MatSetValuesBlocked

 Inserts or adds a block of values into a matrix.

Synopsis

#include "petscmat.h" 
int MatSetValuesBlocked(Mat mat,int m,int *idxm,int n,int *idxn,PetscScalar *v,InsertMode addv)
Not Collective

Input Parameters

mat - the matrix
v - a logically two-dimensional array of values
m, idxm - the number of block rows and their global block indices
n, idxn - the number of block columns and their global block indices
addv - either ADD_VALUES or INSERT_VALUES, where ADD_VALUES adds values to any existing entries, and INSERT_VALUES replaces existing entries with new values

Notes

By default the values, v, are row-oriented and unsorted. So the layout of v is the same as for MatSetValues(). See MatSetOption() for other options.

Calls to MatSetValuesBlocked() with the INSERT_VALUES and ADD_VALUES options cannot be mixed without intervening calls to the assembly routines.

MatSetValuesBlocked() uses 0-based row and column numbers in Fortran as well as in C.

Negative indices may be passed in idxm and idxn, these rows and columns are simply ignored. This allows easily inserting element stiffness matrices with homogeneous Dirchlet boundary conditions that you don't want represented in the matrix.

Each time an entry is set within a sparse matrix via MatSetValues(), internal searching must be done to determine where to place the the data in the matrix storage space. By instead inserting blocks of entries via MatSetValuesBlocked(), the overhead of matrix assembly is reduced.

Restrictions

MatSetValuesBlocked() is currently supported only for the block AIJ matrix format (MATSEQBAIJ and MATMPIBAIJ, which are created via MatCreateSeqBAIJ() and MatCreateMPIBAIJ()).

See Also

MatSetOption(), MatAssemblyBegin(), MatAssemblyEnd(), MatSetValues(), MatSetValuesBlockedLocal()

Level:intermediate
Location:src/mat/interface/matrix.c
Index of all Mat routines
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Index of all manual pages