Exploration

The Exploration tab is the second tab in the interface of Simulx. It simulates a typical individual to explore a model by interactively changing treatments and parameters.





Predicted individual

In Exploration, the predictions are based on only:

    • one set of individual parameters (mandatory),
    • one or several treatments (optional) for one individual,
    • one or several outputs (mandatory) with a single vector of measurement times per output,
    • one set of regressor values, only if regressors are present in the model (mandatory).

These elements are selected in the left panel.

Thus an element of type “Individual parameters” must be selected, and it is not possible to select an element of type “Population parameters“.

If a selected element is a table containing several sets of individual values, then the first row in the table is selected by default, and the “ID” field on top of the plot in the middle allows to select the row in the table corresponding to a particular ID.

[Demo: 1.overview/importFromMonolix_resimulateProject.smlx]

This field is highlighted on the figure below, corresponding to a project that comes from a Monolix project imported into Simulx:

    • the individual parameters come from the table mlx_EBEs contains the EBEs estimates,
    • the treatment mlx_Adm1 contains the individual doses imported from the dataset used in Monolix,
    • the output mlx_Cc contains a single vector of regular measurement times for Cc, the structural model output.

Thus changing the “ID” value will change the row read from the two tables mlx_EBEs and mlx_Adm1.

 

Exploration groups

  • 3.exploration/PK_exploration.smlx

Several treatment elements can be selected, they can be defined in different exploration groups, or combined within an exploration group. Each exploration group is produceds a separate prediction. If several treatments are combined within an exploration group, the prediction corresponds to the treatments given together to the same individual.

In the demo shown below, two exploration groups are defined, the first corresponds to the treatment element singleDose_150, while the second corresponds to the combination of loadingDose_100 and multipleDoses_50. The two exploration groups are represented by two prediction curves in different colors.

 

Exploration outputs

  • 3.exploration/TMDD_exploration.smlx

Only non-random element of type “Output” can be selected in Exploration, thus they should:

    • correspond to continuous variables (consequently excluding time-to-event, categorical or count variables)
    • not include a residual error model in their definition.

If several output elements based on the same variable are selected, they are plotted on the same plot with merged grids.

By default each output is plotted on a separate plot, as seen below. This can be changed in the exploration settings.

 

Interactive modification of parameter values or dosing regimen

  • 3.exploration/PK_exploration.smlx

The right panel can be used to modify interactively the parameters values or the dosing regimens and check in real-time the impact on the model dynamics.

The figure below shows the parameter section highlighted in green, where the values can be changed via the small arrows or by entering new values with the keyboard. The “reset” button highlighted here in blue resets the parameters to their initial values. On the plot, the solid curves correspond to the current predictions, while reference curves has been added as dashed lines.

On the next figure, the section “Treatment” highlighted in green shows the elements from the treatment multipleDoses_50 that can be modified. Reference curves are added by clicking on the button highlighted in purple. Each successive reference curve is represented a line in the panel as highlighted in blue, with an icon to restore the reference parameters or remove the reference.

Moreover, hovering on a reference line highlights the corresponding reference on the plot in yellow, as seen on the following figure:

 

Defining new parameter or treatment elements

  • 3.exploration/PK_exploration.smlx

It is possible to save the modified parameters or treatments as new elements with the button marked as green on the figure below. It opens a window to create a new manual element of type Individual parameters or Treatment. A new parameter element created this way will automatically replace the previously selected element in Exploration, unless the corresponding checkbox is unchecked (blue mark on the figure).

Creating a new Treatment element as shown below replaces by default the initial treatment element with the new one, but it is also possible to add the new treatment to a new exploration group.

 

 

Sending elements to simulation

The button “Send elements to simulation” sends all elements selected in Exploration to the selection in the tab Simulation. Exploration groups are turned into simulation groups with a default size of 1 individual per group.

 

Plots settings

  • 3.exploration/PKPD_exploration.smlx

The panel “Settings” can be used to control some elements of the plots, such as the scale of the curves displayed on each plot.

On the following figure, two variables Cc and E are displayed on separate plots, with logscale on the Y-axis.

Below, the two variables are displayed on the same plot. Each variable keeps its own grid.

 

Exporting plots

 

The “export” button on top of the plots can be used to save the plots as an image in the result folder. Two image formats are available: PNG and SVG (Scalable Vector Graphics).

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