R help - Nov 2012 - What does uniroot return when an error occurs

Hi,

I'm using the uniroot function, and would like to detect an error which
occurs, for instance, when the values at endpoints are not of opposite
signs. For example:

uniroot( function(x) x^2+1, lower=1, upper=2 ).

I want to say something like:

if "error in uniroot(...)" return NA else return uniroot$root

Thanks a lot!

Asaf



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?tryCatch

As in:
> tryCatch(uniroot( function(x) x^2+1, lower=1, upper=2 )$root,
error=function(e){warning(conditionMessage(e)); NA})
Warning in value[[3L]](cond) :
  f() values at end points not of opposite sign
[1] NA
> tryCatch(uniroot( function(x) x^2-1.5, lower=1, upper=2 )$root,
error=function(e){warning(conditionMessage(e)); NA})
[1] 1.224745

Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com

> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at
r-project.org] On Behalf
> Of asafwe
> Sent: Thursday, November 01, 2012 1:00 PM
> To: r-help at r-project.org
> Subject: [R] What does uniroot return when an error occurs
> 
> Hi,
> 
> I'm using the uniroot function, and would like to detect an error which
> occurs, for instance, when the values at endpoints are not of opposite
> signs. For example:
> 
> uniroot( function(x) x^2+1, lower=1, upper=2 ).
> 
> I want to say something like:
> 
> if "error in uniroot(...)" return NA else return uniroot$root
> 
> Thanks a lot!
> 
> Asaf
> 
> 
> 
> --
> View this message in context:
http://r.789695.n4.nabble.com/What-does-uniroot-
> return-when-an-error-occurs-tp4648168.html
> Sent from the R help mailing list archive at Nabble.com.
> 
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