Contents


NAME

     dbcomm - block coordinate matrix-matrix multiply

SYNOPSIS

       SUBROUTINE DBCOMM( TRANSA, MB, N, KB, ALPHA, DESCRA,
      *           VAL, BINDX, BJNDX, BNNZ, LB,
      *           B, LDB, BETA, C, LDC, WORK, LWORK)
       INTEGER    TRANSA, MB, N, KB, DESCRA(5), BNNZ, LB,
      *           LDB, LDC, LWORK
       INTEGER    BINDX(BNNZ), BJNDX(BNNZ)
       DOUBLE PRECISION ALPHA, BETA
       DOUBLE PRECISION VAL(LB*LB*BNNZ), B(LDB,*), C(LDC,*), WORK(LWORK)

       SUBROUTINE DBCOMM_64( TRANSA, MB, N, KB, ALPHA, DESCRA,
      *           VAL, BINDX, BJNDX, BNNZ, LB,
      *           B, LDB, BETA, C, LDC, WORK, LWORK)
       INTEGER*8  TRANSA, MB, N, KB, DESCRA(5), BNNZ, LB,
      *           LDB, LDC, LWORK
       INTEGER*8  BINDX(BNNZ), BJNDX(BNNZ)
       DOUBLE PRECISION ALPHA, BETA
       DOUBLE PRECISION VAL(LB*LB*BNNZ), B(LDB,*), C(LDC,*), WORK(LWORK)

     F95 INTERFACE

        SUBROUTINE BCOMM(TRANSA,MB,[N],KB,ALPHA,DESCRA,VAL,BINDX, BJNDX,
      *   BNNZ, LB, B, [LDB], BETA, C,[LDC], [WORK], [LWORK])
       INTEGER    TRANSA, MB, N, KB, BNNZ, LB
       INTEGER, DIMENSION(:) ::   DESCRA, BINDX, BJNDX
       DOUBLE PRECISION    ALPHA, BETA
       DOUBLE PRECISION, DIMENSION(:) :: VAL
       DOUBLE PRECISION, DIMENSION(:, :) ::  B, C

        SUBROUTINE BCOMM_64(TRANSA,MB,[N],KB,ALPHA,DESCRA,VAL,BINDX, BJNDX,
      *   BNNZ, LB, B, [LDB], BETA, C,[LDC], [WORK], [LWORK])
       INTEGER*8    TRANSA, MB, N, KB, BNNZ, LB
       INTEGER*8, DIMENSION(:) ::   DESCRA, BINDX, BJNDX
       DOUBLE PRECISION    ALPHA, BETA
       DOUBLE PRECISION, DIMENSION(:) :: VAL
       DOUBLE PRECISION, DIMENSION(:, :) ::  B, C

     C INTERFACE

     #include <sunperf.h>

     void dbcomm (int transa, int mb, int n, int kb, double
     alpha, int* descra, double *val, int *bindx, int *bjndx, int
     bnnz, int lb, double *b, int ldb, double beta, double *c,
     int ldc);
     void dbcomm_64(long transa, long mb, long n, long kb, double
     alpha, long *descra, double *val, long *b indx, long *bjndx,
     long bnnz, long lb, double *b, long ldb,
      double beta, double *c, long ldc);

DESCRIPTION

      dbcomm performs one of the matrix-matrix operations

               C <- alpha op(A) B + beta C

      where op( A )  is one  of

      op( A ) = A   or   op( A ) = A'   or   op( A ) = conjg( A' )
                                         ( ' indicates matrix transpose),
      A is an (mb*lb) by (kb*lb) sparse matrix represented in the block
      coordinate format, alpha and beta are scalars, C and B are dense
      matrices.

ARGUMENTS

      TRANSA(input)   On entry, integer TRANSA specifies the form
                      of op( A ) to be used in the matrix
                      multiplication as follows:
                        0 : operate with matrix
                        1 : operate with transpose matrix
                        2 : operate with the conjugate transpose of matrix.
                          2 is equivalent to 1 if matrix is real.
                      Unchanged on exit.

      MB(input)       On entry, integer MB specifies the number of block rows
                      in the matrix A. Unchanged on exit.

