Contents
dskymm - Skyline format matrix-matrix multiply
SUBROUTINE DSKYMM( TRANSA, M, N, K, ALPHA, DESCRA,
* VAL, PNTR,
* B, LDB, BETA, C, LDC, WORK, LWORK)
INTEGER TRANSA, M, N, K, DESCRA(5),
* LDB, LDC, LWORK
INTEGER PNTR(*),
DOUBLE PRECISION ALPHA, BETA
DOUBLE PRECISION VAL(NNZ), B(LDB,*), C(LDC,*), WORK(LWORK)
SUBROUTINE DSKYMM_64( TRANSA, M, N, K, ALPHA, DESCRA,
* VAL, PNTR,
* B, LDB, BETA, C, LDC, WORK, LWORK)
INTEGER*8 TRANSA, M, N, K, DESCRA(5),
* LDB, LDC, LWORK
INTEGER*8 PNTR(*),
DOUBLE PRECISION ALPHA, BETA
DOUBLE PRECISION VAL(NNZ), B(LDB,*), C(LDC,*), WORK(LWORK)
where NNZ = PNTR(K+1)-PNTR(1) (upper triangular)
NNZ = PNTR(M+1)-PNTR(1) (lower triangular)
PNTR() size = (K+1) (upper triangular)
PNTR() size = (M+1) (lower triangular)
F95 INTERFACE
SUBROUTINE SKYMM( TRANSA, M, [N], K, ALPHA, DESCRA, VAL,
* PNTR, B, [LDB], BETA, C, [LDC], [WORK], [LWORK])
INTEGER TRANSA, M, K
INTEGER, DIMENSION(:) :: DESCRA, PNTR
DOUBLE PRECISION ALPHA, BETA
DOUBLE PRECISION, DIMENSION(:) :: VAL
DOUBLE PRECISION, DIMENSION(:, :) :: B, C
SUBROUTINE SKYMM_64( TRANSA, M, [N], K, ALPHA, DESCRA, VAL,
* PNTR, B, [LDB], BETA, C, [LDC], [WORK], [LWORK])
INTEGER*8 TRANSA, M, K
INTEGER*8, DIMENSION(:) :: DESCRA, PNTR
DOUBLE PRECISION ALPHA, BETA
DOUBLE PRECISION, DIMENSION(:) :: VAL
DOUBLE PRECISION, DIMENSION(:, :) :: B, C
C INTERFACE
#include <sunperf.h>
void dskymm (int transa, int m, int n, int k, double alpha,
int *descra, double *val, int *pntr, double *b, int ldb,
double beta, double *c, int ldc);
void dskymm_64 (long transa, long m, long n, long k,
double alpha, long *descra, double *val, long *pntr,
double *b, long ldb, double beta, double *c, long ldc);
dskymm 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 skyline format,
alpha and beta are scalars, C and B are dense matrices.
TRANSA(input) On entry, integer 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, integer M specifies the number of rows in
the matrix A. Unchanged on exit.
N(input) On entry, integer N specifies the number of columns in
the matrix C. Unchanged on exit.
K(input) On entry, integer 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 (NOT SUPPORTED)
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 consisting of
the nonzeros of A in skyline profile form.
Row-oriented if DESCRA(2) = 1 (lower triangular),
column oriented if DESCRA(2) = 2 (upper triangular).
Unchanged on exit.
PNTR (input) On entry, INDX is an integer array of length
M+1 (lower triangular) or K+1 (upper triangular)
such that PNTR(I)-PNTR(1)+1 points to the
location in VAL of the first element of the skyline
profile in row (column) I. 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)
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
NOTES/BUGS
The SKY data structure is not supported for a general matrix
structure (DESCRA(1)=0).
Also not supported:
1. lower triangular matrix A of size m by n where m > n
2. upper triangular matrix A of size m by n where m < n