[Rd] Matrix*vector: coercing sparse to dense matrix for arithmetic

From: Tamas K Papp <tpapp_at_princeton.edu>
Date: Wed 29 Nov 2006 - 15:33:09 GMT


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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