      N(input)        On entry,  N specifies the number of columns
                      in the matrix C. Unchanged on exit.

      KB(input)       On entry, integer KB specifies the number of block
                      columns in the matrix A. Unchanged on exit.

      ALPHA(input)    On entry, ALPHA specifies the scalar alpha.
                      Unchanged on exit.
      DESCRA (input)  Descriptor argument.  Five element integer array:
                      DESCRA(1) matrix structure
                        0 : general
                        1 : symmetric (A=A')
                        2 : Hermitian (A= CONJG(A'))
                        3 : Triangular
                        4 : Skew(Anti)-Symmetric (A=-A')
                        5 : Diagonal
                        6 : Skew-Hermitian (A= -CONJG(A'))
                      DESCRA(2) upper/lower triangular indicator
                        1 : lower
                        2 : upper
                      DESCRA(3) main block diagonal type
                        0 : non-unit
                        1 : unit
                      DESCRA(4) Array base (NOT IMPLEMENTED)
                        0 : C/C++ compatible
                        1 : Fortran compatible
                      DESCRA(5) repeated indices? (NOT IMPLEMENTED)
                        0 : unknown
                        1 : no repeated indices

      VAL(input)      On entry,  VAL is a scalar array of length
                      LB*LB*BNNZ consisting of the non-zero block
                      entries of A, in any order. Each block
                      is stored in standard column-major form.
                      Unchanged on exit.

      BINDX(input)    On entry, BINDX is an integer array of length BNNZ
                      consisting of the block row indices of the non-zero
                      block entries of A. Unchanged on exit.

      BJNDX(input)    On entry, BJNDX is an integer array of length BNNZ
                      consisting of the block column indices of the non-zero
                      block entries of A. Unchanged on exit.

      BNNZ (input)    On entry, integer BNNZ specifies the number of nonzero
                      block entries in A. Unchanged on exit.

      LB (input)      On entry, integer LB specifies the  dimension of dense
                      blocks composing A.  Unchanged on exit.

      B (input)       Array of DIMENSION ( LDB, N ).
                      Before entry with  TRANSA = 0,  the leading  kb*lb by n
                      part of the array  B  must contain the matrix  B,  otherwise
                      the leading  mb*lb by n part of the array B must contain the
                      matrix B. Unchanged on exit.

      LDB (input)     On entry, LDB specifies the first dimension of B as declared
                      in the calling (sub) program. Unchanged on exit.

      BETA (input)    On entry, BETA specifies the scalar beta. Unchanged on exit.
      C(input/output) Array of DIMENSION ( LDC, N ).
                      Before entry with  TRANSA = 0,  the leading  mb*lb by n
                      part of the array  C  must contain the matrix C,  otherwise
                      the leading  kb*lb by n  part of the array C must contain the
                      matrix C. On exit, the array C is overwritten by the matrix
                      ( alpha*op( A )* B  + beta*C ).

      LDC (input)     On entry, LDC specifies the first dimension of C as declared
                      in the calling (sub) program. Unchanged on exit.

      WORK (is not referenced in the current version)

      LWORK (is not referenced in the current version)

SEE ALSO

     Libsunperf  SPARSE BLAS is fully parallel and compatible
     with NIST FORTRAN Sparse Blas but the sources are different.
     Libsunperf SPARSE BLAS is free of bugs found in NIST FORTRAN
     Sparse Blas.  Besides several new features and routines are
     implemented.

     NIST FORTRAN Sparse Blas User's Guide available at:

     http://math.nist.gov/mcsd/Staff/KRemington/fspblas/

     Based on the standard proposed in

     "Document for the Basic Linear Algebra Subprograms (BLAS)
     Standard", University of Tennessee, Knoxville, Tennessee,
     1996:

     http://www.netlib.org/utk/papers/sparse.ps

     The routine is designed so that it provides a possibility to
     use just one sparse matrix representation of a general
     matrix A for computing matrix-matrix multiply for another
     sparse matrix composed  by block triangles and/or the main
     block diagonal of A. The full description of the feature for
     block entry formats is given in section NOTES/BUGS for the
     sbcomm manpage.