Contents
dbscmm - block sparse column matrix-matrix multiply
SUBROUTINE DBSCMM( 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(KB), BPNTRE(KB)
DOUBLE PRECISION ALPHA, BETA
DOUBLE PRECISION VAL(LB*LB*BNNZ), B(LDB,*), C(LDC,*), WORK(LWORK)
SUBROUTINE DBSCMM_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(KB), BPNTRE(KB)
DOUBLE PRECISION ALPHA, BETA
DOUBLE PRECISION VAL(LB*LB*BNNZ), B(LDB,*), C(LDC,*), WORK(LWORK)
where: BNNZ = BPNTRE(KB)-BPNTRB(1)
F95 INTERFACE
SUBROUTINE BSCMM( 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 BSCMM_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 INTERFACE
#include <sunperf.h>
void dbscmm(int transa, int mb, int n, int kb,
double alpha, int *descra, double *val,
int *bindx, int *bpntrb, int *bpntre, int lb, double *b,
int ldb, double beta, double *c, int ldc);
void dbscmm_64(long transa, long mb, long n, long kb,
double alpha, long *descra, double *val, long *bindx, long
*bpntrb, long *bpntre, long lb, double *b, long ldb, double
beta, double *c, long ldc);
dbscmm performs one of the matrix-matrix operations
C <- alpha op(A) B + beta C
where alpha and beta are scalars, C and B are dense matrices,
A is an (mb*lb) by (kb*lb) sparse matrix represented in
block sparse column format and op( A ) is one of
op( A ) = A or op( A ) = A' or op( A ) = conjg( A' ).
( ' indicates matrix transpose)
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.
MB(input) On entry, 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, 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 stored
column-major within each dense block where
BNNZ = BPNTRE(KB)-BPNTRB(1). Unchanged on exit.
BINDX(input) On entry, BINDX is an integer array of length BNNZ consisting
of the block row indices of the block entries of A where
BNNZ = BPNTRE(KB)-BPNTRB(1). Unchanged on exit.
BPNTRB(input) On entry, BPNTRB is an integer array of length KB such
that BPNTRB(J)-BPNTRB(1)+1 points to location in BINDX
of the first block entry of the J-th block column
of A. Unchanged on exit.
BPNTRE(input) On entry, BPNTRE is an integer array of length KB such
that BPNTRE(J)-BPNTRB(1) points to location in BINDX
of the last block entry of the J-th block column
of A. Unchanged on exit.
LB (input) On entry, 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)
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.
NOTES/BUGS
It is known that there exists another representation of the
block sparse column 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 column 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
column format the following calling sequence should be used
CALL SBSCMM( TRANSA, MB, N, KB, ALPHA, DESCRA,
* VAL, BINDX, IA, IA(2), LB,
* B, LDB, BETA, C, LDC, WORK, LWORK )