1ZSYTRI(1)                LAPACK routine (version 3.2)                ZSYTRI(1)
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NAME

6       ZSYTRI  - computes the inverse of a complex symmetric indefinite matrix
7       A using the factorization A = U*D*U**T or  A  =  L*D*L**T  computed  by
8       ZSYTRF
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SYNOPSIS

11       SUBROUTINE ZSYTRI( UPLO, N, A, LDA, IPIV, WORK, INFO )
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13           CHARACTER      UPLO
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15           INTEGER        INFO, LDA, N
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17           INTEGER        IPIV( * )
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19           COMPLEX*16     A( LDA, * ), WORK( * )
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PURPOSE

22       ZSYTRI  computes the inverse of a complex symmetric indefinite matrix A
23       using the factorization A =  U*D*U**T  or  A  =  L*D*L**T  computed  by
24       ZSYTRF.
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ARGUMENTS

27       UPLO    (input) CHARACTER*1
28               Specifies  whether  the details of the factorization are stored
29               as an upper or lower triangular matrix.  = 'U':  Upper triangu‐
30               lar, form is A = U*D*U**T;
31               = 'L':  Lower triangular, form is A = L*D*L**T.
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33       N       (input) INTEGER
34               The order of the matrix A.  N >= 0.
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36       A       (input/output) COMPLEX*16 array, dimension (LDA,N)
37               On  entry, the block diagonal matrix D and the multipliers used
38               to obtain the factor U or L as computed by ZSYTRF.  On exit, if
39               INFO  =  0, the (symmetric) inverse of the original matrix.  If
40               UPLO = 'U', the upper triangular part of the inverse is  formed
41               and the part of A below the diagonal is not referenced; if UPLO
42               = 'L' the lower triangular part of the inverse  is  formed  and
43               the part of A above the diagonal is not referenced.
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45       LDA     (input) INTEGER
46               The leading dimension of the array A.  LDA >= max(1,N).
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48       IPIV    (input) INTEGER array, dimension (N)
49               Details  of  the  interchanges  and the block structure of D as
50               determined by ZSYTRF.
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52       WORK    (workspace) COMPLEX*16 array, dimension (2*N)
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54       INFO    (output) INTEGER
55               = 0: successful exit
56               < 0: if INFO = -i, the i-th argument had an illegal value
57               > 0: if INFO = i, D(i,i) = 0; the matrix is  singular  and  its
58               inverse could not be computed.
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62 LAPACK routine (version 3.2)    November 2008                       ZSYTRI(1)
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