[R] mgcv: bam(), error in models with random intercepts and random slopes

[Fotis Fotiadis]

Hi all

I am using the bam function of the mgcv package to model behavioral data of
a learning experiment. To model individual variation in learning rate, I am
testing models with (a) by-participant random intercepts of trial, (b)
by-participant random slopes and random intercepts of trial, and (c)
by-participant random smooth terms.

While all (a) and (c) models converge, I am getting an error for every
possible variation of a model with random intercepts and random slopes. For
example:

m1.rs<-bam(acc~ 1 + igc + s(ctrial) + s(sbj, bs="re") + s(ctrial, sbj,
bs="re") , data=data_a, family=binomial)
Error in G$smooth[[i]]$first.para:G$smooth[[i]]$last.para :
  argument of length 0

Any idea on what that error might be?

Thank you in advance for your time.
Fotis

P.S.: R version: 3.3.1, mgcv version: 1.8.15

-- 
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University of Athens, Greece.
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