SRC/csytri2.f(3)

NAME
SRC/csytri2.f

SYNOPSIS

  Functions/Subroutines
subroutine csytri2 (uplo, n, a, lda, ipiv, work, lwork, info)
CSYTRI2

Function/Subroutine Documentation

  subroutine csytri2 (character uplo, integer n, complex, dimension( lda, * ) a, integer lda, integer, dimension( * ) ipiv, complex, dimension( * ) work, integer lwork, integer info)

CSYTRI2

Purpose:

     CSYTRI2 computes the inverse of a COMPLEX symmetric indefinite matrix
     A using the factorization A = U*D*U**T or A = L*D*L**T computed by
     CSYTRF. CSYTRI2 sets the LEADING DIMENSION of the workspace
     before calling CSYTRI2X 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 array, dimension (LDA,N)
              On entry, the block diagonal matrix D and the multipliers
              used to obtain the factor U or L as computed by CSYTRF.
              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 block structure of D
              as determined by CSYTRF.

    WORK

              WORK is COMPLEX 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 LWORK = -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 LWORK 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.

Definition at line 126 of file csytri2.f.

Author

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