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      SUBROUTINE DLAUU2F( UPLO, N, A, LDA, INFO )
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*
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*  -- LAPACK auxiliary routine (version 3.1) --
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*     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
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*     November 2006
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*
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*     .. Scalar Arguments ..
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      CHARACTER          UPLO
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      INTEGER            INFO, LDA, N
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*     ..
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*     .. Array Arguments ..
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      DOUBLE PRECISION   A( LDA, * )
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*     ..
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*
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*  Purpose
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*  =======
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*
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*  DLAUU2 computes the product U * U' or L' * L, where the triangular
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*  factor U or L is stored in the upper or lower triangular part of
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*  the array A.
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*
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*  If UPLO = 'U' or 'u' then the upper triangle of the result is stored,
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*  overwriting the factor U in A.
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*  If UPLO = 'L' or 'l' then the lower triangle of the result is stored,
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*  overwriting the factor L in A.
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*
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*  This is the unblocked form of the algorithm, calling Level 2 BLAS.
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*
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*  Arguments
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*  =========
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*
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*  UPLO    (input) CHARACTER*1
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*          Specifies whether the triangular factor stored in the array A
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*          is upper or lower triangular:
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*          = 'U':  Upper triangular
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*          = 'L':  Lower triangular
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*
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*  N       (input) INTEGER
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*          The order of the triangular factor U or L.  N >= 0.
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*
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*  A       (input/output) DOUBLE PRECISION array, dimension (LDA,N)
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*          On entry, the triangular factor U or L.
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*          On exit, if UPLO = 'U', the upper triangle of A is
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*          overwritten with the upper triangle of the product U * U';
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*          if UPLO = 'L', the lower triangle of A is overwritten with
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*          the lower triangle of the product L' * L.
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*
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*  LDA     (input) INTEGER
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*          The leading dimension of the array A.  LDA >= max(1,N).
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*
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*  INFO    (output) INTEGER
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*          = 0: successful exit
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*          < 0: if INFO = -k, the k-th argument had an illegal value
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*
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*  =====================================================================
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*
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*     .. Parameters ..
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      DOUBLE PRECISION   ONE
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      PARAMETER          ( ONE = 1.0D+0 )
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*     ..
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*     .. Local Scalars ..
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      LOGICAL            UPPER
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      INTEGER            I
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      DOUBLE PRECISION   AII
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*     ..
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*     .. External Functions ..
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      LOGICAL            LSAME
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      DOUBLE PRECISION   DDOT
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      EXTERNAL           LSAME, DDOT
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*     ..
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*     .. External Subroutines ..
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      EXTERNAL           DGEMV, DSCAL, XERBLA
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*     ..
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*     .. Intrinsic Functions ..
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      INTRINSIC          MAX
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*     ..
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*     .. Executable Statements ..
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*
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*     Test the input parameters.
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*
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      INFO = 0
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      UPPER = LSAME( UPLO, 'U' )
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      IF( .NOT.UPPER .AND. .NOT.LSAME( UPLO, 'L' ) ) THEN
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         INFO = -1
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      ELSE IF( N.LT.0 ) THEN
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         INFO = -2
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      ELSE IF( LDA.LT.MAX( 1, N ) ) THEN
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         INFO = -4
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      END IF
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      IF( INFO.NE.0 ) THEN
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         CALL XERBLA( 'DLAUU2', -INFO )
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         RETURN
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      END IF
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*
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*     Quick return if possible
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*
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      IF( N.EQ.0 )
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     $   RETURN
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*
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      IF( UPPER ) THEN
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*
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*        Compute the product U * U'.
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*
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         DO 10 I = 1, N
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            AII = A( I, I )
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            IF( I.LT.N ) THEN
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               A( I, I ) = DDOT( N-I+1, A( I, I ), LDA, A( I, I ), LDA )
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               CALL DGEMV( 'No transpose', I-1, N-I, ONE, A( 1, I+1 ),
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     $                     LDA, A( I, I+1 ), LDA, AII, A( 1, I ), 1 )
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            ELSE
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               CALL DSCAL( I, AII, A( 1, I ), 1 )
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            END IF
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   10    CONTINUE
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*
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      ELSE
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*
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*        Compute the product L' * L.
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*
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         DO 20 I = 1, N
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            AII = A( I, I )
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            IF( I.LT.N ) THEN
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               A( I, I ) = DDOT( N-I+1, A( I, I ), 1, A( I, I ), 1 )
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               CALL DGEMV( 'Transpose', N-I, I-1, ONE, A( I+1, 1 ), LDA,
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     $                     A( I+1, I ), 1, AII, A( I, 1 ), LDA )
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            ELSE
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               CALL DSCAL( I, AII, A( I, 1 ), LDA )
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            END IF
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   20    CONTINUE
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      END IF
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*
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      RETURN
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*
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*     End of DLAUU2
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*
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      END