[Rd] Matrix*vector: coercing sparse to dense matrix for arithmetic
Tamas K Papp
tpapp at Princeton.EDU
Wed Nov 29 16:33:09 CET 2006
Hi,
I have a sparse Matrix (kronecker product of spline design matrices),
and I need to multiply each row by a number to get another matrix. If
the matrix is A and the numbers are stored in a vector k, with plain
vanilla matrices I would do
A*k
But when using the Matrix package (class of A is "dgCMatrix"), I get
the warning "coercing sparse to dense matrix for arithmetic". The
error message is perfectly reasonable, I am looking for a way to do it
right (keeping operations in the realm of sparse matrices). Any help
would be appreciated.
Thanks,
Tamas
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