.. _release7_1:

Release 7.1
===========

Today - March 25th, 2009 - we have released a new version of the HUGIN software (v7.1).

The main new features of this release are:

* Parameter estimation from data for continuous nodes using the :ref:`Expectation Maximization (EM) algorithm<em_learning>`. The HUGIN tool has been extended with functionality to perform parameter estimation for both discrete and continuous nodes in a Bayesian network. The parameter estimation is performed using the EM algorithm supporting missing values in data.
* :ref:`Two-way parameter sensitivity analysis<two_way_parameter_sensitivity>` has been included in the Parameter Sensitivity Wizard. The Parameter Sensitivity Wizard has been extended with support to perform two-way parameter sensitivity analysis on an output probability given a set of evidence. This allows the user to efficiently investigate the impact of co-varying two parameters on a posterior probability.
 

HUGIN Graphical User Interface v7.1:
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

The HUGIN Graphical User Interface has been improved with various new features. This includes:

* Learning Wizard: Functionality for saving and loading data preprocessing definitions, e.g., the specification of a discretization operation or value replacements.
* Learning Wizard: Discretization using Information Entropy Minimization (U. M. Fayyad and K. B. Irani. 'Multi-Interval discretization of continuous valued attributes').
* Learning Wizard: Discretization of multiple numeric variables have been improved to become more user friendly.
* :ref:`Analysis Wizard<analysis_wizard>`: Functionality for exporting the results of a series of belief update operations across a set of cases to a CSV file.
* Analysis Wizard: Functionality for generating a PDF report over the results of a series of belief update operations across a set of cases.
* :ref:`Parameter Sensitivity Wizard<Parameter_Sensitivity_Wizard>`: Computing Sensitivity on multiple cases from a case file.
* In addition to parallelizing table operations when compiling and propagating in run-mode. Table operations when learning and in various wizards may also be parallelized.
* Added option for specifying a background image for the :ref:`network panel<network_pane>`.
* Allowing the creation and parsing of invalid Expressions in the :ref:`Expression Builder Wizard<expression_builder_wizard>`.
* Other minor improvements.

Finally, efforts have been put into improving the performance of the HUGIN Graphical User Interface.

HUGIN Decision Engine v7.1:
^^^^^^^^^^^^^^^^^^^^^^^^^^^

The HUGIN Decision Engine has been extended with the following features:

* The EM algorithm has been extended to learn CG distributions for continuous nodes.
* The EM algorithm now permits learning to be enabled/disabled for specific parent configurations: A nonnegative experience count enables learning, while a negative experience count disables learning.
* The EM algorithm now checks that the equilibrium is 'sum' with no evidence incorporated. As a "sanity" check, it also verifies that learning is enabled (that is, there must exist at least one node with a nonnegative experience count), and that case data has been specified.
* Because the EM algorithm is controlled by experience tables, continuous nodes may now also be given experience tables.
* The HKB format has been updated (in order to support parameter learning for continuous nodes).
* The model scoring functions now check that the junction tree potentials are up-to-date with respect to the node tables and their models (if any).
