Sensitivity analysis tab

Last modified by mbenezit on 2014/09/11 12:40

TroiThree sensitivity analysis tools are available in the interface
  • One-at-a-time analysis: It analyses, all other things being equal, the influence on the root attribute of a +1/-1 change of class of the basic attributes of a given option.       
  • Sensitivity Index : It calculates the sensitivity index of all the basic attributes of a DEXi tree. The higher the index, the more important is the impact of the basic attribute on the final result. 
  • Monte Carlo analysis : It represents the probability of reaching each one of the classes of the root attribute by randomly simulating a large number of values taken by the basic attributes. The potential correlations between basic attributes are not taken into account. 
To conduct sensitivity analysis

This tab implements R scripts to conduct sensitivity analysis on the active DEXi model. To achieve these sensitivity analysis, the first thing to do is to download the software R on the computer.

  • on Windows : you need to download the R software via this website: http://cran.r-project.org/bin/windows/base
  • on Debian and Ubuntu: you need to download the following packages: apt-get install r-base libxml2-dev

Then, you have to open R (shortcut in the desktop or directly in the browser's programs) and install the libraries "Algdesign" and "XML"  :

  • either by copying/pasting the following code lines:
 install.packages ("XML", repos = "http://www.omegahat.org/R")
 install.packages("AlgDesign")
  • either by clicking on the following menus :

Packages --> Install package(s) --> France, Lyon(2) --> XML

Packages --> Installe package(s) --> France, Lyon(2) --> AlgDesign

When the user starts a sensitivity analysis from IZI-EVAL for the first time, a window in which you have to indicate the access path to R.exe opens. It is necessary for the interface to start the calculation in R.

Caution: The sensitivity analysis tools do not  work yet for DEXi trees containing linked attributes, attributes of the same name or with names containing special characters such as : é è " ' ù ¨ ^ à & ç - , ; / *).

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Created by Damien Craheix on 2012/06/22 17:04
Translated into en by mbenezit on 2014/06/25 16:47
   
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