R help - Feb 2010 - skip lapply item for conditions(RAM, execution time)

Hi,

I use lapply with a function from a package, and every 20th to 50th function
execution (out of 500 to 10 000 times) fails for some unknown reason. RAM
consumption ever increases (out of limit) and execution time is endless. I am
not going to debug the package. (I rather feel like an end-user.)

If it was Java, I'd wrap the function in a try...catch statement like about

try{
    for(i=1;i<=10000;i++){
        dofunction(i);
        }
    }
catch(outofmemoryexception e){
    kill(dofunctioninstance);
    gc();
    next;
    }


I did not find out how to construct this in R. Is anyone so kind to point me to
a documentation more exhaustive than help(conditions)? Or otherwise provide a
snippet of R code?

Regards, Joachim

Thank you,

but: 
- How do I create a condition object watching for memory overflow? Or,
alternatively, excess time?
- How do I tell R to end the current lapply item, clean up memory and proceed to
the next item? (I know I can write a wrapper function including gc() and direct
lapply to that wrapper function. But what do I do to stop ONLY the original
function, not the whole R process?)


Joachim
> ?tryCatch   
> 
> Bert Gunter
> Genentech Nonclinical Biostatistics
>  
>  
> 
> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at
r-project.org]
> On
> Behalf Of Joachim Harloff
> Sent: Wednesday, February 17, 2010 7:00 AM
> To: r-help at r-project.org
> Subject: [R] skip lapply item for conditions(RAM, execution time)
> 
> Hi,
> 
> I use lapply with a function from a package, and every 20th to 50th 
> function
> execution (out of 500 to 10 000 times) fails for some unknown reason. 
> RAM
> consumption ever increases (out of limit) and execution time is endless. 
> I
> am not going to debug the package. (I rather feel like an end-user.)
> 
> If it was Java, I'd wrap the function in a try...catch statement like 
> about
> 
> try{
>     for(i=1;i<=10000;i++){
>         dofunction(i);
>         }
>     }
> catch(outofmemoryexception e){
>     kill(dofunctioninstance);
>     gc();
>     next;
>     }
> 
> 
> I did not find out how to construct this in R. Is anyone so kind to 
> point me
> to a documentation more exhaustive than help(conditions)? Or otherwise
> provide a snippet of R code?
> 
> Regards, Joachim
> 
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