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## ssyconv()

subroutine ssyconv | ( | character | uplo,
|  | character | way,
|  | integer | n,
|  | real, dimension( lda, * ) | a,
|  | integer | lda,
|  | integer, dimension( * ) | ipiv,
|  | real, dimension( * ) | e,
|  | integer | info )

SSYCONV

Download SSYCONV + dependencies [TGZ] [ZIP] [TXT]

Purpose:

      !>
      !> SSYCONV convert A given by TRF into L and D and vice-versa.
      !> Get Non-diag elements of D (returned in workspace) and
      !> apply or reverse permutation done in TRF.
      !>

Parameters

  [in]

  UPLO

      !>          UPLO is CHARACTER*1
      !>          Specifies whether the details of the factorization are stored
      !>          as an upper or lower triangular matrix.
      !>          = 'U':  Upper triangular, form is A = U*D*U**T;
      !>          = 'L':  Lower triangular, form is A = L*D*L**T.
      !>

  [in]

  WAY

      !>          WAY is CHARACTER*1
      !>          = 'C': Convert
      !>          = 'R': Revert
      !>

  [in]

  N

      !>          N is INTEGER
      !>          The order of the matrix A.  N >= 0.
      !>

  [in,out]

  A

      !>          A is REAL array, dimension (LDA,N)
      !>          The block diagonal matrix D and the multipliers used to
      !>          obtain the factor U or L as computed by SSYTRF.
      !>

  [in]

  LDA

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

  [in]

  IPIV

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

  [out]

  E

      !>          E is REAL array, dimension (N)
      !>          E stores the supdiagonal/subdiagonal of the symmetric 1-by-1
      !>          or 2-by-2 block diagonal matrix D in LDLT.
      !>

  [out]

  INFO

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

Author
  Univ. of Tennessee
  Univ. of California Berkeley
  Univ. of Colorado Denver
  NAG Ltd.