Paul W Vaughan

US Patent:

6446057, Sep 3, 2002

Filed:

Dec 4, 2000

Appl. No.:

09/730481

Inventors:

Paul William Vaughan - Austin TX 78710-9998

International Classification:

G06N 100

US Classification:

706 46, 706 48, 706 58

Abstract:

A technique is used in embodiments of the invention such that backtracking programs can be written in a general purpose computer language (e. g. , C++ or Java) without requiring the control structure of the program to reflect the structure of the decision tree. A data state and a control state are restored during backtracking. For restoring the data state, embodiments of the invention keep track of the changes made to variables and the point in execution at which the changes are made. When backtracking occurs, the data state can be restored by undoing the changes to the desired point in execution. For restoring the control state, the method of the invention provides a âfailureâ exception state that is invoked upon failure in the program (e. g. , a failure to find a solution in a search program). The failure exception is âcaughtâ by catch points established in the execution stack.

US Patent:

6157922, Dec 5, 2000

Filed:

Oct 24, 1997

Appl. No.:

8/957346

Inventors:

Paul William Vaughan - Austin TX

Assignee:

Trilogy Development Group, Inc. - Austin TX

International Classification:

G06N 500

US Classification:

706 46

Abstract:

A technique is used in embodiments of the invention such that backtracking programs can be written in a general purpose computer language (e. g. , C++ or Java) without requiring the control structure of the program to reflect the structure of the decision tree. A data state and a control state are restored during backtracking. For restoring the data state, embodiments of the invention keep track of the changes made to variables and the point in execution at which the changes are made. When backtracking occurs, the data state can be restored by undoing the changes to the desired point in execution. For restoring the control state, the method of the invention provides a "failure" exception state that is invoked upon failure in the program (e. g. , a failure to find a solution in a search program). The failure exception is "caught" by catch points established in the execution stack.