Tutorials

How to use the environment?

Fibonacci with discrete time models

We used the gvle.discrete-time package to model the Fibonacci sequence into the discrete-time extension (package vle.discrete-time)

Video comments:

  • 0:00 : Create the package fibonacci and specify a dependency to the vle.discrete-time package.
  • 0:18 : Create a new atomic model based on the discrete time formalism. By default, its name is NewCpp.
  • 0:25 : Specify the equation F= F(-1) + F(-2) into the Compute section.
  • 0:35 : Declare the variable F and the set an history size of 2.
  • 0:45 : Set initial history F{n=-1}=0 and F{n=0}=1.
  • 0:58 : Rename the atomic model to Fibonacci, configure and build the project.
  • 1:19 : Open the default model empty.vpz and add an atomic model, configure it with the newly created dynamic Fibonacci from package fibonacci.
  • 1:29 : Into the Observables tab, attach the observable port F to the available view of the vpz.
  • 1:38 : Into the Project tab, specify the duration of the simulation to 6.
  • 1:48 : Into the Simulation tab, launch simulation and select the variable F for plotting.

Lotka Volterra equation with Forrester diagrams

We used the gvle.forrester package to model the Lotka Volterra equations into the Ordinary Differential Equations (package vle.ode)

Video Comments:

  • 0:00 : Create the package lotkavolterra and specify a dependency to the vle.ode package.
  • 0:18 : Create a new atomic model based on the Forrester formalism. By default, its name is NewCpp.
  • 0:24 : Define two compartments x and y and give their initial values.
  • 0:46 : Define four parameters alpha, beta, gamma and delta and give their values.
  • 1:36 : Define two material flows flowX and flowY.
  • 1:53 : Declare a hard link from flows to compartments.
  • 1:59 : Declare dependencies between flows and parameters.
  • 2:23 : Give equations of the flows (depending on compartments and parameters).
  • 3:06 : Modify the time step to 0.01, for the Euler method, of the numerical integration.
  • 3:22 : Close the atomic model description and rename it to LotkaVolterra.
  • 3:24 : Configure and build the project.
  • 3:44 : Open the default model empty.vpz and add an atomic model, configure it with the newly created dynamic LotkaVolterra from package lotkavolterra.
  • 3:56 : Into the Observables tab, attach the observable ports to the available view of the vpz.
  • 4:11 : Save file and select the Simulation tab to launch simulation.
  • 4:18 : Change the duration of simulation, re-launch simulation, and plot the compartments x and y.

Old VLE 1.1 tutorials

These tutorials are made for the version 1.1 of VLE.

First model

  • First models: create two models from scratch and assign observation. Keywords: C++, package and observation.

Lotka-Volterra

  • Lotka-Volterra: create a simple Euler model, assign observation and experiment conditions. Keywords: C++, package, observation, conditions and RVLE.

Forrester

This tutorial shows how to use the Forrester extension: