[R] colSum() in Matrix objects
quesada at gmail.com
Mon Apr 16 20:41:46 CEST 2007
I'd like to simply add column-wise using Matrix objects (Csparse).
It looks like one can apply mosty any base function to these objects
(i.e., apply, colSums), but there is a nasty conversion to traditional
matrix objects if one does that.
Is there any workaround? I can see colSum listed in the help for Class
'CsparseMatrix' , but I wonder whether I'm using the default colSums() or
the one specific to CsparseMatrix...
(z = Matrix(c(0,1,0,0), 10,10))
zr = rowSums(z)
class(zr) # numeric; I'd like it to be a CSparseMatrix object
Thanks a lot in advance,
Jose Quesada, PhD.
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