How do I read/write libsvm
data into/from R
?
The libsvm
format is sparse data like
<class/target>[ <attribute number>:<attribute value>]*
(cf. Compressed Row Storage (CRS)) e.g.,
1 10:3.4 123:0.5 34567:0.231
0.2 22:1 456:03
I am sure I can whip some something myself, but I would much rather use something off the shelf. However, R
library foreign
does not seem to provide the necessary functionality.
e1071
is off the shelf:install.packages("e1071")
library(e1071)
read.matrix.csr(...)
write.matrix.csr(...)
Note: it is implemented in R
, not in C
, so it is dog-slow.
It even have a special vignette Support Vector Machines—the Interface to libsvm in package e1071.
r.vw
is bundled with vowpal_wabbit
Note: it is implemented in R
, not in C
, so it is dog-slow.