1CSYTRI(1)                LAPACK routine (version 3.1)                CSYTRI(1)
2
3
4

NAME

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

SYNOPSIS

10       SUBROUTINE CSYTRI( UPLO, N, A, LDA, IPIV, WORK, INFO )
11
12           CHARACTER      UPLO
13
14           INTEGER        INFO, LDA, N
15
16           INTEGER        IPIV( * )
17
18           COMPLEX        A( LDA, * ), WORK( * )
19

PURPOSE

21       CSYTRI computes the inverse of a complex symmetric indefinite matrix  A
22       using  the  factorization  A  =  U*D*U**T  or  A = L*D*L**T computed by
23       CSYTRF.
24
25

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.
32
33       N       (input) INTEGER
34               The order of the matrix A.  N >= 0.
35
36       A       (input/output) COMPLEX 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 CSYTRF.
39
40               On  exit,  if INFO = 0, the (symmetric) inverse of the original
41               matrix.  If UPLO =  'U',  the  upper  triangular  part  of  the
42               inverse  is  formed and the part of A below the diagonal is not
43               referenced; if UPLO = 'L' the  lower  triangular  part  of  the
44               inverse  is  formed and the part of A above the diagonal is not
45               referenced.
46
47       LDA     (input) INTEGER
48               The leading dimension of the array A.  LDA >= max(1,N).
49
50       IPIV    (input) INTEGER array, dimension (N)
51               Details of the interchanges and the block  structure  of  D  as
52               determined by CSYTRF.
53
54       WORK    (workspace) COMPLEX array, dimension (2*N)
55
56       INFO    (output) INTEGER
57               = 0: successful exit
58               < 0: if INFO = -i, the i-th argument had an illegal value
59               >  0:  if  INFO = i, D(i,i) = 0; the matrix is singular and its
60               inverse could not be computed.
61
62
63
64 LAPACK routine (version 3.1)    November 2006                       CSYTRI(1)
Impressum