====== Defining a model ======

As a first step of a Sensitivity analysis, a model is defined or loaded (using the Model editor). A model is generally defined with a number of input parameters and model outputs where the model outputs are allowed to be time dependent. Different kinds of models are supported by Eikos:

  * An expression: a model made up of coupled equations. Each equation is built up of scalar parameters, other equations and mathematical functions (e.g. sin(x), x^y). An expression can also be time dependent by including the reserved variable time.
  * An ecolego model.
  * An external executable model. Windows .exe and .bat executables are supported. [[How_to_access_an_external_model_from_eikos|How to access an external model from eikos]].

The more general case when output samples can somehow be generated given values of input parameters is also supported (see the section [[Importing_and_exporting_data|Importing and exporting data]]).