[R] boot strapping poisson getting warnings and negative values

[Aravindhan, K]

Team,
I am giving the exact code that produces the error.  Please see below.  Can anyone please help ?

Thanks
Aravindhan

PROGRAM
-------------------------------------------------------------------------------------------
rm(list = ls())
x<-c(1,14,49,26,4,10,25,36,79,15)
y<-c(1,5,32,8,4,23,399,79,341,2)
db = data.frame(x,y)
library(car)
db = data.frame(x,y)
print("---------------------------------------------------------==")
summary(m1 <- glm(y~0+x, family = poisson()))
mod.db.hub<-glm(y~0+x,family="poisson",data=db)
fit<-fitted(mod.db.hub)
e<-residuals(mod.db.hub)
X<-model.matrix(mod.db.hub)
boot.huber.fixed<-function(data,indices,maxit=20) {
Y<-fit+e[indices]
mod<-glm(Y~X+0,family="poisson",maxit=maxit)
coefficients(mod)
}
library(boot)
db.fix.boot<-boot(db,boot.huber.fixed,2000,maxit=20)
db.fix.boot
boot.ci(db.fix.boot,index=1,type=c("bca","perc","poisson"))
----------------------------------------------------------------------------------------

The error I get is 
------------------------------------------------------------------------------------------

> db.fix.boot<-boot(db,boot.huber.fixed,2000,maxit=20)
Error in eval(expr, envir, enclos) : 
  negative values not allowed for the 'Poisson' family
In addition: Warning messages:
1: In dpois(y, mu, log = TRUE) : non-integer x = 1.002114
2: In dpois(y, mu, log = TRUE) : non-integer x = 4.050746
3: In dpois(y, mu, log = TRUE) : non-integer x = 44.219309
4: In dpois(y, mu, log = TRUE) : non-integer x = 7.786340
5: In dpois(y, mu, log = TRUE) : non-integer x = 3.189963
6: In dpois(y, mu, log = TRUE) : non-integer x = 10.348190
7: In dpois(y, mu, log = TRUE) : non-integer x = 56.408862
8: In dpois(y, mu, log = TRUE) : non-integer x = 27.751783
9: In dpois(y, mu, log = TRUE) : non-integer x = 480.383098
10: In dpois(y, mu, log = TRUE) : non-integer x = 2.497504
> db.fix.boot
Error: object 'db.fix.boot' not found
> boot.ci(db.fix.boot,index=1,type=c("bca","perc","poisson"))
Error in boot.ci(db.fix.boot, index = 1, type = c("bca", "perc", "poisson")) : 
  object 'db.fix.boot' not found
------------------------------------------------------------------------------------------


-----Original Message-----
From: Aravindhan, K 
Sent: Saturday, November 15, 2014 7:59 AM
To: r-help at r-project.org
Subject: RE: [R] boot strapping poisson getting warnings and negative values

Team,
Has anyone looked at this question from me ?  it will help me immensely if someone can provide an answer to this.

Thanks
Aravindhan

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf Of K Aravindhan
Sent: Friday, August 08, 2014 7:42 PM
To: r-help at r-project.org
Subject: [R] boot strapping poisson getting warnings and negative values

Dear Team,
I am getting this error while running the boot-strapping functions. 

==================================================
mod.db.hub<-glm(TOTAL~1+IPD,family="poisson",data=db)
fit<-fitted(mod.db.hub)
e<-residuals(mod.db.hub)
X<-model.matrix(mod.db.hub)
boot.huber.fixed<-function(data,indices,maxit=20) { Y<-fit+e[indices]
mod<-glm(Y~X-1,family="poisson",maxit=maxit)
coefficients(mod)
}
library(boot)
db.fix.boot<-boot(db,boot.huber.fixed,2000,maxit=20)
db.fix.boot
boot.ci(db.fix.boot,index=1,type=c("bca","perc","poisson"))
boot.ci(db.fix.boot,index=2,type=c("bca","perc","poisson"))
==================================================

Error in eval(expr, envir, enclos) : 
negative values not allowed for the 'Poisson' family In addition: Warning messages:
1: In dpois(y, mu, log = TRUE) : non-integer x = 25.006412
2: In dpois(y, mu, log = TRUE) : non-integer x = 26.969411
3: In dpois(y, mu, log = TRUE) : non-integer x = 66.352323
4: In dpois(y, mu, log = TRUE) : non-integer x = 61.083519
5: In dpois(y, mu, log = TRUE) : non-integer x = 20.596770
6: In dpois(y, mu, log = TRUE) : non-integer x = 43.428258
7: In dpois(y, mu, log = TRUE) : non-integer x = 1108.263554
8: In dpois(y, mu, log = TRUE) : non-integer x = 61.937982
9: In dpois(y, mu, log = TRUE) : non-integer x = 419.991213
10: In dpois(y, mu, log = TRUE) : non-integer x = 47.369133

Can you explain to me how to get rid of these ?

Thanks
Aravindhan

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