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## dtrttp()

subroutine dtrttp | ( | character | uplo,
|  | integer | n,
|  | double precision, dimension( lda, * ) | a,
|  | integer | lda,
|  | double precision, dimension( * ) | ap,
|  | integer | info )

DTRTTP copies a triangular matrix from the standard full format (TR) to the standard packed format (TP).

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

Purpose:

      !>
      !> DTRTTP copies a triangular matrix A from full format (TR) to standard
      !> packed format (TP).
      !>

Parameters

  [in]

  UPLO

      !>          UPLO is CHARACTER*1
      !>          = 'U':  A is upper triangular.
      !>          = 'L':  A is lower triangular.
      !>

  [in]

  N

      !>          N is INTEGER
      !>          The order of the matrices AP and A.  N >= 0.
      !>

  [in]

  A

      !>          A is DOUBLE PRECISION array, dimension (LDA,N)
      !>          On exit, the triangular matrix A.  If UPLO = 'U', the leading
      !>          N-by-N upper triangular part of A contains the upper
      !>          triangular part of the matrix A, and the strictly lower
      !>          triangular part of A is not referenced.  If UPLO = 'L', the
      !>          leading N-by-N lower triangular part of A contains the lower
      !>          triangular part of the matrix A, and the strictly upper
      !>          triangular part of A is not referenced.
      !>

  [in]

  LDA

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

  [out]

  AP

      !>          AP is DOUBLE PRECISION array, dimension (N*(N+1)/2)
      !>          On exit, the upper or lower triangular matrix A, packed
      !>          columnwise in a linear array. The j-th column of A is stored
      !>          in the array AP as follows:
      !>          if UPLO = 'U', AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j;
      !>          if UPLO = 'L', AP(i + (j-1)*(2n-j)/2) = A(i,j) for j<=i<=n.
      !>

  [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.