I think the problem is that you need to add a grouping variable to your DOSEdata and your CONCdata. As the code is currently written, you are doing a single simulation with 6 different doses at time 0, for a cumultive dose of sum(1:6), or 21 milligram. And then you're simultaneously trying to fit all 6 measurements at time 10 to the result of a single simulation at time 10. (We allow different repeated measurements at the same time in order to support technical or biological replicates.)
I'll attach my updated version of your script. But the main changes are that (1) I added the following group identifier line near the top:
ID = (1:6)';
and (2) I updated the groupedData setup as follows:
DOSEdata = groupedData(table(ID, DOSE_TIME, DOSE_AMT));
DOSEdata.Properties.VariableUnits = {'', 'day','milligram'};
CONCdata = groupedData(table(ID, TIME, CONC));
CONCdata.Properties.VariableUnits = {'', 'day','milligram/milliliter'};
If you like, you could create a single groupedData that contains both your dosing information and the measurements. You just need to use NaN values as appropriate to indicate no dose or no measurement at the specific time. For example:
ID = [1 1 2 2]';
TIME = [0 10 0 10]';
DOSE = [1 nan 2 nan]';
CONC = [nan 14 nan 44]';
data = groupedData(table(ID, TIME, DOSE, CONC))
