[R] help on using try() to catch an error

[Juliet Hannah]

Dear R Users,

I have the following glm, which I am running several times in a loop
(I am not including the full code):

reduced_model <- NULL;
full_model <- NULL;
reduced_model <- try(glm.fit(X4,n,family=poisson(link="log")))
full_model <- try(glm.fit(X5,n,family=poisson(link="log")));

On some occasions, an error is produced, which is why I have attempted
to work around this with try().

I then have the following statement, which checks if full_model or
reduced_model are still NULL.

if (is.null(reduced_model) || is.null(full_model)) p <- NA else p <-
pchisq(reduced_model$deviance - full_model$deviance,
reduced_model$df.residual - full_model$df.residual, lower.tail=
FALSE);

This is not solving my problem meaning my program still stops and
gives me the following error:

Error in ifelse(y == 0, 1, y/mu) : dim<- : dims [product 9] do not
match the length of object [18]
Error in pmatrix[perm, ] <- apply(pairs.subset, 1, getLRTp2) :
        nothing to replace with


Can you help me figure out what I have done incorrectly?

Thanks for your time,

Juliet