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Mise à jour de Lapack vers la version 3.3.0

    1:       SUBROUTINE DTRTTP( UPLO, N, A, LDA, AP, INFO )
    2: *
    3: *  -- LAPACK routine (version 3.3.0) --
    4: *  -- Contributed by Fred Gustavson of the IBM Watson Research Center --
    5: *  --            and Julien Langou of the Univ. of Colorado Denver    --
    6: *     November 2010
    7: *
    8: *  -- LAPACK is a software package provided by Univ. of Tennessee,    --
    9: *  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
   10: *
   11: *     .. Scalar Arguments ..
   12:       CHARACTER          UPLO
   13:       INTEGER            INFO, N, LDA
   14: *     ..
   15: *     .. Array Arguments ..
   16:       DOUBLE PRECISION   A( LDA, * ), AP( * )
   17: *     ..
   18: *
   19: *  Purpose
   20: *  =======
   21: *
   22: *  DTRTTP copies a triangular matrix A from full format (TR) to standard
   23: *  packed format (TP).
   24: *
   25: *  Arguments
   26: *  =========
   27: *
   28: *  UPLO    (input) CHARACTER*1
   29: *          = 'U':  A is upper triangular.
   30: *          = 'L':  A is lower triangular.
   31: *
   32: *  N       (input) INTEGER
   33: *          The order of the matrices AP and A.  N >= 0.
   34: *
   35: *  A       (input) DOUBLE PRECISION array, dimension (LDA,N)
   36: *          On exit, the triangular matrix A.  If UPLO = 'U', the leading
   37: *          N-by-N upper triangular part of A contains the upper
   38: *          triangular part of the matrix A, and the strictly lower
   39: *          triangular part of A is not referenced.  If UPLO = 'L', the
   40: *          leading N-by-N lower triangular part of A contains the lower
   41: *          triangular part of the matrix A, and the strictly upper
   42: *          triangular part of A is not referenced.
   43: *
   44: *  LDA     (input) INTEGER
   45: *          The leading dimension of the array A.  LDA >= max(1,N).
   46: *
   47: *  AP      (output) DOUBLE PRECISION array, dimension (N*(N+1)/2
   48: *          On exit, the upper or lower triangular matrix A, packed
   49: *          columnwise in a linear array. The j-th column of A is stored
   50: *          in the array AP as follows:
   51: *          if UPLO = 'U', AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j;
   52: *          if UPLO = 'L', AP(i + (j-1)*(2n-j)/2) = A(i,j) for j<=i<=n.
   53: *
   54: *  INFO    (output) INTEGER
   55: *          = 0:  successful exit
   56: *          < 0:  if INFO = -i, the i-th argument had an illegal value
   57: *
   58: *  =====================================================================
   59: *
   60: *     .. Parameters ..
   61: *     ..
   62: *     .. Local Scalars ..
   63:       LOGICAL            LOWER
   64:       INTEGER            I, J, K
   65: *     ..
   66: *     .. External Functions ..
   67:       LOGICAL            LSAME
   68:       EXTERNAL           LSAME
   69: *     ..
   70: *     .. External Subroutines ..
   71:       EXTERNAL           XERBLA
   72: *     ..
   73: *     .. Executable Statements ..
   74: *
   75: *     Test the input parameters.
   76: *
   77:       INFO = 0
   78:       LOWER = LSAME( UPLO, 'L' )
   79:       IF( .NOT.LOWER .AND. .NOT.LSAME( UPLO, 'U' ) ) THEN
   80:          INFO = -1
   81:       ELSE IF( N.LT.0 ) THEN
   82:          INFO = -2
   83:       ELSE IF( LDA.LT.MAX( 1, N ) ) THEN
   84:          INFO = -4
   85:       END IF
   86:       IF( INFO.NE.0 ) THEN
   87:          CALL XERBLA( 'DTRTTP', -INFO )
   88:          RETURN
   89:       END IF
   90: *
   91:       IF( LOWER ) THEN
   92:          K = 0
   93:          DO J = 1, N
   94:             DO I = J, N
   95:                K = K + 1
   96:                AP( K ) = A( I, J )
   97:             END DO
   98:          END DO
   99:       ELSE
  100:          K = 0
  101:          DO J = 1, N
  102:             DO I = 1, J
  103:                K = K + 1
  104:                AP( K ) = A( I, J )
  105:             END DO
  106:          END DO
  107:       END IF
  108: *
  109: *
  110:       RETURN
  111: *
  112: *     End of DTRTTP
  113: *
  114:       END