[R] write.matrix.csr data conversion

Sam Steingold sds at gnu.org
Tue Nov 6 19:15:04 CET 2012


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!
>>

-- 
Sam Steingold (http://sds.podval.org/) on Ubuntu 12.04 (precise) X 11.0.11103000
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