Contents
dbsrmm - block sparse row format matrix-matrix multiply
SUBROUTINE DBSRMM( TRANSA, MB, N, KB, ALPHA, DESCRA,
* VAL, BINDX, BPNTRB, BPNTRE, LB,
* B, LDB, BETA, C, LDC, WORK, LWORK)
INTEGER TRANSA, MB, N, KB, DESCRA(5), LB,
* LDB, LDC, LWORK
INTEGER BINDX(BNNZ), BPNTRB(MB), BPNTRE(MB)
DOUBLE PRECISION ALPHA, BETA
DOUBLE PRECISION VAL(LB*LB*BNNZ), B(LDB,*), C(LDC,*), WORK(LWORK)
SUBROUTINE DBSRMM_64( TRANSA, MB, N, KB, ALPHA, DESCRA,
* VAL, BINDX, BPNTRB, BPNTRE, LB,
* B, LDB, BETA, C, LDC, WORK, LWORK)
INTEGER*8 TRANSA, MB, N, KB, DESCRA(5), LB,
* LDB, LDC, LWORK
INTEGER*8 BINDX(BNNZ), BPNTRB(MB), BPNTRE(MB)
DOUBLE PRECISION ALPHA, BETA
DOUBLE PRECISION VAL(LB*LB*BNNZ), B(LDB,*), C(LDC,*), WORK(LWORK)
where: BNNZ = BPNTRE(MB)-BPNTRB(1)
F95 INTERFACE
SUBROUTINE BSRMM( TRANSA, MB, [N], KB, ALPHA, DESCRA, VAL, BINDX,
* BPNTRB, BPNTRE, LB, B, [LDB], BETA, C, [LDC], [WORK], [LWORK])
INTEGER TRANSA, MB, KB, LB
INTEGER, DIMENSION(:) :: DESCRA, BINDX, BPNTRB, BPNTRE
DOUBLE PRECISION ALPHA, BETA
DOUBLE PRECISION, DIMENSION(:) :: VAL
DOUBLE PRECISION, DIMENSION(:, :) :: B, C
SUBROUTINE BSRMM_64( TRANSA, MB, [N], KB, ALPHA, DESCRA, VAL, BINDX,
* BPNTRB, BPNTRE, LB, B, [LDB], BETA, C, [LDC], [WORK], [LWORK])
INTEGER*8 TRANSA, MB, KB, LB
INTEGER*8, DIMENSION(:) :: DESCRA, BINDX, BPNTRB, BPNTRE
DOUBLE PRECISION ALPHA, BETA
DOUBLE PRECISION, DIMENSION(:) :: VAL
DOUBLE PRECISION, DIMENSION(:, :) :: B, C
C <- alpha op(A) B + beta C
where ALPHA and BETA are scalar, C and B are dense matrices,
A is a matrix represented in block sparse row format and
op( A ) is one of
op( A ) = A or op( A ) = A' or op( A ) = conjg( A' ).
( ' indicates matrix transpose)
TRANSA Indicates how to operate with the sparse matrix
0 : operate with matrix
1 : operate with transpose matrix
2 : operate with the conjugate transpose of matrix.
2 is equivalent to 1 if matrix A is real.
MB Number of block rows in matrix A
N Number of columns in matrix C
KB Number of block columns in matrix A
ALPHA Scalar parameter
DESCRA() 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() scalar array of length LB*LB*BNNZ consisting
of the block entries stored column-major within
each dense block.
BINDX() integer array of length BNNZ consisting of the
block column indices of the block entries of A.
BPNTRB() integer array of length MB such that
BPNTRB(J)-BPNTRB(1)+1 points to location in BINDX
of the first block entry of the J-th block row of A.
BPNTRE() integer array of length MB such that
BPNTRE(J)-BPNTRB(1) points to location in BINDX
of the last block entry of the J-th block row of A.
LB dimension of dense blocks composing A.
B() rectangular array with first dimension LDB.
LDB leading dimension of B
BETA Scalar parameter
C() rectangular array with first dimension LDC.
LDC leading dimension of C
WORK() scratch array of length LWORK. WORK is not
referenced in the current version.
LWORK length of WORK array. LWORK is not referenced
in the current version.
NIST FORTRAN Sparse Blas User's Guide available at:
http://math.nist.gov/mcsd/Staff/KRemington/fspblas/
"Document for the Basic Linear Algebra Subprograms (BLAS)
Standard", University of Tennessee, Knoxville, Tennessee,
1996:
http://www.netlib.org/utk/papers/sparse.ps
NOTES/BUGS
It is known that there exists another representation of the
block 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 block row in the arrays VAL and BINDX is used
instead of two arrays BPNTRB and BPNTRE. To use the routine
with this kind of block sparse row format the following
calling sequence should be used
CALL SBSRMM( TRANSA, MB, N, KB, ALPHA, DESCRA,
* VAL, BINDX, IA, IA(2), LB,
* B, LDB, BETA, C, LDC, WORK, LWORK )