NAME

jadsm, sjadsm, djadsm, cjadsm, zjadsm - Jagged-diagonal format triangular solve


SYNOPSIS

  SUBROUTINE SJADSM( TRANSA, M, N, UNITD, DV, ALPHA, DESCRA,
 *           VAL, INDX, PNTR, MAXNZ, IPERM,
 *           B, LDB, BETA, C, LDC, WORK, LWORK )
  INTEGER*4  TRANSA, M, N, UNITD, DESCRA(5), MAXNZ,
 *           LDB, LDC, LWORK
  INTEGER*4  INDX(NNZ), PNTR(MAXNZ+1), IPERM(M)
  REAL*4     ALPHA, BETA
  REAL*4     DV(M), VAL(NNZ), B(LDB,*), C(LDC,*), WORK(LWORK)
  SUBROUTINE DJADSM( TRANSA, M, N, UNITD, DV, ALPHA, DESCRA,
 *           VAL, INDX, PNTR, MAXNZ, IPERM,
 *           B, LDB, BETA, C, LDC, WORK, LWORK)
  INTEGER*4  TRANSA, M, N, UNITD, DESCRA(5), MAXNZ,
 *           LDB, LDC, LWORK
  INTEGER*4  INDX(NNZ), PNTR(MAXNZ+1), IPERM(M)
  REAL*8     ALPHA, BETA
  REAL*8     DV(M), VAL(NNZ), B(LDB,*), C(LDC,*), WORK(LWORK)
  SUBROUTINE CJADSM( TRANSA, M, N, UNITD, DV, ALPHA, DESCRA,
 *           VAL, INDX, PNTR, MAXNZ, IPERM,
 *           B, LDB, BETA, C, LDC, WORK, LWORK )
  INTEGER*4  TRANSA, M, N, UNITD, DESCRA(5), MAXNZ,
 *           LDB, LDC, LWORK
  INTEGER*4  INDX(NNZ), PNTR(MAXNZ+1), IPERM(M)
  COMPLEX*8  ALPHA, BETA
  COMPLEX*8  DV(M), VAL(NNZ), B(LDB,*), C(LDC,*), WORK(LWORK)
  SUBROUTINE ZJADSM( TRANSA, M, N, UNITD, DV, ALPHA, DESCRA,
 *           VAL, INDX, PNTR, MAXNZ, IPERM,
 *           B, LDB, BETA, C, LDC, WORK, LWORK)
  INTEGER*4  TRANSA, M, N, UNITD, DESCRA(5), MAXNZ,
 *           LDB, LDC, LWORK
  INTEGER*4  INDX(NNZ), PNTR(MAXNZ+1), IPERM(M)
  COMPLEX*16 ALPHA, BETA
  COMPLEX*16 DV(M), VAL(NNZ), B(LDB,*), C(LDC,*), WORK(LWORK)


DESCRIPTION

   C <- ALPHA  op(A) B + BETA C     C <- ALPHA D op(A) B + BETA C
   C <- ALPHA op(A) D B + BETA C
 where ALPHA and BETA are scalar, C and B are m by n dense matrices,
 D is a diagonal scaling matrix,  A is a unit, or non-unit, upper or 
 lower triangular matrix represented in jagged-diagonal format and    
 op( A )  is one  of
  op( A ) = inv(A) or  op( A ) = inv(A')  or  op( A ) =inv(conjg( A' )) 
  (inv denotes matrix inverse,  ' indicates matrix transpose)


ARGUMENTS

 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
 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 of length M containing the diagonal entries of the
               scaling diagonal matrix D.
 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'))
               Note: For the routine, DESCRA(1)=3 is only supported.
               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 of length NNZ consisting of entries of A.
               VAL can be viewed as a column major ordering of a    
               row permutation of the Ellpack representation of A, 
               where the Ellpack representation is permuted so that
               the rows are non-increasing in the number of nonzero
               entries.  Values added for padding in Ellpack are
               not included in the Jagged-Diagonal format.
 INDX()        array of length NNZ consisting of the column indices
               of the corresponding entries in VAL.
 PNTR()        array of length MAXNZ+1, where PNTR(I)-PNTR(1)+1
               points to the location in VAL of the first element
               in the row-permuted Ellpack represenation of A.
 MAXNZ         max number of nonzeros elements per row.
 IPERM()       integer array of length M such that I = IPERM(I'), 
               where row I in the original Ellpack representation
               corresponds to row I' in the permuted representation. 
               If IPERM(1)=0,   it's assumed by convention that
               IPERM(I)=I. IPERM is used to determine the order 
               in which rows of C are updated.

 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.
               On exit,  if LWORK = -1, WORK(1) returns the optimum LWORK.
 LWORK         length of WORK array.  LWORK should be at least 2*M.

               For good performance, LWORK should generally be larger.
               For optimum performance on multiple processors, LWORK 
               >=2*M*N_CPUS where N_CPUS is the maximum number of 
               processors available to the program.
               If LWORK=0, the routine is to allocate workspace needed.

               If LWORK = -1, then a workspace query is assumed; the
               routine only calculates the optimum size of the WORK
               array, returns this value as the first entry of the WORK
               array, and no error message related to LWORK is issued
               by XERBLA.


SEE ALSO

NIST FORTRAN Sparse Blas User's Guide available at:

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


NOTES/BUGS

No test for singularity or near-singularity is included in this routine. Such tests must be performed before calling this routine.