library(Matrix)
mmT <- as(mm, "dgTMatrix")
str(mmT)
mm3 <- cbind(i = mmT@i, j = mmT@j, x = mmT@x)
write.table(mm3, file = "mm-Matrix.tab", row.names=FALSE)# -> ASCII version
str(mmr <- read.table("mm-Matrix.tab", header = TRUE))
mmr$i <- as.integer(mmr$i)
mmr$j <- as.integer(mmr$j)
mmN <- with(mmr, new("dgTMatrix", Dim = c(max(i)+1:1,max(j)+1:1),
i = i, j = j, x = x))
stopifnot(identical(mmT, mmN)) # !!
## weaker (and hence TRUE too):
stopifnot(all.equal(as(mmN, "matrix"),
as(mmT, "matrix"), tol=0))
mm <- as(mmN, "dgCMatrix")
## save(mm, file = "....../Matrix/data/mm.rda", compress = TRUE)