[R] write.matrix.csr(e1071) bug

[Jeszenszky Peter]

Hello,

The write.matrix.csr() function of the e1071 package contains a bug.
Try the following:

 	library(e1071)
 	m <- 1 - diag(10)
 	sm <- as.matrix.csr(m)
 	write.matrix.csr(sm)

The resulting file (out.dat) contains only the two lines below:

2:1 3:1 4:1 5:1 6:1 7:1 8:1 9:1 10:1
1:1 3:1 4:1 5:1 6:1 7:1 8:1 9:1 10:1

This is obviously wrong as the matrix m has 90 non-zero entries.

The function is implemented as

 	write.matrix.csr <- function (x, file="out.dat", y=NULL) {
 		on.exit(sink())
 		if(!require("methods")) stop("Could not load package 'methods'.")
 		if (!is.null(y) & (length(y) != nrow(x)))
 			stop(paste("Length of y (=", length(y),
 				") does not match number of rows of x (=",
 				nrow(x), ")!", sep=""))
 		sink(file)
 		for (i in 1:nrow(x)) {
 			if (!is.null(y)) cat (y[i],"")
 			if (x at ia[i] <= nrow(x))
 				for (j in x at ia[i]:(x at ia[i+1] - 1))
 					cat(x at ja[j], ":", x at ra[j], " ", sep="")
 			cat("\n")
 		}
 	}

The bug is caused by the line

 	if (x at ia[i] <= nrow(x))

that is completely meaningless. In the above example nrow(x) is 10
and x at ia is the vector

 	1 10 19 28 37 46 55 64 73 82 91

Entries of x at ia has nothing to do with the number of rows in the matrix.

To fix the bug this line must be removed.

Best regards,

Peter