Hi all, I’m new to stan and brms, so I apologise if this is a very silly question and I’m missing something simple. Recently, I have needed to run a zero one inflated beta regression for a data set I am working with. The models have been running great, however, I cannot seem to be able to add LOOIC to the models, as I keep getting the following errors:

Error in validate_ll(log_ratios) : NAs not allowed in input.

Error: Moment matching failed. Perhaps you did not set ‘save_pars = save_pars(all = TRUE)’ when fitting your model? If you are running moment matching on another machine than the one used to fit the model, you may need to set recompile = TRUE.

I have made a dummy data set and put some reproducible code below that gives me the same error as with my actual dataset.

OS = macOS ventura13.1

brms version = 2.20.4

```
# here is a zero one inflated dummy dataset
set.seed(123)
df <- data.frame(treatment = as.factor(seq(1, 5, by = 1)),
hole = as.factor(seq(1, 20, by = 1)),
response = rbeta(n = 100, shape1 = 2, shape2 = 5))
prop_zero = 0.08
prop_one = 0.21
num_zeros = floor(prop_zero * length(df$response))
num_ones = floor(prop_one * length(df$response))
zero_indices = sample(1:length(df$response), num_zeros, replace = FALSE)
df$response[zero_indices] <- 0
one_indices = sample(setdiff(1:length(df$response), zero_indices), num_ones, replace = FALSE)
df$response[one_indices] <- 1
```

```
model_formula2 <- bf(
response ~ treatment + (1|hole),
phi ~ treatment + (1|hole),
zoi ~ treatment + (1|hole),
coi ~ treatment + (1|hole),
family = zero_one_inflated_beta()
)
model2 <- brm(
model_formula2,
data = df,
control = list(adapt_delta = 0.99,
max_treedepth = 12),
chains = 4, iter = 2000, warmup = 500,
cores = 4, threads = threading(2),
backend = "cmdstanr",
seed = 12345,
save_pars = save_pars(all = TRUE)
)
model1 <- add_criterion(model2, "loo", moment_match = TRUE)
```