[R] tryCatch

[Redding, Matthew]

Hi All R-Gurus, 

I am trying to debug a program, and I think tryCatch will help. The functions involved 
process through so many times before I encounter the error, things are a bit slow to 
use debug and browser().

I've read the help file and postings on conditions, and am still having trouble.

While running my program I am getting a NAN from a called function, and I want to know the 
input parameters that generate this, so I have included the following in the code of the main
function (calling function):

tryCatch(delM > S, exception=function(e)print(list(S=S, Si=Si, D=D, theta=S/N, incr=del.t)), finally=print("finally"))

This is actually part of an "if" statement, where delM > S is the condition.
Now if delM is an NAN an error results.  

Now the above tryCatch does not work in the way I wish it.  What sort of condition does this little expression throw when it encounters delM=NAN? is it an exception? What is wrong with the above handler etc?

Kind regards, 

Matt Redding

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