str() is your number one friend in R. Do str(A) and str(A2) after allocating the matrices and you'll be "surprised". My $.02 /Henrik
On Fri, Apr 6, 2012 at 7:35 AM, 卢永芳 <sswwss...@126.com> wrote: > Hello,experts > I am working on a simulation of effect of artificial selection on certain > population in Animal Breeding.I am new beginner in coding. I have already > build a matrix A(500*500) based on this code > A<-matrix(,500,500) > for(i in 1:500){ > for(j in 1:500){ > ifelse(i==j,A[i,j]<-1,A[i,j]<-0) > } > } > and I need to caculate A2 > > base on A and X1(4500*4500).Here are the codes > A2<-matrix(4500,500) > for(i in 1:4500){ > for(j in 1:500){ > A2[i,j]<-(A[X1[i,2],j]+A[X1[i,3],j])/2 > } > } > and error happened like this:Error in A2[i, j] <- (A[X1[i, 2], j] + A[X1[i, > 3], j])/2 : subscript out of bounds > I check the criculation number in for loop and it is perfect match with the > dimension of matrix A and X1. I do not know how this error happened? And > anther inportant question is that how can I build a matrix with very larger > dimension which can not allocate in R.Error in matrix(, 45500, 45500) : > cannot allocate vector of length 2070250000 > > > I am looking forward to hear from you > Kindest Regards > > [[alternative HTML version deleted]] > > > ______________________________________________ > R-help@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. > ______________________________________________ R-help@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.