Hello everyone,

I am using a very simple custom model to fit some dissolution data.

I plan to fit the data to two different equations:

(1) when time<3, Fdiss=kd*(Time^n)

(2) when time>=3, Fdiss=A^(Time)

I am using the following PML model:

test(){ covariate(Time) sequence{ if (Time<3){ Fdiss=kd*(Time^n) } else { Fdiss=A^(Time) } } error(FdissEps = 1) observe(FdissObs(Time) = Fdiss+ FdissEps) fixef(kd = c(, 1, )) fixef(n = c(, 1, )) fixef(A = c(, 1, )) }

However, the following warning message appears: 'Variable 'Fdiss' undefined'

Can anyone help me?

Many thanks in advance

Best regards

Sara