MatDiagonalSet

Computes Y = Y + D, where D is a diagonal matrix that is represented as a vector. Or Y[i,i] = D[i] if InsertMode is INSERT_VALUES.

Synopsis

#include "petscmat.h"  
PetscErrorCode  MatDiagonalSet(Mat Y,Vec D,InsertMode is)

Input Parameters

Y - the input matrix
D - the diagonal matrix, represented as a vector
i - INSERT_VALUES or ADD_VALUES

Neighbor-wise Collective on Mat

Notes

If the matrix Y is missing some diagonal entries this routine can be very slow. To make it fast one should initially fill the matrix so that all diagonal entries have a value (with a value of zero for those locations that would not have an entry).

Level: intermediate

See Also

MatShift(), MatScale(), MatDiagonalScale()

Location:axpy.c