TESTING/LIN/dlavsy.f(3)    Library Functions Manual    TESTING/LIN/dlavsy.f(3)

NAME
       TESTING/LIN/dlavsy.f

SYNOPSIS
   Functions/Subroutines
       subroutine dlavsy (uplo, trans, diag, n, nrhs, a, lda, ipiv, b, ldb,
           info)
           DLAVSY

Function/Subroutine Documentation
   subroutine dlavsy (character uplo, character trans, character diag, integer
       n, integer nrhs, double precision, dimension( lda, * ) a, integer lda,
       integer, dimension( * ) ipiv, double precision, dimension( ldb, * ) b,
       integer ldb, integer info)
       DLAVSY

       Purpose:


            DLAVSY  performs one of the matrix-vector operations
               x := A*x  or  x := A'*x,
            where x is an N element vector and A is one of the factors
            from the block U*D*U' or L*D*L' factorization computed by DSYTRF.

            If TRANS = 'N', multiplies by U  or U * D  (or L  or L * D)
            If TRANS = 'T', multiplies by U' or D * U' (or L' or D * L')
            If TRANS = 'C', multiplies by U' or D * U' (or L' or D * L')

       Parameters
           UPLO

                     UPLO is CHARACTER*1
                     Specifies whether the factor stored in A is upper or lower
                     triangular.
                     = 'U':  Upper triangular
                     = 'L':  Lower triangular

           TRANS

                     TRANS is CHARACTER*1
                     Specifies the operation to be performed:
                     = 'N':  x := A*x
                     = 'T':  x := A'*x
                     = 'C':  x := A'*x

           DIAG

                     DIAG is CHARACTER*1
                     Specifies whether or not the diagonal blocks are unit
                     matrices.  If the diagonal blocks are assumed to be unit,
                     then A = U or A = L, otherwise A = U*D or A = L*D.
                     = 'U':  Diagonal blocks are assumed to be unit matrices.
                     = 'N':  Diagonal blocks are assumed to be non-unit matrices.

           N

                     N is INTEGER
                     The number of rows and columns of the matrix A.  N >= 0.

           NRHS

                     NRHS is INTEGER
                     The number of right hand sides, i.e., the number of vectors
                     x to be multiplied by A.  NRHS >= 0.

           A

                     A is DOUBLE PRECISION array, dimension (LDA,N)
                     The block diagonal matrix D and the multipliers used to
                     obtain the factor U or L as computed by DSYTRF.
                     Stored as a 2-D triangular matrix.

           LDA

                     LDA is INTEGER
                     The leading dimension of the array A.  LDA >= max(1,N).

           IPIV

                     IPIV is INTEGER array, dimension (N)
                     Details of the interchanges and the block structure of D,
                     as determined by DSYTRF.

                     If UPLO = 'U':
                          If IPIV(k) > 0, then rows and columns k and IPIV(k)
                          were interchanged and D(k,k) is a 1-by-1 diagonal block.
                          (If IPIV( k ) = k, no interchange was done).

                          If IPIV(k) = IPIV(k-1) < 0, then rows and
                          columns k-1 and -IPIV(k) were interchanged,
                          D(k-1:k,k-1:k) is a 2-by-2 diagonal block.

                     If UPLO = 'L':
                          If IPIV(k) > 0, then rows and columns k and IPIV(k)
                          were interchanged and D(k,k) is a 1-by-1 diagonal block.
                          (If IPIV( k ) = k, no interchange was done).

                          If IPIV(k) = IPIV(k+1) < 0, then rows and
                          columns k+1 and -IPIV(k) were interchanged,
                          D(k:k+1,k:k+1) is a 2-by-2 diagonal block.

           B

                     B is DOUBLE PRECISION array, dimension (LDB,NRHS)
                     On entry, B contains NRHS vectors of length N.
                     On exit, B is overwritten with the product A * B.

           LDB

                     LDB is INTEGER
                     The leading dimension of the array B.  LDB >= max(1,N).

           INFO

                     INFO is INTEGER
                     = 0: successful exit
                     < 0: if INFO = -k, the k-th argument had an illegal value

       Author
           Univ. of Tennessee

           Univ. of California Berkeley

           Univ. of Colorado Denver

           NAG Ltd.

       Definition at line 153 of file dlavsy.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

LAPACK                          Version 3.12.0         TESTING/LIN/dlavsy.f(3)