The expression block can be used to specify an arbitrary function of the model parameters and /or the quantity in other blocks (such as compartments and lookup tables. The value of this block is available for use during the simulations.
From the Projects window
From the Matrix window
From the Blocks window
Place the mouse cursor over the table and right-click on it. Select Create | Expression from the pop-up menu, or
In the title bar, select Expression from the Type drop-down list and click on the button.
|Note||Most block properties can be edited directly in the blocks window.|
The block editor is shown by right-clicking the block in a window and selecting Edit. In the Blocks window, you can also show the block editor by selecting the block and clicking the button, or by double-clicking the right-most “validation” column of the block.
The block editor has three tabs:
This page lets you edit basic properties such as name, sub-system and base unit. See editing properties for more information.
|Note||When entering an expression, you can also enter names of objects that are not yet created and let Ecolego use automatic object creation to define them.|
This page lets you specify the algebraich expression and other index specific properties. See Editing values for more information.
Dimension - You can specify the dimension of the block by using the Type drop down list. Depending on the dimension the index drop down lists are activated.
Indices - For blocks that are non-scalar, the first columns will specify indices from the index lists. This allows you to specify different expressions for different indices. The top row is named “default” and can be used when the same value should be set for all indices.
Expression - The expression can contain any number of parameters, blocks and functions. The Expression editing tool can be used to quickly find available functions and objects to use in the expression. Also refer to expression syntax for details on mathematical format and how to specify conditions.
Information - By using the Table control button you can display more columns that will help you document your model.
Arguments - Used to define arguments that should be sent to the expression (see below).
In some situations it is useful to require arguments to be sent to the expression. These arguments then be used in the equation, together with parameters and other blocks. The expressions then becomes a function, and will only be used as an “abstract”.
Use the right-hand side table to add (or remove arguments. Click in the table fields to change argument names or to write descriptions for the arguments.
Once an argument has been added, you can use it in the equations of the expressions.
You reference an expression by writing the name (or ID) of the expression. If the expression requires arguments, you also add parenthesis and a comma-separated list of argument values - like with any function.