In the mlxtran model, the following parameters are recognized as individual parameters:
- Only the [LONGITUDINAL] block is present: all parameters of the input list, except those defined as regressors.
- Both the [LONGITUDINAL] and [INDIVIDUAL] blocks are present: parameters defined in the DEFINITION section of the [INDIVIDUAL] block.
Individual parameters can be used in the tab “Exploration” and “Simulation”. An individual parameter definition is either a vector, which has one value per parameter, or a table, where each line correspond to a value of a different individual.
Demo projects: 3.4. individual parameters
Overview
In the “Invidual parameters” tab, elements created automatically after a “new project” or an “import from Monolix/PKanalix” and elements created by the user are shown.
The buttons on the right allow to do the following actions:
- VIEW: display the content of the element (the value of the individual parameters)
- EDIT: modify the content of the element.
- DUPLICATE: open a pop-up window for a new element with the same content as the previous element. Note: elements based on external files cannot be duplicated.
- DELETE: delete the element. When the deleted element is based on an external file located in <result folder>/ExternalFiles, the file itself is also deleted upon save.
- CREATE NEW POP: creates a new element “population parameters” from the individual parameters (e.g V_pop = V). The betas (covariate effects), omegas (standard deviation of the random effects), correlation and error parameters are set to zero. This option is available for individual elements of type “manual” only, which contain a single set of individual parameters.
New individual parameters elements
After loading a model, Simulx generates automatically a default individual parameter element called “IndivParameters” with all values set to 1. This element can be modified (button EDIT). New elements can be created with the button “+”. Two different types of individual parameter elements are available:
- Manual: One value per parameter to type in. The required parameters are automatically listed.
- External: An external text file with either:
- A single row and one column per parameter. The headers must correspond to the parameter names.
- Several rows, a first column with header “id”, occasion columns (optional) and one column per parameter. The headers must correspond to the parameter names, and to the occasion names if applicable.
- A single row and one column per parameter. The headers must correspond to the parameter names.
The external file can be tab, comma or semicolon separated. Available file extension are: .csv or .txt.
Individual parameters elements imported from Monolix
Upon import of a Monolix run, several individual parameters elements are created automatically:
- mlx_IndivInit: [when POP.PARAM task has not run]a vector of individual parameters corresponding to the initial values of the population parameters in Monolix, i.e with covariate betas and random effects set to zero. For instance, \( V=V_{pop,ini} \)
- mlx_PopIndiv: [when POP.PARAM task has run]a vector of individual parameters corresponding to the population parameters estimated by Monolix, i.e with covariate betas and random effects set to zero. For instance, \( V=V_{pop,est} \)
- mlx_PopIndivCov: [when POP.PARAM task has run and covariates are defined in the Monolix data set]a table of individual parameters corresponding to the population parameters and the impact of the covariates, but random effects set to zero. For instance, \( V=V_{pop} \times \left( \frac{WT}{70} \right) ^{\beta_{V,WT}} \)
- mlx_EBEs: [when EBEs task has run] a table of individual parameters corresponding to the EBEs (conditional mode) estimated by Monolix (as displayed in Monolix Results > Indiv. param > Cond. mode.)
- mlx_CondMean: [when COND. DISTRIB. task has run] a table of individual parameters corresponding to the conditional mean estimated by Monolix (as displayed in in Monolix Results > Indiv. param > Cond. mean.)
- mlx_CondDistSample: [when COND. DISTRIB. task has run] a table of individual parameters corresponding to one sample of the conditional distribution (first replicate of the Monolix result file IndividualParameters/simulatedIndividualParameters.txt).
