Enhancement: allow users to modify unit values of parameter results

[Gero1999]

Description

Sometimes user might be interested in changing the standard format of units provided by the app. In one that this may happen frequently is for example clearance (cl.obs), where current units always make very small values (~0) that can confuse when the rounding is used in the summary statistics.

Preferably as a table in the setup section similar to this:

with possible additional option of changing units after NCA in results section

Definition of Done

The requirements for the feature to be complete:

• [ ] allow user to customize in results the units of measure for each parameter
• [ ] scale appropriately parameter values based on new unit measures imputed

[billdenney]

Related to #125

FYI, PKNCA has robust unit conversion methods built-in (https://billdenney.github.io/pknca/articles/v07-unit-conversion.html). I would recommend using that functionality. If it is missing something, please let me know, and we can implement it as part of PKNCA.

[Gero1999]

We are planning to use the conversion methods, however not in the way the app specifies them for PKNCAdata and pk.nca(). Our main idea is that the user defines the units as column names (the same way as the rest of the variables). Our plan is to also address the case in which they want to use different units for each of their concentration or dose groups. The trick for doing this will be to perform the conversion methods once the results are computed in uniform concentration/time units. Hope that makes sense!

[billdenney]

It makes sense, and PKNCA can do most of that for you now. PKNCA does support different units for different groups (for example, if you have two analytes, it can have different units for the different analytes). I have planned to add unit management into the PKNCAconc() and PKNCAdose() functions.

There was no way for you to know that. I just added an issue describing it here billdenney/pknca#336