NAME

       zsytri2.f -

SYNOPSIS

   Functions/Subroutines
       subroutine zsytri2 (UPLO, N, A, LDA, IPIV, WORK, LWORK, INFO)
           ZSYTRI2

Function/Subroutine Documentation

   subroutine zsytri2 (characterUPLO, integerN, complex*16, dimension( lda, * )A, integerLDA,
       integer, dimension( * )IPIV, complex*16, dimension( * )WORK, integerLWORK, integerINFO)
       ZSYTRI2

       Purpose:

            ZSYTRI2 computes the inverse of a COMPLEX*16 symmetric indefinite matrix
            A using the factorization A = U*D*U**T or A = L*D*L**T computed by
            ZSYTRF. ZSYTRI2 sets the LEADING DIMENSION of the workspace
            before calling ZSYTRI2X that actually computes the inverse.

       Parameters:
           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 COMPLEX*16 array, dimension (LDA,N)
                     On entry, the NB diagonal matrix D and the multipliers
                     used to obtain the factor U or L as computed by ZSYTRF.

                     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 NB structure of D
                     as determined by ZSYTRF.

           WORK

                     WORK is COMPLEX*16 array, dimension (N+NB+1)*(NB+3)

           LWORK

                     LWORK is INTEGER
                     The dimension of the array WORK.
                     WORK is size >= (N+NB+1)*(NB+3)
                     If LDWORK = -1, then a workspace query is assumed; the routine
                      calculates:
                         - the optimal size of the WORK array, returns
                     this value as the first entry of the WORK array,
                         - and no error message related to LDWORK is issued by XERBLA.

           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.

       Author:
           Univ. of Tennessee

           Univ. of California Berkeley

           Univ. of Colorado Denver

           NAG Ltd.

       Date:
           September 2012

       Definition at line 128 of file zsytri2.f.

Author

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