====== Tutorial 3 - Creating the model objects ======

===== 2/4 =====

In this lesson we will create the objects required for the turnover model. In the same way as in [[Tutorial_2-Creating_a_compartment_model|Tutorial 2-Creating a compartment model]], you will use the [[Matrix_window|Matrix window]] to create blocks in the [[Interaction_matrix|Interaction matrix]].

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**Creating blocks**

  - Open the [[Matrix_window|Matrix window]].
  - Create the following objects, by right-clicking in the matrix and selecting objects from the pop-up menu. You can see the positions of the different objects in the picture below.

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^Name          ^Type       ^Full name                            ^Symbol           ^Image                 ^
|Source        |Source/Sink|Atmospheric Source                   |                 |"media/Atmoshpere.jpg"|
|Upper_Soil    |Compartment|Upper soil layer                     |A<sub>Upper</sub>|"media/Soil 3.jpg"    |
|Lower_Soil    |Compartment|Lower soil layer                     |A<sub>Lower</sub>|"media/Soil.gif"      |
|Sink          |Source/Sink|                                     |                 |"sources/Drain.jpg"   |
|Deposition    |Transfer   |Deposition transfer rate             |                 |                      |
|Upper_to_Lower|Transfer   |Perculation transfer rate coefficient|                 |                      |
|Lower_to_Sink |Transfer   |Perculation transfer rate coefficient|                 |                      |

  * When editing //Deposition//, make sure that the //TC// check-box in the //Values// tab is unchecked.\\


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{{tutorial3_1.png|Screenshot}}\\

**Creating parameters**

Rather than specifying the initial conditions and transfer rate coefficients directly, we will create parameters for these values. This approach makes it possible to perform probabilistic analysis, sensitivity analysis and parameter optimization. It also makes it easier to enter and review the values.

  - Open the [[Blocks_window|Blocks window]]. The table lists the seven blocks of the model. Enter the following **value** (initial condition/expression) for the [[Block|Block]]s. All the “Unknown values” are [[Parameter|Parameter]]s.

^Name          ^Value  ^
|Deposition    |"input"|
|Lower_Soil    |"ic"   |
|Lower_to_Sink |"TC"   |
|Upper_Soil    |"ic"   |
|Upper_to_Lower|"TC"   |

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{{:tutorial_3_2_2.png|Screenshot}}\\

**Next**

  * [[Tutorial_3-Creating_vector_and_matrix_parameters|Creating vector and matrix parameters (3/4)]]

**Previous**

  * [[Tutorial_3-Using_index_lists|Using index lists (1/4)]]

**References**

  * [[Tutorials|Back to Tutorials]]
  * [[start|Home]]