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--- tutorial:varying_parameters_in_a_simulation [2013/07/23 21:07]
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+++ tutorial:varying_parameters_in_a_simulation [2013/07/27 19:21]
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+====== Varying parameters in a simulation ======
+Nothing should remain constant in a dynamic model. In this respect, Dinamica EGO enables to vary model parameters either in different simulation phases or at each time step.  In the Stack tab, a set of Select Functors can be used to change the values of input parameters according to the model step.
+**Using different transition matrices**
+For examples, instead of using only a constant transition matrix, [[:select_transition_matrix|Select Transition Matrix]] enables the use of different transition matrices in a simulation.
+To start, load the model “simulate_deforestation_using_multiple_transition_matrix.xml” from \ advanced\multiple_parameters\simulate_deforestation_using_multiple_transition_matrix
+{{ :tutorial:advanced_1.jpg |}}
+Using more than one transition matrix in a model is quite simple. In this version of a deforestation model, //Select Transition Matrix// was added to allow the choice of a transition matrix according to the model step. Each transition matrix is entered in a [[:number_transition_matrix|Number Transition Matrix]], click on this functor with the Edit Functor.
+{{:tutorial:advanced_2.jpg |}}
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+**Matrix Number** in this functor indentifies the model step in which this transition matrix begins to operate. The model will use this matrix until it finds a //Number Transition Matrix// with **Matrix Number** that corresponds to the current model step, while from this point onwards //Select Transition Matrix// switches to the new transition matrix.
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+<WRAP column 30%>
+<note tip>**TIP**: you can use as many transition matrices as time steps.  You just need to add more //Number Transition Matrix// functors and number them according to the model time intervals.</note>
+</WRAP>
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+**Using different Weights of Evidence coefficients**
+The same procedure applies to the selection of other model parameters, such as the Weight of Evidence
+coefficients.
+Load the model: “simulate_deforestation_using_multiple_transition_matrix_and_weights.xml” from \Examples\advanced\multiple_parameters\simulate_deforestation_using_multiple_transition_matrix_and_weights
+A //Select Weights// functor is added to the model to enable the selection of more than one Weights of Evidence coefficient files. A //Number Weight// is inserted within the container //Select Weights// for each Weights of Evidence coefficient file. Another //Load Weights// is added to the model in the outside part of the main loop (//Repeat//). This functor loads the coefficients from a file and is connected to one of the// Number Weights// inside the //Select Weights//. Open each one of the// Number Weights// and edit the **Weight Number** field to define the step when each coefficient file begins to take part in the model.
+{{:tutorial:advanced_18.jpg |}}