Contents
zcscmm - compressed sparse column format matrix-matrix
multiply
SUBROUTINE ZCSCMM( 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)
DOUBLE COMPLEX ALPHA, BETA
DOUBLE COMPLEX VAL(NNZ), B(LDB,*), C(LDC,*), WORK(LWORK)
SUBROUTINE ZCSCMM_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)
DOUBLE COMPLEX ALPHA, BETA
DOUBLE COMPLEX 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
DOUBLE COMPLEX ALPHA, BETA
DOUBLE COMPLEX, DIMENSION(:) :: VAL
DOUBLE COMPLEX, 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
DOUBLE COMPLEX ALPHA, BETA
DOUBLE COMPLEX, DIMENSION(:) :: VAL
DOUBLE 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 compressed 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 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
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() scalar array of length NNZ consisting of nonzero
entries of A.
INDX() integer array of length NNZ consisting of the row
indices of nonzero entries of A.
PNTRB() 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.
PNTRE() integer array of length K such that PNTRE(J)-PNTRB(1)
points to location in VAL of the last nonzero element
in column J.
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
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 )