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

6       ZSYCON  -  estimates  the  reciprocal  of  the condition number (in the
7       1-norm) of a complex symmetric matrix A using  the  factorization  A  =
8       U*D*U**T or A = L*D*L**T computed by ZSYTRF
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SYNOPSIS

11       SUBROUTINE ZSYCON( UPLO, N, A, LDA, IPIV, ANORM, RCOND, WORK, INFO )
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13           CHARACTER      UPLO
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15           INTEGER        INFO, LDA, N
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17           DOUBLE         PRECISION ANORM, RCOND
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19           INTEGER        IPIV( * )
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21           COMPLEX*16     A( LDA, * ), WORK( * )
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PURPOSE

24       ZSYCON estimates the reciprocal of the condition number (in the 1-norm)
25       of a complex symmetric matrix A using the factorization A = U*D*U**T or
26       A  =  L*D*L**T  computed  by  ZSYTRF.   An  estimate  is  obtained  for
27       norm(inv(A)), and the reciprocal of the condition number is computed as
28       RCOND = 1 / (ANORM * norm(inv(A))).
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ARGUMENTS

31       UPLO    (input) CHARACTER*1
32               Specifies  whether  the details of the factorization are stored
33               as an upper or lower triangular matrix.  = 'U':  Upper triangu‐
34               lar, form is A = U*D*U**T;
35               = 'L':  Lower triangular, form is A = L*D*L**T.
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37       N       (input) INTEGER
38               The order of the matrix A.  N >= 0.
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40       A       (input) COMPLEX*16 array, dimension (LDA,N)
41               The  block diagonal matrix D and the multipliers used to obtain
42               the factor U or L as computed by ZSYTRF.
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44       LDA     (input) INTEGER
45               The leading dimension of the array A.  LDA >= max(1,N).
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47       IPIV    (input) INTEGER array, dimension (N)
48               Details of the interchanges and the block  structure  of  D  as
49               determined by ZSYTRF.
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51       ANORM   (input) DOUBLE PRECISION
52               The 1-norm of the original matrix A.
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54       RCOND   (output) DOUBLE PRECISION
55               The  reciprocal  of  the condition number of the matrix A, com‐
56               puted as RCOND = 1/(ANORM * AINVNM), where AINVNM is  an  esti‐
57               mate of the 1-norm of inv(A) computed in this routine.
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59       WORK    (workspace) COMPLEX*16 array, dimension (2*N)
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61       INFO    (output) INTEGER
62               = 0:  successful exit
63               < 0:  if INFO = -i, the i-th argument had an illegal value
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67 LAPACK routine (version 3.2)    November 2008                       ZSYCON(1)
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