Ecolego Modelling Software Screenshot
Ecolego Modelling Software Screenshot
Ecolego Modelling Software Screenshot

Ecolego is a powerful and flexible software tool for creating dynamic models and performing deterministic or probabilistic simulations. Ecolego can be used for conducting risk assessments of complex dynamic systems evolving over time with any number of species. Ecolego has specialised databases and other add-ons designed for the field of radiological risk assessment.

The graphical user interface helps the user to define and manage building blocks, parameters, species and simulation settings. Ecolego also helps to create reports, to plot simulation results, to perform probabilistic simulations and sensitivity analysis.


  • Easy management of blocks, parameters, materials and other settings.

  • Hierarchical containers facilitates construction and documentation of large and complex models.

  • Projects are easily managed using the project browser, which displays a hierarchical view of blocks, parameters, contaminants and other objects. Multiple projects can be open simultaneously

  • Copy-paste of parameters, containers, blocks and materials within and between projects.

  • Tool tips present information about selected objects, such as equations, units, “used by” or “uses” relationships.

  • Hyperlinks allow the user to jump to different parts of the model.

  • Creation of models using interaction matrices

  • Sub-system modules can be created to create re-usable components

  • Unit checking

  • Documentation of models using images, hyperlinks, categories, units and comments

  • Parameters and blocks can be created on-the-fly while equations are written

  • Listings of all undefined objects or illegal values

  • Generates full reports that can be saved in many different formats including the Adobe PDF format

  • Automatic handling of nuclide decay and ingrowth (requires Radionuclide Toolbox

  • Possibility to call user-written functions in Java or Matlab during simulation.

  • Powerful numerical solvers for complex and dynamic systems. Fixed and variable step size solvers of ordinary differential equations for stiff problems.

  • Support for probabilistic simulations using Monte Carlo or Latin Hypercube sampling.

  • Advanced editor for probability density functions.

  • Parameter sensitivity analysis. Pearson, Spearman, EASI correlation coefficients and regression coefficients. Several other methods available with the Sensitivity Analysis Toolbox (EIKOS)

  • Many different types of result charts and tables are available for simulation outputs.

  • Subversion support for modelling collaboration and version handling

  • Radionuclide database. Radionuclide Toolbox

  • External parameter database connection for sharing and management of quality assured project parameters. Parameter Database Toolbox

  • Sub-system module library

  • Export and import of parameter values and results to/from Microsoft Excel.

Ecolego Player

Ecolego Modelling Software Screenshot

Ecolego Player is a free software for making assements using models created with Ecolego. This way you can distribute your Ecolego models to customers and colleagues.

Ecolego Player features the same functionality as Ecolego, with the exception that the model structure can not be changed.

  • Select species and other indices
  • Review model structure and equations
  • Assign parameter values and probability density functions
  • Assign time dependent inputs
  • Select simulation outputs
  • Specify simulation settings
  • Run best estimate or Monte Carlo simulations
  • Create charts and tables from simulation output
  • Generate report

Ordinary Differential Equation Toolbox

ODE Toolbox Screenshot

The ODE toolbox feature powerful numerical solvers of ordinary differential equations. Both variable and fixed step size solvers are available, as well as solvers for stiff systems.

  • Set up system of ordinary differential equations using graphical blocks ( compartments and transfers )

  • Supports both linear and non-linear transfers

  • Discrete transfers

  • Saturation limits

  • Variable step size solvers

    • Bogacki-Shampine (Runge-Kutta 2,3)
    • Dormand-Prince (Runge-Kutta 4,5)
    • Dormand-Prince (Runge-Kutta 8,5,3)
    • Adams-Bashforth-Moulton (variable order 1-12)
    • NDF (variable order 1-5)
    • BDF (variable order 1-5)
    • RADAU5 (Runge-Kutta)
    • Rosenbrock (Second order)
    • Trapezoidal
    • TR-BDF2 (Runga-Kutta)
  • Fixed step size solvers * Runge-Kutta 1-5

Sensitivity Analysis Toolbox (Eikos)

Ecolego Modelling Software Screenshot

The Eikos Sensitivy Analysis Toolbox supports “state of the art” sensitivity analysis methods (local as well as global). Sensitivity analysis (SA) is used to assess the influence of model parameters on model predictions.

