1ZPPCON(1)                LAPACK routine (version 3.1)                ZPPCON(1)
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NAME

6       ZPPCON  -  the  reciprocal of the condition number (in the 1-norm) of a
7       complex Hermitian positive definite packed matrix  using  the  Cholesky
8       factorization A = U**H*U or A = L*L**H computed by ZPPTRF
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SYNOPSIS

11       SUBROUTINE ZPPCON( UPLO, N, AP, ANORM, RCOND, WORK, RWORK, INFO )
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13           CHARACTER      UPLO
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15           INTEGER        INFO, N
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17           DOUBLE         PRECISION ANORM, RCOND
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19           DOUBLE         PRECISION RWORK( * )
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21           COMPLEX*16     AP( * ), WORK( * )
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PURPOSE

24       ZPPCON estimates the reciprocal of the condition number (in the 1-norm)
25       of a complex  Hermitian  positive  definite  packed  matrix  using  the
26       Cholesky factorization A = U**H*U or A = L*L**H computed by ZPPTRF.
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28       An  estimate  is  obtained  for norm(inv(A)), and the reciprocal of the
29       condition number is computed as RCOND = 1 / (ANORM * norm(inv(A))).
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ARGUMENTS

33       UPLO    (input) CHARACTER*1
34               = 'U':  Upper triangle of A is stored;
35               = 'L':  Lower triangle of A is stored.
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37       N       (input) INTEGER
38               The order of the matrix A.  N >= 0.
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40       AP      (input) COMPLEX*16 array, dimension (N*(N+1)/2)
41               The triangular factor U or L from the Cholesky factorization  A
42               =  U**H*U  or  A = L*L**H, packed columnwise in a linear array.
43               The j-th column of U or L is stored in the array AP as follows:
44               if  UPLO = 'U', AP(i + (j-1)*j/2) = U(i,j) for 1<=i<=j; if UPLO
45               = 'L', AP(i + (j-1)*(2n-j)/2) = L(i,j) for j<=i<=n.
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47       ANORM   (input) DOUBLE PRECISION
48               The 1-norm (or infinity-norm) of the Hermitian matrix A.
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50       RCOND   (output) DOUBLE PRECISION
51               The reciprocal of the condition number of the  matrix  A,  com‐
52               puted  as  RCOND = 1/(ANORM * AINVNM), where AINVNM is an esti‐
53               mate of the 1-norm of inv(A) computed in this routine.
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55       WORK    (workspace) COMPLEX*16 array, dimension (2*N)
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57       RWORK   (workspace) DOUBLE PRECISION array, dimension (N)
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59       INFO    (output) INTEGER
60               = 0:  successful exit
61               < 0:  if INFO = -i, the i-th argument had an illegal value
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65 LAPACK routine (version 3.1)    November 2006                       ZPPCON(1)
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