scscmm(3P) Sun Performance Library scscmm(3P)NAMEscscmm - compressed sparse column format matrix-matrix multiply
SYNOPSIS
SUBROUTINE SCSCMM( 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(K), PNTRE(K)
REAL ALPHA, BETA
REAL VAL(NNZ), B(LDB,*), C(LDC,*), WORK(LWORK)
SUBROUTINE SCSCMM_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(K), PNTRE(K)
REAL ALPHA, BETA
REAL VAL(NNZ), B(LDB,*), C(LDC,*), WORK(LWORK)
where NNZ = PNTRE(K)-PNTRB(1)
F95 INTERFACE
SUBROUTINE CSCMM( 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
REAL ALPHA, BETA
REAL, DIMENSION(:) :: VAL
REAL, DIMENSION(:, :) :: B, C
SUBROUTINE CSCMM_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
REAL ALPHA, BETA
REAL, DIMENSION(:) :: VAL
REAL, DIMENSION(:, :) :: B, C
C INTERFACE
#include <sunperf.h>
void scscmm (const int transa, const int m, const int n, const int k,
const float alpha, const int* descra, const float* val, const
int* indx, const int* pntrb, const int* pntre, const float*
b, const int ldb, const float beta, float* c, const int ldc);
void scscmm_64 (const long transa, const long m, const long n, const
long k, const float alpha, const long* descra, const float*
val, const long* indx, const long* pntrb, const long* pntre,
const float* b, const long ldb, const float beta, float* c,
const long ldc);
DESCRIPTIONscscmm 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 column
format, alpha and beta are scalars, C and B are dense matrices.
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.
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(K)-PNTRB(1) consisting of nonzero
entries of A. Unchanged on exit.
INDX(input) On entry, INDX is an integer array of length
NNZ = PNTRE(K)-PNTRB(1) consisting of the row
indices of nonzero entries of A.
Unchanged on exit.
PNTRB(input) On entry, PNTRB is an integer array of length K
such that PNTRB(J)-PNTRB(1)+1 points to location
in VAL of the first nonzero element in column J.
Unchanged on exit.
PNTRE(input) On entry, PNTRE is an integer array of length K
such that PNTRE(J)-PNTRB(1) points to location
in VAL of the last nonzero element in column 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 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 trian‐
gles and/or the main diagonal of A. The full description of the feature
for point entry formats in the case of real sparse matrices is given
in the manpage for the scoomm manpage.
NOTES/BUGS
It is known that there exists another representation of the compressed
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 column in the arrays VAL and INDX is used
instead of two arrays PNTRB and PNTRE. To use the routine with this
kind of sparse column format the following calling sequence should be
used
SUBROUTINE SCSCMM( TRANSA, M, N, K, ALPHA, DESCRA,
* VAL, INDX, IA, IA(2), B, LDB, BETA,
* C, LDC, WORK, LWORK )
3rd Berkeley Distribution 6 Mar 2009 scscmm(3P)