Dear Experts, The following is my "Iterator". When I try to write a new function with itel, I got error. This is what I have:> supDist<-function(x,y) return(max(abs(x-y))) > > myIterator <- function(xinit,f,data=NULL,eps=1e-6,itmax=5,verbose=FALSE) {+ xold<-xinit + itel<-0 + repeat { + xnew<-f(xold,data) + if (verbose) { + cat( + "Iteration: ",formatC(itel,width=3, format="d"), + "xold: ",formatC(xold,digits=8,width=12,format="f"), + "xnew: ",formatC(xnew,digits=8,width=12,format="f"), + "\n" + ) + } + if ((supDist(xold,xnew) < eps) || (itel == itmax)) { + return(xnew) + } + xold<-xnew; itel<-itel+1 + } + }> mat<-function (x, data=NULL) {return (1+x^itel)} > myIterator(3, f=mat, verbose=TRUE)Error in f(xold, data) : object 'itel' not found Can anyone please help me to fix the error? -- View this message in context: http://r.789695.n4.nabble.com/Help-with-Iterator-tp3033254p3033254.html Sent from the R help mailing list archive at Nabble.com.
I guess what you want is:
- change the line :
xnew<-f(xold,data)
into
xnew<-f(xold,data, itel)
- change your mat function to take itel as an extra parameter:
mat<-function (x, data=NULL, itel) {return (1+x^itel)}
That should do the trick (though I haven't checked whether the rest of your
code is OK)
Nick Sabbe
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-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On
Behalf Of zhiji19
Sent: dinsdag 9 november 2010 9:02
To: r-help at r-project.org
Subject: [R] Help with Iterator
Dear Experts,
The following is my "Iterator". When I try to write a new function
with
itel, I got error.
This is what I have: > supDist<-function(x,y) return(max(abs(x-y)))
>
> myIterator <- function(xinit,f,data=NULL,eps=1e-6,itmax=5,verbose=FALSE)
{
+ xold<-xinit
+ itel<-0
+ repeat {
+ xnew<-f(xold,data)
+ if (verbose) {
+ cat(
+ "Iteration: ",formatC(itel,width=3, format="d"),
+ "xold: ",formatC(xold,digits=8,width=12,format="f"),
+ "xnew: ",formatC(xnew,digits=8,width=12,format="f"),
+ "\n"
+ )
+ }
+ if ((supDist(xold,xnew) < eps) || (itel == itmax)) {
+ return(xnew)
+ }
+ xold<-xnew; itel<-itel+1
+ }
+ }
> mat<-function (x, data=NULL) {return (1+x^itel)}
> myIterator(3, f=mat, verbose=TRUE)
Error in f(xold, data) : object 'itel' not found
Can anyone please help me to fix the error?
--
View this message in context:
http://r.789695.n4.nabble.com/Help-with-Iterator-tp3033254p3033254.html
Sent from the R help mailing list archive at Nabble.com.
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> -----Original Message----- > From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] > On Behalf Of zhiji19 > Sent: Tuesday, November 09, 2010 12:02 AM > To: r-help at r-project.org > Subject: [R] Help with Iterator > > > Dear Experts, > > The following is my "Iterator". When I try to write a new function with > itel, I got error. > > This is what I have: > > supDist<-function(x,y) return(max(abs(x-y))) > > > > myIterator <- function(xinit,f,data=NULL,eps=1e-6,itmax=5,verbose=FALSE) > { > + xold<-xinit > + itel<-0 > + repeat { > + xnew<-f(xold,data) > + if (verbose) { > + cat( > + "Iteration: ",formatC(itel,width=3, format="d"), > + "xold: ",formatC(xold,digits=8,width=12,format="f"), > + "xnew: ",formatC(xnew,digits=8,width=12,format="f"), > + "\n" > + ) > + } > + if ((supDist(xold,xnew) < eps) || (itel == itmax)) { > + return(xnew) > + } > + xold<-xnew; itel<-itel+1 > + } > + } > > > mat<-function (x, data=NULL) {return (1+x^itel)} > > myIterator(3, f=mat, verbose=TRUE) > Error in f(xold, data) : object 'itel' not found > > > Can anyone please help me to fix the error?It appears to me that your problem is a matter of variable "scope". The error message says that the function f cannot find object 'itel'. That is because itel is defined in the function iterate and is local to that function. You might want to add a third parameter to function f so you can pass in the value of itel. (I would avoid using itel for the parameter name as you will likely end up confusing yourself at some point). I haven't tried to figure out what you are doing so I don't know if that is the best solution. But the problem is that f doesn't know about object 'itel'. Hope this is helpful, Dan Daniel Nordlund Bothell, WA USA