Decision support package documentation

ClowdFlows decision support package documentation

This document provides a short overview of the decision support package. The first section describes the organization, while the second section describes the individual widgets and how they can be used.

Organization

The package follows the recommended code structure of ClowdFlows packages:

workflows/decision_support/
├── db
│   └── package_data.json
├── __init__.py
├── interaction_views.py
├── library.py
├── settings.py
├── static
│   └── decision_support
│       └── icons
│           ├── treeview
│           │   ├── piechart.png
│           │   ├── sensitivity.png
│           │   └── wsm.png
│           └── widget
│               ├── piechart.png
│               ├── sensitivity.png
│               └── wsm.png
├── templates
│   ├── interactions
│   │   └── wsm.html
│   └── visualizations
│       ├── ds_charts.html
│       └── sensitivity_analysis.html
├── visualization_views.py
└── wsm.py

The db folder contains the exported package data (widgets, inputs, outputs and categories) in json. If changes are made to local widgets or new widgets are created, the package data must be updated using the export_package management command.

The settings.py file contains package level settings, same as for any ClowdFlows package, e.g., path to the package data file.

The static folder contains static files used by the package. Currently these include only the icons.

The templates folder contains Django template HTML files. These are divided into interactions and visualizations.

Most widgets in ClowdFlows can be divided into three categories: regular, interactive and visualization widgets. Regular widgets simply take an input and produce an output, while interactive widgets take an input, request some additional input from the user (e.g., setting weights of attributes) and produce an output. Visualization widgets take an input and output a certain visualization based on the input (e.g., displaying a chart or a dataset).

The widget views, i.e., functions which are called when a widget is executed by the user, are divided into:

• library.py
• interaction_views.py
• visualization_views.py

which reflect the categories listed above.

Of course the code can be divided into other Python modules. For example, the wsm.py module includes the class implementing the Weighted sum model, which is used in the views.

Interaction and visualization widgets have corresponding templates. These (usually) also contain JavaScript for handling their GUIs.

Widgets

The package includes the following widgets:

• Weighted sum model, implementing a simple decision support model,
• Sensitivity analysis, offering the mechanism to see how each alternative's score changes while changing the importance of one attribute,
• Decision support charts, implementing several charts, which are useful for making reports and overviewing the data.

An example workflow can be found at: http://clowdflows.org/workflow/383/.

Weighted sum model

Inputs:

• odt: Orange data table, with an optional label meta attribute

Outputs:

• odt: Orange data table, with an added score column and with normalized attribute values
• mdl: the WSM model object, which can be pickled and saved or used in the next two widgets.

Functionality:

When the widget is executed a popup is displayed, where the user can assign a weight to each attribute, as well as the range of values of the attribute and if the attribute should be maximized or minimized.

Weights can be normalized (so that they sum up to 100%) by clicking the Normalize weights button and reset by clicking the Reset button. After clicking the Apply button, the new table and the model are produced.

Sensitivity analysis

Inputs:

• mdl: A decision support model, e.g.: a WSM object.

Outputs:

None.

Functionality:

When the widget is executed a popup is displayed, where the user can choose which attribute to vary. After the selection, a graph corresponding to the sensitivity analysis of this attribute is shown. Thanks to the Highcharts library, the graph can be modified by deselecting certain alternatives and it can be saved in various formats (like PNG, PDF, SVG).

Decision support charts

Inputs:

• mdl: A decision support model, e.g.: a WSM object.

Outputs:

None.

Functionality:

When the widget is executed a popup is displayed, where the user can choose between four charts:

• Weights pie chart: The assigned weights visualized as a pie chart.
• Weights bar chart: The assigned weights visualized as a bar chart.
• Alternatives column chart: The scores of the alternatives visualized as a column chart.
• Attribute values chart: The values for each attribute for each alternative visualized as a bar chart.

Each chart can be saved in various formats (like PNG, PDF, SVG).