I have created this regression model that works well :
Model1 = bam(depend ~ s(indep, by = gender.x,bs = “tp”) + s(Age, by = gender.x, bs = “tp”)+ ti(Age, indep, by=gender.x ) + gender.x + s(Subject, bs = “re”) + s(Age, Subject, bs = “re”)+ s(ImagingCentreCity, bs = “re”), data = M2_SRS_Project, method = “fREML”, family = “gaussian”)
but when introducing the variable ‘timepoints’ :
model2 = bam(depend ~ s(Age, bs=”tp”) + s(indep, bs=”tp”) + s(Age, indep, bs=”tp”, by=gender.x) + gender.x + timepoints + s(Subject, bs=”re”)

• s(Age, Subject, bs=”fs”, m=1), data = M2_SRS_Project)
  the model doesn’t work. The error message is as follows :
  Erreur dans h(simpleError(msg, call)) :
  erreur d’evaluation de l’argument ‘x’ lors de la selection d’une methode pour la fonction ‘chol’ : tableaux de tailles inadéquates

Do you have any ideas on what I can do?”

summary(M2_SRS_Project$timepoints)
BL FU1 FU2 FU3
510 162 457 509

i tried to recoded the timepoints variable