Contents
cskymm - Skyline format matrix-matrix multiply
SUBROUTINE CSKYMM( 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(*),
COMPLEX ALPHA, BETA
COMPLEX VAL(NNZ), B(LDB,*), C(LDC,*), WORK(LWORK)
SUBROUTINE CSKYMM_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(*),
COMPLEX ALPHA, BETA
COMPLEX 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
COMPLEX ALPHA, BETA
COMPLEX, DIMENSION(:) :: VAL
COMPLEX, 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
COMPLEX ALPHA, BETA
COMPLEX, DIMENSION(:) :: VAL
COMPLEX, 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 skyline 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 is real.
M Number of rows in matrix A
N Number of columns in matrix C
K Number of columns in matrix A
ALPHA Scalar parameter
DESCRA() 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() array contain the nonzeros of A in skyline profile form.
Row-oriented if DESCRA(2) = 1 (lower triangular),
column oriented if DESCRA(2) = 2 (upper triangular).
PNTR() 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.
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
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