Setting initial values for different individuals

When adding a species, I can set the InitialAmount, but how can I assign different initial values to individual entities? Should I separately set it as a dependent variable in the dataset (even though it's not the object to be fitted)? Additionally, I'm not quite clear on the distinction between InitialAmount for a species and the initial values for individual entities here.

S1 = addspecies(comp_CARTP, 'B_PB', 1 ,'Units','cell');
    set(S1,'Notes','Cancer cells in the CART compartment');

Answer 1

[Priya Moorthy]

Bohao,

Every quantity (species, parameter or compartment) has an initial value that is set on the model. Thus, when you simulate a model on its own, the InitialAmount value of each species will be used.

Variants allow you to override the initial values specified on the model. In your case, you want to apply a group-specific variant during fitting so that you can use the value from the PB column from your dataset as the initial value of the B_PB species for each individual group.

To do this in a fit program from the Model Analyzer, you need to configure the Data step, which maps how dataset columns are related to the components in your model. At the bottom of the Data step, go to “Add to Map” and click on Variant (circled in blue in the example below). This will add a “variant from data” row to the data map (outlined in red). Here, you must specify the data column (TARGET_T0 in this example), the corresponding species whose initial value you want to modify (Central.Target), as well as whether to apply unit conversion between the data column and species units. The “Variant and Dose Setup” step below will be updated with a new column to reflect the new dataset-derived group-specific variant.

Please see the following documentation pages for more detailed information:

• Variants in SimBiology Models
• Group-specific variants

Best,

Priya