[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


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


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.



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