Actual source code: mpiaijsell.c

      1: #include <../src/mat/impls/aij/mpi/mpiaij.h>
      2: /*@C
      3:    MatCreateMPIAIJSELL - Creates a sparse parallel matrix whose local
      4:    portions are stored as SEQAIJSELL matrices (a matrix class that inherits
      5:    from SEQAIJ but performs some operations in SELL format).  The same
      6:    guidelines that apply to MPIAIJ matrices for preallocating the matrix
      7:    storage apply here as well.

      9:       Collective

     11:    Input Parameters:
     12: +  comm - MPI communicator
     13: .  m - number of local rows (or PETSC_DECIDE to have calculated if M is given)
     14:            This value should be the same as the local size used in creating the
     15:            y vector for the matrix-vector product y = Ax.
     16: .  n - This value should be the same as the local size used in creating the
     17:        x vector for the matrix-vector product y = Ax. (or PETSC_DECIDE to have
     18:        calculated if N is given) For square matrices n is almost always m.
     19: .  M - number of global rows (or PETSC_DETERMINE to have calculated if m is given)
     20: .  N - number of global columns (or PETSC_DETERMINE to have calculated if n is given)
     21: .  d_nz  - number of nonzeros per row in DIAGONAL portion of local submatrix
     22:            (same value is used for all local rows)
     23: .  d_nnz - array containing the number of nonzeros in the various rows of the
     24:            DIAGONAL portion of the local submatrix (possibly different for each row)
     25:            or NULL, if d_nz is used to specify the nonzero structure.
     26:            The size of this array is equal to the number of local rows, i.e 'm'.
     27:            For matrices you plan to factor you must leave room for the diagonal entry and
     28:            put in the entry even if it is zero.
     29: .  o_nz  - number of nonzeros per row in the OFF-DIAGONAL portion of local
     30:            submatrix (same value is used for all local rows).
     31: -  o_nnz - array containing the number of nonzeros in the various rows of the
     32:            OFF-DIAGONAL portion of the local submatrix (possibly different for
     33:            each row) or NULL, if o_nz is used to specify the nonzero
     34:            structure. The size of this array is equal to the number
     35:            of local rows, i.e 'm'.

     37:    Output Parameter:
     38: .  A - the matrix

     40:    Notes:
     41:    If the *_nnz parameter is given then the *_nz parameter is ignored

     43:    m,n,M,N parameters specify the size of the matrix, and its partitioning across
     44:    processors, while d_nz,d_nnz,o_nz,o_nnz parameters specify the approximate
     45:    storage requirements for this matrix.

     47:    If PETSC_DECIDE or PETSC_DETERMINE is used for a particular argument on one
     48:    processor than it must be used on all processors that share the object for
     49:    that argument.

     51:    The user MUST specify either the local or global matrix dimensions
     52:    (possibly both).

     54:    The parallel matrix is partitioned such that the first m0 rows belong to
     55:    process 0, the next m1 rows belong to process 1, the next m2 rows belong
     56:    to process 2 etc.. where m0,m1,m2... are the input parameter 'm'.

     58:    The DIAGONAL portion of the local submatrix of a processor can be defined
     59:    as the submatrix which is obtained by extraction the part corresponding
     60:    to the rows r1-r2 and columns r1-r2 of the global matrix, where r1 is the
     61:    first row that belongs to the processor, and r2 is the last row belonging
     62:    to the this processor. This is a square mxm matrix. The remaining portion
     63:    of the local submatrix (mxN) constitute the OFF-DIAGONAL portion.

     65:    If o_nnz, d_nnz are specified, then o_nz, and d_nz are ignored.

