ZHPCON estimates the reciprocal of the condition number of a complex


 Hermitian packed matrix A using the factorization A = U*D*U**H or


 A = L*D*L**H computed by ZHPTRF.


 An estimate is obtained for norm(inv(A)), and the reciprocal of the


 condition number is computed as RCOND = 1 / (ANORM * norm(inv(A))).

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**H;


          = 'L':  Lower triangular, form is A = L*D*L**H.

N

          N is INTEGER


          The order of the matrix A.  N >= 0.

AP

          AP is COMPLEX*16 array, dimension (N*(N+1)/2)


          The block diagonal matrix D and the multipliers used to


          obtain the factor U or L as computed by ZHPTRF, stored as a


          packed triangular matrix.

IPIV

          IPIV is INTEGER array, dimension (N)


          Details of the interchanges and the block structure of D


          as determined by ZHPTRF.

ANORM

          ANORM is DOUBLE PRECISION


          The 1-norm of the original matrix A.

RCOND

          RCOND is DOUBLE PRECISION


          The reciprocal of the condition number of the matrix A,


          computed as RCOND = 1/(ANORM * AINVNM), where AINVNM is an


          estimate of the 1-norm of inv(A) computed in this routine.

WORK

          WORK is COMPLEX*16 array, dimension (2*N)

INFO

          INFO is INTEGER


          = 0:  successful exit


          < 0:  if INFO = -i, the i-th argument had an illegal value

Univ. of Tennessee

Univ. of California Berkeley

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NAG Ltd.

December 2016