Contents


NAME

     dcsrmm - compressed sparse row format matrix-matrix multiply

SYNOPSIS

       SUBROUTINE DCSRMM( TRANSA, M, N, K, ALPHA, DESCRA,
      *           VAL, INDX, PNTRB, PNTRE,
      *           B, LDB, BETA, C, LDC, WORK, LWORK)
       INTEGER    TRANSA, M, N, K, DESCRA(5),
      *           LDB, LDC, LWORK
       INTEGER    INDX(NNZ), PNTRB(M), PNTRE(M)
       DOUBLE PRECISION ALPHA, BETA
       DOUBLE PRECISION VAL(NNZ), B(LDB,*), C(LDC,*), WORK(LWORK)

       SUBROUTINE DCSRMM_64( TRANSA, M, N, K, ALPHA, DESCRA,
      *           VAL, INDX, PNTRB, PNTRE,
      *           B, LDB, BETA, C, LDC, WORK, LWORK)
       INTEGER*8  TRANSA, M, N, K, DESCRA(5),
      *           LDB, LDC, LWORK
       INTEGER*8  INDX(NNZ), PNTRB(M), PNTRE(M)
       DOUBLE PRECISION ALPHA, BETA
       DOUBLE PRECISION VAL(NNZ), B(LDB,*), C(LDC,*), WORK(LWORK)

       where NNZ = PNTRE(M)-PNTRB(1)

     F95 INTERFACE

       SUBROUTINE CSRMM( TRANSA, M, [N], K, ALPHA, DESCRA, VAL, INDX,
      *   PNTRB, PNTRE, B, [LDB], BETA, C, [LDC], [WORK], [LWORK] )
       INTEGER TRANSA, M, K
       INTEGER, DIMENSION(:) ::   DESCRA, INDX, PNTRB, PNTRE
       DOUBLE PRECISION    ALPHA, BETA
       DOUBLE PRECISION, DIMENSION(:) :: VAL
       DOUBLE PRECISION, DIMENSION(:, :) ::  B, C

       SUBROUTINE CSRMM_64( TRANSA, M, [N], K, ALPHA, DESCRA, VAL, INDX,
      *   PNTRB, PNTRE, B, [LDB], BETA, C, [LDC], [WORK], [LWORK] )
       INTEGER*8 TRANSA, M, K
       INTEGER*8, DIMENSION(:) ::   DESCRA, INDX, PNTRB, PNTRE
       DOUBLE PRECISION    ALPHA, BETA
       DOUBLE PRECISION, DIMENSION(:) :: VAL
       DOUBLE PRECISION, DIMENSION(:, :) ::  B, C

     C INTERFACE

     #include <sunperf.h>

     void dcsrmm(int transa, int m, int n, int k, double alpha,
     int *descra, double *val, int *indx, int *pntrb, int *pntre,
     double *b, int ldb, double beta, double *c, int ldc);
     void  dcsrmm_64(long transa, long m, long n, long  k, double
     alpha, long *descra, double *val, long *indx, long *pntrb,
     long *pntre, double *b, long ldb, double beta, double *c,
     long ldc);

DESCRIPTION

      dcsrmm 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 M-by-K sparse matrix represented in the compressed sparse row
      format, alpha and beta are scalars, C and B are dense matrices.

ARGUMENTS

      TRANSA(input)   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.

      M(input)        On entry,  M  specifies the number of 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.

      K(input)        On entry,  K specifies the number of 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 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
                      NNZ = PNTRE(M)-PNTRB(1) consisting of nonzero entries
                      of A. Unchanged on exit.

      INDX(input)     On entry, INDX is an integer array of length
                      NNZ = PNTRE(M)-PNTRB(1) consisting of the column
                      indices of nonzero entries of A. Unchanged on exit.

      PNTRB(input)    On entry, PNTRB is an integer array of length M such
                      that PNTRB(J)-PNTRB(1)+1 points to location in VAL
                      of the first nonzero element in row J.
                      Unchanged on exit.

      PNTRE(input)    On entry, PNTRE is an integer array of length M
                      such that PNTRE(J)-PNTRB(1) points to location
                      in VAL of the last nonzero element in row J.
                      Unchanged on exit.

      B (input)       Array of DIMENSION ( LDB, N ).
                      Before entry with  TRANSA = 0,  the leading  k by n
                      part of the array  B  must contain the matrix  B,  otherwise
                      the leading  m 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  m by n
                      part of the array  C  must contain the matrix C,  otherwise
                      the leading  k 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  triangles and/or the main
     diagonal of A. The full description of the feature for point
     entry formats is given in section NOTES/BUGS for the scoomm
     manpage.

NOTES/BUGS
     It is known that there exists another representation of the
     compressed sparse row format (see for example Y.Saad,
     "Iterative Methods for Sparse Linear Systems", WPS, 1996).
     Its data structure consists of three array instead of the
     four used in the current implementation.  The main
     difference is that only one array, IA, containing the
     pointers to the beginning of each row in the arrays VAL and
     INDX is used instead of two arrays PNTRB and PNTRE. To use
     the routine with this kind of compressed sparse row format
     the following calling sequence should be used

       SUBROUTINE DCSRMM( TRANSA, M, N, K, ALPHA, DESCRA,
      *           VAL, INDX, IA, IA(2), B, LDB, BETA,
      *           C, LDC, WORK, LWORK )