HP MLIB User's Guide Vol. 1 7th Ed.

Chapter 4 Sparse BLAS Operations 481
Compressed sparse column matrix-matrix multiply SCSCMM/DCSCMM/CCSCMM/ZCSCMM
Name SCSCMM/DCSCMM/CCSCMM/ZCSCMM
Compressed sparse column matrix-matrix multiply
Purpose Compressed sparse column matrix-matrix multiply. These subprograms
compute the matrix-matrix product AB, where A is a m-by-k sparse matrix, and
B is a k-by-n matrix. Optionally, A may be replaced by A
T
or A*, where A
T
or A*
is a k-by-m matrix, and B is a m-by-n matrix. Here A
T
is the transpose and A*
is the conjugate-transpose of A. The product may be stored in the result matrix
C or optionally may be added to or subtracted from it. This is handled in a
convenient, but general way by two scalar arguments, α and β, which are used
as multipliers of the matrix product and the result matrix. Specifically, these
subprograms compute matrix products of the form
Usage VECLIB:
SUBROUTINE SCSCMM
INTEGER*4 transa, m, n, k, ldb, ldc, lwork
INTEGER*4 descra(*), indx(*), pntrb(*), pntre(*)
REAL*4 alpha, beta
REAL*4 val(*), b(ldb,*), c(ldc,*), work(*)
CALL SCSCMM (transa, m, n, k, alpha, descra, val, indx, pntrb, pntre, b,
ldb, beta, c, ldc, work, lwork)
SUBROUTINE DCSCMM
INTEGER*4 transa, m, n, k, ldb, ldc, lwork
INTEGER*4 descra(*), indx(*), pntrb(*), pntre(*)
REAL*8 alpha, beta
REAL*8 val(*), b(ldb,*), c(ldc,*), work(*)
CALL DCSCMM (transa, m, n, k, alpha, descra, val, indx, pntrb, pntre, b,
ldb, beta, c, ldc, work, lwork)
SUBROUTINE CCSCMM
INTEGER*4 transa, m, n, k, ldb, ldc, lwork
INTEGER*4 descra(*), indx(*), pntrb(*), pntre(*)
COMPLEX*8 alpha, beta
COMPLEX*8 val(*), b(ldb,*), c(ldc,*), work(*)
CALL CCSCMM (transa, m, n, k, alpha, descra, val, indx, pntrb, pntre, b,
ldb, beta, c, ldc, work, lwork)
C ←αAB +βC
C ←αA
T
B +βC
C ←αA
∗
B +βC