write.matrix.csr data conversion

David,
thanks for adding the feature.

read.matrix.csr and, especially, write.matrix.csr are extremely slow:

      user    system   elapsed
  8381.988  3810.396 12345.349

for a 2797634 x 224 matrix I have to deal with.

The help page
http://rss.acs.unt.edu/Rdoc/library/e1071/html/read.matrix.csr.html
says

David Meyer (based on C/C++-code by Chih-Chung Chang and Chih-Jen Lin)

is there any chance that you might consider replacing the R code with
the original C/C++?

Thanks a lot!

* David Meyer <qnivq.zrlre at jh.np.ng> [2012-08-27 22:57:17 +0200]:

done, thanks for the suggestion.

David

On 2012-08-27 21:15, Sam Steingold wrote:

* jim holtman <wubygzna at tznvy.pbz> [2012-08-27 14:55:08 -0400]:

Most likely when 'y' is converted to a dataframe (not sure what the
function 'write.matrix.csr' does since you did not say where you got
it),

sorry,
library(e1071)

'0' and '1' are converted to factors which probably show up as 1
and 2 in the file.

sounds reasonable, thanks.

David, could you please add an option `fac' to `write.matrix.csr',
similar to `read.matrix.csr' which already accepts `fac'?

thanks!

* David Meyer <zrlreq at grpuavxhz-jvra.ng> [2012-11-06 19:49:15 +0100]:

there is C-code related to *reading* in such a file, but in the
internal libsvm-format, not the matrix.csr format.

There is certainly a way to speed this up, but I am not likely to do
this in the near future.

On 2012-11-06 19:15, Sam Steingold wrote:

David,
thanks for adding the feature.

read.matrix.csr and, especially, write.matrix.csr are extremely slow:

      user    system   elapsed
  8381.988  3810.396 12345.349

for a 2797634 x 224 matrix I have to deal with.

The help page
http://rss.acs.unt.edu/Rdoc/library/e1071/html/read.matrix.csr.html
says

David Meyer (based on C/C++-code by Chih-Chung Chang and Chih-Jen Lin)

is there any chance that you might consider replacing the R code with
the original C/C++?