[R] help with ff matrix indexing and value assignment

[Ken Nussear]

Hi all

I'm trying to make some assignments to an ffdf using values coming in as
3 columns (row, col, values)

As an example with a regular matrix assigning data (d)  to row r and
column c from a data frame assigns the 3 specific values as desired
reg.mat <- matrix(0, nrow=5, ncol=5)
> reg.mat
     [,1] [,2] [,3] [,4] [,5]
[1,]    0    0    0    0    0
[2,]    0    0    0    0    0
[3,]    0    0    0    0    0
[4,]    0    0    0    0    0
[5,]    0    0    0    0    0


coldat <- data.frame(r = c(1,2,4), c = c(2,1,3), d=c(10,11,12))

> coldat
  r c  d
1 1 2 10
2 2 1 11
3 4 3 12

reg.mat[cbind(coldat$r, coldat$c)] <- coldat$d
> reg.mat
     [,1] [,2] [,3] [,4] [,5]
[1,]    0   10    0    0    0
[2,]   11    0    0    0    0
[3,]    0    0    0    0    0
[4,]    0    0   12    0    0
[5,]    0    0    0    0    0


However using an ff matrix with an incoming 3 column ffdf I cant seem to
get it to go...

ff.mat<-ff(as.integer(0), dim=c(5,5))

> tst.mat
ff (open) integer length=25 (25) dim=c(5,5) dimorder=c(1,2)
     [,1] [,2] [,3] [,4] [,5]
[1,]    0    0    0    0    0
[2,]    0    0    0    0    0
[3,]    0    0    0    0    0
[4,]    0    0    0    0    0
[5,]    0    0    0    0    0

coldatff <-
ffdf(r=ff(as.integer(c(1,2,4))),c=ff(as.integer(c(2,1,3))),d=ff(as.integer(c(10,11,12))))

> coldatff
ffdf (all open) dim=c(3,3), dimorder=c(1,2) row.names=NULL
ffdf virtual mapping
  PhysicalName VirtualVmode PhysicalVmode  AsIs VirtualIsMatrix
PhysicalIsMatrix PhysicalElementNo PhysicalFirstCol PhysicalLastCol
r            r      integer       integer FALSE          
FALSE            FALSE                 1                1               1
c            c      integer       integer FALSE          
FALSE            FALSE                 2                1               1
d            d      integer       integer FALSE          
FALSE            FALSE                 3                1               1
  PhysicalIsOpen
r           TRUE
c           TRUE
d           TRUE
ffdf data
   r  c  d
1  1  2 10
2  2  1 11
3  4  3 12

ff.mat[cbind(coldatff$r,coldatff$c)] <-coldatff$d

> ff.mat
ff (open) integer length=25 (25) dim=c(5,5) dimorder=c(1,2)
     [,1] [,2] [,3] [,4] [,5]
[1,]    0    0    0    0    0
[2,]    0    0    0    0    0
[3,]    0    0    0    0    0
[4,]    0    0    0    0    0
[5,]    0    0    0    0    0

Using cbind = still getting only zeros. Tried a few other methods I just
cant seem to wrap my head around how to do this.....

I had a look at ffindexset, but that looks like assigning whole rows at
a time.

I appreciate any help !!

Thanks

Ken