[R] Stack trace?

[Thomas Lumley]

On Thu, Nov 10, 2011 at 10:35 AM,  <rkevinburton at charter.net> wrote:
>
> Currently I have a for loop executing functions and at the end I get a
> message like:
>
> There were 50 or more warnings (use warnings() to see the first 50)
>
> If I do what it says and type warnings(), I get 50 messages like:
>
> 2: In !is.na(x) & !is.na(rowSums(xreg)) :
>   longer object length is not a multiple of shorter object length
>
> I am not sure what function these errors are originating from. I don't
> think it is from any of the 'R' script that I wrote. I would like to see
> which function is being called when this error is thrown and which
> called that . . . and so on.
>
> I have the same problem with error messages. An error is thrown but I
> don't have a call stack to help trace down the problem. Is there some
> function or technique that I could use to help get a call stack?

traceback() gets you a stack trace at the last error

options(warn=2) makes warnings into errors

options(error=recover) starts the post-mortem debugger at any error,
allowing you to inspect the stack interactively.

  -thomas

-- 
Thomas Lumley
Professor of Biostatistics
University of Auckland