R help - Sep 2011 - Loops

Dear forum,

I would like to forecast e.g. with the arima-model. To figure out which
model works best I am going to predict with this models.

my first code:

for(ar.ord in 1:3){
for(ma.ord in 1:3){
print(predict(arima(para_qtr[1:(n-8),1],order=c(ar.ord,1,ma.ord)),
n.ahead=8)$pred)
}
}

this one works. but I want to "save" my results in a matrix or a
data.frame.

my second code:
foreL<-8
b0f<-matrix(nrow=9, ncol=foreL)
for(i in 1:9){
for(ar.ord in 1:3){
for(ma.ord in 1:3){
b0f[i,]<-c(predict(arima(para_qtr[1:(n-8),1],order=c(ar.ord,1,ma.ord)),
n.ahead=foreL)$pred)
}
}
}
sure- this one doesn't work. the matrix b0f only consists of the forecast of
the ARIMA(3,1,3)-model. I need the forecasts of ARIMA(1,1,1), ARIMA(2,1,1)
ARIMA(3,1,1), ARIMA(3,1,2) and so on ad nauseam in the lines of the b0f
matrix.

I would be glad if someone could help me.

best regards, fred



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A little bit change of your code may do the work

foreL<-8
b0f<-matrix(nrow=9, ncol=foreL)
ct<-1 ### use this as the index of b0f
for(ar.ord in 1:3){
for(ma.ord in 1:3){
b0f[ct,]<-c(predict(arima(para_qtr[1:(n-8),1],order=c(ar.ord,1,ma.ord)),
n.ahead=foreL)$pred)
ct<-ct+1 ### increment the counter
}
}


Weidong Gu


On Wed, Sep 14, 2011 at 5:36 PM, Fred <christoph_wegener at gmx.de>
wrote:
> Dear forum,
>
> I would like to forecast e.g. with the arima-model. To figure out which
> model works best I am going to predict with this models.
>
> my first code:
>
> for(ar.ord in 1:3){
> for(ma.ord in 1:3){
> print(predict(arima(para_qtr[1:(n-8),1],order=c(ar.ord,1,ma.ord)),
> n.ahead=8)$pred)
> }
> }
>
> this one works. but I want to "save" my results in a matrix or a
data.frame.
>
> my second code:
> foreL<-8
> b0f<-matrix(nrow=9, ncol=foreL)
> for(i in 1:9){
> for(ar.ord in 1:3){
> for(ma.ord in 1:3){
> b0f[i,]<-c(predict(arima(para_qtr[1:(n-8),1],order=c(ar.ord,1,ma.ord)),
> n.ahead=foreL)$pred)
> }
> }
> }
> sure- this one doesn't work. the matrix b0f only consists of the
forecast of
> the ARIMA(3,1,3)-model. I need the forecasts of ARIMA(1,1,1), ARIMA(2,1,1)
> ARIMA(3,1,1), ARIMA(3,1,2) and so on ad nauseam in the lines of the b0f
> matrix.
>
> I would be glad if someone could help me.
>
> best regards, fred
>
>
>
> --
> View this message in context:
http://r.789695.n4.nabble.com/Loops-tp3814162p3814162.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

Look at the combinations function in gtools and index by the rows of that output
for a single loop. Pass values as the three parameters.

Sorry for being terse - writing on my phone. 

Michael

On Sep 14, 2011, at 5:36 PM, Fred <christoph_wegener at gmx.de> wrote:
> Dear forum,
> 
> I would like to forecast e.g. with the arima-model. To figure out which
> model works best I am going to predict with this models.
> 
> my first code:
> 
> for(ar.ord in 1:3){
> for(ma.ord in 1:3){
> print(predict(arima(para_qtr[1:(n-8),1],order=c(ar.ord,1,ma.ord)),
> n.ahead=8)$pred)
> }
> }
> 
> this one works. but I want to "save" my results in a matrix or a
data.frame.
> 
> my second code:
> foreL<-8
> b0f<-matrix(nrow=9, ncol=foreL)
> for(i in 1:9){
> for(ar.ord in 1:3){
> for(ma.ord in 1:3){
> b0f[i,]<-c(predict(arima(para_qtr[1:(n-8),1],order=c(ar.ord,1,ma.ord)),
> n.ahead=foreL)$pred)
> }
> }
> }
> sure- this one doesn't work. the matrix b0f only consists of the
forecast of
> the ARIMA(3,1,3)-model. I need the forecasts of ARIMA(1,1,1), ARIMA(2,1,1)
> ARIMA(3,1,1), ARIMA(3,1,2) and so on ad nauseam in the lines of the b0f
> matrix.
> 
> I would be glad if someone could help me.
> 
> best regards, fred
> 
> 
> 
> --
> View this message in context:
http://r.789695.n4.nabble.com/Loops-tp3814162p3814162.html
> Sent from the R help mailing list archive at Nabble.com.
> 
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

Thank you so much! 

foreL<-8
b0f<-matrix(nrow=9, ncol=foreL)
ct<-1 ### use this as the index of b0f
for(ar.ord in 1:3){
for(ma.ord in 1:3){
b0f[ct,]<-c(predict(arima(para_qtr[1:(n-8),1],order=c(ar.ord,1,ma.ord)),
n.ahead=foreL)$pred)
ct<-ct+1 ### increment the counter
}
}
this one works! Best regards!

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