R help - Dec 2011 - error options

Hi,

I'm running simulations that include a function that occasionally fails
because of an unpredictable singularity in a matrix that it tries to invert.
I'd like to have the function return 'NA' when that happens, so that
the
simulations can continue.  I've tried things like:

    test <- function() {
    options(error=return(NA))
    x <- solve(0)
    return(x)
    }

which does return 'NA'.  But it returns 'NA' whether or not
there's an
error in the function:

    test <- function() {
    options(error=return(NA))
    x <- 0
    return(x)
    }

    test()
    [1] NA

What am I missing here?

Thanks in advance
-Paul

Below.

-- Bert

On Wed, Dec 28, 2011 at 11:35 AM, Paul Murtaugh
<murtaugh at science.oregonstate.edu> wrote:
> Hi,
>
> I'm running simulations that include a function that occasionally fails
> because of an unpredictable singularity in a matrix that it tries to
invert.
> I'd like to have the function return 'NA' when that happens, so
that the
> simulations can continue. ?I've tried things like:
>
> ? test <- function() {
> ? options(error=return(NA))
> ? x <- solve(0)
> ? return(x)
> ? }
>
> which does return 'NA'. ?But it returns 'NA' whether or not
there's an
> error in the function:
>
> ? test <- function() {
> ? options(error=return(NA))
> ? x <- 0
> ? return(x)
> ? }
>
> ? test()
> ? [1] NA
>
> What am I missing here?
error trapping.
?try   ##or
?tryCatch

-- Bert
>
> Thanks in advance
> -Paul
>
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-- 

Bert Gunter
Genentech Nonclinical Biostatistics

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