MatAssemblyBegin#

Begins assembling the matrix. This routine should be called after completing all calls to MatSetValues().

Synopsis#

#include "petscmat.h" 
PetscErrorCode MatAssemblyBegin(Mat mat, MatAssemblyType type)

Collective

Input Parameters#

Notes#

MatSetValues() generally caches the values that belong to other MPI processes. The matrix is ready to use only after MatAssemblyBegin() and MatAssemblyEnd() have been called.

Use MAT_FLUSH_ASSEMBLY when switching between ADD_VALUES and INSERT_VALUES in MatSetValues(); use MAT_FINAL_ASSEMBLY for the final assembly before using the matrix.

ALL processes that share a matrix MUST call MatAssemblyBegin() and MatAssemblyEnd() the SAME NUMBER of times, and each time with the same flag of MAT_FLUSH_ASSEMBLY or MAT_FINAL_ASSEMBLY for all processes. Thus you CANNOT locally change from ADD_VALUES to INSERT_VALUES, that is a global collective operation requiring all processes that share the matrix.

Space for preallocated nonzeros that is not filled by a call to MatSetValues() or a related routine are compressed out by assembly. If you intend to use that extra space on a subsequent assembly, be sure to insert explicit zeros before MAT_FINAL_ASSEMBLY so the space is not compressed out.

See Also#

Matrices, Mat, MatAssemblyEnd(), MatSetValues(), MatAssembled()

Level#

beginner

Location#

src/mat/interface/matrix.c

Examples#

src/tao/unconstrained/tutorials/minsurf2.c
src/tao/unconstrained/tutorials/rosenbrock3.c
src/tao/unconstrained/tutorials/burgers_spectral.c
src/tao/complementarity/tutorials/minsurf1.c
src/tao/leastsquares/tutorials/chwirut1.c
src/tao/bound/tutorials/jbearing2.c
src/tao/complementarity/tutorials/blackscholes.c
src/tao/bound/tutorials/plate2.c
src/tao/leastsquares/tutorials/cs1.c
src/tao/leastsquares/tutorials/tomography.c

Implementations#

MatAssemblyBegin_MPIAdj() in src/mat/impls/adj/mpi/mpiadj.c
MatAssemblyBegin_MPIAIJ() in src/mat/impls/aij/mpi/mpiaij.c
MatAssemblyBegin_MPIBAIJ() in src/mat/impls/baij/mpi/mpibaij.c
MatAssemblyBegin_MPIDense() in src/mat/impls/dense/mpi/mpidense.c
MatAssemblyBegin_SeqDense() in src/mat/impls/dense/seq/dense.c
MatAssemblyBegin_Elemental() in src/mat/impls/elemental/matelem.cxx
MatAssemblyBegin_HYPRE() in src/mat/impls/hypre/mhypre.c
MatAssemblyBegin_IS() in src/mat/impls/is/matis.c
MatAssemblyBegin_Nest() in src/mat/impls/nest/matnest.c
MatAssemblyBegin_Preallocator() in src/mat/impls/preallocator/matpreallocator.c
MatAssemblyBegin_MPISBAIJ() in src/mat/impls/sbaij/mpi/mpisbaij.c
MatAssemblyBegin_ScaLAPACK() in src/mat/impls/scalapack/matscalapack.c
MatAssemblyBegin_MPISELL() in src/mat/impls/sell/mpi/mpisell.c


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Index of all manual pages