The Eikos Sensitivity toolbox is an optional fully integrated module for Ecolego and is thus most suitable for using with Ecolego models, although external models are also supported by exporting/importing samples of model inputs and/or model predictions.

Correlations between parameters may be induced by rank order correlation (method of Iman and Conover). The supported sampling techniques are: Monte carlo, Latin Hypercube and Quasi-random LPt. The SA methods included are:

  • Morris screening method
  • Extended Fourier Amplitude Sensitivity Test (EFAST)
  • Sobol (first, custom and total order)
  • Random balance design
  • Local sensitivity
  • Garten’s method

Eikos provides a Graphical User Interface (GUI) which let you:

  • Specify uncertain model parameters and model outputs of interest
  • Generate and inspect input samples
  • Export input and output samples generated in Eikos
  • Import input and outputs samples generated externally into Eikos
  • Simulate and inspect the model output samples
  • Perform Sensitivity Analysis of model predictions
  • Graphically review the results using pie charts, scatter plots, tornado graphs, etc.

It is also possible to perform sensitivity analysis on groups of parameters (using extensions of the Sobol or EFAST methods). In this way the influence of each of the selected parameters as well as any combination of them is accounted for when computing the sensitivity indices on a given output.

Parameter Database Toolbox

Parameter Database Toolbox Screenshot

The parameter database toolbox provides an interface to the parameter database.

  • Parameter values, probability density functions and statistics
  • Lookup table values and settings
  • Export data from your Ecolego project to the database
  • Update parameters and lookup tables.
  • List of parameter names available while writing equations
  • Import parameters on-the-fly while writing equations
  • Update individual parameters or lookup tables with data from the database.

Radionuclide Toolbox

Radionuclide Toolbox

The radionuclide toolbox features a database containing all nuclide isotopes and their decay constants and decay energies. It also contains the parent-daughter relationships between a radionuclide and its decay products.

When the radionuclide toolbox is used together with the ODE toolbox, Ecolego will automatically calculate ingrowth and decay for each state in the model.

  • Import individual radionuclides or decay chains of radionuclides
  • Browse radionuclide energies and decay chains
  • Automatically handle ingrowth and radionuclide decay for state variables

Parameter Database

Parameter Database Screenshot

The parameter database is a free product which can be set up to centralize and quality assure parameter data. Storing parameters in the parameter database assures that data is traceable and transparent.


  • Stores values, time series, statistics and probability density functions.
  • Attach comments, references or documents to any value.
  • Tag parameter instances
  • Role based user permissions make sure that users only access what they are allowed to.
  • Import/export to Microsoft Excel.
  • Built-in usability status ladder for quality assurance


Ecolego and its sub-products are platform independent and run on 32/64 bit Win2000/XP/Vista/7, MacOSX, Linux and Unix.


Ecolego has been sponsored by SSM, Sweden www.ssm.se and NRPA, Norway www.nrpa.no.

Eikos has been sponsored by Posiva OY http://www.posiva.fi/ and NRPA www.nrpa.no.


ECOLEGO - A toolbox for radioecological risk assessment Proceedings of the International Conference on the Protection from the Effects of Ionizing Radiation, IAEA-CN-109/80. Stockholm: International Atomic Energy Agency. 229 - 232.

Further AMBER and Ecolego Intercomparisons SKI Report 2004:05 SSI Report 2004:01

AMBER and Ecolego Intercomparisons using Calculations from SR 97 SKI Report 2003:28, SSI report 2003:11

Ekström P-A, 2005. Eikos. A Simulation Toolbox for Sensitivity Analysis. M.Sc. thesis, Uppsala University, UPTEC Report IT 05 015.

Poster (Proceedings of The 2nd International Conference on Radioactivity in the Environment, ISBN 82-90362-21-8. 2-6 October 2005 in Nice, France. 361-364.)

Ekström P-A, Broed R, 2006. Sensitivity Analysis Methods and a Biosphere Test Case Implemented in Eikos. Posiva Working Report 2006-31, 84 pp.