenever a Variable Fails to Receive a Value
- Whenever a Variable Loses Its Value
- Variable and Parameter Expressions
- Directly Referring to a Variable or Parameter
- Using the Value of Expression
- Using the Has a Value Expression
- Using Current Value Expressions
- Obtaining the Simulated Value of a Variable or Parameter
- Obtaining the Collection Time for a Variable or Parameter
- Obtaining the Expiration Time for a Variable
- Referring to A Variable or Parameter that Gives the Value of an Attribute
- The Variable and Parameter Classes
- Common Attributes
- Variable-Specific Attributes
- Describing Variables and Parameters
Copyright © 1997 Gensym Corporation, Inc.