LAPACK  3.4.2
LAPACK: Linear Algebra PACKage
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cspcon.f File Reference

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Functions/Subroutines

subroutine cspcon (UPLO, N, AP, IPIV, ANORM, RCOND, WORK, INFO)
 CSPCON

Function/Subroutine Documentation

subroutine cspcon ( character  UPLO,
integer  N,
complex, dimension( * )  AP,
integer, dimension( * )  IPIV,
real  ANORM,
real  RCOND,
complex, dimension( * )  WORK,
integer  INFO 
)

CSPCON

Download CSPCON + dependencies [TGZ] [ZIP] [TXT]
Purpose: 
 CSPCON estimates the reciprocal of the condition number (in the
 1-norm) of a complex symmetric packed matrix A using the
 factorization A = U*D*U**T or A = L*D*L**T computed by CSPTRF.

 An estimate is obtained for norm(inv(A)), and the reciprocal of the
 condition number is computed as RCOND = 1 / (ANORM * norm(inv(A))).
Parameters:
[in]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**T;
          = 'L':  Lower triangular, form is A = L*D*L**T.
[in]N
          N is INTEGER
          The order of the matrix A.  N >= 0.
[in]AP
          AP is COMPLEX 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 CSPTRF, stored as a
          packed triangular matrix.
[in]IPIV
          IPIV is INTEGER array, dimension (N)
          Details of the interchanges and the block structure of D
          as determined by CSPTRF.
[in]ANORM
          ANORM is REAL
          The 1-norm of the original matrix A.
[out]RCOND
          RCOND is REAL
          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.
[out]WORK
          WORK is COMPLEX array, dimension (2*N)
[out]INFO
          INFO is INTEGER
          = 0:  successful exit
          < 0:  if INFO = -i, the i-th argument had an illegal value
Author:
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date:
November 2011

Definition at line 119 of file cspcon.f.

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