#include "slepcbv.h" PetscErrorCode BVMult(BV Y,PetscScalar alpha,PetscScalar beta,BV X,Mat Q)Logically Collective
| Y | - first basis vectors context (modified on output) | |
| alpha | - first scalar | |
| beta | - second scalar | |
| X | - second basis vectors context | |
| Q | - (optional) sequential dense matrix |
If matrix Q is NULL, then an AXPY operation Y = beta*Y + alpha*X is done (i.e. results as if Q = identity). If provided, the matrix Q must be a sequential dense Mat, with all entries equal on all processes (otherwise each process will compute a different update). The dimensions of Q must be at least m,n where m is the number of active columns of X and n is the number of active columns of Y.
The leading columns of Y are not modified. Also, if X has leading columns specified, then these columns do not participate in the computation. Hence, only rows (resp. columns) of Q starting from lx (resp. ly) are used, where lx (resp. ly) is the number of leading columns of X (resp. Y).