dsytri2x3

!>
!> DSYTRI2X computes the inverse of a real symmetric indefinite matrix
!> A using the factorization A = U*D*U**T or A = L*D*L**T computed by
!> DSYTRF.
!> 

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.
!> 

N

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

A

!>          A is DOUBLE PRECISION array, dimension (LDA,N)
!>          On entry, the NNB diagonal matrix D and the multipliers
!>          used to obtain the factor U or L as computed by DSYTRF.
!>
!>          On exit, if INFO = 0, the (symmetric) inverse of the original
!>          matrix.  If UPLO = 'U', the upper triangular part of the
!>          inverse is formed and the part of A below the diagonal is not
!>          referenced; if UPLO = 'L' the lower triangular part of the
!>          inverse is formed and the part of A above the diagonal is
!>          not referenced.
!> 

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 NNB structure of D
!>          as determined by DSYTRF.
!> 

WORK

!>          WORK is DOUBLE PRECISION array, dimension (N+NB+1,NB+3)
!> 

NB

!>          NB is INTEGER
!>          Block size
!> 

INFO

!>          INFO is INTEGER
!>          = 0: successful exit
!>          < 0: if INFO = -i, the i-th argument had an illegal value
!>          > 0: if INFO = i, D(i,i) = 0; the matrix is singular and its
!>               inverse could not be computed.
!> 

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