bscsm


NAME

bscsm, sbscsm, dbscsm - block sparse column format triangular solve


SYNOPSIS

  SUBROUTINE SBSCSM( TRANSA, MB, N, UNITD, DV, ALPHA, DESCRA,
 *           VAL, BINDX, BPNTRB, BPNTRE, LB,
 *           B, LDB, BETA, C, LDC, WORK, LWORK )
  INTEGER*4  TRANSA, MB, N, UNITD, DESCRA(5), LB,
 *           LDB, LDC, LWORK
  INTEGER*4  BINDX(BNNZ), BPNTRB(KB), BPNTRE(KB)
  REAL*4     ALPHA, BETA
  REAL*4     DV(NDV), VAL(LB*LB*BNNZ), B(LDB,*), C(LDC,*), WORK(LWORK)
  SUBROUTINE DBSCSM( TRANSA, MB, N, UNITD, DV, ALPHA, DESCRA,
 *           VAL, BINDX, BPNTRB, BPNTRE, LB,
 *           B, LDB, BETA, C, LDC, WORK, LWORK)
  INTEGER*4  TRANSA, MB, N, UNITD, DESCRA(5), LB,
 *           LDB, LDC, LWORK
  INTEGER*4  BINDX(BNNZ), BPNTRB(KB), BPNTRE(KB)
  REAL*8     ALPHA, BETA
  REAL*8     DV(NDV), VAL(LB*LB*BNNZ), B(LDB,*), C(LDC,*), WORK(LWORK)
  where: BNNZ = BPNTRE(KB)- BPNTRB(1)


DESCRIPTION

 C <- alpha D inv(A) B + beta C    C <- alpha D inv(A') B + beta C
 C <- alpha inv(A) D B + beta C    C <- alpha inv(A') D B + beta C
                                    ( ' indicates matrix transpose)


ARGUMENTS

 TRANSA        Indicates how to operate with the sparse matrix
                 0 : operate with matrix
                 1 : operate with transpose matrix
 MB            Number of block rows in matrix A
 N             Number of columns in matrix C
 UNITD         Type of scaling:
                 1 : Identity matrix (argument DV[] is ignored)
                 2 : Scale on left (row scaling)
                 3 : Scale on right (column scaling)
 DV()          Array containing the diagonal entries of the (block)
               diagonal matrix D.
 ALPHA         Scalar parameter
 DESCRA()      Descriptor argument.  Five element integer array
               DESCRA(1) matrix structure
                 0 : general
                 1 : symmetric
                 2 : Hermitian
                 3 : Triangular
                 4 : Skew(Anti-Symmetric
                 5 : Diagonal
               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 containing matrix entries
               stored column-major within each dense block.
 BINDX()       integer array of length BNNZ consisting of the
               block row indices of the block entries of A.
 BPNTRB()      integer array of length KB such that 
               BPNTRB(J)-BPNTRB(1)+1 points to location in BINDX
               of the first block entry of the J-th block column of A.
 BPNTRE()      integer array of length KB such that 
               BPNTRE(J)-BPNTRE(1)+1 points to location in BINDX
               of the last block entry of the J-th block column of A.
 LB            dimension of dense blocks composing A.
 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.  LWORK should be at least
               MAX(MB*LB*LB,N).
 LWORK         length of WORK array


SEE ALSO

NIST FORTRAN Sparse Blas User's Guide available at:

http://math.nist.gov/mcsd/Staff/KRemington/fspblas/


NOTES/BUGS

The NIST FORTRAN Sparse BLAS are currently at version 0.5. Some features (including the ones so noted) may not yet be implemented.