dbscmm(3P) Sun Performance Library dbscmm(3P)NAMEdbscmm - block sparse column matrix-matrix multiply
SYNOPSIS
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 (const int transa, const int mb, const int n, const int kb,
const double alpha, const int* descra, const double* val,
const int* bindx, const int* bpntrb, const int* bpntre, const
int lb, const double* b, const int ldb, const double beta,
double* c, const int ldc);
void dbscmm_64 (const long transa, const long mb, const long n, const
long kb, const double alpha, const long* descra, const dou‐
ble* val, const long* bindx, const long* bpntrb, const long*
bpntre, const long lb, const double* b, const long ldb, const
double beta, double* c, const long ldc);
DESCRIPTIONdbscmm 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)
ARGUMENTSTRANSA(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)
SEE ALSO
Libsunperf SPARSE BLAS is fully parallel and compatible with NIST FOR‐
TRAN 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 )
3rd Berkeley Distribution 6 Mar 2009 dbscmm(3P)
