MatCreateAIJKokkos#
Creates a sparse matrix in MATAIJKOKOS
(compressed row) format (the default parallel PETSc format). This matrix will ultimately pushed down to Kokkos for calculations. For good matrix assembly performance the user should preallocate the matrix storage by setting the parameter nz
(or the array nnz
).
Synopsis#
Collective
Input Parameters#
comm - MPI communicator, set to
PETSC_COMM_SELF
m - number of rows
n - number of columns
nz - number of nonzeros per row (same for all rows)
nnz - array containing the number of nonzeros in the various rows (possibly different for each row) or
NULL
Output Parameter#
A - the matrix
Notes#
It is recommended that one use the MatCreate()
, MatSetType()
and/or MatSetFromOptions()
,
MatXXXXSetPreallocation() paradigm instead of this routine directly.
[MatXXXXSetPreallocation() is, for example, MatSeqAIJSetPreallocation()
]
If nnz
is given then nz
is ignored
The AIJ format, also called compressed row storage), is fully compatible with standard Fortran storage. That is, the stored row and column indices can begin at either one (as in Fortran) or zero.
Specify the preallocated storage with either nz or nnz (not both).
Set nz
= PETSC_DEFAULT
and nnz
= NULL
for PETSc to control dynamic memory
allocation. For large problems you MUST preallocate memory or you
will get TERRIBLE performance, see the users’ manual chapter on matrices.
By default, this format uses inodes (identical nodes) when possible, to improve numerical efficiency of matrix-vector products and solves. We search for consecutive rows with the same nonzero structure, thereby reusing matrix information to achieve increased efficiency.
Developer Note#
This manual page is for the sequential constructor, not the parallel constructor
See Also#
Matrices, Mat
, MATAIJKOKOS
, MATSEQAIJKOKOS
, MATMPIAIJKOKOS
, MatCreate()
, MatCreateAIJ()
, MatSetValues()
,
MatSeqAIJSetColumnIndices()
, MatCreateSeqAIJWithArrays()
, MatCreateAIJ()
, MATMPIAIJKOKKOS
, MATAIJKOKKOS
Level#
intermediate
Location#
src/mat/impls/aij/mpi/kokkos/mpiaijkok.kokkos.cxx
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