[BioC] pamr Error: each class must have >1 sample

[Dick Beyer]

I am having trouble with pamr.train and subsequently pamr.cv.

In the pamr documentation, the following works:

     set.seed(120)
     x <- matrix(rnorm(1000*20),ncol=20)
     y <- sample(c(1:4),size=20,replace=TRUE)
     mydata <- list(x=x,y=y)
     mytrain <-   pamr.train(mydata)
     mycv <- pamr.cv(mytrain,mydata)

But if you change the seed, it doesn't:

     set.seed(1123)
     x <- matrix(rnorm(1000*20),ncol=20)
     y <- sample(c(1:4),size=20,replace=TRUE)
     mydata <- list(x=x,y=y)
     mytrain <-   pamr.train(mydata)
Error in nsc(data$x[gene.subset, sample.subset], y = y, proby = proby,  : 
        Error: each class must have >1 sample

There is discussion in the documents (http://www-stat.stanford.edu/~tibs/PAM/Rdist/doc/readme.html) about "fragile" functions, but I have not been able to understand how to make this error go away.  If anyone has had this problem or has some advice, I would be eternally grateful.

Thanks very much,
Dick 
*******************************************************************************
Richard P. Beyer, Ph.D.	University of Washington
Tel.:(206) 616 7378	Env. & Occ. Health Sci. , Box 354695
Fax: (206) 685 4696	4225 Roosevelt Way NE, # 100
			Seattle, WA 98105-6099
http://depts.washington.edu/ceeh/ServiceCores/FC5/FC5.html