     67:    When calling this routine with a single process communicator, a matrix of
     68:    type SEQAIJSELL is returned.  If a matrix of type MPIAIJSELL is desired
     69:    for this type of communicator, use the construction mechanism:
     70:      MatCreate(...,&A); MatSetType(A,MPIAIJSELL); MatMPIAIJSetPreallocation(A,...);

     72:    Options Database Keys:
     73: .  -mat_aijsell_eager_shadow - Construct shadow matrix upon matrix assembly; default is to take a "lazy" approach, performing this step the first time the matrix is applied

     75:    Level: intermediate

     77: .seealso: MatCreate(), MatCreateSeqAIJSELL(), MatSetValues()
     78: @*/
     79: PetscErrorCode  MatCreateMPIAIJSELL(MPI_Comm comm,PetscInt m,PetscInt n,PetscInt M,PetscInt N,PetscInt d_nz,const PetscInt d_nnz[],PetscInt o_nz,const PetscInt o_nnz[],Mat *A)
     80: {
     82:   PetscMPIInt    size;

     85:   MatCreate(comm,A);
     86:   MatSetSizes(*A,m,n,M,N);
     87:   MPI_Comm_size(comm,&size);
     88:   if (size > 1) {
     89:     MatSetType(*A,MATMPIAIJSELL);
     90:     MatMPIAIJSetPreallocation(*A,d_nz,d_nnz,o_nz,o_nnz);
     91:   } else {
     92:     MatSetType(*A,MATSEQAIJSELL);
     93:     MatSeqAIJSetPreallocation(*A,d_nz,d_nnz);
     94:   }
     95:   return(0);
     96: }

     98: PETSC_INTERN PetscErrorCode MatConvert_SeqAIJ_SeqAIJSELL(Mat,MatType,MatReuse,Mat*);

    100: PetscErrorCode  MatMPIAIJSetPreallocation_MPIAIJSELL(Mat B,PetscInt d_nz,const PetscInt d_nnz[],PetscInt o_nz,const PetscInt o_nnz[])
    101: {
    102:   Mat_MPIAIJ     *b = (Mat_MPIAIJ*)B->data;

    106:   MatMPIAIJSetPreallocation_MPIAIJ(B,d_nz,d_nnz,o_nz,o_nnz);
    107:   MatConvert_SeqAIJ_SeqAIJSELL(b->A, MATSEQAIJSELL, MAT_INPLACE_MATRIX, &b->A);
    108:   MatConvert_SeqAIJ_SeqAIJSELL(b->B, MATSEQAIJSELL, MAT_INPLACE_MATRIX, &b->B);
    109:   return(0);
    110: }

    112: PETSC_INTERN PetscErrorCode MatConvert_MPIAIJ_MPIAIJSELL(Mat A,MatType type,MatReuse reuse,Mat *newmat)
    113: {
    115:   Mat            B = *newmat;

    118:   if (reuse == MAT_INITIAL_MATRIX) {
    119:     MatDuplicate(A,MAT_COPY_VALUES,&B);
    120:   }

    122:   PetscObjectChangeTypeName((PetscObject) B, MATMPIAIJSELL);
    123:   PetscObjectComposeFunction((PetscObject)B,"MatMPIAIJSetPreallocation_C",MatMPIAIJSetPreallocation_MPIAIJSELL);
    124:   *newmat = B;
    125:   return(0);
    126: }

    128: PETSC_EXTERN PetscErrorCode MatCreate_MPIAIJSELL(Mat A)
    129: {

    133:   MatSetType(A,MATMPIAIJ);
    134:   MatConvert_MPIAIJ_MPIAIJSELL(A,MATMPIAIJSELL,MAT_INPLACE_MATRIX,&A);
    135:   return(0);
    136: }

    138: /*MC
    139:    MATAIJSELL - MATAIJSELL = "AIJSELL" - A matrix type to be used for sparse matrices.

    141:    This matrix type is identical to MATSEQAIJSELL when constructed with a single process communicator,
    142:    and MATMPIAIJSELL otherwise.  As a result, for single process communicators,
    143:    MatSeqAIJSetPreallocation() is supported, and similarly MatMPIAIJSetPreallocation() is supported
    144:    for communicators controlling multiple processes.  It is recommended that you call both of
    145:    the above preallocation routines for simplicity.

    147:    Options Database Keys:
    148: . -mat_type aijsell - sets the matrix type to "AIJSELL" during a call to MatSetFromOptions()

    150:   Level: beginner

    152: .seealso: MatCreateMPIAIJSELL(), MATSEQAIJSELL, MATMPIAIJSELL
    153: M*/