* Expands potentials \f$x+=UX\f$ of a target cell. This operation can be
* seen as part of the L2L operation.
*
* @param[in] X compressed local expansion of size \f$r\f$
* @param[out] x local expansion of size \f$\ell^3\f$
*/
voidapplyU(constFReal*constX,FReal*constx)const
{
// FBlas::gemva(nnodes, rank, 1., U, const_cast<FReal*>(X), x);
FBlas::add(nnodes,const_cast<FReal*>(X),x);
}
/**
* Compressed M2L operation \f$X+=C_tY\f$, where \f$Y\f$ is the compressed
* multipole expansion and \f$X\f$ is the compressed local expansion, both
* of size \f$r\f$. The index \f$t\f$ denotes the transfer vector of the
* target cell to the source cell.
*
* @param[in] transfer transfer vector
* @param[in] Y compressed multipole expansion
* @param[out] X compressed local expansion
* @param[in] CellWidth needed for the scaling of the compressed M2L operators which are based on a homogeneous matrix kernel computed for the reference cell width \f$w=2\f$, ie in \f$[-1,1]^3\f$.
*/
// void applyC(const int transfer[3], FReal CellWidth,